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Sample records for introducing natural genetic

  1. Natural genetic transformation in Acinetobacter sp. BD413 Biofilms: introducing natural genetic transformation as a tool for bioenhancement of biofilm reactors

    Energy Technology Data Exchange (ETDEWEB)

    Hendrickx, L

    2002-07-01

    This study focussed on the localization and quantification of natural genetic transformation using neutral and disadvantageous genes in monoculture biofilms to investigate gene transfer and expression of the transferred genes in the absence of a selective advantage. Data obtained by this investigation were regarded as initial steps for evaluating the applicability of adding catabolic traits into the indigenous bacterial community of biofilm reactors by in situ natural genetic transformation. Because Acinetobacter spp. strains are readily found in waste water treatment plants and because Acinetobacter sp. BD413 possesses a high effective level of competence, natural genetic transformation was investigated in monoculture Acinetobacter sp. BD413 biofilms. The genes used for transformation encoded for the green fluorescent protein (GFP) and its variants. Monitoring of transformation events were performed with the use of automated confocal laser scanning microscopy (CLSM) and semi automated digital image processing and analysis. (orig.)

  2. Genetic drift outweighs natural selection at toll-like receptor (TLR) immunity loci in a re-introduced population of a threatened species.

    Science.gov (United States)

    Grueber, Catherine E; Wallis, Graham P; Jamieson, Ian G

    2013-09-01

    During population establishment, genetic drift can be the key driver of changes in genetic diversity, particularly while the population is small. However, natural selection can also play a role in shaping diversity at functionally important loci. We used a well-studied, re-introduced population of the threatened Stewart Island robin (N = 722 pedigreed individuals) to determine whether selection shaped genetic diversity at innate immunity toll-like receptor (TLR) genes, over a 9-year period of population growth following establishment with 12 genetic founders. We found no evidence for selection operating with respect to TLR diversity on first-year overwinter survival for the majority of loci, genotypes and alleles studied. However, survival of individuals with TLR4BE genotype was significantly improved: these birds were less than half as likely to die prior to maturity compared with all other TLR4 genotypes. Furthermore, the population frequency of this genotype, at a two-fold excess over Hardy-Weinberg expectation, was increased by nonrandom mating. Near-complete sampling and full pedigree and reproductive data enabled us to eliminate other potential causes of these patterns including inbreeding, year effects, density dependence, selection on animals at earlier life history stages or genome-level association of the TLR4E allele with 'good genes'. However, comparison of observed levels of gene diversity to predictions under simulated genetic drift revealed results consistent with neutral expectations for all loci, including TLR4. Although selection favoured TLR4BE heterozygotes in this population, these effects were insufficient to outweigh genetic drift. This is the first empirical study to show that genetic drift can overwhelm natural selection in a wild population immediately following establishment. © 2013 John Wiley & Sons Ltd.

  3. Dybowski’s sika deer (Cervus nippon hortulorum): genetic divergence between natural Primorian and introduced Czech populations

    Czech Academy of Sciences Publication Activity Database

    Krojerová-Prokešová, Jarmila; Barančeková, Miroslava; Voloshina, I.; Myslenkov, A.; Lamka, J.; Koubek, Petr

    2013-01-01

    Roč. 104, č. 3 (2013), s. 312-326 ISSN 0022-1503 R&D Projects: GA ČR GA524/09/1569 Institutional support: RVO:68081766 Keywords : bottleneck * founder effect * genetic diversity * inbreeding * microsatellites * mtDNA Subject RIV: GI - Animal Husbandry ; Breeding Impact factor: 1.969, year: 2013

  4. II. Application of genetically modified breeding by introducing foreign ...

    African Journals Online (AJOL)

    Production of salinity tolerant Nile tilapia, Oreochromis niloticus through traditional and modern breeding methods: II. Application of genetically modified breeding by introducing foreign DNA into fish gonads.

  5. Are Africans, Europeans, and Asians Different "Races"? A Guided-Inquiry Lab for Introducing Undergraduate Students to Genetic Diversity and Preparing Them to Study Natural Selection

    Science.gov (United States)

    Kalinowski, Steven T.; Andrews, Tessa M.; Leonard, Mary J.; Snodgrass, Meagan

    2012-01-01

    Many students do not recognize that individual organisms within populations vary, and this may make it difficult for them to recognize the essential role variation plays in natural selection. Also, many students have weak scientific reasoning skills, and this makes it difficult for them to recognize misconceptions they might have. This paper…

  6. Agrobacterium: nature's genetic engineer.

    Science.gov (United States)

    Nester, Eugene W

    2014-01-01

    Agrobacterium was identified as the agent causing the plant tumor, crown gall over 100 years ago. Since then, studies have resulted in many surprising observations. Armin Braun demonstrated that Agrobacterium infected cells had unusual nutritional properties, and that the bacterium was necessary to start the infection but not for continued tumor development. He developed the concept of a tumor inducing principle (TIP), the factor that actually caused the disease. Thirty years later the TIP was shown to be a piece of a tumor inducing (Ti) plasmid excised by an endonuclease. In the next 20 years, most of the key features of the disease were described. The single-strand DNA (T-DNA) with the endonuclease attached is transferred through a type IV secretion system into the host cell where it is likely coated and protected from nucleases by a bacterial secreted protein to form the T-complex. A nuclear localization signal in the endonuclease guides the transferred strand (T-strand), into the nucleus where it is integrated randomly into the host chromosome. Other secreted proteins likely aid in uncoating the T-complex. The T-DNA encodes enzymes of auxin, cytokinin, and opine synthesis, the latter a food source for Agrobacterium. The genes associated with T-strand formation and transfer (vir) map to the Ti plasmid and are only expressed when the bacteria are in close association with a plant. Plant signals are recognized by a two-component regulatory system which activates vir genes. Chromosomal genes with pleiotropic functions also play important roles in plant transformation. The data now explain Braun's old observations and also explain why Agrobacterium is nature's genetic engineer. Any DNA inserted between the border sequences which define the T-DNA will be transferred and integrated into host cells. Thus, Agrobacterium has become the major vector in plant genetic engineering.

  7. Enhancing (crop) plant photosynthesis by introducing novel genetic diversity.

    Science.gov (United States)

    Dann, Marcel; Leister, Dario

    2017-09-26

    Although some elements of the photosynthetic light reactions might appear to be ideal, the overall efficiency of light conversion to biomass has not been optimized during evolution. Because crop plants are depleted of genetic diversity for photosynthesis, efforts to enhance its efficiency with respect to light conversion to yield must generate new variation. In principle, three sources of natural variation are available: (i) rare diversity within extant higher plant species, (ii) photosynthetic variants from algae, and (iii) reconstruction of no longer extant types of plant photosynthesis. Here, we argue for a novel approach that outsources crop photosynthesis to a cyanobacterium that is amenable to adaptive evolution. This system offers numerous advantages, including a short generation time, virtually unlimited population sizes and high mutation rates, together with a versatile toolbox for genetic manipulation. On such a synthetic bacterial platform, 10 000 years of (crop) plant evolution can be recapitulated within weeks. Limitations of this system arise from its unicellular nature, which cannot reproduce all aspects of crop photosynthesis. But successful establishment of such a bacterial host for crop photosynthesis promises not only to enhance the performance of eukaryotic photosynthesis but will also reveal novel facets of the molecular basis of photosynthetic flexibility.This article is part of the themed issue 'Enhancing photosynthesis in crop plants: targets for improvement'. © 2017 The Author(s).

  8. Introducing Natural Farming in Black Pepper (Piper nigrum L. Cultivation

    Directory of Open Access Journals (Sweden)

    Kevin Muyang Tawie Sulok

    2018-01-01

    Full Text Available This paper reviews the role of Natural Farming as an ecological farming method to produce organically grown food of safe and high quality and at the same time improve soil quality and soil health. Currently, there is a dearth of information on the effects of Natural Farming approach on black pepper farms particularly in Sarawak, Malaysia. Previous studies on other crops had indicated positive outcome using the Natural Farming method. Thus, this paper discusses the essential role of effective microorganisms in Natural Farming and their potential in pepper cultivation. Through the action of effective microorganisms, this approach should be able to transform a degraded soil ecosystem into one that is fertile and has high nutrients availability. The mixed culture of effective microorganisms applied must be mutually compatible and coexist with one another to ensure its favorable establishment and interaction in the soil. Therefore, it is anticipated that introducing Natural Farming in black pepper cultivation can enhance the predominance of effective microorganisms in the soil, which in turn could lead to promising growth and yield of the crop.

  9. Textile industry can be less pollutant: introducing naturally colored cotton

    Directory of Open Access Journals (Sweden)

    Solimar Garcia

    2014-07-01

    Full Text Available 800x600 Studies in agribusiness and textile industry, both involved with the production of manufacturing fashion present insufficient development for new products that could represent water savings and reduction of chemical effluents, making this production chain a sustainable business. This paper introduces the colored and organic cotton as an alternative to foster colored cotton producing farmers and improving the concept of sustainability in the textile sector. Results show that the increase in the production of colored and organic cotton, may result in reduction of water use, and consequent reduction in the disposal of effluents in nature. As the colored and organic cotton is produced by small farmers, governmental agencies need to participate in the effort of improving its production and distribution, providing the needed infrastructure to meet the increasing market. This would slowly encourage the reduction of white cotton consumption in exchange for this naturally colored product. The water used, and consequent polluted discharge in the use of colored cotton in the textile industry might be reduced by 70%, assuming a reduction of environmental impact of 5% per year would represent expressive numbers in the next ten years. Normal 0 21 false false false ES X-NONE X-NONE

  10. Genetic Diversity of Local and Introduced Sweet Potato [Ipomoea ...

    African Journals Online (AJOL)

    This study was therefore conducted to estimate the genetic diversity of 114 Sweet potato [Ipomoea batatas (L.) Lam] accessions obtained from Nigeria, Asia, Latin America and Local collections along with two improved varieties. Accessions were planted in 2012/13 cropping season at Haramaya University, eastern Ethiopia ...

  11. Improving diagnosis for congenital cataract by introducing NGS genetic testing.

    Science.gov (United States)

    Musleh, Mohammud; Ashworth, Jane; Black, Graeme; Hall, Georgina

    2016-01-01

    Childhood cataract (CC) has an incidence of 3.5 per 10,000 by age 15 years. Diagnosis of any underlying cause is important to ensure effective and prompt management of multisystem complications, to facilitate accurate genetic counselling and to streamline multidisciplinary care. Next generation sequencing (NGS) has been shown to be effective in providing an underlying diagnosis in 70% of patients with CC in a research setting. This project aimed to integrate NGS testing in CC within six months of presentation and increase the rate of diagnosis. A retrospective case note review was undertaken to define the baseline efficacy of current care in providing a precise diagnosis. Quality improvement methods were used to integrate and optimize NGS testing in clinical care and measure the improvements made. The percentage of children receiving an NGS result within six months increased from 26% to 71% during the project period. The mean time to NGS testing and receiving a report decreased and there was a reduction in variation over the study period. Several patients and families had a change in management or genetic counselling as a direct result of the diagnosis given by the NGS test. The current recommended investigation of patients with bilateral CC is ineffective in identifying a diagnosis. Quality Improvement methods have facilitated successful integration of NGS testing into clinical care, improving time to diagnosis and leading to development of a new care pathway.

  12. Naturalization of introduced plants: ecological drivers of biogeographic patterns

    Czech Academy of Sciences Publication Activity Database

    Richardson, D. M.; Pyšek, Petr

    2012-01-01

    Roč. 196, č. 2 (2012), s. 383-396 ISSN 0028-646X R&D Projects: GA ČR(CZ) GAP504/11/1028 Institutional support: RVO:67985939 Keywords : plant invasions * naturalization * macroecological patterns Subject RIV: EF - Botanics Impact factor: 6.736, year: 2012

  13. Introducing the fluorine doped natural hydroxyapatite-titania nanobiocomposite ceramic

    Energy Technology Data Exchange (ETDEWEB)

    Karamian, Ebrahim [Advanced Materials Research Center, Faculty of Materials Engineering, Najafabad Branch, Islamic Azad University, Najafabad (Iran, Islamic Republic of); Abdellahi, Majid, E-mail: M.Abdellahi@Pa.iut.ac.ir [Advanced Materials Research Center, Faculty of Materials Engineering, Najafabad Branch, Islamic Azad University, Najafabad (Iran, Islamic Republic of); Khandan, Amirsalar [Young Researchers and Elite Club, Khomeinishahr Branch, Islamic Azad University, Isfahan (Iran, Islamic Republic of); Abdellah, Sana [Advanced Materials Research Center, Faculty of Materials Engineering, Najafabad Branch, Islamic Azad University, Najafabad (Iran, Islamic Republic of)

    2016-09-15

    In the present research, natural hydroxyapatite (NHA) was synthesized from bovine bones and then fluorine was doped into the NHA matrix to produce fluorine doped NHA (FNHA; natural fluor-hydroxyapatite) in optimum conditions. At the end an FNHA-TiO{sub 2} nanobiocomposite ceramic with excellent biocompatibility and good chemical stability was synthesized through a mechanochemical route and a subsequent two step sintering (TSS) process. Thermal gravimetric analysis (TGA), Differential scanning calorimetry (DSC), X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM), inductive coupled plasma (ICP), and energy-dispersive X-ray spectroscopy (EDX) were used as the means for gathering and analysis of the results. According to the obtained results, TiO{sub 2} can prevent early decomposition of FNHA by the formation of the CaTiO{sub 3} phases and hence strengthen the interactions between the apatite particles which results in the increase of the mechanical properties. Besides, TiO{sub 2} provides more Si−OH nucleation sites for the formation of the apatite layers and hence more bioactivity. - Highlights: • This work begins with preparing natural hydroxyapatite from bovine bones via a simple method. • With increasing the TiO{sub 2} content reinforced in FNHA matrix, the compaction increases. • TiO{sub 2} can prevent early decomposition of FNHA by the formation of CaTiO{sub 3} phase. • TiO{sub 2} can strengthen the interactions between the apatite particles and increase of compaction. • With increasing TiO{sub 2} content, the Si−OH nucleation sites increases lead to more bioactivity.

  14. Microsatellite genetic diversity and differentiation of native and introduced grass carp populations in three continents

    Science.gov (United States)

    Chapman, Duane C.; Chen, Qin; Wang, Chenghui; Zhao, Jinlian; Lu, Guoqing; Zsigmond, Jeney; Li, Si-Fa

    2012-01-01

    Grass carp (Ctenopharyngodon idella), a freshwater species native to China, has been introduced to about 100 countries/regions and poses both biological and environmental challenges to the receiving ecosystems. In this study, we analyzed genetic variation in grass carp from three introduced river systems (Mississippi River Basin in US, Danube River in Hungary, and Tone River in Japan) as well as its native ranges (Yangtze, Pearl, and Amur Rivers) in China using 21 novel microsatellite loci. The allelic richness, observed heterozygosity, and within-population gene diversity were found to be lower in the introduced populations than in the native populations, presumably due to the small founder population size of the former. Significant genetic differentiation was found between all pairwise populations from different rivers. Both principal component analysis and Bayesian clustering analysis revealed obvious genetic distinction between the native and introduced populations. Interestingly, genetic bottlenecks were detected in the Hungarian and Japanese grass carp populations, but not in the North American population, suggesting that the Mississippi River Basin grass carp has experienced rapid population expansion with potential genetic diversification during the half-century since its introduction. Consequently, the combined forces of the founder effect, introduction history, and rapid population expansion help explaining the observed patterns of genetic diversity within and among both native and introduced populations of the grass carp.

  15. Simulating natural selection in landscape genetics

    Science.gov (United States)

    E. L. Landguth; S. A. Cushman; N. Johnson

    2012-01-01

    Linking landscape effects to key evolutionary processes through individual organism movement and natural selection is essential to provide a foundation for evolutionary landscape genetics. Of particular importance is determining how spatially- explicit, individual-based models differ from classic population genetics and evolutionary ecology models based on ideal...

  16. [Genetic structure of natural populations

    International Nuclear Information System (INIS)

    1988-01-01

    Our efforts in the first eight months were concentrated in obtaining a genomic clone of the copper-zinc superoxide dismutase (SOD) in Drosophila melanogaster and other Drosophila species. This we have now successfully accomplished. We seek to understand the role of SOD in radioresistance; how genetic variation in this enzyme is maintained in populations; and relevant aspects of its evolution that may contribute to these goals as well as to an understanding of molecular evolution in general. To accomplish these goals we are undertaking the following experiments: cloning and sequencing of (at least) one F allele, one S allele, and the null allele for SOD; cloning and sequencing SOD from species related to D. melanogaster; and cloning and sequencing the SOD gene from several independently sampled S and F alleles in D. melanogaster. We are also preparing to test the radioprotective effects of SOD. 67 refs

  17. The New Genetics and Natural versus Artificial Genetic Modification

    Directory of Open Access Journals (Sweden)

    Mae-Wan Ho

    2013-11-01

    Full Text Available The original rationale and impetus for artificial genetic modification was the “central dogma” of molecular biology that assumed DNA carries all the instructions for making an organism, which are transmitted via RNA to protein to biological function in linear causal chains. This is contrary to the reality of the “fluid genome” that has emerged since the mid-1970s. In order to survive, the organism needs to engage in natural genetic modification in real time, an exquisitely precise molecular dance of life with RNA and DNA responding to and participating in “downstream” biological functions. Artificial genetic modification, in contrast, is crude, imprecise, and interferes with the natural process. It drives natural systems towards maximum biosemiotic entropy as the perturbations are propagated and amplified through the complex cascades of interactions between subsystems that are essential for health and longevity.

  18. The Natural Evolutionary Potential of Tree Populations to Cope with Newly Introduced Pests and Pathogens

    DEFF Research Database (Denmark)

    Budde, Katharina Birgit; Nielsen, Lene Rostgaard; Ravn, Hans Peter

    2016-01-01

    Emerging diseases often originate from host shifts of introduced pests or pathogens. Genetic resistance of the host to such diseases might be limited or absent due to the lack of coevolutionary history. We review six examples of major disease outbreaks on native tree species caused by different...

  19. Hierarchical genetic structure of the introduced wasp Vespula germanica in Australia.

    Science.gov (United States)

    Goodisman, M A; Matthews, R W; Crozier, R H

    2001-06-01

    The wasp Vespula germanica is a highly successful invasive pest. This study examined the population genetic structure of V. germanica in its introduced range in Australia. We sampled 1320 workers and 376 males from 141 nests obtained from three widely separated geographical areas on the Australian mainland and one on the island of Tasmania. The genotypes of all wasps were assayed at three polymorphic DNA microsatellite markers. Our analyses uncovered significant allelic differentiation among all four V. germanica populations. Pairwise estimates of genetic divergence between populations agreed with the results of a model-based clustering algorithm which indicated that the Tasmanian population was particularly distinct from the other populations. Within-population analyses revealed that genetic similarity declined with spatial distance, indicating that wasps from nests separated by more than approximately 25 km belonged to separate mating pools. We suggest that the observed genetic patterns resulted from frequent bottlenecks experienced by the V. germanica populations during their colonization of Australia.

  20. Genetic diversity and variation of mitochondrial DNA in native and introduced bighead carp

    Science.gov (United States)

    Li, Si-Fa; Yang, Qin-Ling; Xu, Jia-Wei; Wang, Cheng-Hui; Chapman, Duane C.; Lu, Guoping

    2010-01-01

    The bighead carp Hypophthalmichthys nobilis is native to China but has been introduced to over 70 countries and is established in many large river systems. Genetic diversity and variation in introduced bighead carp have not previously been evaluated, and a systematic comparison among fish from different river systems was unavailable. In this study, 190 bighead carp specimens were sampled from five river systems in three countries (Yangtze, Pearl, and Amur rivers, China; Danube River, Hungary; Mississippi River basin, USA) and their mitochondrial 16S ribosomal RNA gene and D-loop region were sequenced (around 1,345 base pairs). Moderate genetic diversity was found in bighead carp, ranging from 0.0014 to 0.0043 for nucleotide diversity and from 0.6879 to 0.9333 for haplotype diversity. Haplotype analysis provided evidence that (1) multiple haplotype groups might be present among bighead carp, (2) bighead carp probably originated from the Yangtze River, and (3) bighead carp in the Mississippi River basin may have some genetic ancestry in the Danube River. The analysis of molecular variance showed significant genetic differentiation among these five populations but also revealed limited differentiation between the Yangtze and Amur River bighead carp. This large-scale study of bighead carp genetic diversity and variation provides the first global perspective of bighead carp in the context of biodiversity conservation as well as invasive species control and management.

  1. Genetic diversity of pheasants from natural habitat and farm ...

    African Journals Online (AJOL)

    The original source of the pheasants living in the natural habitat is the farm, and the present genetic variation between the two groups of birds can be interpreted as an effect of natural selection. Keywords: Common pheasant (Phasianus colchicus), genetic distance, genetic polymorphism, genetic similarities, genetic ...

  2. A comparison of the recruitment success of introduced and native species under natural conditions.

    Directory of Open Access Journals (Sweden)

    Habacuc Flores-Moreno

    Full Text Available It is commonly accepted that introduced species have recruitment advantages over native species. However, this idea has not been widely tested, and those studies that have compared survival of introduced and native species have produced mixed results. We compiled data from the literature on survival through germination (seed to seedling survival, early seedling survival (survival through one week from seedling emergence and survival to adulthood (survival from germination to first reproduction under natural conditions for 285 native and 63 introduced species. Contrary to expectations, we found that introduced and native species do not significantly differ in survival through germination, early seedling survival, or survival from germination to first reproduction. These comparisons remained non-significant after accounting for seed mass, longevity and when including a random effect for site. Results remained consistent after excluding naturalized species from the introduced species data set, after performing phylogenetic independent contrasts, and after accounting for the effect of life form (woody/non-woody. Although introduced species sometimes do have advantages over native species (for example, through enemy release, or greater phenotypic plasticity, our findings suggest that the overall advantage conferred by these factors is either counterbalanced by advantages of native species (such as superior adaptation to local conditions or is simply too small to be detected at a broad scale.

  3. Genetic Diversity and Hybridisation between Native and Introduced Salmonidae Fishes in a Swedish Alpine Lake.

    Directory of Open Access Journals (Sweden)

    Leanne Faulks

    Full Text Available Understanding the processes underlying diversification can aid in formulating appropriate conservation management plans that help maintain the evolutionary potential of taxa, particularly under human-induced activities and climate change. Here we assessed the microsatellite genetic diversity and structure of three salmonid species, two native (Arctic charr, Salvelinus alpinus and brown trout, Salmo trutta and one introduced (brook charr, Salvelinus fontinalis, from an alpine lake in sub-arctic Sweden, Lake Ånn. The genetic diversity of the three species was similar and sufficiently high from a conservation genetics perspective: corrected total heterozygosity, H'T = 0.54, 0.66, 0.60 and allelic richness, AR = 4.93, 5.53 and 5.26 for Arctic charr, brown trout and brook charr, respectively. There were indications of elevated inbreeding coefficients in brown trout (GIS = 0.144 and brook charr (GIS = 0.129 although sibling relationships were likely a confounding factor, as a high proportion of siblings were observed in all species within and among sampling locations. Overall genetic structure differed between species, Fst = 0.01, 0.02 and 0.04 in Arctic charr, brown trout and brook charr respectively, and there was differentiation at only a few specific locations. There was clear evidence of hybridisation between the native Arctic charr and the introduced brook charr, with 6% of individuals being hybrids, all of which were sampled in tributary streams. The ecological and evolutionary consequences of the observed hybridisation are priorities for further research and the conservation of the evolutionary potential of native salmonid species.

  4. Molecular analysis for genetic diversity and distance of introduced Grus antigone sharpii L. to Thailand.

    Science.gov (United States)

    Tanee, T; Chaveerach, A; Anuniwat, A; Tanomtong, A; Pinthong, K; Sudmoon, R; Mokkamul, P

    2009-01-15

    The genetic relationship was examined in a population of Grus antigone sharpii L. using DNA markers from the ISSR technique for applying towards breeding purposes for conservation of species. Since their extinction from Thailand, sixteen eastern sarus cranes: Grus antigone sharpii L. provided from Cambodia were fed and bred to sixty individuals at Nakhonratchasima Zoo, Northeastern Thailand to re-exist in Thai natural sites. Their genetic diversity and distance were examined to test their possibility to adapt to environmental variation. Blood samples from 27 individuals of Grus antigone sharpii L. were collected and DNA was extracted. These DNA samples were amplified using the successful fifteen from twenty four primers inter simple sequences repeat markers. A dendrogram was constructed and shows distance values of the species between 12.1 and 53.5. The samples produced 63.96% polymorphic banding profiles. The genetic diversity (H') in this population was estimated using Shannon's index. The high H' value of 0.501 reflected the somewhat wide range of distribution sites, which would adapt to environmental variations. Genetic evenness is 0.152. This value supports that all the studied samples have a small equal genetic abundance.

  5. Microsatellite Analysis of the Population Genetic Structure of Anolis carolinensis Introduced to the Ogasawara Islands.

    Science.gov (United States)

    Sugawara, Hirotaka; Takahashi, Hiroo; Hayashi, Fumio

    2015-01-01

    DNA analysis can reveal the origins and dispersal patterns of invasive species. The green anole Anolis carolinensis is one such alien animal, which has been dispersed widely by humans from its native North America to many Pacific Ocean islands. In the Ogasawara (Bonin) Islands, this anole was recorded from Chichi-jima at the end of the 1960s, and then from Haha-jima in the early 1980s. These two islands are inhabited. In 2013, it was also found on the uninhabited Ani-jima, close to Chichi-jima. Humans are thought to have introduced the anole to Haha-jima, while the mode of introduction to Ani-jima is unknown. To clarify its dispersal patterns within and among these three islands, we assessed the fine-scale population genetic structure using five microsatellite loci. The results show a homogeneous genetic structure within islands, but different genetic structures among islands, suggesting that limited gene flow occurs between islands. The recently established Ani-jima population may have originated from several individuals simultaneously, or by repeated immigration from Chichi-jima. We must consider frequent incursions among these islands to control these invasive lizard populations and prevent their negative impact on native biodiversity.

  6. Natural genetic engineering: intelligence & design in evolution?

    DEFF Research Database (Denmark)

    Ussery, David

    2011-01-01

    There are many things that I like about James Shapiro's new book "Evolution: A View from the 21st Century" (FT Press Science, 2011). He begins the book by saying that it is the creation of novelty, and not selection, that is important in the history of life. In the presence of heritable traits...... function. Shapiro argues that what we see in genomes is 'Natural Genetic Engineering', or designed evolution: "Thinking about genomes from an informatics perspective, it is apparent that systems engineering is a better metaphor for the evolutionary process than the conventional view of evolution...... as a select-biased random walk through limitless space of possible DNA configurations" (page 6). In this review, I will have a look at four topics: 1.) why I think genomics is not the whole story; 2.) my own perspective of E. coli genomics, and how I think it relates to this book; 3.) a brief discussion...

  7. The effects of introducing natural gas in the Canary Islands for electricity generation

    International Nuclear Information System (INIS)

    Ramos-Real, Francisco Javier; Moreno-Piquero, Juan Carlos; Ramos-Henriquez, Jose Manuel

    2007-01-01

    This study analyses the economic effects of introducing natural gas in the Canary Islands to generate electricity in combined cycle gas turbine (CCGT) plants. To this end we will evaluate how this measure contributes to achieving the objectives of the islands' energy policy and we calculate the cost of generating a kWh from this technology. For this calculation we obtain the net present value (NPV) of the total production costs during the economic lifetime of the plant so as to subsequently find the unitary cost per kWh generated. The result obtained indicates that the kWh cost is some 25% lower than the cost of using petroleum derivatives. Additionally, if we consider the positive effect of CO 2 emissions reductions, the cost is 41% lower. The introduction of natural gas will also be a decisive factor in complying with Kyoto requirements and in diversifying supply sources in the Canaries

  8. The genomic ancestry, landscape genetics and invasion history of introduced mice in New Zealand

    Science.gov (United States)

    Russell, James C.; King, Carolyn M.

    2018-01-01

    The house mouse (Mus musculus) provides a fascinating system for studying both the genomic basis of reproductive isolation, and the patterns of human-mediated dispersal. New Zealand has a complex history of mouse invasions, and the living descendants of these invaders have genetic ancestry from all three subspecies, although most are primarily descended from M. m. domesticus. We used the GigaMUGA genotyping array (approximately 135 000 loci) to describe the genomic ancestry of 161 mice, sampled from 34 locations from across New Zealand (and one Australian city—Sydney). Of these, two populations, one in the south of the South Island, and one on Chatham Island, showed complete mitochondrial lineage capture, featuring two different lineages of M. m. castaneus mitochondrial DNA but with only M. m. domesticus nuclear ancestry detectable. Mice in the northern and southern parts of the North Island had small traces (approx. 2–3%) of M. m. castaneus nuclear ancestry, and mice in the upper South Island had approximately 7–8% M. m. musculus nuclear ancestry including some Y-chromosomal ancestry—though no detectable M. m. musculus mitochondrial ancestry. This is the most thorough genomic study of introduced populations of house mice yet conducted, and will have relevance to studies of the isolation mechanisms separating subspecies of mice. PMID:29410804

  9. The genomic ancestry, landscape genetics and invasion history of introduced mice in New Zealand.

    Science.gov (United States)

    Veale, Andrew J; Russell, James C; King, Carolyn M

    2018-01-01

    The house mouse ( Mus musculus ) provides a fascinating system for studying both the genomic basis of reproductive isolation, and the patterns of human-mediated dispersal. New Zealand has a complex history of mouse invasions, and the living descendants of these invaders have genetic ancestry from all three subspecies, although most are primarily descended from M. m. domesticus . We used the GigaMUGA genotyping array (approximately 135 000 loci) to describe the genomic ancestry of 161 mice, sampled from 34 locations from across New Zealand (and one Australian city-Sydney). Of these, two populations, one in the south of the South Island, and one on Chatham Island, showed complete mitochondrial lineage capture, featuring two different lineages of M. m. castaneus mitochondrial DNA but with only M. m. domesticus nuclear ancestry detectable. Mice in the northern and southern parts of the North Island had small traces (approx. 2-3%) of M. m. castaneus nuclear ancestry, and mice in the upper South Island had approximately 7-8% M. m. musculus nuclear ancestry including some Y-chromosomal ancestry-though no detectable M. m. musculus mitochondrial ancestry. This is the most thorough genomic study of introduced populations of house mice yet conducted, and will have relevance to studies of the isolation mechanisms separating subspecies of mice.

  10. Lack of adaptation from standing genetic variation despite the presence of putatively adaptive alleles in introduced sweet vernal grass (Anthoxanthum odoratum).

    Science.gov (United States)

    Gould, B; Geber, M

    2016-01-01

    Population genetic theory predicts that the availability of appropriate standing genetic variation should facilitate rapid evolution when species are introduced to new environments. However, few tests of rapid evolution have been paired with empirical surveys for the presence of previously identified adaptive genetic variants in natural populations. In this study, we examined local adaptation to soil Al toxicity in the introduced range of sweet vernal grass (Anthoxanthum odoratum), and we genotyped populations for the presence of Al tolerance alleles previously identified at the long-term ecological Park Grass Experiment (PGE, Harpenden, UK) in the species native range. We found that markers associated with Al tolerance at the PGE were present at appreciable frequency in introduced populations. Despite this, there was no strong evidence of local adaptation to soil Al toxicity among populations. Populations demonstrated significantly different intrinsic root growth rates in the absence of Al. This suggests that selection on correlated root growth traits may constrain the ability of populations to evolve significantly different root growth responses to Al. Our results demonstrate that genotype-phenotype associations may differ substantially between the native and introduced parts of a species range and that adaptive alleles from a native species range may not necessarily promote phenotypic differentiation in the introduced range. © 2015 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2015 European Society For Evolutionary Biology.

  11. Significant genetic differentiation between native and introduced silver carp (Hypophthalmichthys molitrix) inferred from mtDNA analysis

    Science.gov (United States)

    Li, S.-F.; Xu, J.-W.; Yang, Q.-L.; Wang, C.H.; Chapman, D.C.; Lu, G.

    2011-01-01

    Silver carp Hypophthalmichthys molitrix (Cyprinidae) is native to China and has been introduced to over 80 countries. The extent of genetic diversity in introduced silver carp and the genetic divergence between introduced and native populations remain largely unknown. In this study, 241 silver carp sampled from three major native rivers and two non-native rivers (Mississippi River and Danube River) were analyzed using nucleotide sequences of mitochondrial COI gene and D-loop region. A total of 73 haplotypes were observed, with no haplotype found common to all the five populations and eight haplotypes shared by two to four populations. As compared with introduced populations, all native populations possess both higher haplotype diversity and higher nucleotide diversity, presumably a result of the founder effect. Significant genetic differentiation was revealed between native and introduced populations as well as among five sampled populations, suggesting strong selection pressures might have occurred in introduced populations. Collectively, this study not only provides baseline information for sustainable use of silver carp in their native country (i.e., China), but also offers first-hand genetic data for the control of silver carp in countries (e.g., the United States) where they are considered invasive.

  12. Population Genetics and Natural Selection in Rheumatic Disease.

    Science.gov (United States)

    Ramos, Paula S

    2017-08-01

    Human genetic diversity is the result of population genetic forces. This genetic variation influences disease risk and contributes to health disparities. Natural selection is an important influence on human genetic variation. Because immune and inflammatory function genes are enriched for signals of positive selection, the prevalence of rheumatic disease-risk alleles seen in different populations is partially the result of differing selective pressures (eg, due to pathogens). This review summarizes the genetic regions associated with susceptibility to different rheumatic diseases and concomitant evidence for natural selection, including known agents of selection exerting selective pressure in these regions. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Genetic algorithms

    Science.gov (United States)

    Wang, Lui; Bayer, Steven E.

    1991-01-01

    Genetic algorithms are mathematical, highly parallel, adaptive search procedures (i.e., problem solving methods) based loosely on the processes of natural genetics and Darwinian survival of the fittest. Basic genetic algorithms concepts are introduced, genetic algorithm applications are introduced, and results are presented from a project to develop a software tool that will enable the widespread use of genetic algorithm technology.

  14. The devil is in the details: genetic variation in introduced populations and its contributions to invasion.

    Science.gov (United States)

    Dlugosch, Katrina M; Anderson, Samantha R; Braasch, Joseph; Cang, F Alice; Gillette, Heather D

    2015-05-01

    The influence of genetic variation on invasion success has captivated researchers since the start of the field of invasion genetics 50 years ago. We review the history of work on this question and conclude that genetic variation-as surveyed with molecular markers-appears to shape invasion rarely. Instead, there is a significant disconnect between marker assays and ecologically relevant genetic variation in introductions. We argue that the potential for adaptation to facilitate invasion will be shaped by the details of genotypes affecting phenotypes, and we highlight three areas in which we see opportunities to make powerful new insights. (i) The genetic architecture of adaptive variation. Traits shaped by large-effect alleles may be strongly impacted by founder events yet more likely to respond to selection when genetic drift is strong. Large-effect loci may be especially relevant for traits involved in biotic interactions. (ii) Cryptic genetic variation exposed during invasion. Introductions have strong potential to uncover masked variation due to alterations in genetic and ecological environments. (iii) Genetic interactions during admixture of multiple source populations. As divergence among sources increases, positive followed by increasingly negative effects of admixture should be expected. Although generally hypothesized to be beneficial during invasion, admixture is most often reported among sources of intermediate divergence, supporting the possibility that incompatibilities among divergent source populations might be limiting their introgression. Finally, we note that these details of invasion genetics can be coupled with comparative demographic analyses to link genetic changes to the evolution of invasiveness itself. © 2015 John Wiley & Sons Ltd.

  15. Consumer Perceptions towards Introducing a Genetically Modified Banana (Musa spp.) in Uganda

    NARCIS (Netherlands)

    Kikulwe, E.M.; Wesseler, J.H.H.; Falck-Zepeda, J.

    2010-01-01

    The introduction of a genetically modified (GM) banana (Musa spp.) in Uganda is not without controversy. It is likely to generate a wide portfolio of concerns as the technology of genetic engineering is still in its early stages of development in Uganda. The purpose of this study is to show how

  16. Introducing medical genetics services in Ethiopia using the MiGene Family History App.

    Science.gov (United States)

    Quinonez, Shane C; Yeshidinber, Abate; Lourie, Michael A; Bekele, Delayehu; Mekonnen, Yemisrach; Nigatu, Balkachew; Metaferia, Gesit; Jebessa, Solomie

    2018-06-11

    Almost all low-income countries and many middle-income countries lack the capacity to deliver medical genetics services. We developed the MiGene Family History App (MFHA), which assists doctors with family history collection and population-level epidemiologic analysis. The MFHA was studied at St. Paul's Hospital in Addis Ababa, Ethiopia. A needs assessment was used to assess Ethiopian physicians' experience with genetics services. The MFHA then collected patient data over a 6-month period. The majority of doctors provide genetics services, with only 16% reporting their genetics knowledge is sufficient. A total of 1699 patients from the pediatric ward (n = 367), neonatal intensive care unit (NICU) (n = 477), and antenatal clinic (n = 855) were collected using the MFHA with a 4% incidence of a MFHA-screened condition present. The incidence was 11.7% in the pediatric ward, 3% in the NICU, and 0.5% in the antenatal clinic. Heart malformations (5.5% of patients) and trisomy 21 (4.4% of patients) were the most common conditions in the pediatric ward. Medical genetics services are needed in Ethiopia. As other countries increase their genetics capacity, the MFHA can provide fundamental genetics services and collect necessary epidemiologic data.

  17. Genetic engineering versus natural evolution: Genetic algorithms with deterministic operators

    NARCIS (Netherlands)

    Jozwiak, L.; Postula, A.

    2002-01-01

    Genetic algorithms (GA) have several important features that predestine them to solve design problems. Their main disadvantage however is the excessively long run-time that is needed to deliver satisfactory results for large instances of complex design problems. The main aims of this paper are (1)

  18. Inter- and intra-population genetic variability of introduced silkworm (Bombyx mori L.) strains raised in Bulgaria

    OpenAIRE

    Teodora Staykova

    2013-01-01

    The genetic variability of four populations belonging to two introduced silkworm strains (Bombyx mori L.) of various origins has been studied using isoenzymic analysis of six enzyme systems. Nonspecific esterases, phosphoglucomutase, malate dehydrogenase, acid phosphatase, alkaline phosphatase and hexokinase from different tissue of larvae 5th instar have been analysed using PAGE. Polymorphism in six from a total of nine loci has been found. Inter- and intra-population differences have been a...

  19. Invasion genetics of the introduced black rat (Rattus rattus) in Senegal, West Africa

    Czech Academy of Sciences Publication Activity Database

    Konečný, Adam; Estoup, A.; Duplantier, J.-M.; Bryja, Josef; Ba, K.; Galan, M.; Tatard, C.; Cosson, J.-F.

    2013-01-01

    Roč. 22, č. 2 (2013), s. 286-300 ISSN 0962-1083 R&D Project s: GA AV ČR IAA6093404; GA ČR GAP506/10/0983 Institutional support: RVO:68081766 Keywords : approximate bayesian computation * bioinvasion * Bayesian clustering * founder effects * genetic admixture * microsatellites * multiple introductions Subject RIV: EG - Zoology Impact factor: 5.840, year: 2013

  20. Aedes aegypti on Madeira Island (Portugal): genetic variation of a recently introduced dengue vector.

    Science.gov (United States)

    Seixas, Gonçalo; Salgueiro, Patrícia; Silva, Ana Clara; Campos, Melina; Spenassatto, Carine; Reyes-Lugo, Matías; Novo, Maria Teresa; Ribolla, Paulo Eduardo Martins; Silva Pinto, João Pedro Soares da; Sousa, Carla Alexandra

    2013-01-01

    The increasing population of Aedes aegypti mosquitoes on Madeira Island (Portugal) resulted in the first autochthonous dengue outbreak, which occurred in October 2012. Our study establishes the first genetic evaluation based on the mitochondrial DNA (mtDNA) genes [cytochrome oxidase subunit I (COI) and NADH dehydrogenase subunit 4 (ND4)] and knockdown resistance (kdr) mutations exploring the colonisation history and the genetic diversity of this insular vector population. We included mosquito populations from Brazil and Venezuela in the analysis as putative geographic sources. The Ae. aegypti population from Madeira showed extremely low mtDNA genetic variability, with a single haplotype for COI and ND4. We also detected the presence of two important kdr mutations and the quasi-fixation of one of these mutations (F1534C). These results are consistent with a unique recent founder event that occurred on the island of Ae. aegypti mosquitoes that carry kdr mutations associated with insecticide resistance. Finally, we also report the presence of the F1534C kdr mutation in the Brazil and Venezuela populations. To our knowledge, this is the first time this mutation has been found in South American Ae. aegypti mosquitoes. Given the present risk of Ae. aegypti re-invading continental Europe from Madeira and the recent dengue outbreaks on the island, this information is important to plan surveillance and control measures.

  1. Genetic damage from low-level and natural background radiation

    International Nuclear Information System (INIS)

    Oftedal, P.

    1988-01-01

    Relevant predictions that have been made of possible low level biological effects on man are reviewed, and the estimate of genetic damage is discussed. It is concluded that in spite of a number of attempts, no clear-cut case of effects in human populations of radiation at natural levels has been demonstrated. The stability of genetic material is dynamic, with damage, repair and selection running as continuous processes. Genetic materials are well protected and are conservative in the extreme, not least because evolution by genetic adaptation is an expensive process: Substitution of one allele A 1 by another A 2 means the death of the whole A 1 population

  2. Exploiting a natural auxotrophy for genetic selection.

    Science.gov (United States)

    Ramage, Elizabeth; Gallagher, Larry; Manoil, Colin

    2012-08-01

    We exploited the natural histidine auxotrophy of Francisella species to develop hisD (encodes histidinol dehydrogenase) as a positive selection marker. A shuttle plasmid (pBR103) carrying Escherichia coli hisD and designed for cloning of PCR fragments replicated in both attenuated and highly virulent Francisella strains. During this work, we formulated a simplified defined growth medium for Francisella novicida.

  3. Introducing Taiwanese Undergraduate Students to the Nature of Science through Nobel Prize Stories

    Science.gov (United States)

    Eshach, Haim; Hwang, Fu-Kwun; Wu, Hsin-Kai; Hsu, Ying-Shao

    2013-01-01

    Although there is a broad agreement among scientists and science educators that students should not only learn science, but also acquire some sense of its nature, it has been reported that undergraduate students possess an inadequate grasp of the nature of science (NOS). The study presented here examined the potential and effectiveness of Nobel…

  4. How do the high school biology textbooks introduce the nature of science?

    Science.gov (United States)

    Lee, Young H.

    2007-05-01

    Although helping students to achieve an adequate understanding of the nature of science has been a consistent goal for science education for over half a century, current research reveals that the majority of students and teachers have naive views of the nature of science (Abd-El-khalick & Akerson, 2004; Bianchini & Colburn, 2000). This problem could be attributed not only to the complex nature of science, but also to the way the nature of science is presented to students during instruction. Thus, research must be conducted to examine how the science is taught, especially in science textbooks, which are a major instructional resource for teaching science. The aim of this study was to conduct a content analysis of the first chapter of four high school biology textbooks, which typically discusses "What is science?" and "What is biology?" This research used a content analysis technique to analyze the four high school biology textbooks, using a conceptual framework that has been used often for science textbook analysis. This conceptual framework consists of four themes of the nature of science: (a) science as a body of knowledge, (b) science as a way of thinking, (c) science as a way of investigating, and (d) the interaction of science, technology, and society. For this study, the four-theme-framework was modified to incorporate descriptors from national-level documents, such as Science for All Americans (AAAS, 1990) Benchmarks for Science Literacy (AAAS, 1993) and the National Science Education Standards (NRC, 1996), as well as science education research reports. A scoring procedure was used that resulted in good to excellent intercoder agreement with Cohen's kappa (k) ranging from .63 to .96. The findings show that the patterns of presentation of the four themes of the nature of science in the four high school biology textbooks are similar across the different locations of data, text, figures, and assessments. On the other hand, the pattern of presentation of the four

  5. Inter- and intra-population genetic variability of introduced silkworm (Bombyx mori L. strains raised in Bulgaria

    Directory of Open Access Journals (Sweden)

    Teodora Staykova

    2013-01-01

    Full Text Available The genetic variability of four populations belonging to two introduced silkworm strains (Bombyx mori L. of various origins has been studied using isoenzymic analysis of six enzyme systems. Nonspecific esterases, phosphoglucomutase, malate dehydrogenase, acid phosphatase, alkaline phosphatase and hexokinase from different tissue of larvae 5th instar have been analysed using PAGE. Polymorphism in six from a total of nine loci has been found. Inter- and intra-population differences have been ascertained expressed in different allele composition of the gene pool and different frequencies of alleles. A higher degree of inter-population variability has been reported on the acid phosphatase and a lower one – on the phosphoglucomutase.

  6. Introducing Taiwanese undergraduate students to the nature of science through Nobel Prize stories

    Directory of Open Access Journals (Sweden)

    Haim Eshach

    2013-04-01

    Full Text Available Although there is a broad agreement among scientists and science educators that students should not only learn science, but also acquire some sense of its nature, it has been reported that undergraduate students possess an inadequate grasp of the nature of science (NOS. The study presented here examined the potential and effectiveness of Nobel Prize stories as a vehicle for teaching NOS. For this purpose, a 36-hour course, “Albert Einstein’s Nobel Prize and the Nature of Science,” was developed and conducted in Taiwan Normal University. Ten undergraduate physics students participated in the course. Analysis of the Views of Nature of Science questionnaires completed by the students before and after the course, as well as the students’ own presentations of Nobel Prize stories (with an emphasis on how NOS characteristics are reflected in the story, showed that the students who participated in the course enriched their views concerning all aspects of NOS. The paper concludes with some suggestions for applying the novel idea of using Nobel Prize stories in physics classrooms.

  7. Prelude to practice: Introducing a practice based approach to forest and nature governance

    NARCIS (Netherlands)

    Arts, B.J.M.; Behagel, J.H.; Bommel, van S.; Koning, de J.; Turnhout, E.

    2013-01-01

    ‘Forest and nature governance’ is a field that has recently emerged from forestry sciences. It analyses the governance of a diverse set of issues, including deforestation, biodiversity loss and illegal logging, producing insights useful for science and policy. Its main theoretical base consists of

  8. The genetic consequences of selection in natural populations.

    Science.gov (United States)

    Thurman, Timothy J; Barrett, Rowan D H

    2016-04-01

    The selection coefficient, s, quantifies the strength of selection acting on a genetic variant. Despite this parameter's central importance to population genetic models, until recently we have known relatively little about the value of s in natural populations. With the development of molecular genetic techniques in the late 20th century and the sequencing technologies that followed, biologists are now able to identify genetic variants and directly relate them to organismal fitness. We reviewed the literature for published estimates of natural selection acting at the genetic level and found over 3000 estimates of selection coefficients from 79 studies. Selection coefficients were roughly exponentially distributed, suggesting that the impact of selection at the genetic level is generally weak but can occasionally be quite strong. We used both nonparametric statistics and formal random-effects meta-analysis to determine how selection varies across biological and methodological categories. Selection was stronger when measured over shorter timescales, with the mean magnitude of s greatest for studies that measured selection within a single generation. Our analyses found conflicting trends when considering how selection varies with the genetic scale (e.g., SNPs or haplotypes) at which it is measured, suggesting a need for further research. Besides these quantitative conclusions, we highlight key issues in the calculation, interpretation, and reporting of selection coefficients and provide recommendations for future research. © 2016 John Wiley & Sons Ltd.

  9. Assessing demand when introducing a new fuel: natural gas on Java

    International Nuclear Information System (INIS)

    Groenendaal, W.J.H. van

    1995-01-01

    The Indonesian government is investing in a gas transmission system on Java. For the evaluation of this investment a forecast of the demand for natural gas by the manufacturing sector is needed. To obtain this forecast the manufacturing sector is divided into subsectors according to energy use in production processes. On the level of production processes the opportunities for natural gas are based on net present value evaluations of its future benefits in production. This results in the desired fuel mix for manufacturing subsectors, from which the gas intensity ratios per subsector for existing production and new investments are calculated. Gas demand can then be forecast by combining the gas intensity ratios with subsectoral (growth in) gross value-added. This approach leads to a flexible forecasting tool that can readily account for changes in economic structure and energy prices, as encountered by rapidly developing economies. (author)

  10. Introducing 'The Diverse Nature of Defence Healthcare' university module for DMS personnel.

    Science.gov (United States)

    Carter, Chris; Blake, L

    2015-12-01

    Over the past 10 years the UK Defence Medical Services has deployed healthcare personnel to a variety of operational areas in support of UK Operations. The unique nature of every operational deployment, in conjunction with the wide variety of roles which healthcare staff undertake, necessitates bespoke educational preparation of the military healthcare force. This paper explores the creation and development of one of the four modules which comprise the BSc (Hons) in Defence Health Care studies, entitled 'The Diverse Nature of Defence Healthcare'. It demonstrates the unique contribution that the Defence School of Healthcare Education makes towards Generation and Preparation of the Force for deployment. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  11. Introducing the Forensic Research/Reference on Genetics knowledge base, FROG-kb.

    Science.gov (United States)

    Rajeevan, Haseena; Soundararajan, Usha; Pakstis, Andrew J; Kidd, Kenneth K

    2012-09-01

    Online tools and databases based on multi-allelic short tandem repeat polymorphisms (STRPs) are actively used in forensic teaching, research, and investigations. The Fst value of each CODIS marker tends to be low across the populations of the world and most populations typically have all the common STRP alleles present diminishing the ability of these systems to discriminate ethnicity. Recently, considerable research is being conducted on single nucleotide polymorphisms (SNPs) to be considered for human identification and description. However, online tools and databases that can be used for forensic research and investigation are limited. The back end DBMS (Database Management System) for FROG-kb is Oracle version 10. The front end is implemented with specific code using technologies such as Java, Java Servlet, JSP, JQuery, and GoogleCharts. We present an open access web application, FROG-kb (Forensic Research/Reference on Genetics-knowledge base, http://frog.med.yale.edu), that is useful for teaching and research relevant to forensics and can serve as a tool facilitating forensic practice. The underlying data for FROG-kb are provided by the already extensively used and referenced ALlele FREquency Database, ALFRED (http://alfred.med.yale.edu). In addition to displaying data in an organized manner, computational tools that use the underlying allele frequencies with user-provided data are implemented in FROG-kb. These tools are organized by the different published SNP/marker panels available. This web tool currently has implemented general functions possible for two types of SNP panels, individual identification and ancestry inference, and a prediction function specific to a phenotype informative panel for eye color. The current online version of FROG-kb already provides new and useful functionality. We expect FROG-kb to grow and expand in capabilities and welcome input from the forensic community in identifying datasets and functionalities that will be most helpful

  12. Naturally selecting solutions: the use of genetic algorithms in bioinformatics.

    Science.gov (United States)

    Manning, Timmy; Sleator, Roy D; Walsh, Paul

    2013-01-01

    For decades, computer scientists have looked to nature for biologically inspired solutions to computational problems; ranging from robotic control to scheduling optimization. Paradoxically, as we move deeper into the post-genomics era, the reverse is occurring, as biologists and bioinformaticians look to computational techniques, to solve a variety of biological problems. One of the most common biologically inspired techniques are genetic algorithms (GAs), which take the Darwinian concept of natural selection as the driving force behind systems for solving real world problems, including those in the bioinformatics domain. Herein, we provide an overview of genetic algorithms and survey some of the most recent applications of this approach to bioinformatics based problems.

  13. Science Camps for Introducing Nature of Scientific Inquiry Through Student Inquiries in Nature: Two Applications with Retention Study

    Science.gov (United States)

    Leblebicioglu, G.; Abik, N. M.; Capkinoglu, E.; Metin, D.; Dogan, E. Eroglu; Cetin, P. S.; Schwartz, R.

    2017-08-01

    Scientific inquiry is widely accepted as a method of science teaching. Understanding its characteristics, called Nature of Scientific Inquiry (NOSI), is also necessary for a whole conception of scientific inquiry. In this study NOSI aspects were taught explicitly through student inquiries in nature in two summer science camps. Students conducted four inquiries through their questions about surrounding soil, water, plants, and animals under the guidance of university science educators. At the end of each investigation, students presented their inquiry. NOSI aspects were made explicit by one of the science educators in the context of the investigations. Effectiveness of the science camp program and its retention were determined by applying Views of Scientific Inquiry (VOSI-S) (Schwartz et al. 2008) questionnaire as pre-, post-, and retention test after two months. The patterns in the data were similar. The science camp program was effective in developing three of six NOSI aspects which were questions guide scientific research, multiple methods of research, and difference between data and evidence. Students' learning of these aspects was retained. Discussion about these and the other three aspects is included in the paper. Implications of differences between school and out-of-school science experiences are also discussed.

  14. Genetic variation in natural honeybee populations, Apis mellifera capensis

    Science.gov (United States)

    Hepburn, Randall; Neumann, Peter; Radloff, Sarah E.

    2004-09-01

    Genetic variation in honeybee, Apis mellifera, populations can be considerably influenced by breeding and commercial introductions, especially in areas with abundant beekeeping. However, in southern Africa apiculture is based on the capture of wild swarms, and queen rearing is virtually absent. Moreover, the introduction of European subspecies constantly failed in the Cape region. We therefore hypothesize a low human impact on genetic variation in populations of Cape honeybees, Apis mellifera capensis. A novel solution to studying genetic variation in honeybee populations based on thelytokous worker reproduction is applied to test this hypothesis. Environmental effects on metrical morphological characters of the phenotype are separated to obtain a genetic residual component. The genetic residuals are then re-calculated as coefficients of genetic variation. Characters measured included hair length on the abdomen, width and length of wax plate, and three wing angles. The data show for the first time that genetic variation in Cape honeybee populations is independent of beekeeping density and probably reflects naturally occurring processes such as gene flow due to topographic and climatic variation on a microscale.

  15. Introducing a new bond reactivity index: Philicities for natural bond orbitals.

    Science.gov (United States)

    Sánchez-Márquez, Jesús; Zorrilla, David; García, Víctor; Fernández, Manuel

    2017-12-22

    In the present work, a new methodology defined for obtaining reactivity indices (philicities) is proposed. This is based on reactivity functions such as the Fukui function or the dual descriptor, and makes it possible to project the information from reactivity functions onto molecular orbitals, instead of onto the atoms of the molecule (atomic reactivity indices). The methodology focuses on the molecules' natural bond orbitals (bond reactivity indices) because these orbitals have the advantage of being localized, allowing the reaction site of an electrophile or nucleophile to be determined within a very precise molecular region. This methodology provides a "philicity" index for every NBO, and a representative set of molecules has been used to test the new definition. A new methodology has also been developed to compare the "finite difference" and the "frontier molecular orbital" approximations. To facilitate their use, the proposed methodology as well as the possibility of calculating the new indices have been implemented in a new version of UCA-FUKUI software. In addition, condensation schemes based on atomic populations of the "atoms in molecules" theory, the Hirshfeld population analysis, the approximation of Mulliken (with a minimal basis set) and electrostatic potential-derived charges have also been implemented, including the calculation of "bond reactivity indices" defined in previous studies. Graphical abstract A new methodology defined for obtaining bond reactivity indices (philicities) is proposed and makes it possible to project the information from reactivity functions onto molecular orbitals. The proposed methodology as well as the possibility of calculating the new indices have been implemented in a new version of UCA-FUKUI software. In addition, this version can use new atomic condensation schemes and new "utilities" have also been included in this second version.

  16. Co-operation - the way out (introducing the Natural Materials Radiation Control Initiative)

    International Nuclear Information System (INIS)

    Kruger, I.D.

    2002-01-01

    The Natural Materials Radiation Control Initiative (NMRCI), a forum of regulators, advisory bodies and operators in NORM industries from Australia, Brazil, Malaysia, Netherlands, Poland, South Africa and USA, reported on its activities that were aimed at addressing NORM regulatory issues through industry/regulatory co-operation. The objective was to generate comprehensive information on quantifying exposures to both workers and the general public, through the consolidation of existing data and the collection of data from new studies. In its interactions with the IAEA to date, the NMRCI had proposed that it assist in drafting a Safety Report identifying exposure sources and providing information on suggested methods for national regulatory bodies, advisory bodies and NORM industries to make quantitative assessments and to identify how best to meet the requirements of the BSS. It was envisaged that the Safety Report should reflect the principles contained in ICRP recommendations and IAEA Safety Standards, should make maximum use of measured data, and should deal separately with different industries such as phosphates, coal and niobium, taking account of the differences in chemical, physical and radiological properties of the materials as well as differences in work practices. It had been decided that occupational exposure issues should be addressed as a first priority, before moving on to the public exposure arena where waste management issues such as waste disposal and remediation of contaminated sites would be addressed. The NMRCI also aimed to promote co-operation between NORM industries and regulatory authorities on the matter of regulations and their impact on international trade in commodities containing NORM

  17. Human fertility, molecular genetics, and natural selection in modern societies.

    Directory of Open Access Journals (Sweden)

    Felix C Tropf

    Full Text Available Research on genetic influences on human fertility outcomes such as number of children ever born (NEB or the age at first childbirth (AFB has been solely based on twin and family-designs that suffer from problematic assumptions and practical limitations. The current study exploits recent advances in the field of molecular genetics by applying the genomic-relationship-matrix based restricted maximum likelihood (GREML methods to quantify for the first time the extent to which common genetic variants influence the NEB and the AFB of women. Using data from the UK and the Netherlands (N = 6,758, results show significant additive genetic effects on both traits explaining 10% (SE = 5 of the variance in the NEB and 15% (SE = 4 in the AFB. We further find a significant negative genetic correlation between AFB and NEB in the pooled sample of -0.62 (SE = 0.27, p-value = 0.02. This finding implies that individuals with genetic predispositions for an earlier AFB had a reproductive advantage and that natural selection operated not only in historical, but also in contemporary populations. The observed postponement in the AFB across the past century in Europe contrasts with these findings, suggesting an evolutionary override by environmental effects and underscoring that evolutionary predictions in modern human societies are not straight forward. It emphasizes the necessity for an integrative research design from the fields of genetics and social sciences in order to understand and predict fertility outcomes. Finally, our results suggest that we may be able to find genetic variants associated with human fertility when conducting GWAS-meta analyses with sufficient sample size.

  18. Equitably sharing benefits from the utilization of natural genetic resources: the Brazilian interpretation of the Convention of Biological Diversity

    NARCIS (Netherlands)

    Pena-Neira, S.; Dieperink, C.; Addink, G.H.

    2002-01-01

    The utilization of natural genetic resources could yield great benefits. The Convention on Biological Diversity introduced a number of rules concerning the sharing of these benefits. However, the interpretation and application (legal implementation) of these rules is a matter of discussion among

  19. Human genetics studies in areas of high natural radiation, 7

    International Nuclear Information System (INIS)

    Freire-Maia, A.

    1975-01-01

    Two methods to estimate the inbreeding load, employed in our analysis, are reviewed. Besides the total population, a sample constituted of individuals with no alien ancestral is also analysed. The measurements by genetic load models show any clear effect of natural radioactivity (especially for abortions, pre-natal mortality, anomalies, and abnormalities in general). The results on stillbirths and post-natal and total mortalities are discussed and it is concluded that uncontrolled concomitant variables (if not chance alone) cause the differences [pt

  20. Genetics of a butterfly relocation: large, small and introduced populations of the mountain endemic Erebia epiphron silesiana

    Czech Academy of Sciences Publication Activity Database

    Schmitt, T.; Čížek, Oldřich; Konvička, Martin

    2005-01-01

    Roč. 123, č. 1 (2005), s. 11-18 ISSN 0006-3207 R&D Projects: GA AV ČR(CZ) KJB6007306 Institutional research plan: CEZ:AV0Z50070508 Keywords : conservation genetics * genetic diversity * genetic erosion Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.581, year: 2005

  1. Temporal genetic monitoring of hybridization between native westslope cutthroat trout and introduced rainbow trout in the Stehekin River, Washington

    Science.gov (United States)

    Ostberg, Carl O.; Chase, Dorothy M.

    2012-01-01

    Introgressive hybridization with introduced rainbow trout (RBT) (Oncorhynchus mykiss) has led to the loss of native cutthroat trout species (O. clarkii) throughout their range, creating conservation concerns. Monitoring temporal hybridization trends provides resource managers with a tool for determining population status and information for establishing conservation goals for native cutthroat trout. In this study, we re-sampled six locations in 2010 within the Stehekin River watershed, North Cascades National Park, which were originally sampled between 1999 and 2003. We used genetic markers to monitor changes in hybridization levels between sampling periods in the native westslope cutthroat trout (WCT) (O. c. lewisi) stemming from past RBT introductions. Additionally, two new locations from the lower Stehekin drainage were added to the baseline data. We found that the frequency of WCT, RBT, and their hybrids was not significantly different between monitoring periods, but that RBT allele frequencies decreased in two locations and increased in one location. We also found a consistent, substantial reduction in the frequency of RBT alleles over the monitoring period in the Stehekin River upstream of Bridge Creek (SR3) compared to the Stehekin River downstream of Bridge Creek (SR1 -2) and within lower Bridge Creek (BR1) although these three locations are confined to a small geographic area (approximately 5 km). Ecological and/or evolutionary processes likely restrict the dispersal of RBT alleles in the Stehekin River upstream of Bridge Creek.

  2. Genetic Diversity in Natural Populations of New World Leishmania

    Directory of Open Access Journals (Sweden)

    Cupolillo Elisa

    1998-01-01

    Full Text Available Our results have shown the wide diversity of parasites within New World Leishmania. Biochemical and molecular characterization of species within the genus has revealed that much of the population heterogeneity has a genetic basis. The source of genetic diversity among Leishmania appears to arise from predominantly asexual, clonal reproduction, although occasional bouts of sexual reproduction can not be ruled out. Genetic variation is extensive with some clones widely distributed and others seemingly unique and localized to a particular endemic focus. Epidemiological studies of leishmaniasis has been directed to the ecology and dynamics of transmission of Leishmania species/variants, particularly in localized areas. Future research using molecular techniques should aim to identify and follow Leishmania types in nature and correlate genetic typing with important clinical characteristics such as virulence, pathogenicity, drug resistance and antigenic variation. The epidemiological significance of such variation not only has important implications for the control of the leishmaniases, but would also help to elucidate the evolutionary biology of the causative agents.

  3. Design of Self-Healing Supramolecular Rubbers by Introducing Ionic Cross-Links into Natural Rubber via a Controlled Vulcanization.

    Science.gov (United States)

    Xu, Chuanhui; Cao, Liming; Lin, Baofeng; Liang, Xingquan; Chen, Yukun

    2016-07-13

    Introducing ionic associations is one of the most effective approaches to realize a self-healing behavior for rubbers. However, most of commercial rubbers are nonpolar rubbers without now available functional groups to be converted into ionic groups. In this paper, our strategy was based on a controlled peroxide-induced vulcanization to generate massive ionic cross-links via polymerization of zinc dimethacrylate (ZDMA) in natural rubber (NR) and exploited it as a potential self-healable material. We controlled vulcanization process to retard the formation of covalent cross-link network, and successfully generated a reversible supramolecular network mainly constructed by ionic cross-links. Without the restriction of covalent cross-linkings, the NR chains in ionic supramolecular network had good flexibility and mobility. The nature that the ionic cross-links was easily reconstructed and rearranged facilitating the self-healing behavior, thereby enabling a fully cut sample to rejoin and retain to its original properties after a suitable self-healing process at ambient temperature. This study thus demonstrates a feasible approach to impart an ionic association induced self-healing function to commercial rubbers without ionic functional groups.

  4. Ecological genomics in Xanthomonas: the nature of genetic adaptation with homologous recombination and host shifts

    KAUST Repository

    Huang, Chao-Li

    2015-03-15

    Background: Comparative genomics provides insights into the diversification of bacterial species. Bacterial speciation usually takes place with lasting homologous recombination, which not only acts as a cohering force between diverging lineages but brings advantageous alleles favored by natural selection, and results in ecologically distinct species, e.g., frequent host shift in Xanthomonas pathogenic to various plants. Results: Using whole-genome sequences, we examined the genetic divergence in Xanthomonas campestris that infected Brassicaceae, and X. citri, pathogenic to a wider host range. Genetic differentiation between two incipient races of X. citri pv. mangiferaeindicae was attributable to a DNA fragment introduced by phages. In contrast to most portions of the genome that had nearly equivalent levels of genetic divergence between subspecies as a result of the accumulation of point mutations, 10% of the core genome involving with homologous recombination contributed to the diversification in Xanthomonas, as revealed by the correlation between homologous recombination and genomic divergence. Interestingly, 179 genes were under positive selection; 98 (54.7%) of these genes were involved in homologous recombination, indicating that foreign genetic fragments may have caused the adaptive diversification, especially in lineages with nutritional transitions. Homologous recombination may have provided genetic materials for the natural selection, and host shifts likely triggered ecological adaptation in Xanthomonas. To a certain extent, we observed positive selection nevertheless contributed to ecological divergence beyond host shifting. Conclusion: Altogether, mediated with lasting gene flow, species formation in Xanthomonas was likely governed by natural selection that played a key role in helping the deviating populations to explore novel niches (hosts) or respond to environmental cues, subsequently triggering species diversification. © Huang et al.

  5. Ecological genomics in Xanthomonas: the nature of genetic adaptation with homologous recombination and host shifts

    KAUST Repository

    Huang, Chao-Li; Pu, Pei-Hua; Huang, Hao-Jen; Sung, Huang-Mo; Liaw, Hung-Jiun; Chen, Yi-Min; Chen, Chien-Ming; Huang, Ming-Ban; Osada, Naoki; Gojobori, Takashi; Pai, Tun-Wen; Chen, Yu-Tin; Hwang, Chi-Chuan; Chiang, Tzen-Yuh

    2015-01-01

    Background: Comparative genomics provides insights into the diversification of bacterial species. Bacterial speciation usually takes place with lasting homologous recombination, which not only acts as a cohering force between diverging lineages but brings advantageous alleles favored by natural selection, and results in ecologically distinct species, e.g., frequent host shift in Xanthomonas pathogenic to various plants. Results: Using whole-genome sequences, we examined the genetic divergence in Xanthomonas campestris that infected Brassicaceae, and X. citri, pathogenic to a wider host range. Genetic differentiation between two incipient races of X. citri pv. mangiferaeindicae was attributable to a DNA fragment introduced by phages. In contrast to most portions of the genome that had nearly equivalent levels of genetic divergence between subspecies as a result of the accumulation of point mutations, 10% of the core genome involving with homologous recombination contributed to the diversification in Xanthomonas, as revealed by the correlation between homologous recombination and genomic divergence. Interestingly, 179 genes were under positive selection; 98 (54.7%) of these genes were involved in homologous recombination, indicating that foreign genetic fragments may have caused the adaptive diversification, especially in lineages with nutritional transitions. Homologous recombination may have provided genetic materials for the natural selection, and host shifts likely triggered ecological adaptation in Xanthomonas. To a certain extent, we observed positive selection nevertheless contributed to ecological divergence beyond host shifting. Conclusion: Altogether, mediated with lasting gene flow, species formation in Xanthomonas was likely governed by natural selection that played a key role in helping the deviating populations to explore novel niches (hosts) or respond to environmental cues, subsequently triggering species diversification. © Huang et al.

  6. Natural Selection and Genetic Diversity in the Butterfly Heliconius melpomene.

    Science.gov (United States)

    Martin, Simon H; Möst, Markus; Palmer, William J; Salazar, Camilo; McMillan, W Owen; Jiggins, Francis M; Jiggins, Chris D

    2016-05-01

    A combination of selective and neutral evolutionary forces shape patterns of genetic diversity in nature. Among the insects, most previous analyses of the roles of drift and selection in shaping variation across the genome have focused on the genus Drosophila A more complete understanding of these forces will come from analyzing other taxa that differ in population demography and other aspects of biology. We have analyzed diversity and signatures of selection in the neotropical Heliconius butterflies using resequenced genomes from 58 wild-caught individuals of Heliconius melpomene and another 21 resequenced genomes representing 11 related species. By comparing intraspecific diversity and interspecific divergence, we estimate that 31% of amino acid substitutions between Heliconius species are adaptive. Diversity at putatively neutral sites is negatively correlated with the local density of coding sites as well as nonsynonymous substitutions and positively correlated with recombination rate, indicating widespread linked selection. This process also manifests in significantly reduced diversity on longer chromosomes, consistent with lower recombination rates. Although hitchhiking around beneficial nonsynonymous mutations has significantly shaped genetic variation in H. melpomene, evidence for strong selective sweeps is limited overall. We did however identify two regions where distinct haplotypes have swept in different populations, leading to increased population differentiation. On the whole, our study suggests that positive selection is less pervasive in these butterflies as compared to fruit flies, a fact that curiously results in very similar levels of neutral diversity in these very different insects. Copyright © 2016 by the Genetics Society of America.

  7. Human genetics studies in areas of high natural radiation. VII. Genetic load

    Energy Technology Data Exchange (ETDEWEB)

    Freire-Maia, A [Faculdade de Ciencias Medicas e Biologicas de Botucatu (Brazil). Departamento de Genetica

    1975-01-01

    Two methods to estimate the inbreeding load, employed in our analysis, are reviewed. Besides the total population, a sample constituted of individuals with no alien ancesters is also analyzed. The measurements by genetic load models show a clear effect of natural radioactivity (especially for abortions, pre-natal mortality, anomalies, and abnormalities in general). The results on stillbirths and post-natal and total mortalities are discussed and it is concluded that uncontrolled concomitant variables (if not chance alone) cause the differences.

  8. Genetic diversity of macauba from natural populations of Brazil.

    Science.gov (United States)

    da Conceição, Léo Duc Haa Carson Schwartzhaupt; Antoniassi, Rosemar; Junqueira, Nilton Tadeu Vilela; Braga, Marcelo Fideles; de Faria-Machado, Adelia Ferreira; Rogério, Joice Barbosa; Duarte, Iara Duprat; Bizzo, Humberto Ribeiro

    2015-09-04

    The macauba has been identified as the most promising native species for the production of vegetable oil and biomass. Several studies confirm its potential for numerous purposes (liquid and solid biofuels, food, cosmetics and pharmaceuticals), but this Brazilian biodiversity resource has been little explored, and work aimed at their domestication and genetic improvement are relatively recent. This study consisted of a multivariate approach to levels of trans fatty acids, oil yield and physical characteristics found in fruits of macauba of natural populations. The objective was to quantify the genetic variability among 35 genotypes of natural populations of macauba from 16 locations in different regions of Brazil. Euclidean Distance measurements were estimated and the cluster analysis obtained by the UPGMA method considering separately the fatty acid profile, and traits related to physical part and the fruits oil content. It was observed the formation of seven groups for the profile of fatty acids and five groups for physical characteristics and oil yield. Large variations were observed for different types of mesocarp (pulp) fatty acids and kernel. Oleic acid (18: 1) in mesocarp was the largest contribution to the total divergence. The results indicate variations to the physical characteristics and oil yield, especially the oil percentage in mesocarp and weight of the whole fruit which contributed 64.58% of the divergence between genotypes. The study identified genotypes potential to generate variability and obtaining selection gains, directing plant breeding programs according with demands of oils market.

  9. A new genetic mechanism of natural gas accumulation.

    Science.gov (United States)

    Yang, Chengyu; Ni, Zhiyong; Wang, Tieguan; Chen, Zhonghong; Hong, Haitao; Wen, Long; Luo, Bing; Wang, Wenzhi

    2018-05-29

    Natural gas of organic origin is primarily biogenic or thermogenic; however, the formation of natural gas is occasionally attributed to hydrothermal activity. The Precambrian dolomite reservoir of the Anyue gas field is divided into three stages. Dolomite-quartz veins were precipitated after two earlier stages of dolomite deposition. Fluid inclusions in the dolomite and quartz are divided into pure methane (P-type), methane-bearing (M-type), aqueous (W-type), and solid bitumen-bearing (S-type) inclusions. The W-type inclusions within the quartz and buried dolomite homogenized between 107 °C and 223 °C. Furthermore, the trapping temperatures and pressures of the fluid (249 °C to 319 °C and 1619 bar to 2300 bar, respectively) are obtained from the intersections of the isochores of the P-type and the coeval W-type inclusions in the quartz. However, the burial history of the reservoir indicates that the maximum burial temperature did not exceed 230 °C. Thus, the generation of the natural gas was not caused solely by the burial of the dolomite reservoir. The results are also supported by the presence of paragenetic pyrobitumen and MVT lead-zinc ore. A coupled system of occasional invasion by hydrothermal fluids and burial of the reservoir may represent a new genetic model for natural gas accumulation in this gas field.

  10. Human genetic studies in areas of high natural radiation

    International Nuclear Information System (INIS)

    Freire-Maia, A.; Krieger, H.

    1978-01-01

    Data have been obtained by a genetic-epidemiological survey of a population living in the State of Espirito Santo (Brazil), and subjected to mean levels of natural radiation, per locality, ranging from 7 to 133 μrad/hr. Multiple regression models have been applied to the data, and the results showed no detectable effect of natural radiation on the sex ratio at birth, on the occurrence of congenital anomalies, and on the numbers of pregnancy terminations, stillbirths, livebirths, and post-infant mortality in the children, as well as fecundity and fertility of the couples (these observations contradict some data from the literature, based on official records and without analyses of the concomitant effects of other variables). However, nonsignificant results cannot be considered as disproving harmful effects of natural radiation on mortality and morbidity. These results may simply mean that other causes of mortality and morbidity are so important, under the conditions of the study, that the contribution of low-level, chronic natural radiation is made negligible. (author)

  11. A Comparative Study on Recently-Introduced Nature-Based Global Optimization Methods in Complex Mechanical System Design

    Directory of Open Access Journals (Sweden)

    Abdulbaset El Hadi Saad

    2017-10-01

    Full Text Available Advanced global optimization algorithms have been continuously introduced and improved to solve various complex design optimization problems for which the objective and constraint functions can only be evaluated through computation intensive numerical analyses or simulations with a large number of design variables. The often implicit, multimodal, and ill-shaped objective and constraint functions in high-dimensional and “black-box” forms demand the search to be carried out using low number of function evaluations with high search efficiency and good robustness. This work investigates the performance of six recently introduced, nature-inspired global optimization methods: Artificial Bee Colony (ABC, Firefly Algorithm (FFA, Cuckoo Search (CS, Bat Algorithm (BA, Flower Pollination Algorithm (FPA and Grey Wolf Optimizer (GWO. These approaches are compared in terms of search efficiency and robustness in solving a set of representative benchmark problems in smooth-unimodal, non-smooth unimodal, smooth multimodal, and non-smooth multimodal function forms. In addition, four classic engineering optimization examples and a real-life complex mechanical system design optimization problem, floating offshore wind turbines design optimization, are used as additional test cases representing computationally-expensive black-box global optimization problems. Results from this comparative study show that the ability of these global optimization methods to obtain a good solution diminishes as the dimension of the problem, or number of design variables increases. Although none of these methods is universally capable, the study finds that GWO and ABC are more efficient on average than the other four in obtaining high quality solutions efficiently and consistently, solving 86% and 80% of the tested benchmark problems, respectively. The research contributes to future improvements of global optimization methods.

  12. On theoretical models of gene expression evolution with random genetic drift and natural selection.

    Directory of Open Access Journals (Sweden)

    Osamu Ogasawara

    2009-11-01

    Full Text Available The relative contributions of natural selection and random genetic drift are a major source of debate in the study of gene expression evolution, which is hypothesized to serve as a bridge from molecular to phenotypic evolution. It has been suggested that the conflict between views is caused by the lack of a definite model of the neutral hypothesis, which can describe the long-run behavior of evolutionary change in mRNA abundance. Therefore previous studies have used inadequate analogies with the neutral prediction of other phenomena, such as amino acid or nucleotide sequence evolution, as the null hypothesis of their statistical inference.In this study, we introduced two novel theoretical models, one based on neutral drift and the other assuming natural selection, by focusing on a common property of the distribution of mRNA abundance among a variety of eukaryotic cells, which reflects the result of long-term evolution. Our results demonstrated that (1 our models can reproduce two independently found phenomena simultaneously: the time development of gene expression divergence and Zipf's law of the transcriptome; (2 cytological constraints can be explicitly formulated to describe long-term evolution; (3 the model assuming that natural selection optimized relative mRNA abundance was more consistent with previously published observations than the model of optimized absolute mRNA abundances.The models introduced in this study give a formulation of evolutionary change in the mRNA abundance of each gene as a stochastic process, on the basis of previously published observations. This model provides a foundation for interpreting observed data in studies of gene expression evolution, including identifying an adequate time scale for discriminating the effect of natural selection from that of random genetic drift of selectively neutral variations.

  13. Small founding number and low genetic diversity in an introduced species exhibiting limited invasion success (speckled dace, Rhinichthys ocsulus)

    Science.gov (United States)

    Andrew Kinziger; Rodney Nakamoto; Eric Anderson; Bret Harvey

    2011-01-01

    Molecular evaluations of successful invaders are common, however studies of introduced species that have had limited invasion success, or have died out completely, are rare. We studied an introduced population of speckled dace (Rhinichthys osculus) from northern California, USA that has rapidly increased in abundance but remained restricted to a 25-km stretch of river...

  14. Natural Variation and Genetics of Photoperiodism in Wyeomyia smithii.

    Science.gov (United States)

    Bradshaw, William E; Holzapfel, Christina M

    2017-01-01

    Seasonal change in the temperate and polar regions of Earth determines how the world looks around us and, in fact, how we live our day-to-day lives. For biological organisms, seasonal change typically involves complex physiological and metabolic reorganization, the majority of which is regulated by photoperiodism. Photoperiodism is the ability of animals and plants to use day length or night length, resulting in life-historical transformations, including seasonal development, migration, reproduction, and dormancy. Seasonal timing determines not only survival and reproductive success but also the structure and organization of complex communities and, ultimately, the biomes of Earth. Herein, a small mosquito, Wyeomyia smithii, that lives only in the water-filled leaves of a carnivorous plant over a wide geographic range, is used to explore the genetic and evolutionary basis of photoperiodism. Photoperiodism in W. smithii is considered in the context of its historical biogeography in nature to examine the startling finding that recent rapid climate change can drive genetic change in plants and animals at break-neck speed, and to challenge the ponderous 80+ year search for connections between daily and seasonal time-keeping mechanisms. Finally, a model is proposed that reconciles the seemingly disparate 24-h daily clock driven by the invariant rotation of Earth about its axis with the evolutionarily flexible seasonal timer orchestrated by variable seasonality driven by the rotation of Earth about the Sun. © 2017 Elsevier Inc. All rights reserved.

  15. Genetic structure of natural populations: Final technical report

    International Nuclear Information System (INIS)

    Ayala, F.J.

    1987-01-01

    We determined the LD 50 for individuals with any one of four genetic constitutions. The LD 50 was in kR units (S and F refer to the two common alleles found in natural populations and N is a mull allele) S/S 5.31, F/F 4.61, S/F 4.19, N/N 3.16. These results are as expected under the hypothesis the SOD is involved in radio-resistance and the degree of protection is a function of SOD specific activity. S codes for an allozyme that has the highest in vitro specific activity while N reduces the amount of enzyme to 3.5% of the normal level. Natural selection experiments in population cages were carried out for 13 generations. In control populations, the frequency of the S allele decreases from the initial frequency of 0.50 to an equilibrium value 0.1 to 0.2 in about 10 generations. In populations with the larvae receiving 4 KR in each generation, s reaches an equilibrium frequency of 0.6; when the irradiation was no longer applied, the frequency of S started declining, eventually reaching 0.1 to 0.2. These results corroborate the hypothesis that SOD protects against irradiation and that the degree of protection is correlated by the in vitro specific activity of the allozymes. 29 refs., 4 tabs

  16. Transformation of natural genetic variation into Haemophilus influenzae genomes.

    Directory of Open Access Journals (Sweden)

    Joshua Chang Mell

    2011-07-01

    Full Text Available Many bacteria are able to efficiently bind and take up double-stranded DNA fragments, and the resulting natural transformation shapes bacterial genomes, transmits antibiotic resistance, and allows escape from immune surveillance. The genomes of many competent pathogens show evidence of extensive historical recombination between lineages, but the actual recombination events have not been well characterized. We used DNA from a clinical isolate of Haemophilus influenzae to transform competent cells of a laboratory strain. To identify which of the ~40,000 polymorphic differences had recombined into the genomes of four transformed clones, their genomes and their donor and recipient parents were deep sequenced to high coverage. Each clone was found to contain ~1000 donor polymorphisms in 3-6 contiguous runs (8.1±4.5 kb in length that collectively comprised ~1-3% of each transformed chromosome. Seven donor-specific insertions and deletions were also acquired as parts of larger donor segments, but the presence of other structural variation flanking 12 of 32 recombination breakpoints suggested that these often disrupt the progress of recombination events. This is the first genome-wide analysis of chromosomes directly transformed with DNA from a divergent genotype, connecting experimental studies of transformation with the high levels of natural genetic variation found in isolates of the same species.

  17. Extremely low genetic variation in endangered Tatra chamois and evidence for hybridization with an introduced Alpine population

    Czech Academy of Sciences Publication Activity Database

    Zemanová, Barbora; Hájková, Petra; Hájek, B.; Martínková, Natália; Mikulíček, Peter; Zima, Jan; Bryja, Josef

    2015-01-01

    Roč. 16, č. 3 (2015), s. 729-741 ISSN 1566-0621 R&D Projects: GA AV ČR IAA600930609 Institutional support: RVO:68081766 Keywords : Rupicapra rupicapra tatrica * Ungulate * Non-invasive genetic sampling * Bottleneck * Inbreeding * Hybrid detection Subject RIV: EG - Zoology Impact factor: 2.040, year: 2015

  18. Genetic differentiation between introduced Central European sika and source populations in Japan: effects of isolation and demographic events

    Czech Academy of Sciences Publication Activity Database

    Krojerová-Prokešová, Jarmila; Barančeková, Miroslava; Kawata, Y.; Oshida, T.; Igota, H.; Koubek, Petr

    2017-01-01

    Roč. 19, č. 7 (2017), s. 2125-2141 ISSN 1387-3547 R&D Projects: GA ČR GA524/09/1569 Institutional support: RVO:68081766 Keywords : Bottleneck * Founder effect * Genetic diversity * Invasion * Microsatellite loci Subject RIV: EG - Zoology OBOR OECD: Biodiversity conservation Impact factor: 2.473, year: 2016

  19. Temporal Genetic Variance and Propagule-Driven Genetic Structure Characterize Naturalized Rainbow Trout (Oncorhynchus mykiss) from a Patagonian Lake Impacted by Trout Farming.

    Science.gov (United States)

    Benavente, Javiera N; Seeb, Lisa W; Seeb, James E; Arismendi, Ivan; Hernández, Cristián E; Gajardo, Gonzalo; Galleguillos, Ricardo; Cádiz, Maria I; Musleh, Selim S; Gomez-Uchida, Daniel

    2015-01-01

    Knowledge about the genetic underpinnings of invasions-a theme addressed by invasion genetics as a discipline-is still scarce amid well documented ecological impacts of non-native species on ecosystems of Patagonia in South America. One of the most invasive species in Patagonia's freshwater systems and elsewhere is rainbow trout (Oncorhynchus mykiss). This species was introduced to Chile during the early twentieth century for stocking and promoting recreational fishing; during the late twentieth century was reintroduced for farming purposes and is now naturalized. We used population- and individual-based inference from single nucleotide polymorphisms (SNPs) to illuminate three objectives related to the establishment and naturalization of Rainbow Trout in Lake Llanquihue. This lake has been intensively used for trout farming during the last three decades. Our results emanate from samples collected from five inlet streams over two seasons, winter and spring. First, we found that significant intra- population (temporal) genetic variance was greater than inter-population (spatial) genetic variance, downplaying the importance of spatial divergence during the process of naturalization. Allele frequency differences between cohorts, consistent with variation in fish length between spring and winter collections, might explain temporal genetic differences. Second, individual-based Bayesian clustering suggested that genetic structure within Lake Llanquihue was largely driven by putative farm propagules found at one single stream during spring, but not in winter. This suggests that farm broodstock might migrate upstream to breed during spring at that particular stream. It is unclear whether interbreeding has occurred between "pure" naturalized and farm trout in this and other streams. Third, estimates of the annual number of breeders (Nb) were below 73 in half of the collections, suggestive of genetically small and recently founded populations that might experience substantial

  20. Genetics Education in Nurse Residency Programs: A Natural Fit.

    Science.gov (United States)

    Hamilton, Nalo M; Stenman, Christina W; Sang, Elaine; Palmer, Christina

    2017-08-01

    Scientific advances are shedding light on the genetic underpinning of common diseases. With such insight, the entire health care team is faced with the need to address patient questions regarding genetic risk, testing, and the psychosocial aspects of genetics information. Nurses are in a prime position to help with patient education about genetic conditions, yet they often lack adequate genetics education within their nursing curriculum to address patient questions and provide resources. One mechanism to address this knowledge deficit is the incorporation of a genetics-based curriculum into nurse residency programs. This article describes a novel genetics-based curriculum designed and implemented in the UCLA Health System Nurse Residency Program. J Contin Educ Nurs. 2017;48(8):379-384. Copyright 2017, SLACK Incorporated.

  1. Population Genetics of Franciscana Dolphins (Pontoporia blainvillei: Introducing a New Population from the Southern Edge of Their Distribution.

    Directory of Open Access Journals (Sweden)

    María Constanza Gariboldi

    Full Text Available Due to anthropogenic factors, the franciscana dolphin, Pontoporia blainvillei, is the most threatened small cetacean on the Atlantic coast of South America. Four Franciscana Management Areas have been proposed: Espiritu Santo to Rio de Janeiro (FMA I, São Paulo to Santa Catarina (FMA II, Rio Grande do Sul to Uruguay (FMA III, and Argentina (FMA IV. Further genetic studies distinguished additional populations within these FMAs. We analyzed the population structure, phylogeography, and demographic history in the southernmost portion of the species range. From the analysis of mitochondrial DNA control region sequences, 5 novel haplotypes were found, totalizing 60 haplotypes for the entire distribution range. The haplotype network did not show an apparent phylogeographical signal for the southern FMAs. Two populations were identified: Monte Hermoso (MH and Necochea (NC+Claromecó (CL+Río Negro (RN. The low levels of genetic variability, the relative constant size over time, and the low levels of gene flow may indicate that MH has been colonized by a few maternal lineages and became isolated from geographically close populations. The apparent increase in NC+CL+RN size would be consistent with the higher genetic variability found, since genetic diversity is generally higher in older and expanding populations. Additionally, RN may have experienced a recent split from CL and NC; current high levels of gene flow may be occurring between the latter ones. FMA IV would comprise four franciscana dolphin populations: Samborombón West+Samborombón South, Cabo San Antonio+Buenos Aires East, NC+CL+Buenos Aires Southwest+RN and MH. Results achieved in this study need to be taken into account in order to ensure the long-term survival of the species.

  2. Colony social organization and population genetic structure of an introduced population of formosan subterranean termite from New Orleans, Louisiana.

    Science.gov (United States)

    Husseneder, Claudia; Messenger, Matthew T; Su, Nan-Yao; Grace, J Kenneth; Vargo, Edward L

    2005-10-01

    The Formosan subterranean termite, Coptotermes formosanus Shiraki, is an invasive species in many parts of the world, including the U.S. mainland. The reasons for its invasive success may have to do with the flexible social and spatial organization of colonies. We investigated the population and breeding structure of 14 C. formosanus colonies in Louis Armstrong Park, New Orleans, LA. This population has been the focus of extensive study for many years, providing the opportunity to relate aspects of colony breeding structure to previous findings on colony characteristics such as body weight and number of workers, wood consumption, and intercolony aggression. Eight colonies were headed by a single pair of outbred reproductives (simple families), whereas six colonies were headed by low numbers of multiple kings and/or queens that were likely the neotenic descendants of the original colony (extended families). Within the foraging area of one large extended family colony, we found genetic differentiation among different collection sites, suggesting the presence of separate reproductive centers. No significant difference between simple family colonies and extended family colonies was found in worker body weight, soldier body weight, foraging area, population size, or wood consumption. However, level of inbreeding within colonies was negatively correlated with worker body weight and positively correlated with wood consumption. Also, genetic distance between colonies was positively correlated with aggression levels, suggesting a genetic basis to nestmate discrimination cues in this termite population. No obvious trait associated with colony reproductive structure was found that could account for the invasion success of this species.

  3. A Multicultural, Multidisciplinary Short Course to Introduce Recently Graduated Engineers to the Global Nature of Professional Practice

    Science.gov (United States)

    Hazelton, Pam; Malone, Molly; Gardner, Anne

    2009-01-01

    Since 2001, the International Institute of Women in Engineering (IIWE) at EPF, Ecole d'ingenieurs generaliste, Sceaux, France, has conducted a 3 week short course for culturally and discipline diverse, recently graduated and final year engineering students. The aim of this course is to introduce young engineers to broad global concepts and issues…

  4. Natural Genetic Transformation Generates a Population of Merodiploids in Streptococcus pneumoniae.

    OpenAIRE

    Johnston, Calum; Caymaris, Stéphanie; Zomer, Aldert; Bootsma, Hester J.; Prudhomme, Marc; Granadel, Chantal; Hermans, Peter W. M.; Polard, Patrice; Martin, Bernard; Claverys, Jean-Pierre

    2013-01-01

    Partial duplication of genetic material is prevalent in eukaryotes and provides potential for evolution of new traits. Prokaryotes, which are generally haploid in nature, can evolve new genes by partial chromosome duplication, known as merodiploidy. Little is known about merodiploid formation during genetic exchange processes, although merodiploids have been serendipitously observed in early studies of bacterial transformation. Natural bacterial transformation involves internalization of exog...

  5. Is there a positive relationship between naturalness and genetic diversity in forest tree communities?

    OpenAIRE

    Wehenkel, C.; Corral-Rivas, J. J.; Castellanos-Bocaz, H. A.; Pinedo-Alvarez, A.

    2009-01-01

    The concepts of genetic diversity and naturalness are well known as measures of conservation values and as descriptors of state or condition. A lack of research evaluating the relationship between genetic diversity and naturalness in biological communities, along with the possible implications in terms of evolutionary aspects and conservation management, make this subject particularly important as regards forest tree communities.We therefore examined the following hypothesis: the genetic dive...

  6. Natural genetic variation in Calligonum Tunisian genus analyzed by ...

    African Journals Online (AJOL)

    Jane

    2011-08-29

    Aug 29, 2011 ... available meager resources of Tunisian desert region is to characterize ... enzymatic loci, and to the high degree of genetic relation- ship among the ... of intraspecific polymorphism, such as hexaploid wheat ...... Relationship between hybrid performance and genetic ... Runo MS, Muluvi GM (2004). Analysis ...

  7. "Wrecks of Ancient Life": Genetic Variants Vetted by Natural Selection.

    Science.gov (United States)

    Postlethwait, John H

    2015-07-01

    The Genetics Society of America's George W. Beadle Award honors individuals who have made outstanding contributions to the community of genetics researchers and who exemplify the qualities of its namesake as a respected academic, administrator, and public servant. The 2015 recipient is John Postlethwait. He has made groundbreaking contributions in developing the zebrafish as a molecular genetic model and in understanding the evolution of new gene functions in vertebrates. He built the first zebrafish genetic map and showed that its genome, along with that of distantly related teleost fish, had been duplicated. Postlethwait played an integral role in the zebrafish genome-sequencing project and elucidated the genomic organization of several fish species. Postlethwait is also honored for his active involvement with the zebrafish community, advocacy for zebrafish as a model system, and commitment to driving the field forward. Copyright © 2015 by the Genetics Society of America.

  8. Alien plants introduced by different pathways differ in invasion success: unintentional introductions as a threat to natural areas

    Czech Academy of Sciences Publication Activity Database

    Pyšek, Petr; Jarošík, Vojtěch; Pergl, Jan

    2011-01-01

    Roč. 6, č. 9 (2011), e24890 E-ISSN 1932-6203 R&D Projects: GA MŠk LC06073; GA ČR(CZ) GAP504/11/1028 Institutional research plan: CEZ:AV0Z60050516 Keywords : plant invasions * pathways * naturalization and invasion Subject RIV: EF - Botanics Impact factor: 4.092, year: 2011

  9. Gregor Mendel's classic paper and the nature of science in genetics courses.

    Science.gov (United States)

    Westerlund, Julie F; Fairbanks, Daniel J

    2010-12-01

    The discoveries of Gregor Mendel, as described by Mendel in his 1866 paper Versuche uber Pflanzen-Hybriden (Experiments on plant hybrids), can be used in undergraduate genetics and biology courses to engage students about specific nature of science characteristics and their relationship to four of his major contributions to genetics. The use of primary source literature as an instructional tool to enhance genetics students' understanding of the nature of science helps students more clearly understand how scientists work and how the science of genetics has evolved as a discipline. We offer a historical background of how the nature of science developed as a concept and show how Mendel's investigations of heredity can enrich biology and genetics courses by exemplifying the nature of science. © 2010 The Authors.

  10. REACTION OF INTRODUCED BEAN (PHASEOLUS ACCESSIONS TO THE INFESTATION BY THIELAVIOPSIS BASICOLA (BERKELEY & BROOME UNDER NATURAL EPIPHYTOTIC CONDITIONS

    Directory of Open Access Journals (Sweden)

    O. Georgieva

    2015-01-01

    Full Text Available A periodic phytopathology field monitoring was conducted on 35 introduced common bean (Phaseolus accessions at Maritsa Vegetable Crops Research Institute in 2014. The epiphytotic disease black root rot on the bean crops (over 75 % reduction of the stand was recorded for the first time for the area of Bulgaria. The causal agent isolated from the plant tissue was identified as the fungus Thielaviopsis basicola (Berkeley Ferraris. A strong relationship between disease severity variation and environmental and soil conditions was established. Black root rot was most severe when cool and wet weather occurred from seedling time to about three weeks after planting, combined with increased soil compaction. Field resistance was recorded in Bulgarian var. “Plovdivski zult”, var. “Starozagorski tzer” and line № 564 (3,66%, 5.33% and 6,50 % dumping-off of bean seedlings, respectively. Bean accession introduced from dry climate areas were highly susceptible to black root rot pathogen (over 76.0 % dumping-off of bean seedlings. Indirect relationship was found between bean tolerance to Th. basicola and presence of the anthocyanin in the hypocotyl and seed coat color. Install the average negative correlation between seed color signs (and hypocotyl and the resistance of plants to Th. basicola. Samples with resistance to black root rot belong to the group with beige, red, brown or black color of seeds. The presence of phenolic compounds (anthocyanins in the seed coat and hypocotyls beans can serve as an indirect indication of the selection of resistant to black rot breeding materials.

  11. Introducing the RadBioStat Educational Software: Computer-Assisted Teaching of the Random Nature of Cell Killing

    Directory of Open Access Journals (Sweden)

    Safari A

    2014-06-01

    Full Text Available The interaction of radiation with cells and tissues has a random nature. Therefore, understanding the random nature of cell killing that is determined by Poisson distribution statistics is an essential point in education of radiation biology. RadBioStat is a newly developed educational MATLAB-based software designed for computer-assisted learning of the target theory in radiation biology. Although its potential applications is developing rapidly, currently RadBioStat software can be a useful tool in computerassisted education of radiobiological models such as single target single hit, multiple target single hit and multiple target multiple hit. Scholars’ feedback is valuable to the producers of this software and help them continuously improve this product, add new features and increase its desirability and functionality.

  12. Natural genetic variation in Calligonum Tunisian genus analyzed by ...

    African Journals Online (AJOL)

    The Calligonum genus is one of the most economically important resources of the Tunisian desert, playing an important role in the lives of desert local population. A great range of genetic diversity could be seen in diverse populations of this genus which are spread all over Tunisian areas. DNA-based molecular markers are ...

  13. Introducing a gender-neutral pronoun in a natural gender language: The influence of time on attitudes and behavior

    Directory of Open Access Journals (Sweden)

    Marie eGustafsson Sendén

    2015-07-01

    Full Text Available The implementation of gender fair language is often associated with negative reactions and hostile attack on people who propose a change. This was also the case in Sweden in 2012 when a third gender-neutral pronoun hen was proposed as an addition to the already existing Swedish pronouns for she and he. The pronoun hen can be used both generically, when gender is unknown or irrelevant, and as a transgender pronoun for people who categorize themselves outside the gender dichotomy. In this article we review the process from 2012 to 2015 when hen has been introduced in the Swedish Dictionary. No other language has so far added a third gender-neutral pronoun that actually has reached the broader population of language users, which makes the situation in Sweden unique. We present data on attitudes toward hen during the recent four years and study how time is associated with the attitudes. In 2012 the majority of the Swedish population was negative to the word, but already in 2014 there was a significant shift to more positive attitudes. Time was one of the strongest predictors for attitudes also when other relevant factors were controlled for. Even though to a lesser extent than the attitudes, the actual use of the word has also increased. We conclude that new words challenging the binary gender system evoke hostile and negative reactions, but also that attitudes can normalize rather quickly. This is very positive because it should motivate language amendments and initiatives for gender-fair language although the first responses are negative.

  14. Introducing a gender-neutral pronoun in a natural gender language: the influence of time on attitudes and behavior.

    Science.gov (United States)

    Gustafsson Sendén, Marie; Bäck, Emma A; Lindqvist, Anna

    2015-01-01

    The implementation of gender fair language is often associated with negative reactions and hostile attacks on people who propose a change. This was also the case in Sweden in 2012 when a third gender-neutral pronoun hen was proposed as an addition to the already existing Swedish pronouns for she (hon) and he (han). The pronoun hen can be used both generically, when gender is unknown or irrelevant, and as a transgender pronoun for people who categorize themselves outside the gender dichotomy. In this article we review the process from 2012 to 2015. No other language has so far added a third gender-neutral pronoun, existing parallel with two gendered pronouns, that actually have reached the broader population of language users. This makes the situation in Sweden unique. We present data on attitudes toward hen during the past 4 years and analyze how time is associated with the attitudes in the process of introducing hen to the Swedish language. In 2012 the majority of the Swedish population was negative to the word, but already in 2014 there was a significant shift to more positive attitudes. Time was one of the strongest predictors for attitudes also when other relevant factors were controlled for. The actual use of the word also increased, although to a lesser extent than the attitudes shifted. We conclude that new words challenging the binary gender system evoke hostile and negative reactions, but also that attitudes can normalize rather quickly. We see this finding very positive and hope it could motivate language amendments and initiatives for gender-fair language, although the first responses may be negative.

  15. Naturally occurring and radiation-induced tumors in SPF mice, and genetic influence in radiation leukemogenesis

    International Nuclear Information System (INIS)

    Kasuga, T.

    1979-01-01

    The data obtained so far in this study point to a strong genetic influence not only on the types and incidence of naturally occurring and radiation-induced tumors but also on radiation leukemogenesis. (Auth.)

  16. History of Science as an Instructional Context: Student Learning in Genetics and Nature of Science

    Science.gov (United States)

    Kim, Sun Young; Irving, Karen E.

    2010-01-01

    This study (1) explores the effectiveness of the contextualized history of science on student learning of nature of science (NOS) and genetics content knowledge (GCK), especially interrelationships among various genetics concepts, in high school biology classrooms; (2) provides an exemplar for teachers on how to utilize history of science in…

  17. Natural variation, an underexploited resource of genetic variation for plant genetics

    NARCIS (Netherlands)

    Alonso-Blanco, C.; Koornneef, M.

    2000-01-01

    The definition of gene functions requires the phenotypic characterization of genetic variants. Currently, such functional analysis of Arabidopsis genes is based largely on laboratory-induced mutants that are selected in forward and reverse genetic studies. An alternative complementary source of

  18. BELFAST nonagenarians: nature or nurture? Immunological, cardiovascular and genetic factors

    Directory of Open Access Journals (Sweden)

    Rea I M

    2010-05-01

    Full Text Available Abstract Nonagenarians are the fastest growing sector of populations across Western European and the developed world. They are some of the oldest members of our societies and survivors of their generation and may help us understand how to age not only longer, but better. The Belfast Longevity Group enlisted the help of 500 community-living, mobile, mentally competent, 'elite' nonagenarians, as part of an ongoing study of ageing. We assessed some immunological, cardiovascular, nutritional and genetic factors and some aspects of their interaction in this group of 'oldest old'. Here we present some of the evidence related to genetic and nutritional factors which seem to be important for good quality ageing in nonagenarians from the Belfast Elderly Longitudinal Free-living Ageing STudy (BELFAST.

  19. Ecological and Genetic Barriers Differentiate Natural Populations of Saccharomyces cerevisiae.

    Science.gov (United States)

    Clowers, Katie J; Heilberger, Justin; Piotrowski, Jeff S; Will, Jessica L; Gasch, Audrey P

    2015-09-01

    How populations that inhabit the same geographical area become genetically differentiated is not clear. To investigate this, we characterized phenotypic and genetic differences between two populations of Saccharomyces cerevisiae that in some cases inhabit the same environment but show relatively little gene flow. We profiled stress sensitivity in a group of vineyard isolates and a group of oak-soil strains and found several niche-related phenotypes that distinguish the populations. We performed bulk-segregant mapping on two of the distinguishing traits: The vineyard-specific ability to grow in grape juice and oak-specific tolerance to the cell wall damaging drug Congo red. To implicate causal genes, we also performed a chemical genomic screen in the lab-strain deletion collection and identified many important genes that fell under quantitative trait loci peaks. One gene important for growth in grape juice and identified by both the mapping and the screen was SSU1, a sulfite-nitrite pump implicated in wine fermentations. The beneficial allele is generated by a known translocation that we reasoned may also serve as a genetic barrier. We found that the translocation is prevalent in vineyard strains, but absent in oak strains, and presents a postzygotic barrier to spore viability. Furthermore, the translocation was associated with a fitness cost to the rapid growth rate seen in oak-soil strains. Our results reveal the translocation as a dual-function locus that enforces ecological differentiation while producing a genetic barrier to gene flow in these sympatric populations. © The Author 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  20. The genetic basis of natural variation in mushroom body size in Drosophila melanogaster.

    Science.gov (United States)

    Zwarts, Liesbeth; Vanden Broeck, Lies; Cappuyns, Elisa; Ayroles, Julien F; Magwire, Michael M; Vulsteke, Veerle; Clements, Jason; Mackay, Trudy F C; Callaerts, Patrick

    2015-12-11

    Genetic variation in brain size may provide the basis for the evolution of the brain and complex behaviours. The genetic substrate and the selective pressures acting on brain size are poorly understood. Here we use the Drosophila Genetic Reference Panel to map polymorphic variants affecting natural variation in mushroom body morphology. We identify 139 genes and 39 transcription factors and confirm effects on development and adult plasticity. We show correlations between morphology and aggression, sleep and lifespan. We propose that natural variation in adult brain size is controlled by interaction of the environment with gene networks controlling development and plasticity.

  1. Genetic signature of natural selection in first Americans.

    Science.gov (United States)

    Amorim, Carlos Eduardo; Nunes, Kelly; Meyer, Diogo; Comas, David; Bortolini, Maria Cátira; Salzano, Francisco Mauro; Hünemeier, Tábita

    2017-02-28

    When humans moved from Asia toward the Americas over 18,000 y ago and eventually peopled the New World they encountered a new environment with extreme climate conditions and distinct dietary resources. These environmental and dietary pressures may have led to instances of genetic adaptation with the potential to influence the phenotypic variation in extant Native American populations. An example of such an event is the evolution of the fatty acid desaturases ( FADS ) genes, which have been claimed to harbor signals of positive selection in Inuit populations due to adaptation to the cold Greenland Arctic climate and to a protein-rich diet. Because there was evidence of intercontinental variation in this genetic region, with indications of positive selection for its variants, we decided to compare the Inuit findings with other Native American data. Here, we use several lines of evidence to show that the signal of FADS-positive selection is not restricted to the Arctic but instead is broadly observed throughout the Americas. The shared signature of selection among populations living in such a diverse range of environments is likely due to a single and strong instance of local adaptation that took place in the common ancestral population before their entrance into the New World. These first Americans peopled the whole continent and spread this adaptive variant across a diverse set of environments.

  2. Autosomal dominant cyclic hematopoiesis: Genetics, phenotype, and natural history

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, S.E.; Stephens, K.; Dale, D.C. [Univ. of Washington, Seattle, WA (United States)

    1994-09-01

    Autosomal dominant cyclic hematopoiesis (ADCH; cyclic neutropenia) is a rare disorder manifested by transient neutropenia that recurs every three weeks. To facilitate mapping the ADCH gene by genetic linkage analysis, we studied 9 ADCH families with 42 affected individuals. Pedigrees revealed AD inheritance with no evidence for decreased penetrance. Similar intra- and interfamilial variable expression was observed, with no evidence to support heterogeneity. At least 3 families displayed apparent new mutations. Many adults developed chronic neutropenia, while offspring always cycled during childhood. Children displayed recurrent oral ulcers, gingivitis, lymphadenopathy, fever, and skin and other infections with additional symptoms. Interestingly, there were no cases of neonatal infection. Some children required multiple hospitalizations for treatment. Four males under age 18 died of Clostridium sepsis following necrotizing enterocolitis; all had affected mothers. No other deaths due to ADCH were found; most had improvement of symptoms and infections as adults. Adults experienced increased tooth loss prior to age 30 (16 out of 27 adults, with 9 edentulous). No increase in myelodysplasia, malignancy, or congenital anomalies was observed. Recombinant G-CSF treatment resulted in dramatic improvement of symptoms and infections. The results suggest that ADCH is not a benign disorder, especially in childhood, and abdominal pain requires immediate evaluation. Diagnosis of ADCH requires serial blood counts in the proband and at least one CBC in relatives to exclude similar disorders. Genetic counseling requires specific histories as well as CBCs of each family member at risk to determine status regardless of symptom history, especially to assess apparent new mutations.

  3. Genetic resources of teak (Tectona grandis Linn. f.)—strong genetic structure among natural populations

    DEFF Research Database (Denmark)

    Hansen, Ole Kim; Changtragoon, Suchitra; Ponoy, Bundit

    2015-01-01

    had the highest genetic diversity while provenances from Laos showed the lowest. In the eastern part of the natural distribution area, comprising Myanmar, Thailand and Laos, there was a strong clinal decrease in genetic diversity the further east the provenance was located. Overall, the pattern......) the Indian provenances from the dry interior and the moist west coast and (3) the provenances from northern Myanmar. The provenances from southern Myanmar were placed close to the root of the tree together with the three provenances from the semi-moist east coast of India. A Bayesian cluster analysis using...

  4. Human genetic studies in areas of high natural radiation VI. Genetical load and ethnic group

    Energy Technology Data Exchange (ETDEWEB)

    Freire-Maia, A [Faculdade de Ciencias Medicas e Biologicas de Botucatu (Brazil). Departamento de Genetica

    1974-01-01

    The load of mutations disclosed by inbreeding, according to the ethnic group of the parents, has been analyzed in our data. Besides the total of the population, a sample with no alien ancestrals has also been analyzed. Genetic load has been studied for absortions, still births, pos-natal mortality, total mortality, anomalies, total mortality + anomalies, and abnormalities in general.

  5. Human genetic studies in areas of high natural radiation VI. Genetical load and ethnic group

    International Nuclear Information System (INIS)

    Freire-Maia, A.

    1974-01-01

    The load of mutations disclosed by inbreeding, according to the ethnic group of the parents, has been analyzed in our data. Besides the total of the population, a sample with no alien ancestrals has also been analyzed. Genetic load has been studied for absortions, still births, pos-natal mortality, total mortality, anomalies, total mortality + anomalies, and abnormalities in general [pt

  6. Introducing Mudbox

    CERN Document Server

    Kermanikian, Ara

    2010-01-01

    One of the first books on Autodesk's new Mudbox 3D modeling and sculpting tool!. Autodesk's Mudbox was used to create photorealistic creatures for The Dark Knight , The Mist , and others films. Now you can join the crowd interested in learning this exciting new digital modeling and sculpting tool with this complete guide. Get up to speed on all of Mudbox's features and functions, learn how sculpt and paint, and master the art of using effective workflows to make it all go easier.: Introduces Autodesk's Mudbox, an exciting 3D modeling and sculpting tool that enables you to create photorealistic

  7. Determining the source and genetic fingerprint of natural gases using noble gas geochemistry: a northern Appalachian Basin case study

    Science.gov (United States)

    Hunt, Andrew G.; Darrah, Thomas H.; Poreda, Robert J.

    2012-01-01

    Silurian and Devonian natural gas reservoirs present within New York state represent an example of unconventional gas accumulations within the northern Appalachian Basin. These unconventional energy resources, previously thought to be noneconomically viable, have come into play following advances in drilling (i.e., horizontal drilling) and extraction (i.e., hydraulic fracturing) capabilities. Therefore, efforts to understand these and other domestic and global natural gas reserves have recently increased. The suspicion of fugitive mass migration issues within current Appalachian production fields has catalyzed the need to develop a greater understanding of the genetic grouping (source) and migrational history of natural gases in this area. We introduce new noble gas data in the context of published hydrocarbon carbon (C1,C2+) (13C) data to explore the genesis of thermogenic gases in the Appalachian Basin. This study includes natural gases from two distinct genetic groups: group 1, Upper Devonian (Marcellus shale and Canadaway Group) gases generated in situ, characterized by early mature (13C[C1  C2][13C113C2]: –9), isotopically light methane, with low (4He) (average, 1  103 cc/cc) elevated 4He/40Ar and 21Ne/40Ar (where the asterisk denotes excess radiogenic or nucleogenic production beyond the atmospheric ratio), and a variable, atmospherically (air-saturated–water) derived noble gas component; and group 2, a migratory natural gas that emanated from Lower Ordovician source rocks (i.e., most likely, Middle Ordovician Trenton or Black River group) that is currently hosted primarily in Lower Silurian sands (i.e., Medina or Clinton group) characterized by isotopically heavy, mature methane (13C[C1 – C2] [13C113C2]: 3), with high (4He) (average, 1.85  103 cc/cc) 4He/40Ar and 21Ne/40Ar near crustal production levels and elevated crustal noble gas content (enriched 4He,21Ne, 40Ar). Because the release of each crustal noble gas (i.e., He, Ne, Ar

  8. Natural selection affects multiple aspects of genetic variation at putatively peutral sites across the human genome

    DEFF Research Database (Denmark)

    Lohmueller, Kirk E; Albrechtsen, Anders; Li, Yingrui

    2011-01-01

    A major question in evolutionary biology is how natural selection has shaped patterns of genetic variation across the human genome. Previous work has documented a reduction in genetic diversity in regions of the genome with low recombination rates. However, it is unclear whether other summaries...... these questions by analyzing three different genome-wide resequencing datasets from European individuals. We document several significant correlations between different genomic features. In particular, we find that average minor allele frequency and diversity are reduced in regions of low recombination...... and that human diversity, human-chimp divergence, and average minor allele frequency are reduced near genes. Population genetic simulations show that either positive natural selection acting on favorable mutations or negative natural selection acting against deleterious mutations can explain these correlations...

  9. Introducing Toxics

    OpenAIRE

    David C. Bellinger

    2013-01-01

    With this inaugural issue, Toxics begins its life as a peer-reviewed, open access journal focusing on all aspects of toxic chemicals. We are interested in publishing papers that present a wide range of perspectives on toxicants and naturally occurring toxins, including exposure, biomarkers, kinetics, biological effects, fate and transport, treatment, and remediation. Toxics differs from many other journals in the absence of a page or word limit on contributions, permitting authors to present ...

  10. Genetic Diversity and Structure of Natural Quercus variabilis Population in China as Revealed by Microsatellites Markers

    Directory of Open Access Journals (Sweden)

    Xiaomeng Shi

    2017-12-01

    Full Text Available Quercus variabilis is a tree species of ecological and economic value that is widely distributed in China. To effectively evaluate, use, and conserve resources, we applied 25 pairs of simple sequence repeat (SSR primers to study its genetic diversity and genetic structure in 19 natural forest or natural secondary forest populations of Q. variabilis (a total of 879 samples. A total of 277 alleles were detected. Overall, the average expected heterozygosity (He was 0.707 and average allelic richness (AR was 7.79. Q. variabilis manifested a loss of heterozygosity, and the mean of inbreeding coefficient (FIS was 0.044. Less differentiation among populations was observed, and the genetic differentiation coefficient (FST was 0.063. Bayesian clustering analysis indicated that the 19 studied populations could be divided into three groups based on their genetic makeup, namely, the Southwest group, Central group, and Northeastern group. The Central group, compared to the populations of the Southwest and Northeast group, showed higher genetic diversities and lower genetic differentiations. As a widely distributed species, the historical migration of Q. variabilis contributed to its genetic differentiation.

  11. Genetic radiation effects and natural radioactivity of human population in Brazil

    International Nuclear Information System (INIS)

    Freire-Maia, A.

    1972-01-01

    A study on areas of natural radioactivity is done, covering the genetic effects on human population. The study is done in depth dealing with aspecto such as radioactive area involved, discussion of materials and methods, errors and fallacies, influential factors, models, buildup and natural radioactivity, hypotheses, results and perspectives, etc. It covers 24 localites, 8.572 couples and 43.930 pregnancy cases [pt

  12. Introducing Toxics

    Directory of Open Access Journals (Sweden)

    David C. Bellinger

    2013-04-01

    Full Text Available With this inaugural issue, Toxics begins its life as a peer-reviewed, open access journal focusing on all aspects of toxic chemicals. We are interested in publishing papers that present a wide range of perspectives on toxicants and naturally occurring toxins, including exposure, biomarkers, kinetics, biological effects, fate and transport, treatment, and remediation. Toxics differs from many other journals in the absence of a page or word limit on contributions, permitting authors to present their work in as much detail as they wish. Toxics will publish original research papers, conventional reviews, meta-analyses, short communications, theoretical papers, case reports, commentaries and policy perspectives, and book reviews (Book reviews will be solicited and should not be submitted without invitation. Toxins and toxicants concern individuals from a wide range of disciplines, and Toxics is interested in receiving papers that represent the full range of approaches applied to their study, including in vitro studies, studies that use experimental animal or non-animal models, studies of humans or other biological populations, and mathematical modeling. We are excited to get underway and look forward to working with authors in the scientific and medical communities and providing them with a novel venue for sharing their work. [...

  13. Genetic composition of social groups influences male aggressive behaviour and fitness in natural genotypes of Drosophila melanogaster.

    Science.gov (United States)

    Saltz, Julia B

    2013-11-22

    Indirect genetic effects (IGEs) describe how an individual's behaviour-which is influenced by his or her genotype-can affect the behaviours of interacting individuals. IGE research has focused on dyads. However, insights from social networks research, and other studies of group behaviour, suggest that dyadic interactions are affected by the behaviour of other individuals in the group. To extend IGE inferences to groups of three or more, IGEs must be considered from a group perspective. Here, I introduce the 'focal interaction' approach to study IGEs in groups. I illustrate the utility of this approach by studying aggression among natural genotypes of Drosophila melanogaster. I chose two natural genotypes as 'focal interactants': the behavioural interaction between them was the 'focal interaction'. One male from each focal interactant genotype was present in every group, and I varied the genotype of the third male-the 'treatment male'. Genetic variation in the treatment male's aggressive behaviour influenced the focal interaction, demonstrating that IGEs in groups are not a straightforward extension of IGEs measured in dyads. Further, the focal interaction influenced male mating success, illustrating the role of IGEs in behavioural evolution. These results represent the first manipulative evidence for IGEs at the group level.

  14. Natural Genetic Variation and Candidate Genes for Morphological Traits in Drosophila melanogaster

    Science.gov (United States)

    Carreira, Valeria Paula; Mensch, Julián; Hasson, Esteban; Fanara, Juan José

    2016-01-01

    Body size is a complex character associated to several fitness related traits that vary within and between species as a consequence of environmental and genetic factors. Latitudinal and altitudinal clines for different morphological traits have been described in several species of Drosophila and previous work identified genomic regions associated with such variation in D. melanogaster. However, the genetic factors that orchestrate morphological variation have been barely studied. Here, our main objective was to investigate genetic variation for different morphological traits associated to the second chromosome in natural populations of D. melanogaster along latitudinal and altitudinal gradients in Argentina. Our results revealed weak clinal signals and a strong population effect on morphological variation. Moreover, most pairwise comparisons between populations were significant. Our study also showed important within-population genetic variation, which must be associated to the second chromosome, as the lines are otherwise genetically identical. Next, we examined the contribution of different candidate genes to natural variation for these traits. We performed quantitative complementation tests using a battery of lines bearing mutated alleles at candidate genes located in the second chromosome and six second chromosome substitution lines derived from natural populations which exhibited divergent phenotypes. Results of complementation tests revealed that natural variation at all candidate genes studied, invected, Fasciclin 3, toucan, Reticulon-like1, jing and CG14478, affects the studied characters, suggesting that they are Quantitative Trait Genes for morphological traits. Finally, the phenotypic patterns observed suggest that different alleles of each gene might contribute to natural variation for morphological traits. However, non-additive effects cannot be ruled out, as wild-derived strains differ at myriads of second chromosome loci that may interact

  15. THE EFFECT OF INTRODUCED FORAGE LEGUMES ON IMPROVEMENT OF SOIL FERTILITY IN NATURAL PASTURES OF SEMI-ARID RANGELANDS OF KAJIADO DISTRICT, KENYA

    Directory of Open Access Journals (Sweden)

    Peter N Macharia

    2010-11-01

    Full Text Available A two phase study was carried out from 2002 to 2005 in the semi-arid rangelands of Kajiado District, Kenya to determine the effect of introduced forage legumes on soil fertility improvement of natural pastures. During legume evaluation phase, Neonotonia wightii (Glycine, Macroptilium atropurpureum (Siratro, Lablab purpureus cv. Rongai (Dolichos, Mucuna pruriens (Velvet bean and Stylosanthes scabra var. Seca (Stylo were screened for adaptability and growth performance under the semi-arid conditions for two years. Results of soil analysis showed there were significant increases in soil pH (4.92 to 5.36, organic carbon (1.17 to 2.57% , nitrogen (0.17 to 0.22% and potassium (1.23 to 1.68 me% probably due to the large amounts of organic residues produced by the legumes (particularly Glycine, Siratro and Stylo which are perennials. The calcium content decreased significantly from 7.97 to 4.50 me% (which was attributed to plant uptake while the decrease of phosphorus was not significant. During the second phase of study for 1½ years Glycine, Siratro and Stylo were integrated into natural pastures. The results showed that only the soil pH significantly increased from 5.23 to 5.31 while all the other nutrients decreased results, which were attributed to production of less organic residues by the legumes compared to the residues produced during the legume evaluation phase. The study concluded that Glycine, Siratro and Stylo were capable of improving the soil fertility of semi-arid natural pastures only if the respective dry matter production was 10.31, 7.81 and 3.52 tha-1, amounts which were able to produce large amounts of organic residues. Â

  16. Structure and genetic diversity of natural Brazilian pepper populations (Schinus terebinthifolius Raddi).

    Science.gov (United States)

    Álvares-Carvalho, S V; Duarte, J F; Santos, T C; Santos, R M; Silva-Mann, R; Carvalho, D

    2016-06-17

    In the face of a possible loss of genetic diversity in plants due the environmental changes, actions to ensure the genetic variability are an urgent necessity. The extraction of Brazilian pepper fruits is a cause of concern because it results in the lack of seeds in soil, hindering its distribution in space and time. It is important to address this concern and explore the species, used by riparian communities and agro-factories without considering the need for keeping the seeds for natural seed banks and for species sustainability. The objective of this study was to evaluate the structure and the genetic diversity in natural Brazilian pepper populations (Schinus terebinthifolius Raddi). Twenty-two alleles in 223 individuals were identified from eight forest remnants located in the states of Minas Gerais, Espírito Santo, and Sergipe. All populations presented loci in Hardy-Weinberg equilibrium deviation. Four populations presented six combinations of loci in linkage disequilibrium. Six exclusive alleles were detected in four populations. Analysis of molecular variance showed the absence of diversity between regions and that between the populations (GST) was 41%. Genetic diversity was structured in seven clusters (ΔK7). Brazilian pepper populations were not structured in a pattern of isolation by distance and present genetic bottleneck. The populations São Mateus, Canastra, Barbacena, and Ilha das Flores were identified as management units and may support conservation projects, ecological restoration and in implementation of management plans for Brazilian pepper in the State of Sergipe.

  17. Reducing the Cytotoxicity of Lipid Nanoparticles Associated with a Fusogenic Cationic Lipid in a Natural Killer Cell Line by Introducing a Polycation-Based siRNA Core.

    Science.gov (United States)

    Nakamura, Takashi; Yamada, Koharu; Fujiwara, Yuki; Sato, Yusuke; Harashima, Hideyoshi

    2018-06-04

    Introducing siRNA into human immune cells by an artificial delivery system continues to be a challenging issue. We previously developed a multifunctional envelope-type nanodevice (MEND) containing the YSK12-C4, a fusogenic cationic lipid, (YSK12-MEND) and succeeded in the efficient delivery of siRNA into human immune cell lines. Significant cytotoxicity, however, was observed at siRNA doses needed for gene silencing in NK-92 cells. NK-92 cells, a unique natural killer (NK) cell line, would be applicable for use in clinical NK therapy. Thus, reducing the cytotoxicity of the YSK12-MEND in NK-92 cells would strengthen the efficacy of NK-92 cell-based therapy. The amount of the YSK12-C4 in the MEND needed to be reduced to reduce the cytotoxicity, because the cytotoxicity was directly associated with the YSK12-C4. In the present study, we decreased the total amount of lipid, including the YSK12-C4, by introducing a core formed by electrostatic interactions of siRNA with a polycation (protamine) (siRNA core), which led to a decrease in cytotoxicity in NK-92 cells. We prepared a YSK12-MEND containing an siRNA core (YSK12-MEND/core) at charge ratios (CR: YSK12-C4/siRNA) of 10, 5, 3, and 2.5 and compared the YSK12-MEND/core with that for a YSK12-MEND (CR16.9). Cell viability was increased by more than 2 times at a CR5 or less. On the other hand, the YSK12-MEND/core (CR5) maintained the same gene silencing efficiency (60%) as the YSK12-MEND. Interestingly, the cellular uptake efficiency and hemolytic activity of the YSK12-MEND/core (CR5) was reduced compared to that for the YSK12-MEND. In calculating the silencing activity per cellular uptake efficiency and hemolytic activity, the value for the YSK12-MEND/core (CR5) was more than 2 times as high as that of the YSK12-MEND. The fact indicates that after endosomal escape, the process can be enhanced by using a YSK12-MEND/core (CR5). Thus, introducing an siRNA core into lipid nanoparticles can be a potent strategy for decreasing

  18. Natural selection affects multiple aspects of genetic variation at putatively neutral sites across the human genome.

    Science.gov (United States)

    Lohmueller, Kirk E; Albrechtsen, Anders; Li, Yingrui; Kim, Su Yeon; Korneliussen, Thorfinn; Vinckenbosch, Nicolas; Tian, Geng; Huerta-Sanchez, Emilia; Feder, Alison F; Grarup, Niels; Jørgensen, Torben; Jiang, Tao; Witte, Daniel R; Sandbæk, Annelli; Hellmann, Ines; Lauritzen, Torsten; Hansen, Torben; Pedersen, Oluf; Wang, Jun; Nielsen, Rasmus

    2011-10-01

    A major question in evolutionary biology is how natural selection has shaped patterns of genetic variation across the human genome. Previous work has documented a reduction in genetic diversity in regions of the genome with low recombination rates. However, it is unclear whether other summaries of genetic variation, like allele frequencies, are also correlated with recombination rate and whether these correlations can be explained solely by negative selection against deleterious mutations or whether positive selection acting on favorable alleles is also required. Here we attempt to address these questions by analyzing three different genome-wide resequencing datasets from European individuals. We document several significant correlations between different genomic features. In particular, we find that average minor allele frequency and diversity are reduced in regions of low recombination and that human diversity, human-chimp divergence, and average minor allele frequency are reduced near genes. Population genetic simulations show that either positive natural selection acting on favorable mutations or negative natural selection acting against deleterious mutations can explain these correlations. However, models with strong positive selection on nonsynonymous mutations and little negative selection predict a stronger negative correlation between neutral diversity and nonsynonymous divergence than observed in the actual data, supporting the importance of negative, rather than positive, selection throughout the genome. Further, we show that the widespread presence of weakly deleterious alleles, rather than a small number of strongly positively selected mutations, is responsible for the correlation between neutral genetic diversity and recombination rate. This work suggests that natural selection has affected multiple aspects of linked neutral variation throughout the human genome and that positive selection is not required to explain these observations.

  19. Population genetic structure in natural and reintroduced beaver (Castor fiber populations in Central Europe

    Directory of Open Access Journals (Sweden)

    Kautenburger, R.

    2008-12-01

    Full Text Available Castor fiber Linnaeus, 1758 is the only indigenous species of the genus Castor in Europe and Asia. Due to extensive hunting until the beginning of the 20th century, the distribution of the formerly widespread Eurasian beaver was dramatically reduced. Only a few populations remained and these were in isolated locations, such as the region of the German Elbe River. The loss of genetic diversity in small or captive populations throughgenetic drift and inbreeding is a severe conservation problem. However, the reintroduction of beaver populations from several regions in Europe has shown high viability and populations today are growing fast. In the present study we analysed the population genetic structure of a natural and two reintroduced beaver populations in Germany and Austria. Furthermore, we studied the genetic differentiation between two beaver species, C. fiber and the American beaver (C. canadensis, using RAPD (Random Amplified Polymorphic DNA as a genetic marker. The reintroduced beaver populations of different origins and the autochthonous population of the Elbe River showed a similar low genetic heterogeneity. There was an overall high genetic similarity in the species C. fiber, and no evidence was found for a clear subspecific structure in the populations studied.

  20. Maintenance of a genetic polymorphism with disruptive natural selection in stickleback.

    Science.gov (United States)

    Marchinko, Kerry B; Matthews, Blake; Arnegard, Matthew E; Rogers, Sean M; Schluter, Dolph

    2014-06-02

    The role of natural selection in the maintenance of genetic variation in wild populations remains a major problem in evolution. The influence of disruptive natural selection on genetic variation is especially interesting because it might lead to the evolution of assortative mating or dominance [1, 2]. In theory, variation can persist at a gene under disruptive natural selection, but the process is little studied and there are few examples [3, 4]. We report a stable polymorphism in the bony armor of threespine stickleback maintained with a deficit of heterozygotes at the major underlying gene, Ectodysplasin (Eda) [5]. The deficit vanishes at the embryo life stage only to re-emerge in adults, indicating that disruptive natural selection, rather than nonrandom mating, is the cause. The mechanism enabling long-term persistence of the polymorphism is unknown, but disruptive selection is predicted to be frequency dependent, favoring homozygous genotypes when they become rare. Further research on the ecological and evolutionary processes affecting individual genes will ultimately lead to a better understanding of the causes of genetic variation in populations. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Invasive plants and their escape from root herbivory: a worldwide comparison of the root-feeding nematode communities of the dune grass Ammophila arenaria in natural and introduced ranges

    NARCIS (Netherlands)

    Putten, van der W.H.; Yeates, G.W.; Duyts, H.; Schreck Reis, C.; Karssen, G.

    2005-01-01

    Invasive plants generally have fewer aboveground pathogens and viruses in their introduced range than in their natural range, and they also have fewer pathogens than do similar plant species native to the introduced range. However, although plant abundance is strongly controlled by root herbivores

  2. The Genetic Architecture of Natural Variation in Recombination Rate in Drosophila melanogaster.

    Science.gov (United States)

    Hunter, Chad M; Huang, Wen; Mackay, Trudy F C; Singh, Nadia D

    2016-04-01

    Meiotic recombination ensures proper chromosome segregation in many sexually reproducing organisms. Despite this crucial function, rates of recombination are highly variable within and between taxa, and the genetic basis of this variation remains poorly understood. Here, we exploit natural variation in the inbred, sequenced lines of the Drosophila melanogaster Genetic Reference Panel (DGRP) to map genetic variants affecting recombination rate. We used a two-step crossing scheme and visible markers to measure rates of recombination in a 33 cM interval on the X chromosome and in a 20.4 cM interval on chromosome 3R for 205 DGRP lines. Though we cannot exclude that some biases exist due to viability effects associated with the visible markers used in this study, we find ~2-fold variation in recombination rate among lines. Interestingly, we further find that recombination rates are uncorrelated between the two chromosomal intervals. We performed a genome-wide association study to identify genetic variants associated with recombination rate in each of the two intervals surveyed. We refined our list of candidate variants and genes associated with recombination rate variation and selected twenty genes for functional assessment. We present strong evidence that five genes are likely to contribute to natural variation in recombination rate in D. melanogaster; these genes lie outside the canonical meiotic recombination pathway. We also find a weak effect of Wolbachia infection on recombination rate and we confirm the interchromosomal effect. Our results highlight the magnitude of population variation in recombination rate present in D. melanogaster and implicate new genetic factors mediating natural variation in this quantitative trait.

  3. The Genetic Architecture of Natural Variation in Recombination Rate in Drosophila melanogaster.

    Directory of Open Access Journals (Sweden)

    Chad M Hunter

    2016-04-01

    Full Text Available Meiotic recombination ensures proper chromosome segregation in many sexually reproducing organisms. Despite this crucial function, rates of recombination are highly variable within and between taxa, and the genetic basis of this variation remains poorly understood. Here, we exploit natural variation in the inbred, sequenced lines of the Drosophila melanogaster Genetic Reference Panel (DGRP to map genetic variants affecting recombination rate. We used a two-step crossing scheme and visible markers to measure rates of recombination in a 33 cM interval on the X chromosome and in a 20.4 cM interval on chromosome 3R for 205 DGRP lines. Though we cannot exclude that some biases exist due to viability effects associated with the visible markers used in this study, we find ~2-fold variation in recombination rate among lines. Interestingly, we further find that recombination rates are uncorrelated between the two chromosomal intervals. We performed a genome-wide association study to identify genetic variants associated with recombination rate in each of the two intervals surveyed. We refined our list of candidate variants and genes associated with recombination rate variation and selected twenty genes for functional assessment. We present strong evidence that five genes are likely to contribute to natural variation in recombination rate in D. melanogaster; these genes lie outside the canonical meiotic recombination pathway. We also find a weak effect of Wolbachia infection on recombination rate and we confirm the interchromosomal effect. Our results highlight the magnitude of population variation in recombination rate present in D. melanogaster and implicate new genetic factors mediating natural variation in this quantitative trait.

  4. Natural transformation of Vibrio parahaemolyticus: A rapid method to create genetic deletions.

    Science.gov (United States)

    Chimalapati, Suneeta; de Souza Santos, Marcela; Servage, Kelly; De Nisco, Nicole J; Dalia, Ankur B; Orth, Kim

    2018-03-19

    The Gram-negative bacterium Vibrio parahaemolyticus is an opportunistic human pathogen and the leading cause of seafood borne acute gastroenteritis worldwide. Recently, this bacterium was implicated as the etiologic agent of a severe shrimp disease with consequent devastating outcomes to shrimp farming. In both cases, acquisition of genetic material via horizontal transfer provided V. parahaemolyticus with new virulence tools to cause disease. Dissecting the molecular mechanisms of V. parahaemolyticus pathogenesis often requires manipulating its genome. Classically, genetic deletions in V. parahaemolyticus are performed using a laborious, lengthy, multi-step process. Herein, we describe a fast and efficient method to edit this bacterium's genome based on V. parahaemolyticus natural competence. Although this method is similar to one previously described, V. parahaemolyticus requires counter selection for curing of acquired plasmids due to its recalcitrant nature of retaining extrachromosomal DNA. We believe this approach will be of use to the Vibrio community. Importance Spreading of Vibrios throughout the world correlates with increased global temperatures. As they spread, they find new niches to survive, proliferate and invade. Therefore, genetic manipulation of Vibrios is of utmost importance for studying these species. Herein, we have delineated and validated a rapid method to create genetic deletions in Vibrio parahaemolyticus This study provides insightful methodology for studies with other Vibrio species. Copyright © 2018 American Society for Microbiology.

  5. Cytoplasmic genetic variation and extensive cytonuclear interactions influence natural variation in the metabolome

    DEFF Research Database (Denmark)

    Joseph, Bindu; Corwin, Jason A.; Li, Baohua

    2013-01-01

    Understanding genome to phenotype linkages has been greatly enabled by genomic sequencing. However, most genome analysis is typically confined to the nuclear genome. We conducted a metabolomic QTL analysis on a reciprocal RIL population structured to examine how variation in the organelle genomes...... was a central hub in the epistatic network controlling the plant metabolome. This epistatic influence manifested such that the cytoplasmic background could alter or hide pairwise epistasis between nuclear loci. Thus, cytoplasmic genetic variation plays a central role in controlling natural variation...... in metabolomic networks. This suggests that cytoplasmic genomes must be included in any future analysis of natural variation....

  6. Genetic characterization of natural populations of pineapple guava (Acca sellowiana, with heterologous microsatellites markers

    Directory of Open Access Journals (Sweden)

    Karine Louise dos Santos

    2011-12-01

    Full Text Available Pineapple guava (Acca sellowiana is a native species from south Brazil and northeast Uruguay, and due to the unique flavor of its fruits, it is an income-generating alternative to small farmers. Knowledge on genetic diversity is an important tool for genetic improvement and conservation. Aiming to increase the knowledge with regarde to the species genetic diversity, fi ve natural populations of A. sellowiana were analyzed through microsatellites markers developed from Eucalyptus grandis W. Hill ex Maiden x E. urophylla S.T. Blake complex. Using 10 pairs of selected markers, 122 plants were characterized. The mean values for expected and observed heterozigosity were 0.42 and 0.47, respectively. The fˆ estimates did not differ from zero to four out of the five populations evaluated, suggesting a small inbreeding effect. In addition, private alleles and high genetic divergence was observed. the average genetic divergence among the populations was st Fˆ = 0,13 e st Rˆ = 0,14, mostly due to the incidenceof rare or exclusive alleles among some populations.

  7. Genetic polymorphism and natural selection of Duffy binding protein of Plasmodium vivax Myanmar isolates

    Science.gov (United States)

    2012-01-01

    Background Plasmodium vivax Duffy binding protein (PvDBP) plays an essential role in erythrocyte invasion and a potential asexual blood stage vaccine candidate antigen against P. vivax. The polymorphic nature of PvDBP, particularly amino terminal cysteine-rich region (PvDBPII), represents a major impediment to the successful design of a protective vaccine against vivax malaria. In this study, the genetic polymorphism and natural selection at PvDBPII among Myanmar P. vivax isolates were analysed. Methods Fifty-four P. vivax infected blood samples collected from patients in Myanmar were used. The region flanking PvDBPII was amplified by PCR, cloned into Escherichia coli, and sequenced. The polymorphic characters and natural selection of the region were analysed using the DnaSP and MEGA4 programs. Results Thirty-two point mutations (28 non-synonymous and four synonymous mutations) were identified in PvDBPII among the Myanmar P. vivax isolates. Sequence analyses revealed that 12 different PvDBPII haplotypes were identified in Myanmar P. vivax isolates and that the region has evolved under positive natural selection. High selective pressure preferentially acted on regions identified as B- and T-cell epitopes of PvDBPII. Recombination may also be played a role in the resulting genetic diversity of PvDBPII. Conclusions PvDBPII of Myanmar P. vivax isolates displays a high level of genetic polymorphism and is under selective pressure. Myanmar P. vivax isolates share distinct types of PvDBPII alleles that are different from those of other geographical areas. These results will be useful for understanding the nature of the P. vivax population in Myanmar and for development of PvDBPII-based vaccine. PMID:22380592

  8. Genetic evidence for natural selection in humans in the contemporary United States.

    Science.gov (United States)

    Beauchamp, Jonathan P

    2016-07-12

    Recent findings from molecular genetics now make it possible to test directly for natural selection by analyzing whether genetic variants associated with various phenotypes have been under selection. I leverage these findings to construct polygenic scores that use individuals' genotypes to predict their body mass index, educational attainment (EA), glucose concentration, height, schizophrenia, total cholesterol, and (in females) age at menarche. I then examine associations between these scores and fitness to test whether natural selection has been occurring. My study sample includes individuals of European ancestry born between 1931 and 1953 who participated in the Health and Retirement Study, a representative study of the US population. My results imply that natural selection has been slowly favoring lower EA in both females and males, and are suggestive that natural selection may have favored a higher age at menarche in females. For EA, my estimates imply a rate of selection of about -1.5 mo of education per generation (which pales in comparison with the increases in EA observed in contemporary times). Although they cannot be projected over more than one generation, my results provide additional evidence that humans are still evolving-albeit slowly, especially compared with the rapid changes that have occurred over the past few generations due to cultural and environmental factors.

  9. Population genetic structure and natural selection of Plasmodium falciparum apical membrane antigen-1 in Myanmar isolates.

    Science.gov (United States)

    Kang, Jung-Mi; Lee, Jinyoung; Moe, Mya; Jun, Hojong; Lê, Hương Giang; Kim, Tae Im; Thái, Thị Lam; Sohn, Woon-Mok; Myint, Moe Kyaw; Lin, Khin; Shin, Ho-Joon; Kim, Tong-Soo; Na, Byoung-Kuk

    2018-02-07

    Plasmodium falciparum apical membrane antigen-1 (PfAMA-1) is one of leading blood stage malaria vaccine candidates. However, genetic variation and antigenic diversity identified in global PfAMA-1 are major hurdles in the development of an effective vaccine based on this antigen. In this study, genetic structure and the effect of natural selection of PfAMA-1 among Myanmar P. falciparum isolates were analysed. Blood samples were collected from 58 Myanmar patients with falciparum malaria. Full-length PfAMA-1 gene was amplified by polymerase chain reaction and cloned into a TA cloning vector. PfAMA-1 sequence of each isolate was sequenced. Polymorphic characteristics and effect of natural selection were analysed with using DNASTAR, MEGA4, and DnaSP programs. Polymorphic nature and natural selection in 459 global PfAMA-1 were also analysed. Thirty-seven different haplotypes of PfAMA-1 were identified in 58 Myanmar P. falciparum isolates. Most amino acid changes identified in Myanmar PfAMA-1 were found in domains I and III. Overall patterns of amino acid changes in Myanmar PfAMA-1 were similar to those in global PfAMA-1. However, frequencies of amino acid changes differed by country. Novel amino acid changes in Myanmar PfAMA-1 were also identified. Evidences for natural selection and recombination event were observed in global PfAMA-1. Among 51 commonly identified amino acid changes in global PfAMA-1 sequences, 43 were found in predicted RBC-binding sites, B-cell epitopes, or IUR regions. Myanmar PfAMA-1 showed similar patterns of nucleotide diversity and amino acid polymorphisms compared to those of global PfAMA-1. Balancing natural selection and intragenic recombination across PfAMA-1 are likely to play major roles in generating genetic diversity in global PfAMA-1. Most common amino acid changes in global PfAMA-1 were located in predicted B-cell epitopes where high levels of nucleotide diversity and balancing natural selection were found. These results highlight the

  10. Population genetic structure and natural selection of apical membrane antigen-1 in Plasmodium vivax Korean isolates.

    Science.gov (United States)

    Kang, Jung-Mi; Lee, Jinyoung; Cho, Pyo-Yun; Moon, Sung-Ung; Ju, Hye-Lim; Ahn, Seong Kyu; Sohn, Woon-Mok; Lee, Hyeong-Woo; Kim, Tong-Soo; Na, Byoung-Kuk

    2015-11-16

    Plasmodium vivax apical membrane antigen-1 (PvAMA-1) is a leading candidate antigen for blood stage malaria vaccine. However, antigenic variation is a major obstacle in the development of an effective vaccine based on this antigen. In this study, the genetic structure and the effect of natural selection of PvAMA-1 among Korean P. vivax isolates were analysed. Blood samples were collected from 66 Korean patients with vivax malaria. The entire PvAMA-1 gene was amplified by polymerase chain reaction and cloned into a TA cloning vector. The PvAMA-1 sequence of each isolate was sequenced and the polymorphic characteristics and effect of natural selection were analysed using the DNASTAR, MEGA4, and DnaSP programs. Thirty haplotypes of PvAMA-1, which were further classified into seven different clusters, were identified in the 66 Korean P. vivax isolates. Domain II was highly conserved among the sequences, but substantial nucleotide diversity was observed in domains I and III. The difference between the rates of non-synonymous and synonymous mutations suggested that the gene has evolved under natural selection. No strong evidence indicating balancing or positive selection on PvAMA-1 was identified. Recombination may also play a role in the resulting genetic diversity of PvAMA-1. This study is the first comprehensive analysis of nucleotide diversity across the entire PvAMA-1 gene using a single population sample from Korea. Korean PvAMA-1 had limited genetic diversity compared to PvAMA-1 in global isolates. The overall pattern of genetic polymorphism of Korean PvAMA-1 differed from other global isolates and novel amino acid changes were also identified in Korean PvAMA-1. Evidences for natural selection and recombination event were observed, which is likely to play an important role in generating genetic diversity across the PvAMA-1. These results provide useful information for the understanding the population structure of P. vivax circulating in Korea and have important

  11. Site-specific selfish genes as tools for the control and genetic engineering of natural populations.

    Science.gov (United States)

    Burt, Austin

    2003-05-07

    Site-specific selfish genes exploit host functions to copy themselves into a defined target DNA sequence, and include homing endonuclease genes, group II introns and some LINE-like transposable elements. If such genes can be engineered to target new host sequences, then they can be used to manipulate natural populations, even if the number of individuals released is a small fraction of the entire population. For example, a genetic load sufficient to eradicate a population can be imposed in fewer than 20 generations, if the target is an essential host gene, the knockout is recessive and the selfish gene has an appropriate promoter. There will be selection for resistance, but several strategies are available for reducing the likelihood of it evolving. These genes may also be used to genetically engineer natural populations, by means of population-wide gene knockouts, gene replacements and genetic transformations. By targeting sex-linked loci just prior to meiosis one may skew the population sex ratio, and by changing the promoter one may limit the spread of the gene to neighbouring populations. The proposed constructs are evolutionarily stable in the face of the mutations most likely to arise during their spread, and strategies are also available for reversing the manipulations.

  12. Genetic parameters of performance traits in Sul-Mato-Grossenses naturalized sheep

    Directory of Open Access Journals (Sweden)

    Daniele Portela de Oliveira

    2014-02-01

    Full Text Available Estimates of genetic parameters are important to study characteristics that are to be included in a breeding program of a genetic group. The information of 594 weights from 211 lambs of a genetic group of naturalized Sul-mato-grossenses sheep belonging to Manoel de Barros Foundation and breeding at Centro Tecnologico de Ovinos from Anhanguera-Uniderp University was used. The estimation of variance components in unicaracter and bicaracter analysis were carried out through Bayesian inference. Estimates of heritability ranged from unicaracter analyses (0.22 to 0.47 and the bicaracter analyses (0.13 to 0.78. The maternal environmental permanent effect was higher in birth weight and average daily gain from birth to 50 days in 24.2% and 19.5%, respectively, in the observed variation. Estimates of heritability, maternal environmental permanent effect participation, phenotypic and genetic correlations indicate that selection for average daily gain from birth to 90 days would imply increases in weight at 50 days, weight at 90 days and average daily gain from 50 to 90 days of lambs with no significant increase in birth weight and average daily gain birth at 50 days.

  13. Genetic resistance to natural coccidiosis infection in goats in a semi-arid region of India

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    P.K. Rout

    2015-12-01

    Full Text Available Coccidiosis is one of the major causes of kid mortality in tropical regions and causes significant loss to farmers by affecting growth and feed efficiency in the growing kid. The strategy to control the coccidiosis is mainly through drug usage and is not efficacious at present. Therefore, an alternative strategy is required to control the disease in goats. Increasing genetic resistance to coccidiosis may be an appropriate complementary control strategy. The purpose of this study was to analyse the genetic variation in severity of natural coccidiosis infections in kids in the semi-arid region. The observations were recorded in 227 kids of Barbari and Jamunapari goats. Barbari goats had higher mean faecal oocyst counts (FOC than Jamunapari goats at 3 and 6 months of age. The heritability for FOC was 0.05 and 0.15 at 3 and 6 months of age, respectively. All phenotypic and environmental correlations between FOC and live weight traits were low and negative, indicating a tendency for more heavily infected kids in the flock to grow more slowly. Genetic correlations were largely similar, but had large standard errors. The results suggest that genetic resistance control strategy can potentially be useful for the better performance in the existing managemental condition.

  14. Genetic diversity in natural populations of Jacaranda decurrens Cham. determined using RAPD and AFLP markers

    Directory of Open Access Journals (Sweden)

    Bianca W. Bertoni

    2010-01-01

    Full Text Available Jacaranda decurrens (Bignoniaceae is an endemic species of the Cerrado with validated antitumoral activity. The genetic diversity of six populations of J. decurrens located in the State of São Paulo was determined in this study by using molecular markers for randomly amplified polymorphic DNA (RAPD and amplified fragment length polymorphism (AFLP. Following optimization of the amplification reaction, 10 selected primers generated 78 reproducible RAPD fragments that were mostly (69.2% polymorphic. Two hundred and five reproducible AFLP fragments were generated by using four selected primer combinations; 46.3% of these fragments were polymorphic, indicating a considerable level of genetic diversity. Analysis of molecular variance (AMOVA using these two groups of markers indicated that variability was strongly structured amongst populations. The unweighted pair group method with arithmatic mean (UPGMA and Pearson's correlation coefficient (RAPD -0.16, p = 0.2082; AFLP 0.37, p = 0.1006 between genetic matrices and geographic distances suggested that the population structure followed an island model in which a single population of infinite size gave rise to the current populations of J. decurrens, independently of their spatial position. The results of this study indicate that RAPD and AFLP markers were similarly efficient in measuring the genetic variability amongst natural populations of J. decurrens. These data may be useful for developing strategies for the preservation of this medicinal species in the Cerrado.

  15. Natural Genetic Transformation Generates a Population of Merodiploids in Streptococcus pneumoniae

    Science.gov (United States)

    Zomer, Aldert; Bootsma, Hester J.; Prudhomme, Marc; Granadel, Chantal; Hermans, Peter W. M.; Polard, Patrice; Martin, Bernard; Claverys, Jean-Pierre

    2013-01-01

    Partial duplication of genetic material is prevalent in eukaryotes and provides potential for evolution of new traits. Prokaryotes, which are generally haploid in nature, can evolve new genes by partial chromosome duplication, known as merodiploidy. Little is known about merodiploid formation during genetic exchange processes, although merodiploids have been serendipitously observed in early studies of bacterial transformation. Natural bacterial transformation involves internalization of exogenous donor DNA and its subsequent integration into the recipient genome by homology. It contributes to the remarkable plasticity of the human pathogen Streptococcus pneumoniae through intra and interspecies genetic exchange. We report that lethal cassette transformation produced merodiploids possessing both intact and cassette-inactivated copies of the essential target gene, bordered by repeats (R) corresponding to incomplete copies of IS861. We show that merodiploidy is transiently stimulated by transformation, and only requires uptake of a ∼3-kb DNA fragment partly repeated in the chromosome. We propose and validate a model for merodiploid formation, providing evidence that tandem-duplication (TD) formation involves unequal crossing-over resulting from alternative pairing and interchromatid integration of R. This unequal crossing-over produces a chromosome dimer, resolution of which generates a chromosome with the TD and an abortive chromosome lacking the duplicated region. We document occurrence of TDs ranging from ∼100 to ∼900 kb in size at various chromosomal locations, including by self-transformation (transformation with recipient chromosomal DNA). We show that self-transformation produces a population containing many different merodiploid cells. Merodiploidy provides opportunities for evolution of new genetic traits via alteration of duplicated genes, unrestricted by functional selective pressure. Transient stimulation of a varied population of merodiploids by

  16. Natural genetic transformation generates a population of merodiploids in Streptococcus pneumoniae.

    Directory of Open Access Journals (Sweden)

    Calum Johnston

    Full Text Available Partial duplication of genetic material is prevalent in eukaryotes and provides potential for evolution of new traits. Prokaryotes, which are generally haploid in nature, can evolve new genes by partial chromosome duplication, known as merodiploidy. Little is known about merodiploid formation during genetic exchange processes, although merodiploids have been serendipitously observed in early studies of bacterial transformation. Natural bacterial transformation involves internalization of exogenous donor DNA and its subsequent integration into the recipient genome by homology. It contributes to the remarkable plasticity of the human pathogen Streptococcus pneumoniae through intra and interspecies genetic exchange. We report that lethal cassette transformation produced merodiploids possessing both intact and cassette-inactivated copies of the essential target gene, bordered by repeats (R corresponding to incomplete copies of IS861. We show that merodiploidy is transiently stimulated by transformation, and only requires uptake of a ~3-kb DNA fragment partly repeated in the chromosome. We propose and validate a model for merodiploid formation, providing evidence that tandem-duplication (TD formation involves unequal crossing-over resulting from alternative pairing and interchromatid integration of R. This unequal crossing-over produces a chromosome dimer, resolution of which generates a chromosome with the TD and an abortive chromosome lacking the duplicated region. We document occurrence of TDs ranging from ~100 to ~900 kb in size at various chromosomal locations, including by self-transformation (transformation with recipient chromosomal DNA. We show that self-transformation produces a population containing many different merodiploid cells. Merodiploidy provides opportunities for evolution of new genetic traits via alteration of duplicated genes, unrestricted by functional selective pressure. Transient stimulation of a varied population of

  17. Introducing eHealth and other innovative options into clinical genetic patient care in view of increased efficiency and maintenance of quality of care : Patients' and providers' perspectives

    NARCIS (Netherlands)

    Otten, Ellen

    2015-01-01

    Innovations in clinical genetics patient care This year some 40,000 patients will visit a clinical geneticist. This number is increasing because there are ever-expanding possibilities for DNA testing. Most patients are seen individually in an outpatient clinic. But partly because the healthcare

  18. The nature of creativity: The roles of genetic factors, personality traits, cognitive abilities, and environmental sources.

    Science.gov (United States)

    Kandler, Christian; Riemann, Rainer; Angleitner, Alois; Spinath, Frank M; Borkenau, Peter; Penke, Lars

    2016-08-01

    This multitrait multimethod twin study examined the structure and sources of individual differences in creativity. According to different theoretical and metrological perspectives, as well as suggestions based on previous research, we expected 2 aspects of individual differences, which can be described as perceived creativity and creative test performance. We hypothesized that perceived creativity, reflecting typical creative thinking and behavior, should be linked to specific personality traits, whereas test creativity, reflecting maximum task-related creative performance, should show specific associations with cognitive abilities. Moreover, we tested whether genetic variance in intelligence and personality traits account for the genetic component of creativity. Multiple-rater and multimethod data (self- and peer reports, observer ratings, and test scores) from 2 German twin studies-the Bielefeld Longitudinal Study of Adult Twins and the German Observational Study of Adult Twins-were analyzed. Confirmatory factor analyses yielded the expected 2 correlated aspects of creativity. Perceived creativity showed links to openness to experience and extraversion, whereas tested figural creativity was associated with intelligence and also with openness. Multivariate behavioral genetic analyses indicated that the heritability of tested figural creativity could be accounted for by the genetic component of intelligence and openness, whereas a substantial genetic component in perceived creativity could not be explained. A primary source of individual differences in creativity was due to environmental influences, even after controlling for random error and method variance. The findings are discussed in terms of the multifaceted nature and construct validity of creativity as an individual characteristic. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  19. Naturally occurring genetic variability in expression of Gsta4 is associated with differential survival of axotomized rat motoneurons

    DEFF Research Database (Denmark)

    Mikael, Ström; Al Nimer, Faiez; Lindblom, Rickard

    2012-01-01

    A large number of molecular pathways have been implicated in the degeneration of axotomized motoneurons. We previously have demonstrated substantial differences in the survival rate of axotomized motoneurons across different rat strains. Identification of genetic differences underlying such natur...

  20. Genetic variation in native populations of the laurel wilt pathogen, Raffaelea lauricola , in Taiwan and Japan and the introduced population in the United States

    Science.gov (United States)

    Caroline E. Wuest; Thomas C. Harrington; Stephen W. Fraedrich; Hye-Young Yun; Sheng-Shan Lu

    2017-01-01

    Laurel wilt is a vascular wilt disease caused by Raffaelea lauricola, a mycangial symbiont of an ambrosia beetle, Xyleborus glabratus. The fungus and vector are native to Asia but were apparently introduced to the Savannah, GA, area 15 or more years ago. Laurel wilt has caused widespread mortality on redbay (Persea borbonia) and other members of the Lauraceae in the...

  1. Nature, Genetics and the Biophilia Connection: Exploring Linkages with Social Work Values and Practice

    Directory of Open Access Journals (Sweden)

    Fred H. Besthorn

    2003-05-01

    Full Text Available Social work’s notion of environment and its environmental responsibilities has always been narrowly defined. The profession has tended to either neglect natural environmental issues or accept shallow, ecological conceptualizations of nature as something other, quite separate from the human enterprise and/or outside the reach of social work activity. The Biophilia Hypothesis, first articulated by Harvard biologist E.O.Wilson in 1984, offers social work as a fundamentally different view of the person/environment construct and argues for a primary shift in the way the profession views its relationship with the natural world. This article traces the conceptual development of the Biophilic theory and reviews pivotal empirical evidence explicitly arguing for the essential Biophilic premise that humans have acquired, through their long evolutionary history, a strong genetic predisposition for nature and natural settings. It offers key insights and examples for incorporating Biophilia into social work’s values and knowledge base and how it may impact the profession’s practice strategies and techniques.

  2. Characterizing Male–Female Interactions Using Natural Genetic Variation in Drosophila melanogaster

    Science.gov (United States)

    Reinhart, Michael; Carney, Tara; Clark, Andrew G.

    2015-01-01

    Drosophila melanogaster females commonly mate with multiple males establishing the opportunity for pre- and postcopulatory sexual selection. Traits impacting sexual selection can be affected by a complex interplay of the genotypes of the competing males, the genotype of the female, and compatibilities between the males and females. We scored males from 96 2nd and 94 3rd chromosome substitution lines for traits affecting reproductive success when mated with females from 3 different genetic backgrounds. The traits included male-induced female refractoriness, male remating ability, the proportion of offspring sired under competitive conditions and male-induced female fecundity. We observed significant effects of male line, female genetic background, and strong male by female interactions. Some males appeared to be “generalists” and performed consistently across the different females; other males appeared to be “specialists” and performed very well with a particular female and poorly with others. “Specialist” males did not, however, prefer to court those females with whom they had the highest reproductive fitness. Using 143 polymorphisms in male reproductive genes, we mapped several genes that had consistent effects across the different females including a derived, high fitness allele in Acp26Aa that may be the target of adaptive evolution. We also identified a polymorphism upstream of PebII that may interact with the female genetic background to affect male-induced refractoriness to remating. These results suggest that natural variation in PebII might contribute to the observed male–female interactions. PMID:25425680

  3. Biochemical traits useful for the determination of genetic variation in a natural population of Myracrodruon urundeuva

    Directory of Open Access Journals (Sweden)

    Abdala Ludmila

    2002-01-01

    Full Text Available The objectives of this work were to analyze seeds from 20 trees of aroeira (Myracrodruon urundeuva Fr. All. of a natural population located in the region of Selvíria, State of Mato Grosso do Sul, Brazil, in order to evaluate their protein, lipid and carbohydrate contents, and to estimate their genetic variation. A completely randomized experimental design consisting of 20 treatments (families was set up, with two replications. Four types of proteins were detected: albumin (35.0 to 107.3 mg/g seed, globulin (3.4 to 9.3 mg/g, prolamin (60.0 to 135.2 mg/g and glutelin (118.0 to 286.0 mg/g. The lipid content varied between 200 and 334 mg/g seed. The total sugars also varied (26.5 to 46.3 mg/g seed, with a predominance of polyols (arabinitol, mannitol, glucitol and xylitol. The main monosaccharides detected were glucose and arabinose. Total hydrolysis of the sugars indicated the presence of neutral arabinan and xylan oligosaccharides. The starch content varied from 0.35 to 1.58 mg/g seed. These biochemical traits showed considerable genetic variability, indicating that only the collection of seeds from many different trees can provide a representative sample of the population for conservation and genetic improvement.

  4. Introducing Scientific Literature to Honors General Chemistry Students: Teaching Information Literacy and the Nature of Research to First-Year Chemistry Students

    Science.gov (United States)

    Ferrer-Vinent, Ignacio J.; Bruehl, Margaret; Pan, Denise; Jones, Galin L.

    2015-01-01

    This paper describes the methodology and implementation of a case study introducing the scientific literature and creative experiment design to honors general chemistry laboratory students. The purpose of this study is to determine whether first-year chemistry students can develop information literacy skills while they engage with the primary…

  5. Genetic diversity and natural selection of Plasmodium knowlesi merozoite surface protein 1 paralog gene in Malaysia.

    Science.gov (United States)

    Ahmed, Md Atique; Fauzi, Muh; Han, Eun-Taek

    2018-03-14

    Human infections due to the monkey malaria parasite Plasmodium knowlesi is on the rise in most Southeast Asian countries specifically Malaysia. The C-terminal 19 kDa domain of PvMSP1P is a potential vaccine candidate, however, no study has been conducted in the orthologous gene of P. knowlesi. This study investigates level of polymorphisms, haplotypes and natural selection of full-length pkmsp1p in clinical samples from Malaysia. A total of 36 full-length pkmsp1p sequences along with the reference H-strain and 40 C-terminal pkmsp1p sequences from clinical isolates of Malaysia were downloaded from published genomes. Genetic diversity, polymorphism, haplotype and natural selection were determined using DnaSP 5.10 and MEGA 5.0 software. Genealogical relationships were determined using haplotype network tree in NETWORK software v5.0. Population genetic differentiation index (F ST ) and population structure of parasite was determined using Arlequin v3.5 and STRUCTURE v2.3.4 software. Comparison of 36 full-length pkmsp1p sequences along with the H-strain identified 339 SNPs (175 non-synonymous and 164 synonymous substitutions). The nucleotide diversity across the full-length gene was low compared to its ortholog pvmsp1p. The nucleotide diversity was higher toward the N-terminal domains (pkmsp1p-83 and 30) compared to the C-terminal domains (pkmsp1p-38, 33 and 19). Phylogenetic analysis of full-length genes identified 2 distinct clusters of P. knowlesi from Malaysian Borneo. The 40 pkmsp1p-19 sequences showed low polymorphisms with 16 polymorphisms leading to 18 haplotypes. In total there were 10 synonymous and 6 non-synonymous substitutions and 12 cysteine residues were intact within the two EGF domains. Evidence of strong purifying selection was observed within the full-length sequences as well in all the domains. Shared haplotypes of 40 pkmsp1p-19 were identified within Malaysian Borneo haplotypes. This study is the first to report on the genetic diversity and natural

  6. Nontraditional inheritance: Genetics and the nature of science, now titled, The puzzle of inheritance: Genetics and the methods of science. Final report

    Energy Technology Data Exchange (ETDEWEB)

    McInerney, J.D.

    1998-08-31

    This project led to the development of an instructional module designed for use in high school biology classes. The module contains two major components. The first is an overview for teachers, which introduces the module, describes the Human Genome Project, and addresses issues in the philosophy of science and some of the ethical, legal, and social implications of research in genetics. It provides a survey of fundamental genetics concepts and of new, nontraditional concepts of inheritance. The second component provides six instructional activities appropriate for high school or introductory college students.

  7. Maintenance of Genetic Diversity in Natural Spawning of Captively-Reared Endangered Sockeye Salmon, Oncorhynchus nerka

    Directory of Open Access Journals (Sweden)

    Ruth E. Withler

    2014-06-01

    Full Text Available Captive propagation of Pacific salmon is routine, but few captive breeding programs have been conducted to successfully re-establish extirpated wild populations. A captive breeding program for endangered Sakinaw Lake sockeye salmon was established from 84 adults between 2002 and 2005, just prior to extirpation of the wild population. After several years of absence, sockeye salmon released from captivity returned to spawn in Sakinaw Lake in 2010 and in all years thereafter. Freshwater survival rates of released hatchery fry and naturally produced progeny of reintroduced sockeye salmon have not limited abundance of the reintroduced population. In contrast, marine survival rates for Sakinaw sockeye salmon have been <1%, a level that precludes population restoration in the absence of supplementation. Genetic diversity commensurate with the number of parental founders has been maintained in captivity. The 517 adult second-generation captive fish that spawned in Sakinaw Lake in 2011 produced a smolt emigration of almost 28,000 juvenile fish with an effective population size of 132. Allelic richness and gene diversity levels in the smolts were similar to those observed in captivity. This indicates genetic contributions from all or most founding parents have been retained both in captivity and in the nascent reintroduced natural population.

  8. Genetic Structure of Natural Populations of Escherichia coli in Wild Hosts on Different Continents

    Science.gov (United States)

    Souza, Valeria; Rocha, Martha; Valera, Aldo; Eguiarte, Luis E.

    1999-01-01

    plasmids than did strains isolated from wild mammals. Previous studies have shown that natural populations of E. coli harbor an extensive genetic diversity that is organized in a limited number of clones. However, knowledge of this worldwide bacterium has been limited. Here, we suggest that the strains from a wide range of wild hosts from different regions of the world are organized in an ecotypic structure where adaptation to the host plays an important role in the population structure. PMID:10427022

  9. Characteristics of physical properties in soil profiles under selected introduced trees in the Nature Reserve Arboretum Mlyňany, Slovakia

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    Polláková Nora

    2017-12-01

    Full Text Available The relationship between introduced trees roots and soils in which they grow is the most important factor influencing the adaptation, growth and health of these trees. Therefore, the objective of this study was to identify which physical soil properties enhance or limit the vitality of the studied introduced trees in the Arboretum Mlyňany. Soil properties were studied in seven soil profiles under dense monocultures of Chamaecyparis lawsoniana, Liriodendron tulipifera, Juniperus Chinensis, Thuja orientalis, Thuja plicata, Picea orientalis and Pinus nigra. The results showed that all stagnic horizons had exceeded the limit values of total porosity and bulk density, hence these horizons were compacted. Based on the soil and climatic requirements of the examined trees we conclude that the soil properties of their sites in arboretum are suitable for: Chamaecyparis lawsoniana, Liriodendron tulipifera, Thuja orientalis and Pinus nigra. Nevertheless, physical properties in profiles under Picea orientalis and Juniperus Chinensis do not permit rapid drainage of water, what is unfavourable for healthy development of these two species; while Thuja plicata demanding high moisture supply is grown on soil with high coarse porosity, a prerequisite of fast rainwater drainage. However, since none of the studied introduced trees had suffered from physiological disorders or diseases, they may be declared acclimatized well in the soil-climate conditions described in this study.

  10. Introduced cryptic species of parasites exhibit different invasion pathways.

    Science.gov (United States)

    Miura, Osamu; Torchin, Mark E; Kuris, Armand M; Hechinger, Ryan F; Chiba, Satoshi

    2006-12-26

    Sometimes infectious agents invade and become established in new geographic regions. Others may be introduced yet never become established because of the absence of suitable hosts in the new region. This phenomenon may be particularly true for the many parasites with complex life cycles, where various life stages require different host species. Homogenization of the world's biota through human-mediated invasions may reunite hosts and parasites, resulting in disease outbreaks in novel regions. Here we use molecular genetics to differentiate invasion pathways for two digenean trematode parasites and their exotic host, the Asian mud snail, Batillaria attramentaria. All of the snail haplotypes found in introduced populations in North America were identical to haplotypes common in the areas of Japan that provided oysters for cultivation in North America, supporting the hypothesis that the snails were introduced from Japan with seed oysters. Two cryptic trematode species were introduced to North American populations in high frequencies. We found a marked reduction of genetic variation in one of these species, suggesting it experienced a bottleneck or founder event comparable to that of the host snail. In contrast, no genetic variation was lost in the other parasite species. We hypothesize that this parasite was and is dispersed naturally by migratory shorebirds and was able to establish only after the host snail, B. attramentaria, was introduced to North America. Evaluation of the nature of invasion pathways and postinvasion consequences will aid mitigation of spreading diseases of humans, livestock, and wildlife in an increasingly globalized world.

  11. Detection by real-time PCR and pyrosequencing of the cry1Ab and cry1Ac genes introduced in genetically modified (GM) constructs.

    Science.gov (United States)

    Debode, Frederic; Janssen, Eric; Bragard, Claude; Berben, Gilbert

    2017-08-01

    The presence of genetically modified organisms (GMOs) in food and feed is mainly detected by the use of targets focusing on promoters and terminators. As some genes are frequently used in genetically modified (GM) construction, they also constitute excellent screening elements and their use is increasing. In this paper we propose a new target for the detection of cry1Ab and cry1Ac genes by real-time polymerase chain reaction (PCR) and pyrosequencing. The specificity, sensitivity and robustness of the real-time PCR method were tested following the recommendations of international guidelines and the method met the expected performance criteria. This paper also shows how the robustness testing was assessed. This new cry1Ab/Ac method can provide a positive signal with a larger number of GM events than do the other existing methods using double dye-probes. The method permits the analysis of results with less ambiguity than the SYBRGreen method recommended by the European Reference Laboratory (EURL) GM Food and Feed (GMFF). A pyrosequencing method was also developed to gain additional information thanks to the sequence of the amplicon. This method of sequencing-by-synthesis can determine the sequence between the primers used for PCR. Pyrosequencing showed that the sequences internal to the primers present differences following the GM events considered and three different sequences were observed. The sensitivity of the pyrosequencing was tested on reference flours with a low percentage GM content and different copy numbers. Improvements in the pyrosequencing protocol provided correct sequences with 50 copies of the target. Below this copy number, the quality of the sequence was more random.

  12. Genetic diversity and population structure of Lactobacillus delbrueckii subspecies bulgaricus isolated from naturally fermented dairy foods.

    Science.gov (United States)

    Song, Yuqin; Sun, Zhihong; Guo, Chenyi; Wu, Yarong; Liu, Wenjun; Yu, Jie; Menghe, Bilige; Yang, Ruifu; Zhang, Heping

    2016-03-04

    Lactobacillus delbrueckii subsp. bulgaricus is one of the most widely used starter culture strains in industrial fermented dairy manufacture. It is also common in naturally fermented dairy foods made using traditional methods. The subsp. bulgaricus strains found in naturally fermented foods may be useful for improving current industrial starter cultures; however, little is known regarding its genetic diversity and population structure. Here, a collection of 298 L. delbrueckii strains from naturally fermented products in Mongolia, Russia, and West China was analyzed by multi-locus sequence typing based on eight conserved genes. The 251 confirmed subsp. bulgaricus strains produced 106 unique sequence types, the majority of which were assigned to five clonal complexes (CCs). The geographical distribution of CCs was uneven, with CC1 dominated by Mongolian and Russian isolates, and CC2-CC5 isolates exclusively from Xinjiang, China. Population structure analysis suggested six lineages, L1-L6, with various homologous recombination rates. Although L2-L5 were mainly restricted within specific regions, strains belonging to L1 and L6 were observed in diverse regions, suggesting historical transmission events. These results greatly enhance our knowledge of the population diversity of subsp. bulgaricus strains, and suggest that strains from CC1 and L4 may be useful as starter strains in industrial fermentation.

  13. The Genetics Underlying Natural Variation in the Biotic Interactions of Arabidopsis thaliana: The Challenges of Linking Evolutionary Genetics and Community Ecology.

    Science.gov (United States)

    Roux, F; Bergelson, J

    2016-01-01

    In the context of global change, predicting the responses of plant communities in an ever-changing biotic environment calls for a multipronged approach at the interface of evolutionary genetics and community ecology. However, our understanding of the genetic basis of natural variation involved in mediating biotic interactions, and associated adaptive dynamics of focal plants in their natural communities, is still in its infancy. Here, we review the genetic and molecular bases of natural variation in the response to biotic interactions (viruses, bacteria, fungi, oomycetes, herbivores, and plants) in the model plant Arabidopsis thaliana as well as the adaptive value of these bases. Among the 60 identified genes are a number that encode nucleotide-binding site leucine-rich repeat (NBS-LRR)-type proteins, consistent with early examples of plant defense genes. However, recent studies have revealed an extensive diversity in the molecular mechanisms of defense. Many types of genetic variants associate with phenotypic variation in biotic interactions, even among the genes of large effect that tend to be identified. In general, we found that (i) balancing selection rather than directional selection explains the observed patterns of genetic diversity within A. thaliana and (ii) the cost/benefit tradeoffs of adaptive alleles can be strongly dependent on both genomic and environmental contexts. Finally, because A. thaliana rarely interacts with only one biotic partner in nature, we highlight the benefit of exploring diffuse biotic interactions rather than tightly associated host-enemy pairs. This challenge would help to improve our understanding of coevolutionary quantitative genetics within the context of realistic community complexity. © 2016 Elsevier Inc. All rights reserved.

  14. From Nature to the Lab: Establishing Drosophila Resources for Evolutionary Genetics

    Directory of Open Access Journals (Sweden)

    Vítor G. Faria

    2017-06-01

    Full Text Available In recent years important tools have been developed in Drosophila to capture with the greatest possible accuracy the variation found in nature. Efforts, such as the Drosophila melanogaster Genetic Reference Panel (DGRP or the Drosophila Synthetic Population Resource (DSPR allied to the advances in whole-genome sequencing and analysis have propelled to unprecedented level our capacity to dissect the genotype-phenotype map. However, several practical problems arise upstream of these analyses starting with the collection and identification of wild specimens. These problems are dealt with in different ways by each researcher generating solutions not necessarily compatible across laboratories. Here, we provide a systematic coverage of every phase of this process based on our experience, and suggest procedures to maximize and share the generated resources potentiating future applications. We propose a detailed pipeline to guide researchers from collection in the wild to the development of a large array of molecular and genetic resources. We designed a multiplex-PCR that distinguishes sister species D. melanogaster and D. simulans and is diagnostic of the presence/absence of Wolbachia infection. These procedures may extend to other cryptic species pairs and endosymbionts. We developed a standardized protocol to create, replicate and maintain isofemale lines and outbred populations. Finally, we explore the potential of outbred populations across several applications from experimental evolution, to introgression of transgenic constructs or mutant alleles, and genomic analyses. We hope to contribute to the success in developing Drosophila resources for evolutionary genetics studies and facilitate exchanges across laboratories based on a common set of procedures.

  15. Large-Scale Culture and Genetic Modification of Human Natural Killer Cells for Cellular Therapy.

    Science.gov (United States)

    Lapteva, Natalia; Parihar, Robin; Rollins, Lisa A; Gee, Adrian P; Rooney, Cliona M

    2016-01-01

    Recent advances in methods for the ex vivo expansion of human natural killer (NK) cells have facilitated the use of these powerful immune cells in clinical protocols. Further, the ability to genetically modify primary human NK cells following rapid expansion allows targeting and enhancement of their immune function. We have successfully adapted an expansion method for primary NK cells from peripheral blood mononuclear cells or from apheresis products in gas permeable rapid expansion devices (G-Rexes). Here, we describe an optimized protocol for rapid and robust NK cell expansion as well as a method for highly efficient retroviral transduction of these ex vivo expanded cells. These methodologies are good manufacturing practice (GMP) compliant and could be used for clinical-grade product manufacturing.

  16. ANT: Software for Generating and Evaluating Degenerate Codons for Natural and Expanded Genetic Codes.

    Science.gov (United States)

    Engqvist, Martin K M; Nielsen, Jens

    2015-08-21

    The Ambiguous Nucleotide Tool (ANT) is a desktop application that generates and evaluates degenerate codons. Degenerate codons are used to represent DNA positions that have multiple possible nucleotide alternatives. This is useful for protein engineering and directed evolution, where primers specified with degenerate codons are used as a basis for generating libraries of protein sequences. ANT is intuitive and can be used in a graphical user interface or by interacting with the code through a defined application programming interface. ANT comes with full support for nonstandard, user-defined, or expanded genetic codes (translation tables), which is important because synthetic biology is being applied to an ever widening range of natural and engineered organisms. The Python source code for ANT is freely distributed so that it may be used without restriction, modified, and incorporated in other software or custom data pipelines.

  17. Genetic basis of hindlimb loss in a naturally occurring vertebrate model

    Directory of Open Access Journals (Sweden)

    Emily K. Don

    2016-03-01

    Full Text Available Here we genetically characterise pelvic finless, a naturally occurring model of hindlimb loss in zebrafish that lacks pelvic fin structures, which are homologous to tetrapod hindlimbs, but displays no other abnormalities. Using a hybrid positional cloning and next generation sequencing approach, we identified mutations in the nuclear localisation signal (NLS of T-box transcription factor 4 (Tbx4 that impair nuclear localisation of the protein, resulting in altered gene expression patterns during pelvic fin development and the failure of pelvic fin development. Using a TALEN-induced tbx4 knockout allele we confirm that mutations within the Tbx4 NLS (A78V; G79A are sufficient to disrupt pelvic fin development. By combining histological, genetic, and cellular approaches we show that the hindlimb initiation gene tbx4 has an evolutionarily conserved, essential role in pelvic fin development. In addition, our novel viable model of hindlimb deficiency is likely to facilitate the elucidation of the detailed molecular mechanisms through which Tbx4 functions during pelvic fin and hindlimb development.

  18. Improving efficacy of cancer immunotherapy by genetic modification of natural killer cells.

    Science.gov (United States)

    Burga, Rachel A; Nguyen, Tuongvan; Zulovich, Jane; Madonna, Sarah; Ylisastigui, Loyda; Fernandes, Rohan; Yvon, Eric

    2016-11-01

    Natural killer (NK) cells are members of the innate immune system that recognize target cells via activating and inhibitory signals received through cell receptors. Derived from the lymphoid lineage, NK cells are able to produce cytokines and exert a cytotoxic effect on viral infected and malignant cells. It is their unique ability to lyse target cells rapidly and without prior education that renders NK cells a promising effector cell for adoptive cell therapy. However, both viruses and tumors employ evasion strategies to avoid attack by NK cells, which represent biological challenges that need to be harnessed to fully exploit the cytolytic potential of NK cells. Using genetic modification, the function of NK cells can be enhanced to improve their homing, cytolytic activity, in vivo persistence and safety. Examples include gene modification to express chemokine, high-affinity Fc receptor and chimeric antigen receptors, suicide genes and the forced expression of cytokines such as interleukin (IL)-2 and IL-15. Preclinical studies have clearly demonstrated that such approaches are effective in improving NK-cell function, homing and safety. In this review, we summarize the recent advances in the genetic manipulations of NK cells and their application for cellular immunotherapeutic strategies. Copyright © 2016 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

  19. The myth of natural barriers. Is transgene introgression by genetically modified crops an environmental risk?

    Science.gov (United States)

    Guarnieri, Vincenzo; Benessia, Alice; Camino, Elena; Barbiero, Giuseppe

    2008-01-01

    Genetically modified (GM) crops under open field conditions are a complex and controversial issue. Ecologists are discussing about the possibility that a transgene belonging to GM plants could spread to native populations through a process known as introgression the stable incorporation of a gene in the host genome able to generate a differentiated population. The ecological consequences of a transgene introgression in plants or bacteria are not yet well understood, but could be significant. In this critical review we consider vertical and horizontal introgression. We analyse the biochemical and genetic constraints, and environmental factors that limit the possibility of transgene spread; meanwhile we show cases in which the natural barriers are overcome. Then we discuss the overall management of GM crops, noting the shortcomings and approximations of risk assessment based on linear thinking typical of the biomolecular approach. Finally we suggest to explicitly weight facts together with values and we encourage the undertaking of an ecological perspective, encompassing the complexity of (non-linear) relations between organisms and the environment.

  20. Molecular mechanisms of drug resistance in natural Leishmania populations vary with genetic background.

    Directory of Open Access Journals (Sweden)

    Saskia Decuypere

    Full Text Available The evolution of drug-resistance in pathogens is a major global health threat. Elucidating the molecular basis of pathogen drug-resistance has been the focus of many studies but rarely is it known whether a drug-resistance mechanism identified is universal for the studied pathogen; it has seldom been clarified whether drug-resistance mechanisms vary with the pathogen's genotype. Nevertheless this is of critical importance in gaining an understanding of the complexity of this global threat and in underpinning epidemiological surveillance of pathogen drug resistance in the field. This study aimed to assess the molecular and phenotypic heterogeneity that emerges in natural parasite populations under drug treatment pressure. We studied lines of the protozoan parasite Leishmania (L. donovani with differential susceptibility to antimonial drugs; the lines being derived from clinical isolates belonging to two distinct genetic populations that circulate in the leishmaniasis endemic region of Nepal. Parasite pathways known to be affected by antimonial drugs were characterised on five experimental levels in the lines of the two populations. Characterisation of DNA sequence, gene expression, protein expression and thiol levels revealed a number of molecular features that mark antimonial-resistant parasites in only one of the two populations studied. A final series of in vitro stress phenotyping experiments confirmed this heterogeneity amongst drug-resistant parasites from the two populations. These data provide evidence that the molecular changes associated with antimonial-resistance in natural Leishmania populations depend on the genetic background of the Leishmania population, which has resulted in a divergent set of resistance markers in the Leishmania populations. This heterogeneity of parasite adaptations provides severe challenges for the control of drug resistance in the field and the design of molecular surveillance tools for widespread

  1. Resistance to water pollution in natural gudgeon (Gobio gobio) populations may be due to genetic adaptation

    Energy Technology Data Exchange (ETDEWEB)

    Knapen, Dries; Bervoets, Lieven; Verheyen, Erik; Blust, Ronny

    2004-04-14

    Anthropogenic disturbances cause the environment to change relatively fast. It is reasonable to assume that it is very unlikely for individuals to develop genetic adaptations to their polluted habitats, since adaptation through natural selection is a relatively slow process. Nevertheless, several studies have shown that such adaptations to changing environmental conditions may develop faster than anticipated. This study investigates the impact of historical metal pollution on a natural population of the gudgeon, Gobio gobio. Specimens from a contaminated site and a reference population were subjected to a series of three exposure experiments to cadmium after an acclimation period to reconstituted fresh water of 36 days. First, we performed an acute toxicity test on a sub-sample of both experimental groups to determine times-to-death (TTD) and lethal body burdens (LBB). The remaining individuals were used in a chronic Cd-exposure experiment, after which total Cd-body concentration, as well as Cd-concentrations and metallothionein-like protein (MTLP) levels in liver and gill tissue were determined. From the specimens that were not sacrificed for these measurements, a random subsample was subjected to a second acute toxicity test to evaluate the effect of chronic Cd-exposure (acclimation) on TTD and LBB. Our results show that, particularly after an extra acclimation period to a sublethal Cd-concentration, specimens originating from the contaminated sample area survived the acute exposure experiments better, despite the fact that neither the average Cd-accumulation rate, nor the lethal body concentrations differed between fishes from both groups. We also find that gudgeons from both populations translocated Cd from the gills (and probably also from other compartments) to the liver, where it can be more efficiently detoxified by MTLPs. Indeed, MTLP levels were found to increase faster in liver and gill tissue of specimens from the contaminated site, resulting in

  2. Resistance to water pollution in natural gudgeon (Gobio gobio) populations may be due to genetic adaptation

    International Nuclear Information System (INIS)

    Knapen, Dries; Bervoets, Lieven; Verheyen, Erik; Blust, Ronny

    2004-01-01

    Anthropogenic disturbances cause the environment to change relatively fast. It is reasonable to assume that it is very unlikely for individuals to develop genetic adaptations to their polluted habitats, since adaptation through natural selection is a relatively slow process. Nevertheless, several studies have shown that such adaptations to changing environmental conditions may develop faster than anticipated. This study investigates the impact of historical metal pollution on a natural population of the gudgeon, Gobio gobio. Specimens from a contaminated site and a reference population were subjected to a series of three exposure experiments to cadmium after an acclimation period to reconstituted fresh water of 36 days. First, we performed an acute toxicity test on a sub-sample of both experimental groups to determine times-to-death (TTD) and lethal body burdens (LBB). The remaining individuals were used in a chronic Cd-exposure experiment, after which total Cd-body concentration, as well as Cd-concentrations and metallothionein-like protein (MTLP) levels in liver and gill tissue were determined. From the specimens that were not sacrificed for these measurements, a random subsample was subjected to a second acute toxicity test to evaluate the effect of chronic Cd-exposure (acclimation) on TTD and LBB. Our results show that, particularly after an extra acclimation period to a sublethal Cd-concentration, specimens originating from the contaminated sample area survived the acute exposure experiments better, despite the fact that neither the average Cd-accumulation rate, nor the lethal body concentrations differed between fishes from both groups. We also find that gudgeons from both populations translocated Cd from the gills (and probably also from other compartments) to the liver, where it can be more efficiently detoxified by MTLPs. Indeed, MTLP levels were found to increase faster in liver and gill tissue of specimens from the contaminated site, resulting in

  3. Age at natural menopause genetic risk score in relation to age at natural menopause and primary open-angle glaucoma in a US-based sample.

    Science.gov (United States)

    Pasquale, Louis R; Aschard, Hugues; Kang, Jae H; Bailey, Jessica N Cooke; Lindström, Sara; Chasman, Daniel I; Christen, William G; Allingham, R Rand; Ashley-Koch, Allison; Lee, Richard K; Moroi, Sayoko E; Brilliant, Murray H; Wollstein, Gadi; Schuman, Joel S; Fingert, John; Budenz, Donald L; Realini, Tony; Gaasterland, Terry; Gaasterland, Douglas; Scott, William K; Singh, Kuldev; Sit, Arthur J; Igo, Robert P; Song, Yeunjoo E; Hark, Lisa; Ritch, Robert; Rhee, Douglas J; Gulati, Vikas; Havens, Shane; Vollrath, Douglas; Zack, Donald J; Medeiros, Felipe; Weinreb, Robert N; Pericak-Vance, Margaret A; Liu, Yutao; Kraft, Peter; Richards, Julia E; Rosner, Bernard A; Hauser, Michael A; Haines, Jonathan L; Wiggs, Janey L

    2017-02-01

    Several attributes of female reproductive history, including age at natural menopause (ANM), have been related to primary open-angle glaucoma (POAG). We assembled 18 previously reported common genetic variants that predict ANM to determine their association with ANM or POAG. Using data from the Nurses' Health Study (7,143 women), we validated the ANM weighted genetic risk score in relation to self-reported ANM. Subsequently, to assess the relation with POAG, we used data from 2,160 female POAG cases and 29,110 controls in the National Eye Institute Glaucoma Human Genetics Collaboration Heritable Overall Operational Database (NEIGHBORHOOD), which consists of 8 datasets with imputed genotypes to 5.6+ million markers. Associations with POAG were assessed in each dataset, and site-specific results were meta-analyzed using the inverse weighted variance method. The genetic risk score was associated with self-reported ANM (P = 2.2 × 10) and predicted 4.8% of the variance in ANM. The ANM genetic risk score was not associated with POAG (Odds Ratio (OR) = 1.002; 95% Confidence Interval (CI): 0.998, 1.007; P = 0.28). No single genetic variant in the panel achieved nominal association with POAG (P ≥0.20). Compared to the middle 80 percent, there was also no association with the lowest 10 percentile or highest 90 percentile of genetic risk score with POAG (OR = 0.75; 95% CI: 0.47, 1.21; P = 0.23 and OR = 1.10; 95% CI: 0.72, 1.69; P = 0.65, respectively). A genetic risk score predicting 4.8% of ANM variation was not related to POAG; thus, genetic determinants of ANM are unlikely to explain the previously reported association between the two phenotypes.

  4. Getting genetic access to natural adenovirus genomes to explore vector diversity.

    Science.gov (United States)

    Zhang, Wenli; Ehrhardt, Anja

    2017-10-01

    Recombinant vectors based on the human adenovirus type 5 (HAdV5) have been developed and extensively used in preclinical and clinical studies for over 30 years. However, certain restrictions of HAdV5-based vectors have limited their clinical applications because they are rather inefficient in specifically transducing cells of therapeutic interest that lack the coxsackievirus and adenovirus receptor (CAR). Moreover, enhanced vector-associated toxicity and widespread preexisting immunity have been shown to significantly hamper the effectiveness of HAdV-5-mediated gene transfer. However, evolution of adenoviruses in the natural host is driving the generation of novel types with altered virulence, enhanced transmission, and altered tissue tropism. As a consequence, an increasing number of alternative adenovirus types were identified, which may represent a valuable resource for the development of novel vector types. Thus, researchers are focusing on the other naturally occurring adenovirus types, which are structurally similar but functionally different from HAdV5. To this end, several strategies have been devised for getting genetic access to adenovirus genomes, resulting in a new panel of adenoviral vectors. Importantly, these vectors were shown to have a host range different from HAdV5 and to escape the anti-HAdV5 immune response, thus underlining the great potential of this approach. In summary, this review provides a state-of-the-art overview of one essential step in adenoviral vector development.

  5. Hybrid of Natural Element Method (NEM with Genetic Algorithm (GA to find critical slip surface

    Directory of Open Access Journals (Sweden)

    Shahriar Shahrokhabadi

    2014-06-01

    Full Text Available One of the most important issues in geotechnical engineering is the slope stability analysis for determination of the factor of safety and the probable slip surface. Finite Element Method (FEM is well suited for numerical study of advanced geotechnical problems. However, mesh requirements of FEM creates some difficulties for solution processing in certain problems. Recently, motivated by these limitations, several new Meshfree methods such as Natural Element Method (NEM have been used to analyze engineering problems. This paper presents advantages of using NEM in 2D slope stability analysis and Genetic Algorithm (GA optimization to determine the probable slip surface and the related factor of safety. The stress field is produced under plane strain condition using natural element formulation to simulate material behavior analysis utilized in conjunction with a conventional limit equilibrium method. In order to justify the preciseness and convergence of the proposed method, two kinds of examples, homogenous and non-homogenous, are conducted and results are compared with FEM and conventional limit equilibrium methods. The results show the robustness of the NEM in slope stability analysis.

  6. Do natural methods for fertility regulation increase the risks of genetic errors?

    Science.gov (United States)

    Serra, A

    1981-09-01

    Genetic errors of many kinds are connected with the reproductive processes and are favored by a nunber of largely uncontrollable, endogenous, and/or exogenous factors. For a long time human beings have taken into their own hands the control of this process. The regulation of fertility is clearly a forceful request to any family, to any community, were it only to lower the level of the consequences of genetic errors. In connection with this request, and in the context of the Congress for the Family of Africa and Europe (Catholic University, January 1981), 1 question must still be raised and possibly answered. The question is: do or can the so called "natural methods" for the regulation of fertility increase the risks of genetic errors with their generally dramatic effects on families and on communities. It is important to try to give as far as possible a scientifically based answer to this question. Fr. Haring, a moral theologian, citing scientific evidence finds it shocking that the rhythm method, so strongly and recently endorsed again by Church authorities, should be classified among the means of "birth control" by way of spontaneous abortion or at least by spontaneous loss of a large number of zygotes which, due to the concrete application of the rhythm method, lack of necessary vitality for survival. He goes on to state that the scientific research provides overwhelming evidence that the rhythm method in its traditional form is responsible for a disproportionate waste of zygotes and a disproportionate frequency of spontaneous abortions and a defective childern. Professor Hilgers, a reproductive physiologist, takes on opposite view, maintaining that the hypotheses are arbitrary and the alarm false. The strongest evidence upon which Fr. Haring bases his moral principles about the use of the natural methods of fertility regulation is a paper by Guerrero and Rojos (1975). These authors examined, retrospectively, the success of 965 pregnancies which occurred in

  7. Seasonal fluctuation in susceptibility to insecticides within natural populations of Drosophila melanogaster. II. Features of genetic variation in susceptibility to organophosphate insecticides within natural populations of D. melanogaster.

    Science.gov (United States)

    Miyo, Takahiro; Oguma, Yuzuru; Charlesworth, Brian

    2006-08-01

    To elucidate genetic variation in susceptibility to organophosphate insecticides within natural populations of Drosophila melanogaster, we conducted an analysis of variance for mortality data sets of isofemale lines (10-286 lines) used in the previous studies. Susceptibility of isofemale lines to the three organophosphate insecticides was continuously distributed within each natural population, ranging from susceptible to resistant. Analysis of variance showed highly significant variation among isofemale lines in susceptibility to each insecticide for each natural population. Significant genetic variances in susceptibility to the three chemicals were estimated for the Katsunuma population; 0.0529-0.2722 for malathion, 0.0492-0.1603 for prothiophos, and 0.0469-0.1696 for fenitrothion. Contrary to the consistent seasonal tendency towards an increase in mean susceptibility in the fall, reported in the previous study, genetic variances in susceptibility to the three organophosphates did not change significantly in 1997 but tended to increase by 2- to 5-times in 1998. We tested whether both the observed situations, maintenance and increase in genetic variance in organophosphate resistance, can be generated under circumstances in which the levels of resistance to the three organophosphates tended to decrease, by conducting a simulation analysis, based on the hypothesis that resistant genotypes have lower fitnesses than susceptible ones under the density-independent condition. The simulation analysis generally explained the pattern in the mean susceptibility and genetic variances in susceptibility to the three organophosphates, observed in the Katsunuma population of D. melanogaster. It was suggested that the differences in the frequencies of resistance genes in the summer population could affect the patterns in genetic variance in organophosphate resistance in the fall population.

  8. Genetic diversity between herds of Alpine and Saanen dairy goats and the naturalized Brazilian Moxotó breed

    Directory of Open Access Journals (Sweden)

    Adriana Mello de Araújo

    2006-01-01

    Full Text Available Brazilian naturalized goat breeds are adapted to the semiarid conditions prevalent in the Northeast region of the country (which has the largest Brazilian goat heard and represent an as yet uninvestigated source of genetic diversity. Currently, imported goat breeds are crossed with Brazilian naturalized goat breeds, endangering the genetic potential of the naturalized breeds. We used 11 microsatellite markers to determine the genetic diversity among imported (non-naturalized dairy Alpine and Saanen goats and naturalized Brazilian Moxotó goats. We genotyped 292 goats from three herds (one private, one from the University of Minas Gerais and the Moxotó conservation herd from Embrapa Caprinos and found that the general heterozygosity was 0.6952 for Alpine, 0.7043 for Saanen and 0.4984 for Moxotó goats. The number of alleles ranged from 5 (INRA005 to 11 (BM3205, with an average of 7 alleles per locus in the imported breeds and 3.5 alleles per locus in the Moxotó breed. Mean differentiation between populations was higher for herds (F ST S = 0.0768 than for breeds (F ST P = 0.0263, indicating similarity between the imported breeds and the existence of crosses between them. Nei's genetic distance was highest between the Moxotó breed and the imported breeds. These indicate that further studies using these molecular markers would be fruitful.

  9. Loads Bias Genetic and Signaling Switches in Synthetic and Natural Systems

    Science.gov (United States)

    Medford, June; Prasad, Ashok

    2014-01-01

    Biological protein interactions networks such as signal transduction or gene transcription networks are often treated as modular, allowing motifs to be analyzed in isolation from the rest of the network. Modularity is also a key assumption in synthetic biology, where it is similarly expected that when network motifs are combined together, they do not lose their essential characteristics. However, the interactions that a network module has with downstream elements change the dynamical equations describing the upstream module and thus may change the dynamic and static properties of the upstream circuit even without explicit feedback. In this work we analyze the behavior of a ubiquitous motif in gene transcription and signal transduction circuits: the switch. We show that adding an additional downstream component to the simple genetic toggle switch changes its dynamical properties by changing the underlying potential energy landscape, and skewing it in favor of the unloaded side, and in some situations adding loads to the genetic switch can also abrogate bistable behavior. We find that an additional positive feedback motif found in naturally occurring toggle switches could tune the potential energy landscape in a desirable manner. We also analyze autocatalytic signal transduction switches and show that a ubiquitous positive feedback switch can lose its switch-like properties when connected to a downstream load. Our analysis underscores the necessity of incorporating the effects of downstream components when understanding the physics of biochemical network motifs, and raises the question as to how these effects are managed in real biological systems. This analysis is particularly important when scaling synthetic networks to more complex organisms. PMID:24676102

  10. Temporal genetic stability in natural populations of the waterflea Daphnia magna in response to strong selection pressure.

    Science.gov (United States)

    Orsini, Luisa; Marshall, Hollie; Cuenca Cambronero, Maria; Chaturvedi, Anurag; Thomas, Kelley W; Pfrender, Michael E; Spanier, Katina I; De Meester, Luc

    2016-12-01

    Studies monitoring changes in genetic diversity and composition through time allow a unique understanding of evolutionary dynamics and persistence of natural populations. However, such studies are often limited to species with short generation times that can be propagated in the laboratory or few exceptional cases in the wild. Species that produce dormant stages provide powerful models for the reconstruction of evolutionary dynamics in the natural environment. A remaining open question is to what extent dormant egg banks are an unbiased representation of populations and hence of the species' evolutionary potential, especially in the presence of strong environmental selection. We address this key question using the water flea Daphnia magna, which produces dormant stages that accumulate in biological archives over time. We assess temporal genetic stability in three biological archives, previously used in resurrection ecology studies showing adaptive evolutionary responses to rapid environmental change. We show that neutral genetic diversity does not decline with the age of the population and it is maintained in the presence of strong selection. In addition, by comparing temporal genetic stability in hatched and unhatched populations from the same biological archive, we show that dormant egg banks can be consulted to obtain a reliable measure of genetic diversity over time, at least in the multidecadal time frame studied here. The stability of neutral genetic diversity through time is likely mediated by the buffering effect of the resting egg bank. © 2016 John Wiley & Sons Ltd.

  11. X-ray topographic study of diamonds: implications for the genetic nature of inclusions in diamond

    Science.gov (United States)

    Agrosì, Giovanna; Nestola, Fabrizio; Tempesta, Gioacchino; Bruno, Marco; Scandale, Eugenio; Harris, Jeff W.

    2014-05-01

    In recent years, several studies have focused on the growth conditions of the diamonds through the analysis of the mineral inclusions trapped in them (Howell, 2012 and references therein). Nevertheless, to obtain rigorous information about chemical and physical conditions of diamond formation, it is crucial to determine if the crystallization of the inclusions occurred before (protogenetic nature), during (syngenetic nature) or after (epigenetic nature) the growth of diamond (Wiggers de Vries et al., 2011). X-ray topography (XRDT) can be a helpful tool to verify the genetic nature of inclusions in diamond. This technique characterizes the extended defects and reconstructs the growth history of the samples (Agrosì et al., 2013 and references therein) and, consequently contributes to elucidation of the relationship between the inclusions and the host-diamond. With this aim a diamond from the Udachnaya kimberlite, Siberia, was investigated. The diamond crystal was the one previously studied by Nestola et al. (2011) who performed in-situ crystal structure refinement of the inclusions to obtain data about the formation pressure. The inclusions were iso-oriented olivines that did not show evident cracks and subsequently could not be considered epigenetic. Optical observations revealed an anomalous birefringence in the adjacent diamond and the inclusions had typical "diamond-imposed cubo-octahedral" shape for the largest olivine. The diffraction contrast study shows that the diamond exhibits significant deformation fields related to plastic post growth deformation. The crystallographic direction of strains was established applying the extinction criterion. Section topographs were taken to minimize the overlapping of the strain field associate with the different defects and revealed that no dislocations nucleated from the olivine inclusions. Generally, when a solid inclusion has been incorporated in the growing crystal, the associated volume distortion can be minimized by

  12. Genetic variation in plant volatile emission does not result in differential attraction of natural enemies in the field.

    Science.gov (United States)

    Wason, Elizabeth L; Hunter, Mark D

    2014-02-01

    Volatile organic chemical (VOC) emission by plants may serve as an adaptive plant defense by attracting the natural enemies of herbivores. For plant VOC emission to evolve as an adaptive defense, plants must show genetic variability for the trait. To date, such variability has been investigated primarily in agricultural systems, yet relatively little is known about genetic variation in VOCs emitted by natural populations of native plants. Here, we investigate intraspecific variation in constitutive and herbivore-induced plant VOC emission using the native common milkweed plant (Asclepias syriaca) and its monarch caterpillar herbivore (Danaus plexippus) in complementary field and common garden greenhouse experiments. In addition, we used a common garden field experiment to gauge natural enemy attraction to milkweed VOCs induced by monarch damage. We found evidence of genetic variation in the total constitutive and induced concentrations of VOCs and the composition of VOC blends emitted by milkweed plants. However, all milkweed genotypes responded similarly to induction by monarchs in terms of their relative change in VOC concentration and blend. Natural enemies attacked decoy caterpillars more frequently on damaged than on undamaged milkweed, and natural enemy visitation was associated with higher total VOC concentrations and with VOC blend. Thus, we present evidence that induced VOCs emitted by milkweed may function as a defense against herbivores. However, plant genotypes were equally attractive to natural enemies. Although milkweed genotypes diverge phenotypically in their VOC concentrations and blends, they converge into similar phenotypes with regard to magnitude of induction and enemy attraction.

  13. Clonality, genetic diversity and support for the diversifying selection hypothesis in natural populations of a flower-living yeast.

    Science.gov (United States)

    Herrera, C M; Pozo, M I; Bazaga, P

    2011-11-01

    Vast amounts of effort have been devoted to investigate patterns of genetic diversity and structuring in plants and animals, but similar information is scarce for organisms of other kingdoms. The study of the genetic structure of natural populations of wild yeasts can provide insights into the ecological and genetic correlates of clonality, and into the generality of recent hypotheses postulating that microbial populations lack the potential for genetic divergence and allopatric speciation. Ninety-one isolates of the flower-living yeast Metschnikowia gruessii from southeastern Spain were DNA fingerprinted using amplified fragment length polymorphism (AFLP) markers. Genetic diversity and structuring was investigated with band-based methods and model- and nonmodel-based clustering. Linkage disequilibrium tests were used to assess reproduction mode. Microsite-dependent, diversifying selection was tested by comparing genetic characteristics of isolates from bumble bee vectors and different floral microsites. AFLP polymorphism (91%) and genotypic diversity were very high. Genetic diversity was spatially structured, as shown by amova (Φ(st)  = 0.155) and clustering. The null hypothesis of random mating was rejected, clonality seeming the prevailing reproductive mode in the populations studied. Genetic diversity of isolates declined from bumble bee mouthparts to floral microsites, and frequency of five AFLP markers varied significantly across floral microsites, thus supporting the hypothesis of diversifying selection on clonal lineages. Wild populations of clonal fungal microbes can exhibit levels of genetic diversity and spatial structuring that are not singularly different from those shown by sexually reproducing plants or animals. Microsite-dependent, divergent selection can maintain high local and regional genetic diversity in microbial populations despite extensive clonality. © 2011 Blackwell Publishing Ltd.

  14. RAPID-COMMUNICATION Genetic diversity and differentiation in natural populations of Arapaima gigas from lower Amazon revealed by microsatellites.

    Science.gov (United States)

    Fazzi-Gomes, P F; Melo, N; Palheta, G; Guerreiro, S; Amador, M; Ribeiro-Dos-Santos, A K; Santos, S; Hamoy, I

    2017-02-08

    Genetic variability is one of the important criteria for species conservation decisions. This study aimed to analyze the genetic diversity and the population differentiation of two natural populations of Arapaima gigas, a species with a long history of being commercially exploited. We collected 87 samples of A. gigas from Grande Curuai Lake and Paru Lake, located in the Lower Amazon region of Amazônia, Brazil, and genotyped these samples using a multiplex panel of microsatellite markers. Our results showed that the populations of A. gigas analyzed had high levels of genetic variability, which were similar to those described in previous studies. These two populations had a significant population differentiation supported by the estimates of F ST and R ST (0.06), by Bayesian analysis (K = 2), and by population assignment tests, which revealed a moderate genetic distance.

  15. Mendelian Genetics as a Platform for Teaching about Nature of Science and Scientific Inquiry: The Value of Textbooks

    Science.gov (United States)

    Campanile, Megan F.; Lederman, Norman G.; Kampourakis, Kostas

    2015-01-01

    The purpose of this study was to analyze seven widely used high school biology textbooks in order to assess the nature of science knowledge (NOS) and scientific inquiry (SI) aspects they, explicitly or implicitly, conveyed in the Mendelian genetics sections. Textbook excerpts that directly and/or fully matched our statements about NOS and SI were…

  16. Random genetic drift, natural selection, and noise in human cranial evolution.

    Science.gov (United States)

    Roseman, Charles C

    2016-08-01

    This study assesses the extent to which relationships among groups complicate comparative studies of adaptation in recent human cranial variation and the extent to which departures from neutral additive models of evolution hinder the reconstruction of population relationships among groups using cranial morphology. Using a maximum likelihood evolutionary model fitting approach and a mixed population genomic and cranial data set, I evaluate the relative fits of several widely used models of human cranial evolution. Moreover, I compare the goodness of fit of models of cranial evolution constrained by genomic variation to test hypotheses about population specific departures from neutrality. Models from population genomics are much better fits to cranial variation than are traditional models from comparative human biology. There is not enough evolutionary information in the cranium to reconstruct much of recent human evolution but the influence of population history on cranial variation is strong enough to cause comparative studies of adaptation serious difficulties. Deviations from a model of random genetic drift along a tree-like population history show the importance of environmental effects, gene flow, and/or natural selection on human cranial variation. Moreover, there is a strong signal of the effect of natural selection or an environmental factor on a group of humans from Siberia. The evolution of the human cranium is complex and no one evolutionary process has prevailed at the expense of all others. A holistic unification of phenome, genome, and environmental context, gives us a strong point of purchase on these problems, which is unavailable to any one traditional approach alone. Am J Phys Anthropol 160:582-592, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  17. Genetic variation among natural and laboratory colony populations of Lutzomyia longipalpis (Lutz & Neiva, 1912)(Diptera: Psychodidae) from Colombia.

    Science.gov (United States)

    Lanzaro, G C; Alexander, B; Mutebi, J P; Montoya-Lerma, J; Warburg, A

    1998-01-01

    Genetic diversity among three field populations of Lutzomyia longipalpis in Colombia was studied using isozyme analysis. Study sites were as much as 598 km apart and included populations separated by the eastern Cordillera of the Andes. Genetic variability among populations, estimated by heterozygosity, was within values typical for insects in general (8.1%). Heterozygosity for field populations were compared with a laboratory colony from Colombia (Melgar colony) and were only slightly lower. These results suggest that establishment and long term maintenance of the Melgar colony has had little effect on the level of isozyme variability it carries. Genetic divergences between populations was evaluated using estimates of genetic distance. Genetic divergence among the three field populations was low (D = 0.021), suggesting they represent local populations within a single species. Genetic distance between field populations and the Melgar colony was also low (D = 0.016), suggesting that this colony population does not depart significantly from natural populations. Finally, comparisons were made between Colombian populations and colonies from Brazil and Costa Rica. Genetic distance values were high between Colombian and both Brazil and Costa Rica colony populations (D = 0.199 and 0.098 respectively) providing additional support for our earlier report that populations from the three countries represent distinct species.

  18. Genetic Variation among Natural and Laboratory Colony Populations of Lutzomyia longipalpis (Lutz & Neiva, 1912(Diptera:Psychodidae from Colombia

    Directory of Open Access Journals (Sweden)

    Lanzaro Gregory C

    1998-01-01

    Full Text Available Genetic diversity among three field populations of Lutzomyia longipalpis in Colombia was studied using isozyme analysis. Study sites were as much as 598 km apart and included populations separated by the eastern Cordillera of the Andes. Genetic variability among populations, estimated by heterozygosity, was within values typical for insects in general (8.1%. Heterozygosity for field populations were compared with a laboratory colony from Colombia (Melgar colony and were only slightly lower. These results suggest that establishment and long term maintenance of the Melgar colony has had little effect on the level of isozyme variability it carries. Genetic divergences between populations was evaluated using estimates of genetic distance. Genetic divergence among the three field populations was low (D=0.021, suggesting they represent local populations within a single species. Genetic distance between field populations and the Melgar colony was also low (D=0.016, suggesting that this colony population does not depart significantly from natural populations. Finally, comparisons were made between Colombian populations and colonies from Brazil and Costa Rica. Genetic distance values were high between Colombian and both Brazil and Costa Rica colony populations (D=0.199 and 0.098 respectively providing additional support for our earlier report that populations from the three countries represent distinct species

  19. Epidemiology, genetic, natural history and clinical presentation of giant cerebral aneurysms.

    Science.gov (United States)

    Lonjon, M; Pennes, F; Sedat, J; Bataille, B

    2015-12-01

    Giant cerebral aneurysms represent 5% of intracranial aneurysms, and become symptomatic between 40 and 70 years with a female predominance. In the paediatric population, the giant aneurysm rate is higher than in the adult population. Classified as saccular, fusiform and serpentine, the natural history of giant cerebral aneurysms is characterized by thrombosis, growth and rupture. The pathogenesis of these giant aneurysms is influenced by a number of risk factors, including genetic variables. Genome-wide association studies have identified some chromosomes highlighting candidate genes. Although these giant aneurysms can occur at the same locations as their smaller counterparts, a predilection for the cavernous location has been observed. Giant aneurysms present with symptoms caused by a mass effect depending on their location or by rupture; ischemic manifestations rarely reveal the aneurysm. If the initial clinical descriptions have been back up by imagery, the clinical context with a pertinent analysis of the risk factors remain the cornerstone for the management decisions of these lesions. Five year cumulative rupture rates for patients with giant aneurysm were 40% for those located on the anterior part of circle of Willis and 50% for those on the posterior part. The poor outcome of untreated patients justifies the therapeutic risks. Copyright © 2015. Published by Elsevier Masson SAS.

  20. The genetic basis of natural variation in oenological traits in Saccharomyces cerevisiae.

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    Francisco Salinas

    Full Text Available Saccharomyces cerevisiae is the main microorganism responsible for wine alcoholic fermentation. The oenological phenotypes resulting from fermentation, such as the production of acetic acid, glycerol, and residual sugar concentration are regulated by multiple genes and vary quantitatively between different strain backgrounds. With the aim of identifying the quantitative trait loci (QTLs that regulate oenological phenotypes, we performed linkage analysis using three crosses between highly diverged S. cerevisiae strains. Segregants from each cross were used as starter cultures for 20-day fermentations, in synthetic wine must, to simulate actual winemaking conditions. Linkage analysis on phenotypes of primary industrial importance resulted in the mapping of 18 QTLs. We tested 18 candidate genes, by reciprocal hemizygosity, for their contribution to the observed phenotypic variation, and validated five genes and the chromosome II right subtelomeric region. We observed that genes involved in mitochondrial metabolism, sugar transport, nitrogen metabolism, and the uncharacterized ORF YJR030W explained most of the phenotypic variation in oenological traits. Furthermore, we experimentally validated an exceptionally strong epistatic interaction resulting in high level of succinic acid between the Sake FLX1 allele and the Wine/European MDH2 allele. Overall, our work demonstrates the complex genetic basis underlying wine traits, including natural allelic variation, antagonistic linked QTLs and complex epistatic interactions between alleles from strains with different evolutionary histories.

  1. Graphical models for genetic analyses

    DEFF Research Database (Denmark)

    Lauritzen, Steffen Lilholt; Sheehan, Nuala A.

    2003-01-01

    This paper introduces graphical models as a natural environment in which to formulate and solve problems in genetics and related areas. Particular emphasis is given to the relationships among various local computation algorithms which have been developed within the hitherto mostly separate areas...... of graphical models and genetics. The potential of graphical models is explored and illustrated through a number of example applications where the genetic element is substantial or dominating....

  2. Genetic Evaluation of Natural Populations of the Endangered Conifer Thuja koraiensis Using Microsatellite Markers by Restriction-Associated DNA Sequencing

    Directory of Open Access Journals (Sweden)

    Lu Hou

    2018-04-01

    Full Text Available Thuja koraiensis Nakai is an endangered conifer of high economic and ecological value in Jilin Province, China. However, studies on its population structure and conservation genetics have been limited by the lack of genomic data. Here, 37,761 microsatellites (simple sequence repeat, SSR were detected based on 875,792 de novo-assembled contigs using a restriction-associated DNA (RAD approach. Among these SSRs, 300 were randomly selected to test for polymorphisms and 96 obtained loci were able to amplify a fragment of expected size. Twelve polymorphic SSR markers were developed to analyze the genetic diversity and population structure of three natural populations. High genetic diversity (mean NA = 5.481, HE = 0.548 and moderate population differentiation (pairwise Fst = 0.048–0.078, Nm = 2.940–4.958 were found in this species. Molecular variance analysis suggested that most of the variation (83% existed within populations. Combining the results of STRUCTURE, principal coordinate, and neighbor-joining analysis, the 232 individuals were divided into three genetic clusters that generally correlated with their geographical distributions. Finally, appropriate conservation strategies were proposed to protect this species. This study provides genetic information for the natural resource conservation and utilization of T. koraiensis and will facilitate further studies of the evolution and phylogeography of the species.

  3. Molecular phylogeny of mangroves IV. nature and extent of intra-specific genetic variation and species diversity in mangroves

    International Nuclear Information System (INIS)

    Parida, A.; Parani, M.; Lakshmi, M.; Elango, S.; Ram, N.; Anuratha, C.S.

    1998-01-01

    Mangroves occupy estuarine ecosystems in the tropical regions of the world. Despite their highly productive nature and the protective roles they play in the coastal region, the ecosystem as a whole is under severe threat due to various climatic and anthropogenic factors. Therefore, the need for conservation of mangroves is widely emphasised. However, information on existing genetic diversity based on which a strategy for genetic conservation is to be drawn is not available for mangroves. This is primarily because conventional genetic analysis is difficult in these species for various reasons. Therefore, as an aid to our on-going conservation programme, efforts were made to assess the nature and extent of diversity in a number of mangrove species of the Indian coast using molecular markers. The nature and extent of intra-population diversity in sixteen mangrove species and detailed analysis of inter-population genetic polymorphism in four species, Acanthus ilicifolius, Excoecaria agallocha, Avicennia spp and Rhizophora (species and hybrid), is reported in the present communication. (author)

  4. Molecular phylogeny of mangroves IV. nature and extent of intra-specific genetic variation and species diversity in mangroves

    Energy Technology Data Exchange (ETDEWEB)

    Parida, A; Parani, M; Lakshmi, M; Elango, S; Ram, N; Anuratha, C S [M.S. Swaminathan Research Foundation, Taramani, Madras (India)

    1998-10-01

    Mangroves occupy estuarine ecosystems in the tropical regions of the world. Despite their highly productive nature and the protective roles they play in the coastal region, the ecosystem as a whole is under severe threat due to various climatic and anthropogenic factors. Therefore, the need for conservation of mangroves is widely emphasised. However, information on existing genetic diversity based on which a strategy for genetic conservation is to be drawn is not available for mangroves. This is primarily because conventional genetic analysis is difficult in these species for various reasons. Therefore, as an aid to our on-going conservation programme, efforts were made to assess the nature and extent of diversity in a number of mangrove species of the Indian coast using molecular markers. The nature and extent of intra-population diversity in sixteen mangrove species and detailed analysis of inter-population genetic polymorphism in four species, Acanthus ilicifolius, Excoecaria agallocha, Avicennia spp and Rhizophora (species and hybrid), is reported in the present communication. (author) 25 refs, 2 figs, 2 tabs

  5. Genetic variability of Taenia solium cysticerci recovered from experimentally infected pigs and from naturally infected pigs using microsatellite markers.

    Science.gov (United States)

    Pajuelo, Mónica J; Eguiluz, María; Roncal, Elisa; Quiñones-García, Stefany; Clipman, Steven J; Calcina, Juan; Gavidia, Cesar M; Sheen, Patricia; Garcia, Hector H; Gilman, Robert H; Gonzalez, Armando E; Zimic, Mirko

    2017-12-01

    The adult Taenia solium, the pork tapeworm, usually lives as a single worm in the small intestine of humans, its only known definitive host. Mechanisms of genetic variation in T. solium are poorly understood. Using three microsatellite markers previously reported [1], this study explored the genetic variability of T. solium from cysts recovered from experimentally infected pigs. It then explored the genetic epidemiology and transmission in naturally infected pigs and adult tapeworms recovered from human carriers from an endemic rural community in Peru. In an initial study on experimental infection, two groups of three piglets were each infected with proglottids from one of two genetically different tapeworms for each of the microsatellites. After 7 weeks, pigs were slaughtered and necropsy performed. Thirty-six (92.3%) out of 39 cysts originated from one tapeworm, and 27 (100%) out of 27 cysts from the other had exactly the same genotype as the parental tapeworm. This suggests that the microsatellite markers may be a useful tool for studying the transmission of T. solium. In the second study, we analyzed the genetic variation of T. solium in cysts recovered from eight naturally infected pigs, and from adult tapeworms recovered from four human carriers; they showed genetic variability. Four pigs had cysts with only one genotype, and four pigs had cysts with two different genotypes, suggesting that multiple infections of genetically distinct parental tapeworms are possible. Six pigs harbored cysts with a genotype corresponding to one of the identified tapeworms from the human carriers. In the dendrogram, cysts appeared to cluster within the corresponding pigs as well as with the geographical origin, but this association was not statistically significant. We conclude that genotyping of microsatellite size polymorphisms is a potentially important tool to trace the spread of infection and pinpoint sources of infection as pigs spread cysts with a shared parental genotype.

  6. Genetic variability of Taenia solium cysticerci recovered from experimentally infected pigs and from naturally infected pigs using microsatellite markers.

    Directory of Open Access Journals (Sweden)

    Mónica J Pajuelo

    2017-12-01

    Full Text Available The adult Taenia solium, the pork tapeworm, usually lives as a single worm in the small intestine of humans, its only known definitive host. Mechanisms of genetic variation in T. solium are poorly understood. Using three microsatellite markers previously reported [1], this study explored the genetic variability of T. solium from cysts recovered from experimentally infected pigs. It then explored the genetic epidemiology and transmission in naturally infected pigs and adult tapeworms recovered from human carriers from an endemic rural community in Peru. In an initial study on experimental infection, two groups of three piglets were each infected with proglottids from one of two genetically different tapeworms for each of the microsatellites. After 7 weeks, pigs were slaughtered and necropsy performed. Thirty-six (92.3% out of 39 cysts originated from one tapeworm, and 27 (100% out of 27 cysts from the other had exactly the same genotype as the parental tapeworm. This suggests that the microsatellite markers may be a useful tool for studying the transmission of T. solium. In the second study, we analyzed the genetic variation of T. solium in cysts recovered from eight naturally infected pigs, and from adult tapeworms recovered from four human carriers; they showed genetic variability. Four pigs had cysts with only one genotype, and four pigs had cysts with two different genotypes, suggesting that multiple infections of genetically distinct parental tapeworms are possible. Six pigs harbored cysts with a genotype corresponding to one of the identified tapeworms from the human carriers. In the dendrogram, cysts appeared to cluster within the corresponding pigs as well as with the geographical origin, but this association was not statistically significant. We conclude that genotyping of microsatellite size polymorphisms is a potentially important tool to trace the spread of infection and pinpoint sources of infection as pigs spread cysts with a shared

  7. Analysis of Genetic Diversity of Two Mangrove Species with Morphological Alterations in a Natural Environment

    Directory of Open Access Journals (Sweden)

    Catarina Fonseca Lira-Medeiros

    2015-04-01

    Full Text Available Mangrove is an ecosystem subjected to tide, salinity and nutrient variations. These conditions are stressful to most plants, except to mangrove plants that are well-adapted. However, many mangrove areas have extremely stressful conditions, such as salt marshes, and the plants nearby usually present morphological alterations. In Sepetiba Bay, two species of mangrove plants, Avicennia schaueriana and Laguncularia racemosa, have poor development near a salt marsh (SM compared to plants at the riverside (RS, which is considered a favorable habitat in mangroves. The level of genetic diversity and its possible correlation with the morphological divergence of SM and RS plants of both species were assessed by AFLP molecular markers. We found moderate genetic differentiation between A. schaueriana plants from SM and RS areas and depleted genetic diversity on SM plants. On the other hand, Laguncularia racemosa plants had no genetic differentiation between areas. It is possible that a limited gene flow among the studied areas might be acting more intensely on A. schaueriana plants, resulting in the observed genetic differentiation. The populations of Laguncularia racemosa appear to be well connected, as genetic differentiation was not significant between the SM and RS populations. Gene flow and genetic drift are acting on neutral genetic diversity of these two mangrove species in the studied areas, and the observed genetic differentiation of A. schaueriana plants might be correlated with its morphological variation. For L. racemosa, morphological alterations could be related to epigenetic phenomena or adaptive loci polymorphism that should be further investigated.

  8. Should We Add History of Science to Provide Nature of Science into Vietnamese Biology Textbook: A Case of Evolution and Genetics Teaching?

    Science.gov (United States)

    Diem, Huynh Thi Thuy; Yuenyong, Chokchai

    2018-01-01

    History of science (HOS) plays a substantial role in the enhancement of rooted understanding in science teaching and learning. HOS of evolution and genetics has not been included in Vietnamese biology textbooks. This study aims to investigate the necessity of introducing evolution and genetics HOS into Vietnamese textbooks. A case study approach…

  9. A comparative study on genetic effects of artificial and natural habitat fragmentation on Loropetalum chinense (Hamamelidaceae) in Southeast China.

    Science.gov (United States)

    Yuan, N; Comes, H P; Cao, Y N; Guo, R; Zhang, Y H; Qiu, Y X

    2015-06-01

    Elucidating the demographic and landscape features that determine the genetic effects of habitat fragmentation has become fundamental to research in conservation and evolutionary biology. Land-bridge islands provide ideal study areas for investigating the genetic effects of habitat fragmentation at different temporal and spatial scales. In this context, we compared patterns of nuclear microsatellite variation between insular populations of a shrub of evergreen broad-leaved forest, Loropetalum chinense, from the artificially created Thousand-Island Lake (TIL) and the Holocene-dated Zhoushan Archipelago of Southeast China. Populations from the TIL region harboured higher levels of genetic diversity than those from the Zhoushan Archipelago, but these differences were not significant. There was no correlation between genetic diversity and most island features, excepting a negative effect of mainland-island distance on allelic richness and expected heterozygosity in the Zhoushan Archipelago. In general, levels of gene flow among island populations were moderate to high, and tests of alternative models of population history strongly favoured a gene flow-drift model over a pure drift model in each region. In sum, our results showed no obvious genetic effects of habitat fragmentation due to recent (artificial) or past (natural) island formation. Rather, they highlight the importance of gene flow (most likely via seed) in maintaining genetic variation and preventing inter-population differentiation in the face of habitat 'insularization' at different temporal and spatial scales.

  10. The influence of natural barriers in shaping the genetic structure of Maharashtra populations.

    Directory of Open Access Journals (Sweden)

    Kumarasamy Thangaraj

    Full Text Available BACKGROUND: The geographical position of Maharashtra state makes it rather essential to study the dispersal of modern humans in South Asia. Several hypotheses have been proposed to explain the cultural, linguistic and geographical affinity of the populations living in Maharashtra state with other South Asian populations. The genetic origin of populations living in this state is poorly understood and hitherto been described at low molecular resolution level. METHODOLOGY/PRINCIPAL FINDINGS: To address this issue, we have analyzed the mitochondrial DNA (mtDNA of 185 individuals and NRY (non-recombining region of Y chromosome of 98 individuals belonging to two major tribal populations of Maharashtra, and compared their molecular variations with that of 54 South Asian contemporary populations of adjacent states. Inter and intra population comparisons reveal that the maternal gene pool of Maharashtra state populations is composed of mainly South Asian haplogroups with traces of east and west Eurasian haplogroups, while the paternal haplogroups comprise the South Asian as well as signature of near eastern specific haplogroup J2a. CONCLUSIONS/SIGNIFICANCE: Our analysis suggests that Indian populations, including Maharashtra state, are largely derived from Paleolithic ancient settlers; however, a more recent (∼10 Ky older detectable paternal gene flow from west Asia is well reflected in the present study. These findings reveal movement of populations to Maharashtra through the western coast rather than mainland where Western Ghats-Vindhya Mountains and Narmada-Tapti rivers might have acted as a natural barrier. Comparing the Maharastrian populations with other South Asian populations reveals that they have a closer affinity with the South Indian than with the Central Indian populations.

  11. The influence of natural barriers in shaping the genetic structure of Maharashtra populations.

    Science.gov (United States)

    Thangaraj, Kumarasamy; Naidu, B Prathap; Crivellaro, Federica; Tamang, Rakesh; Upadhyay, Shashank; Sharma, Varun Kumar; Reddy, Alla G; Walimbe, S R; Chaubey, Gyaneshwer; Kivisild, Toomas; Singh, Lalji

    2010-12-20

    The geographical position of Maharashtra state makes it rather essential to study the dispersal of modern humans in South Asia. Several hypotheses have been proposed to explain the cultural, linguistic and geographical affinity of the populations living in Maharashtra state with other South Asian populations. The genetic origin of populations living in this state is poorly understood and hitherto been described at low molecular resolution level. To address this issue, we have analyzed the mitochondrial DNA (mtDNA) of 185 individuals and NRY (non-recombining region of Y chromosome) of 98 individuals belonging to two major tribal populations of Maharashtra, and compared their molecular variations with that of 54 South Asian contemporary populations of adjacent states. Inter and intra population comparisons reveal that the maternal gene pool of Maharashtra state populations is composed of mainly South Asian haplogroups with traces of east and west Eurasian haplogroups, while the paternal haplogroups comprise the South Asian as well as signature of near eastern specific haplogroup J2a. Our analysis suggests that Indian populations, including Maharashtra state, are largely derived from Paleolithic ancient settlers; however, a more recent (∼10 Ky older) detectable paternal gene flow from west Asia is well reflected in the present study. These findings reveal movement of populations to Maharashtra through the western coast rather than mainland where Western Ghats-Vindhya Mountains and Narmada-Tapti rivers might have acted as a natural barrier. Comparing the Maharastrian populations with other South Asian populations reveals that they have a closer affinity with the South Indian than with the Central Indian populations.

  12. Fine-scale genetic structure of natural Tuber aestivum sites in southern Germany

    Czech Academy of Sciences Publication Activity Database

    Molinier, V.; Murat, C.; Baltensweiler, A.; Büntgen, Ulf; Martin, F.; Meier, B.; Moser, B.; Sproll, L.; Stobbe, U.; Tegel, W.; Egli, S.; Peter, M.

    2016-01-01

    Roč. 26, č. 8 (2016), s. 895-907 ISSN 0940-6360 Institutional support: RVO:67179843 Keywords : mating-type distribution * vegetative incompatibility * ectomycorrhizal communities * truffle cultivation * population-genetics * genus tuber * Burgundy truffle * Mating-type genes * Population genetics * Propagation strategy * SSR markers Subject RIV: EH - Ecology, Behaviour Impact factor: 3.047, year: 2016

  13. Genetic diversity of Brazilian natural populations of Anthonomus grandis Boheman (Coleoptera: Curculionidae), the major cotton pest in the New World.

    Science.gov (United States)

    Martins, W F S; Ayres, C F J; Lucena, W A

    2007-01-27

    Twenty-five RAPD loci and 6 isozyme loci were studied to characterize the genetic variability of natural populations of Anthonomus grandis from two agroecosystems of Brazil. The random-amplified polymorphic DNA data disclosed a polymorphism that varied from 52 to 84% and a heterozygosity of 0.189 to 0.347. The index of genetic differentiation (GST) among the six populations was 0.258. The analysis of isozymes showed a polymorphism and a heterozygosity ranging from 25 to 100% and 0.174 to 0.277, respectively. The genetic differentiation (FST) among the populations obtained by isozyme data was 0.544. It was possible to observe rare alleles in the populations from the Northeast region. The markers examined allowed us to distinguish populations from large-scale, intensive farming region (cotton belts) versus populations from areas of small-scale farming

  14. Directional genetic selection by pulp mill effluent on multiple natural populations of three-spined stickleback (Gasterosteus aculeatus).

    Science.gov (United States)

    Lind, Emma E; Grahn, Mats

    2011-05-01

    Contamination can cause a rapid environmental change which may require populations to respond with evolutionary changes. To evaluate the effects of pulp mill effluents on population genetics, we sampled three-spined sticklebacks (Gasterosteus aculeatus) near four pulp mills and four adjacent reference sites and analyzed Amplified Fragment Length Polymorphism (AFLP) to compare genetic variability. A fine scale genetic structure was detected and samples from polluted sites separated from reference sites in multidimensional scaling plots (Pselection. When removing 13 F(ST)-outlier loci, significant at the Pselective agent on natural populations of G. aculeatus, causing a convergence in genotype composition change at multiple sites in an open environment. © The Author(s) 2011. This article is published with open access at Springerlink.com

  15. Genetic, epigenetic, and HPLC fingerprint differentiation between natural and ex situ populations of Rhodiola sachalinensis from Changbai Mountain, China.

    Directory of Open Access Journals (Sweden)

    Wei Zhao

    Full Text Available Rhodiola sachalinensis is an endangered species with important medicinal value. We used inter-simple sequence repeat (ISSR and methylation-sensitive amplified polymorphism (MSAP markers to analyze genetic and epigenetic differentiation in different populations of R. sachalinensis, including three natural populations and an ex situ population. Chromatographic fingerprint was used to reveal HPLC fingerprint differentiation. According to our results, the ex situ population of R. sachalinensis has higher level genetic diversity and greater HPLC fingerprint variation than natural populations, but shows lower epigenetic diversity. Most genetic variation (54.88% was found to be distributed within populations, and epigenetic variation was primarily distributed among populations (63.87%. UPGMA cluster analysis of ISSR and MSAP data showed identical results, with individuals from each given population grouping together. The results of UPGMA cluster analysis of HPLC fingerprint patterns was significantly different from results obtained from ISSR and MSAP data. Correlation analysis revealed close relationships among altitude, genetic structure, epigenetic structure, and HPLC fingerprint patterns (R2 = 0.98 for genetic and epigenetic distance; R2 = 0.90 for DNA methylation level and altitude; R2 = -0.95 for HPLC fingerprint and altitude. Taken together, our results indicate that ex situ population of R. sachalinensis show significantly different genetic and epigenetic population structures and HPLC fingerprint patterns. Along with other potential explanations, these findings suggest that the ex situ environmental factors caused by different altitude play an important role in keeping hereditary characteristic of R. sachalinensis.

  16. Genetic, epigenetic, and HPLC fingerprint differentiation between natural and ex situ populations of Rhodiola sachalinensis from Changbai Mountain, China.

    Science.gov (United States)

    Zhao, Wei; Shi, Xiaozheng; Li, Jiangnan; Guo, Wei; Liu, Chengbai; Chen, Xia

    2014-01-01

    Rhodiola sachalinensis is an endangered species with important medicinal value. We used inter-simple sequence repeat (ISSR) and methylation-sensitive amplified polymorphism (MSAP) markers to analyze genetic and epigenetic differentiation in different populations of R. sachalinensis, including three natural populations and an ex situ population. Chromatographic fingerprint was used to reveal HPLC fingerprint differentiation. According to our results, the ex situ population of R. sachalinensis has higher level genetic diversity and greater HPLC fingerprint variation than natural populations, but shows lower epigenetic diversity. Most genetic variation (54.88%) was found to be distributed within populations, and epigenetic variation was primarily distributed among populations (63.87%). UPGMA cluster analysis of ISSR and MSAP data showed identical results, with individuals from each given population grouping together. The results of UPGMA cluster analysis of HPLC fingerprint patterns was significantly different from results obtained from ISSR and MSAP data. Correlation analysis revealed close relationships among altitude, genetic structure, epigenetic structure, and HPLC fingerprint patterns (R2 = 0.98 for genetic and epigenetic distance; R2 = 0.90 for DNA methylation level and altitude; R2 = -0.95 for HPLC fingerprint and altitude). Taken together, our results indicate that ex situ population of R. sachalinensis show significantly different genetic and epigenetic population structures and HPLC fingerprint patterns. Along with other potential explanations, these findings suggest that the ex situ environmental factors caused by different altitude play an important role in keeping hereditary characteristic of R. sachalinensis.

  17. Genetic risk of extranodal natural killer T-cell lymphoma: a genome-wide association study.

    Science.gov (United States)

    Li, Zheng; Xia, Yi; Feng, Li-Na; Chen, Jie-Rong; Li, Hong-Min; Cui, Jing; Cai, Qing-Qing; Sim, Kar Seng; Nairismägi, Maarja-Liisa; Laurensia, Yurike; Meah, Wee Yang; Liu, Wen-Sheng; Guo, Yun-Miao; Chen, Li-Zhen; Feng, Qi-Sheng; Pang, Chi Pui; Chen, Li Jia; Chew, Soo Hong; Ebstein, Richard P; Foo, Jia Nee; Liu, Jianjun; Ha, Jeslin; Khoo, Lay Poh; Chin, Suk Teng; Zeng, Yi-Xin; Aung, Tin; Chowbay, Balram; Diong, Colin Phipps; Zhang, Fen; Liu, Yan-Hui; Tang, Tiffany; Tao, Miriam; Quek, Richard; Mohamad, Farid; Tan, Soo Yong; Teh, Bin Tean; Ng, Siok Bian; Chng, Wee Joo; Ong, Choon Kiat; Okada, Yukinori; Raychaudhuri, Soumya; Lim, Soon Thye; Tan, Wen; Peng, Rou-Jun; Khor, Chiea Chuen; Bei, Jin-Xin

    2016-09-01

    Extranodal natural killer T-cell lymphoma (NKTCL), nasal type, is a rare and aggressive malignancy that occurs predominantly in Asian and Latin American populations. Although Epstein-Barr virus infection is a known risk factor, other risk factors and the pathogenesis of NKTCL are not well understood. We aimed to identify common genetic variants affecting individual risk of NKTCL. We did a genome-wide association study of 189 patients with extranodal NKTCL, nasal type (WHO classification criteria; cases) and 957 controls from Guangdong province, southern China. We validated our findings in four independent case-control series, including 75 cases from Guangdong province and 296 controls from Hong Kong, 65 cases and 983 controls from Guangdong province, 125 cases and 1110 controls from Beijing (northern China), and 60 cases and 2476 controls from Singapore. We used imputation and conditional logistic regression analyses to fine-map the associations. We also did a meta-analysis of the replication series and of the entire dataset. Associations exceeding the genome-wide significance threshold (p<5 × 10(-8)) were seen at 51 single-nucleotide polymorphisms (SNPs) mapping to the class II MHC region on chromosome 6, with rs9277378 (located in HLA-DPB1) having the strongest association with NKTCL susceptibility (p=4·21 × 10(-19), odds ratio [OR] 1·84 [95% CI 1·61-2·11] in meta-analysis of entire dataset). Imputation-based fine-mapping across the class II MHC region suggests that four aminoacid residues (Gly84-Gly85-Pro86-Met87) in near-complete linkage disequilibrium at the edge of the peptide-binding groove of HLA-DPB1 could account for most of the association between the rs9277378*A risk allele and NKTCL susceptibility (OR 2·38, p value for haplotype 2·32 × 10(-14)). This association is distinct from MHC associations with Epstein-Barr virus infection. To our knowledge, this is the first time that a genetic variant conferring an NKTCL risk is noted at

  18. An important natural genetic resource of Oreochromis niloticus (Linnaeus, 1758) threatened by aquaculture activities in Loboi drainage, Kenya.

    Science.gov (United States)

    Ndiwa, Titus Chemandwa; Nyingi, Dorothy Wanja; Agnese, Jean-François

    2014-01-01

    The need to improve food security in Africa through culture of tilapias has led to transfer of different species from their natural ranges causing negative impacts on wild fish genetic resources. Loboi swamp in Kenya is fed by three hot springs: Lake Bogoria Hotel, Chelaba and Turtle Springs, hosting natural populations of Oreochromis niloticus. The present study aimed at better genetic characterization of these threatened populations. Partial mtDNA sequences of the D-loop region and variations at 16 microsatellite loci were assessed in the three hot spring populations and compared with three other natural populations of O. niloticus in the region. Results obtained indicated that the hot spring populations had mitochondrial and nuclear genetic variability similar to or higher than the large closely related populations. This may be attributed to the perennial nature of the hot springs, which do not depend on rainfall but rather receive permanent water supply from deep aquifers. The study also revealed that gene flow between the three different hot spring populations was sufficiently low thus allowing their differentiation. This differentiation was unexpected considering the very close proximity of the springs to each other. It is possible that the swamp creates a barrier to free movement of fish from one spring to the other thereby diminishing gene flow. Finally, the most surprising and worrying results were that the three hot spring populations are introgressed by mtDNA genes of O. leucostictus, while microsatellite analysis suggested that some nuclear genes may also have crossed the species barrier. It is very likely that the recent intensification of aquaculture activities in the Loboi drainage may be responsible for these introgressions. Taking into account the importance of these new genetic resources, protection and management actions of the Loboi swamp should be accorded top priority to prevent the loss of these spring populations.

  19. An important natural genetic resource of Oreochromis niloticus (Linnaeus, 1758 threatened by aquaculture activities in Loboi drainage, Kenya.

    Directory of Open Access Journals (Sweden)

    Titus Chemandwa Ndiwa

    Full Text Available The need to improve food security in Africa through culture of tilapias has led to transfer of different species from their natural ranges causing negative impacts on wild fish genetic resources. Loboi swamp in Kenya is fed by three hot springs: Lake Bogoria Hotel, Chelaba and Turtle Springs, hosting natural populations of Oreochromis niloticus. The present study aimed at better genetic characterization of these threatened populations. Partial mtDNA sequences of the D-loop region and variations at 16 microsatellite loci were assessed in the three hot spring populations and compared with three other natural populations of O. niloticus in the region. Results obtained indicated that the hot spring populations had mitochondrial and nuclear genetic variability similar to or higher than the large closely related populations. This may be attributed to the perennial nature of the hot springs, which do not depend on rainfall but rather receive permanent water supply from deep aquifers. The study also revealed that gene flow between the three different hot spring populations was sufficiently low thus allowing their differentiation. This differentiation was unexpected considering the very close proximity of the springs to each other. It is possible that the swamp creates a barrier to free movement of fish from one spring to the other thereby diminishing gene flow. Finally, the most surprising and worrying results were that the three hot spring populations are introgressed by mtDNA genes of O. leucostictus, while microsatellite analysis suggested that some nuclear genes may also have crossed the species barrier. It is very likely that the recent intensification of aquaculture activities in the Loboi drainage may be responsible for these introgressions. Taking into account the importance of these new genetic resources, protection and management actions of the Loboi swamp should be accorded top priority to prevent the loss of these spring populations.

  20. Genetic origin and composition of a natural hybrid poplar Populus???jrtyschensis from two distantly related species

    OpenAIRE

    Jiang, Dechun; Feng, Jianju; Dong, Miao; Wu, Guili; Mao, Kangshan; Liu, Jianquan

    2016-01-01

    Background The factors that contribute to and maintain hybrid zones between distinct species are highly variable, depending on hybrid origins, frequencies and fitness. In this study, we aimed to examine genetic origins, compositions and possible maintenance of Populus???jrtyschensis, an assumed natural hybrid between two distantly related species. This hybrid poplar occurs mainly on the floodplains along the river valleys between the overlapping distributions of the two putative parents. Resu...

  1. Genetically modified crops and the scientific paradigms from which they emerge in the light of the rights of nature

    Directory of Open Access Journals (Sweden)

    Elizabeth Bravo Velásquez

    2014-10-01

    Full Text Available In this work the scientific paradigms in which the genetic modified organisms were developed are analysed, and how the right of nature are violated, since in the process of developing then, the DNA structure is altered and consequently, the functions of the manipulated organisms, with impacts on the biological cycles and the processes of evolution. The Constitution of Ecuador on rights of nature is the base to analyse violations occurring at the stage of commercial production and handling of GM crops.

  2. Chemotaxonomic markers of organic, natural, and genetically modified soybeans detected by direct infusion electrospray ionization mass spectrometry

    International Nuclear Information System (INIS)

    Santos, L.S.; Catharino, R.R.; Eberlin, M.N.; Tsai, S.M.

    2006-01-01

    The crude methanolic extracts of a single bean from samples of organic, natural or genetically modified (GM) soybeans [Glycine max. (Merrill) L.] were analyzed by direct infusion electrospray ionization mass spectrometry (ESI-MS). These extracts, containing the most polar natural products of soybeans (free aglycones, monoglucosides, diglucosides and esters including isoflavones and flavones) provide characteristic fingerprinting mass spectra owing to different proportions or sets of components. Spectra distinctiveness is confirmed by chemometric multivariate analysis of the ESIMS data, which place the three-types of beans into well-defined groups. When ESI-MS is applied, these polar components constitute therefore unique chemotaxonomic markers able to provide fast soybean typification. (author)

  3. Population genetic structure in Atlantic and Pacific Ocean common murres (Uria aalge): Natural replicate tests of post-Pleistocene evolution

    Science.gov (United States)

    Morris-Pocock, J. A.; Taylor, S.A.; Birt, T.P.; Damus, M.; Piatt, John F.; Warheit, K.I.; Friesen, Vicki L.

    2008-01-01

    Understanding the factors that influence population differentiation in temperate taxa can be difficult because the signatures of both historic and contemporary demographics are often reflected in population genetic patterns. Fortunately, analyses based on coalescent theory can help untangle the relative influence of these historic and contemporary factors. Common murres (Uria aalge) are vagile seabirds that breed in the boreal and low arctic waters of the Northern Hemisphere. Previous analyses revealed that Atlantic and Pacific populations are genetically distinct; however, less is known about population genetic structure within ocean basins. We employed the mitochondrial control region, four microsatellite loci and four intron loci to investigate population genetic structure throughout the range of common murres. As in previous studies, we found that Atlantic and Pacific populations diverged during the Pleistocene and do not currently exchange migrants. Therefore, Atlantic and Pacific murre populations can be used as natural replicates to test mechanisms of population differentiation. While we found little population genetic structure within the Pacific, we detected significant east-west structuring among Atlantic colonies. The degree that population genetic structure reflected contemporary population demographics also differed between ocean basins. Specifically, while the low levels of population differentiation in the Pacific are at least partially due to high levels of contemporary gene flow, the east-west structuring of populations within the Atlantic appears to be the result of historic fragmentation of populations rather than restricted contemporary gene flow. The contrasting results in the Atlantic and Pacific Oceans highlight the necessity of carefully considering multilocus nonequilibrium population genetic approaches when reconstructing the demographic history of temperate Northern Hemisphere taxa. ?? 2008 The Authors.

  4. A Short History and Description of Drosophila melanogaster Classical Genetics: Chromosome Aberrations, Forward Genetic Screens, and the Nature of Mutations.

    Science.gov (United States)

    Kaufman, Thomas C

    2017-06-01

    The purpose of this chapter in FlyBook is to acquaint the reader with the Drosophila genome and the ways in which it can be altered by mutation. Much of what follows will be familiar to the experienced Fly Pusher but hopefully will be useful to those just entering the field and are thus unfamiliar with the genome, the history of how it has been and can be altered, and the consequences of those alterations. I will begin with the structure, content, and organization of the genome, followed by the kinds of structural alterations (karyotypic aberrations), how they affect the behavior of chromosomes in meiotic cell division, and how that behavior can be used. Finally, screens for mutations as they have been performed will be discussed. There are several excellent sources of detailed information on Drosophila husbandry and screening that are recommended for those interested in further expanding their familiarity with Drosophila as a research tool and model organism. These are a book by Ralph Greenspan and a review article by John Roote and Andreas Prokop, which should be required reading for any new student entering a fly lab for the first time. Copyright © 2017 by the Genetics Society of America.

  5. Genetics

    International Nuclear Information System (INIS)

    Hubitschek, H.E.

    1975-01-01

    Progress is reported on the following research projects: genetic effects of high LET radiations; genetic regulation, alteration, and repair; chromosome replication and the division cycle of Escherichia coli; effects of radioisotope decay in the DNA of microorganisms; initiation and termination of DNA replication in Bacillus subtilis; mutagenesis in mouse myeloma cells; lethal and mutagenic effects of near-uv radiation; effect of 8-methoxypsoralen on photodynamic lethality and mutagenicity in Escherichia coli; DNA repair of the lethal effects of far-uv; and near uv irradiation of bacterial cells

  6. Genetic mating systems and reproductive natural histories of fishes: lessons for ecology and evolution.

    Science.gov (United States)

    Avise, John C; Jones, Adam G; Walker, DeEtte; DeWoody, J Andrew

    2002-01-01

    Fish species have diverse breeding behaviors that make them valuable for testing theories on genetic mating systems and reproductive tactics. Here we review genetic appraisals of paternity and maternity in wild fish populations. Behavioral phenomena quantified by genetic markers in various species include patterns of multiple mating by both sexes; frequent cuckoldry by males and rare cuckoldry by females in nest-tending species; additional routes to surrogate parentage via nest piracy and egg-thievery; egg mimicry by nest-tending males; brood parasitism by helper males in cooperative breeders; clutch mixing in oral brooders; kinship in schooling fry of broadcast spawners; sperm storage by dams in female-pregnant species; and sex-role reversal, polyandry, and strong sexual selection on females in some male-pregnant species. Additional phenomena addressed by genetic parentage analyses in fishes include clustered mutations, filial cannibalism, and local population size. All results are discussed in the context of relevant behavioral and evolutionary theory.

  7. Genetic variations in marine natural population - Measurement and utility in resource management and conservation: A review

    Digital Repository Service at National Institute of Oceanography (India)

    Menezes, M.R.; Parulekar, A.H.

    A number of molecular and biochemical tools which can be applied to the identification of species and the detection of genetic variation within species have been developed in recent years. All these methods rely on the ability to distinguish between...

  8. The influence of age and genetics on natural resistance to experimentally induced feline infectious peritonitis.

    Science.gov (United States)

    Pedersen, Niels C; Liu, Hongwei; Gandolfi, Barbara; Lyons, Leslie A

    2014-11-15

    Naturally occurring feline infectious peritonitis (FIP) is usually fatal, giving the impression that immunity to the FIP virus (FIPV) is extremely poor. This impression may be incorrect, because not all cats experimentally exposed to FIPV develop FIP. There is also a belief that the incidence of FIP may be affected by a number of host, virus, and environmental cofactors. However, the contribution of these cofactors to immunity and disease incidence has not been determined. The present study followed 111 random-bred specific pathogen free (SPF) cats that were obtained from a single research breeding colony and experimentally infected with FIPV. The cats were from several studies conducted over the past 5 years, and as a result, some of them had prior exposure to feline enteric coronavirus (FECV) or avirulent FIPVs. The cats were housed under optimized conditions of nutrition, husbandry, and quarantine to eliminate most of the cofactors implicated in FIPV infection outcome and were uniformly challenge exposed to the same field strain of serotype 1 FIPV. Forty of the 111 (36%) cats survived their initial challenge exposure to a Type I cat-passaged field strains of FIPV. Six of these 40 survivors succumbed to FIP to a second or third challenge exposure, suggesting that immunity was not always sustained. Exposure to non-FIP-inducing feline coronaviruses prior to challenge with virulent FIPV did not significantly affect FIP incidence but did accelerate the disease course in some cats. There were no significant differences in FIP incidence between males and females, but resistance increased significantly between 6 months and 1 or more years of age. Genetic testing was done on 107 of the 111 infected cats. Multidimensional scaling (MDS) segregated the 107 cats into three distinct families based primarily on a common sire(s), and resistant and susceptible cats were equally distributed within each family. Genome-wide association studies (GWAS) on 73 cats that died of FIP

  9. Genetics

    DEFF Research Database (Denmark)

    Christensen, Kaare; McGue, Matt

    2016-01-01

    The sequenced genomes of individuals aged ≥80 years, who were highly educated, self-referred volunteers and with no self-reported chronic diseases were compared to young controls. In these data, healthy ageing is a distinct phenotype from exceptional longevity and genetic factors that protect...

  10. Nature, nurture, and capital punishment: How evidence of a genetic-environment interaction, future dangerousness, and deliberation affect sentencing decisions.

    Science.gov (United States)

    Gordon, Natalie; Greene, Edie

    2018-01-01

    Research has shown that the low-activity MAOA genotype in conjunction with a history of childhood maltreatment increases the likelihood of violent behaviors. This genetic-environment (G × E) interaction has been introduced as mitigation during the sentencing phase of capital trials, yet there is scant data on its effectiveness. This study addressed that issue. In a factorial design that varied mitigating evidence offered by the defense [environmental (i.e., childhood maltreatment), genetic, G × E, or none] and the likelihood of the defendant's future dangerousness (low or high), 600 mock jurors read sentencing phase evidence in a capital murder trial, rendered individual verdicts, and half deliberated as members of a jury to decide a sentence of death or life imprisonment. The G × E evidence had little mitigating effect on sentencing preferences: participants who received the G × E evidence were no less likely to sentence the defendant to death than those who received evidence of childhood maltreatment or a control group that received neither genetic nor maltreatment evidence. Participants with evidence of a G × E interaction were more likely to sentence the defendant to death when there was a high risk of future dangerousness than when there was a low risk. Sentencing preferences were more lenient after deliberation than before. We discuss limitations and future directions. Copyright © 2017 John Wiley & Sons, Ltd.

  11. Genetically distinct isolates of Spirocerca sp. from a naturally infected red fox (Vulpes vulpes) from Denmark

    DEFF Research Database (Denmark)

    Al-Sabi, Mohammad Nafi Solaiman; Hansen, Mette Sif; Chriél, Mariann

    2014-01-01

    sugar-salt solu-tion, and sieving failed to detect eggs of Spirocerca sp. in feces collected from the colon.This is the first report of spirocercosis in Denmark, and may have been caused by a recentintroduction by migrating paratenic or definitive host. Analysis of two overlapping par-tial sequences...... of the cox1 gene, from individual worms, revealed distinct genetic variation(7–9%) between the Danish worms and isolates of S. lupi from Europe, Asia and Africa.This was confirmed by phylogenetic analysis that clearly separated the Danish worms fromother isolates of S. lupi. The distinct genetic differences...

  12. Assessment of genetically significant doses to the Sofia population from natural gamma background

    International Nuclear Information System (INIS)

    Vasilev, G.; Khristova, M.

    1977-01-01

    Genetically significant dose to the population of Sofia city was assessed within a program covering larger urban communities in the country. Measurements were made of gamma background exposure rates in the gonadal region. Gonad doses were estimated using a screening factor of 0.73. Based on statistical data for total number of inhabitants and number of people of reproductive age, and on the mean annual gonad doses derived, calculations were made of genetically significant dose to the Sofia population. Base-line data were thus provided for an assessment of extra radiation dose resulting from occupational radiation exposure. (author)

  13. Modern spandrels: the roles of genetic drift, gene flow and natural selection in the evolution of parallel clines.

    Science.gov (United States)

    Santangelo, James S; Johnson, Marc T J; Ness, Rob W

    2018-05-16

    Urban environments offer the opportunity to study the role of adaptive and non-adaptive evolutionary processes on an unprecedented scale. While the presence of parallel clines in heritable phenotypic traits is often considered strong evidence for the role of natural selection, non-adaptive evolutionary processes can also generate clines, and this may be more likely when traits have a non-additive genetic basis due to epistasis. In this paper, we use spatially explicit simulations modelled according to the cyanogenesis (hydrogen cyanide, HCN) polymorphism in white clover ( Trifolium repens ) to examine the formation of phenotypic clines along urbanization gradients under varying levels of drift, gene flow and selection. HCN results from an epistatic interaction between two Mendelian-inherited loci. Our results demonstrate that the genetic architecture of this trait makes natural populations susceptible to decreases in HCN frequencies via drift. Gradients in the strength of drift across a landscape resulted in phenotypic clines with lower frequencies of HCN in strongly drifting populations, giving the misleading appearance of deterministic adaptive changes in the phenotype. Studies of heritable phenotypic change in urban populations should generate null models of phenotypic evolution based on the genetic architecture underlying focal traits prior to invoking selection's role in generating adaptive differentiation. © 2018 The Author(s).

  14. Natural resistance to experimental feline infectious peritonitis virus infection is decreased rather than increased by positive genetic selection.

    Science.gov (United States)

    Pedersen, Niels C; Liu, Hongwei; Durden, Monica; Lyons, Leslie A

    2016-03-01

    A previous study demonstrated the existence of a natural resistance to feline infectious peritonitis virus (FIPV) among 36% of randomly bred laboratory cats. A genome wide association study (GWAS) on this population suggested that resistance was polygenic but failed to identify any strong specific associations. In order to enhance the power of GWAS or whole genome sequencing to identify strong genetic associations, a decision was made to positively select for resistance over three generations. The inbreeding experiment began with a genetically related parental (P) population consisting of three toms and four queens identified from among the survivors of the earlier study and belonging to a closely related subgroup (B). The subsequent effects of inbreeding were measured using 42 genome-wide STR markers. P generation cats produced 57 first filial (F1) kittens, only five of which (9.0%) demonstrated a natural resistance to FIPV infection. One of these five F1 survivors was then used to produce six F1/P-backcrosses kittens, only one of which proved resistant to FIP. Six of eight of the F1 and F1/P survivors succumbed to a secondary exposure 4-12 months later. Therefore, survival after both primary and secondary infection was decreased rather than increased by positive selection for resistance. The common genetic factor associated with this diminished resistance was a loss of heterozygosity. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  15. Using Random Amplified Polymorphic DNA to Assess Genetic Diversity and Structure of Natural Calophyllum brasiliense (Clusiaceae Populations in Riparian Forests

    Directory of Open Access Journals (Sweden)

    Evânia Galvão Mendonça

    2014-01-01

    Full Text Available The objective of this study was to assess the genetic variability in two natural populations of Calophyllum brasiliense located along two different rivers in the state of Minas Gerais, Brazil, using RAPD molecular markers. Eighty-two polymorphic fragments were amplified using 27 primers. The values obtained for Shannon index (I were 0.513 and 0.530 for the populations located on the margins of the Rio Grande and Rio das Mortes, respectively, demonstrating the high genetic diversity in the studied populations. Nei’s genetic diversity (He was 0.341 for the Rio Grande population and 0.357 for the Rio das Mortes population. These results were not significantly different between populations and suggest a large proportion of heterozygote individuals within both populations. AMOVA showed that 70.42% of the genetic variability is found within populations and 29.58% is found among populations (ФST=0.2958. The analysis of kinship coefficients detected the existence of family structures in both populations. Average kinship coefficients between neighboring individuals were 0.053 (P<0.001 in Rio das Mortes and 0.040 (P<0.001 in Rio Grande. This could be due to restricted pollen and seed dispersal and the history of anthropogenic disturbance in the area. These factors are likely to contribute to the relatedness observed among these genotypes.

  16. Why Are High Altitude Natives So Strong at High Altitude? Nature vs. Nurture: Genetic Factors vs. Growth and Development.

    Science.gov (United States)

    Brutsaert, Tom

    Among high-altitude natives there is evidence of a general hypoxia tolerance leading to enhanced performance and/or increased capacity in several important domains. These domains likely include an enhanced physical work capacity, an enhanced reproductive capacity, and an ability to resist several common pathologies of chronic high-altitude exposure. The "strength" of the high-altitude native in this regard may have both a developmental and a genetic basis, although there is better evidence for the former (developmental effects) than for the latter. For example, early-life hypoxia exposure clearly results in lung growth and remodeling leading to an increased O2 diffusing capacity in adulthood. Genetic research has yet to reveal a population genetic basis for enhanced capacity in high-altitude natives, but several traits are clearly under genetic control in Andean and Tibetan populations e.g., resting and exercise arterial O2 saturation (SaO2). This chapter reviews the effects of nature and nurture on traits that are relevant to the process of gas exchange, including pulmonary volumes and diffusion capacity, the maximal oxygen consumption (VO2max), the SaO2, and the alveolar-arterial oxygen partial pressure difference (A-aDO2) during exercise.

  17. Genetic diversity and population structure of Anastrepha striata (Diptera: Tephritidae) in three natural regions of southwestern Colombia using mitochondrial sequences.

    Science.gov (United States)

    Gallo-Franco, Jenny Johana; Velasco-Cuervo, Sandra Marcela; Aguirre-Ramirez, Elkin; González Obando, Ranulfo; Carrejo, Nancy Soraya; Toro-Perea, Nelson

    2017-02-01

    Anastrepha striata is widely distributed across the Americas and is a pest of economically important crops, especially crops of the Myrtaceae family. Insect population structures can be influenced by the presence of physical barriers or characteristics associated with habitat differences. This study evaluated the effect of the Western Andes on the population structure of A. striata. Individuals were collected from Psidium guajava fruits from three natural regions of southwestern Colombia (Pacific Coast, mountainous region and the inter-Andean valley of the Cauca River). Based on a 1318 bp concatenated of the genes Cytochrome Oxidase subunit I (COI) and NADH dehydrogenase subunit 6 (ND6), 14 haplotypes with few changes among them (between 1 and 3) were found. There was only one dominant haplotype in all three regions. No genetic structure associated with the three eco-geographical regions of the study was found. Moreover, the Western Andes are not an effective barrier for the genetic isolation of the populations from the Pacific Coast compared with the inter-Andean valley populations. This genetic homogeneity could be partially due to anthropogenic intervention, which acts as a dispersal agent of infested fruits. Another hypothesis to explain the lack of structure would be the relatively recent arrival of A. striata to the region, as indicated by an analysis of the demographic history, which reveals a process of population expansion. This study represents the first attempt to understand the population genetics of A. striata in Colombia and could contribute to the integral management of this pest.

  18. Introduced Terrestrial Species Richness

    Data.gov (United States)

    U.S. Environmental Protection Agency — These data represent predicted current distributions of all introduced mammals, birds, reptiles, amphibians and butterflies in the Middle-Atlantic region. These data...

  19. Genetic diversity of naturalized cacao (Theobroma cacao L.) in Puerto Rico

    Science.gov (United States)

    Identification of genetically diverse cacao with disease resistance, high productivity and desirable organoleptic traits is vitally important to the agricultural crop’s long-term sustainability. Environmental changes, pests and diseases as well as nation’s sovereign property rights have led to a de...

  20. Genetic diversity and natural selection footprints of the glycine amidinotransferase gene in various human populations.

    Science.gov (United States)

    Khan, Asifullah; Tian, Lei; Zhang, Chao; Yuan, Kai; Xu, Shuhua

    2016-01-05

    The glycine amidinotransferase gene (GATM) plays a vital role in energy metabolism in muscle tissues and is associated with multiple clinically important phenotypes. However, the genetic diversity of the GATM gene remains poorly understood within and between human populations. Here we analyzed the 1,000 Genomes Project data through population genetics approaches and observed significant genetic diversity across the GATM gene among various continental human populations. We observed considerable variations in GATM allele frequencies and haplotype composition among different populations. Substantial genetic differences were observed between East Asian and European populations (FST = 0.56). In addition, the frequency of a distinct major GATM haplotype in these groups was congruent with population-wide diversity at this locus. Furthermore, we identified GATM as the top differentiated gene compared to the other statin drug response-associated genes. Composite multiple analyses identified signatures of positive selection at the GATM locus, which was estimated to have occurred around 850 generations ago in European populations. As GATM catalyzes the key step of creatine biosynthesis involved in energy metabolism, we speculate that the European prehistorical demographic transition from hunter-gatherer to farming cultures was the driving force of selection that fulfilled creatine-based metabolic requirement of the populations.

  1. Natural Selection and Evolution: Using Multimedia Slide Shows to Emphasize the Role of Genetic Variation

    Science.gov (United States)

    Malone, Molly

    2012-01-01

    Most middle school students comprehend that organisms have adaptations that enable their survival and that successful adaptations prevail in a population over time. Yet they often miss that those bird beaks, moth-wing colors, or whatever traits are the result of random, normal genetic variations that just happen to confer a negative, neutral, or…

  2. Nature vs nurture: are leaders born or made? A behavior genetic investigation of leadership style.

    Science.gov (United States)

    Johnson, A M; Vernon, P A; McCarthy, J M; Molson, M; Harris, J A; Jang, K L

    1998-12-01

    With the recent resurgence in popularity of trait theories of leadership, it is timely to consider the genetic determination of the multiple factors comprising the leadership construct. Individual differences in personality traits have been found to be moderately to highly heritable, and so it follows that if there are reliable personality trait differences between leaders and non-leaders, then there may be a heritable component to these individual differences. Despite this connection between leadership and personality traits, however, there are no studies of the genetic basis of leadership using modern behavior genetic methodology. The present study proposes to address the lack of research in this area by examining the heritability of leadership style, as measured by self-report psychometric inventories. The Multifactor Leadership Questionnaire (MLQ), the Leadership Ability Evaluation, and the Adjective Checklist were completed by 247 adult twin pairs (183 monozygotic and 64 same-sex dizygotic). Results indicated that most of the leadership dimensions examined in this study are heritable, as are two higher level factors (resembling transactional and transformational leadership) derived from an obliquely rotated principal components factors analysis of the MLQ. Univariate analyses suggested that 48% of the variance in transactional leadership may be explained by additive heritability, and 59% of the variance in transformational leadership may be explained by non-additive (dominance) heritability. Multivariate analyses indicated that most of the variables studied shared substantial genetic covariance, suggesting a large overlap in the underlying genes responsible for the leadership dimensions.

  3. Quantitative genetic methods depending on the nature of the phenotypic trait.

    Science.gov (United States)

    de Villemereuil, Pierre

    2018-01-24

    A consequence of the assumptions of the infinitesimal model, one of the most important theoretical foundations of quantitative genetics, is that phenotypic traits are predicted to be most often normally distributed (so-called Gaussian traits). But phenotypic traits, especially those interesting for evolutionary biology, might be shaped according to very diverse distributions. Here, I show how quantitative genetics tools have been extended to account for a wider diversity of phenotypic traits using first the threshold model and then more recently using generalized linear mixed models. I explore the assumptions behind these models and how they can be used to study the genetics of non-Gaussian complex traits. I also comment on three recent methodological advances in quantitative genetics that widen our ability to study new kinds of traits: the use of "modular" hierarchical modeling (e.g., to study survival in the context of capture-recapture approaches for wild populations); the use of aster models to study a set of traits with conditional relationships (e.g., life-history traits); and, finally, the study of high-dimensional traits, such as gene expression. © 2018 New York Academy of Sciences.

  4. Nature, nurture, and item response theory: a psychometric approach to behaviour genetics

    NARCIS (Netherlands)

    Schwabe, Inga

    2016-01-01

    This dissertation discusses a number of psychometric issues that require special attention in the analysis of genetically-informative data, such as data on twins. These include heterogeneous measurement error, scaling and scale transformation, and harmonization of phenotypes. It is shown how

  5. Nature and nurture: environmental influences on a genetic rat model of depression.

    Science.gov (United States)

    Mehta-Raghavan, N S; Wert, S L; Morley, C; Graf, E N; Redei, E E

    2016-03-29

    In this study, we sought to learn whether adverse events such as chronic restraint stress (CRS), or 'nurture' in the form of environmental enrichment (EE), could modify depression-like behavior and blood biomarker transcript levels in a genetic rat model of depression. The Wistar Kyoto More Immobile (WMI) is a genetic model of depression that aided in the identification of blood transcriptomic markers, which successfully distinguished adolescent and adult subjects with major depressive disorders from their matched no-disorder controls. Here, we followed the effects of CRS and EE in adult male WMIs and their genetically similar control strain, the Wistar Kyoto Less Immobile (WLI), that does not show depression-like behavior, by measuring the levels of these transcripts in the blood and hippocampus. In WLIs, increased depression-like behavior and transcriptomic changes were present in response to CRS, but in WMIs no behavioral or additive transcriptomic changes occurred. Environmental enrichment decreased both the inherent depression-like behavior in the WMIs and the behavioral difference between WMIs and WLIs, but did not reverse basal transcript level differences between the strains. The inverse behavioral change induced by CRS and EE in the WLIs did not result in parallel inverse expression changes of the transcriptomic markers, suggesting that these behavioral responses to the environment work via separate molecular pathways. In contrast, 'trait' transcriptomic markers with expression differences inherent and unchanging between the strains regardless of the environment suggest that in our model, environmental and genetic etiologies of depression work through independent molecular mechanisms.

  6. Genetic and Environmental Links between Natural Language Use and Cognitive Ability in Toddlers

    Science.gov (United States)

    Canfield, Caitlin F.; Edelson, Lisa R.; Saudino, Kimberly J.

    2017-01-01

    Although the phenotypic correlation between language and nonverbal cognitive ability is well-documented, studies examining the etiology of the covariance between these abilities are scant, particularly in very young children. The goal of this study was to address this gap in the literature by examining the genetic and environmental links between…

  7. Genetic and Pathological Follow-Up Study of Goats Experimentally and Naturally Exposed to a Sheep Scrapie Isolate

    Science.gov (United States)

    Maestrale, Caterina; Cancedda, Maria G.; Pintus, Davide; Masia, Mariangela; Nonno, Romolo; Ru, Giuseppe; Carta, Antonello; Demontis, Francesca; Santucciu, Cinzia

    2015-01-01

    ABSTRACT Thirty-seven goats carrying different prion protein genotypes (PRNP) were orally infected with a classical scrapie brain homogenate from wild-type (ARQ/ARQ) sheep and then mated to obtain 2 additional generations of offspring, which were kept in the same environment and allowed to be naturally exposed to scrapie. Occurrence of clinical or subclinical scrapie was observed in the experimentally infected goats (F0) and in only one (F1b) of the naturally exposed offspring groups. In both groups (F0 and F1b), goats carrying the R154H, H154H, R211Q, and P168Q-P240P dimorphisms died of scrapie after a longer incubation period than wild-type, G37V, Q168Q-P240P, and S240P goats. In contrast, D145D and Q222K goats were resistant to infection. The immunobiochemical signature of the scrapie isolate and its pathological aspects observed in the sheep donors were substantially maintained over 2 goat generations, i.e., after experimental and natural transmission. This demonstrates that the prion protein gene sequence, which is shared by sheep and goats, is more powerful than any possible but unknown species-related factors in determining scrapie phenotypes. With regard to genetics, our study confirms that the K222 mutation protects goats even against ovine scrapie isolates, and for the first time, a possible association of D145 mutation with scrapie resistance is shown. In addition, it is possible that the sole diverse frequencies of these genetic variants might, at least in part, shape the prevalence of scrapie among naturally exposed progenies in affected herds. IMPORTANCE This study was aimed at investigating the genetic and pathological features characterizing sheep-to-goat transmission of scrapie. We show that in goats with different prion protein gene mutations, the K222 genetic variant is associated with scrapie resistance after natural and experimental exposure to ovine prion infectivity. In addition, we observed for the first time a protective effect of the D145

  8. Cost and performance optimization of natural draft dry cooling towers using genetic algorithm. Paper no. IGEC-1-002

    International Nuclear Information System (INIS)

    Shokuhmand, H.; Ghaempanah, B.

    2005-01-01

    In this paper the cost - performance optimization of natural draft dry cooling towers with specific kind of heat exchangers, known as Forgo T60 has been investigated. These cooling towers are used in combined and steam cycle power plants. The optimization has been done using genetic algorithm. The objective function has two parts, which are minimizing the cost and maximizing the performance. In the first part the geometrical and operating parameters are defined and for the next part the performance of the designed tower for different ambient temperatures during a year is calculated considering the characteristic curve of the turbine. The applied genetic algorithm has been tuned up using the data of some working power cycles. The results show it is possible to find an optimum for all design parameters; however it is very dependent on how exact the cost analysis is. (author)

  9. Naturally occurring genetic variation affecting the expression of sn-glycerol-3-phosphate dehydrogenase in Drosophila melanogaster.

    Science.gov (United States)

    Laurie-Ahlberg, C C; Bewley, G C

    1983-10-01

    Genetic variation among second and third chromosomes from natural populations of Drosophila melanogaster affects the activity level of sn-glycerol-3-phosphate dehydrogenase (EC 1.1.1.8; GPDH) at both the larval and the adult stages. The genetic effects, represented by differences among chromosome substitution lines with coisogenic backgrounds, are very repeatable over time and are generally substantially larger than environmental and measurement error effects. Neither the GPDH allozyme, the geographic origin, nor the karyotype of the chromosome contributes significantly to GPDH activity variation. The strong relationship between GPDH activity level and GPDH-specific CRM level, as well as our failure to find any thermostability variation among the lines, indicates that most, if not all, of the activity variation is due to variation in the steady-state quantity of enzyme rather than in its catalytic properties. The lack of a strong relationship between adult and larval activity levels suggests the importance of stage- or isozyme-specific effects.

  10. Spatial phenotypic and genetic structure of threespine stickleback (Gasterosteus aculeatus) in a heterogeneous natural system, Lake Mývatn, Iceland.

    Science.gov (United States)

    Millet, Antoine; Kristjánsson, Bjarni K; Einarsson, Arni; Räsänen, Katja

    2013-09-01

    Eco-evolutionary responses of natural populations to spatial environmental variation strongly depend on the relative strength of environmental differences/natural selection and dispersal/gene flow. In absence of geographic barriers, as often is the case in lake ecosystems, gene flow is expected to constrain adaptive divergence between environments - favoring phenotypic plasticity or high trait variability. However, if divergent natural selection is sufficiently strong, adaptive divergence can occur in face of gene flow. The extent of divergence is most often studied between two contrasting environments, whereas potential for multimodal divergence is little explored. We investigated phenotypic (body size, defensive structures, and feeding morphology) and genetic (microsatellites) structure in threespine stickleback (Gasterosteus aculeatus) across five habitat types and two basins (North and South) within the geologically young and highly heterogeneous Lake Mývatn, North East Iceland. We found that (1) North basin stickleback were, on average, larger and had relatively longer spines than South basin stickleback, whereas (2) feeding morphology (gill raker number and gill raker gap width) differed among three of five habitat types, and (3) there was only subtle genetic differentiation across the lake. Overall, our results indicate predator and prey mediated phenotypic divergence across multiple habitats in the lake, in face of gene flow.

  11. Enhancing the thermal stability of natural rubber/recycled ethylene–propylene–diene rubber blends by means of introducing pre-vulcanised ethylene–propylene–diene rubber and electron beam irradiation

    International Nuclear Information System (INIS)

    Nabil, H.; Ismail, H.

    2014-01-01

    Highlights: • New route of processing was introduced to optimise the thermal stability of NR/R-EPDM blends. • Pre-vulcanised EPDM and EB irradiation were introduced into NR/R-EPDM blends. • Thermal stability is obviously enhanced by applying these two techniques. • Applying new route of processing methods is clearly successful to NR/R-EPDM blends. - Abstract: Most rubber materials are subjected to oxidation. The rate of oxidation depends on the type of rubber, processing method, and end-use conditions. The oxidation of rubber can result in the loss of physical properties, such as tensile strength, elongation, and flexibility. Hence, the service life is determined by oxidation stability. Thermal properties are relevant to the potential use of polymeric materials in many consumer oriented applications. Thermo-oxidative ageing and thermogravimetric analysis (TGA) have been proven to be successful techniques in determining the thermal stability of polymers and polymer blends. In this article, preparation of a series of natural rubber/recycled ethylene–propylene–diene rubber (NR/R-EPDM) blends is described. Processing of the blends, by means of introducing pre-vulcanised EPDM and electron beam (EB) irradiation, was carried out. Two thermal analysis methods, namely thermo-oxidative ageing and thermogravimetric analysis, were conducted. The results indicated that pre-vulcanising EPDM for 1.45 min (ts − 2) is sufficient to gain the optimum retained tensile and elongation at break. It was simultaneously observed that the introduction of pre-vulcanised EPDM increased decomposition temperature and activation energy by showing optimum values at a pre-vulcanising time of 3.45 min (ts). In the latter study, the retained properties increased after EB irradiation. The results can be verified by the thermal decomposition temperature and their activation energy. The obtained TG profiles and the calculated kinetic parameters indicated that introducing EB irradiation

  12. Can the experimental evolution programme help us elucidate the genetic basis of adaptation in nature?

    DEFF Research Database (Denmark)

    Bailey, Susan; Bataillon, Thomas

    2015-01-01

    and continue to play an important role in shaping adaptive evolution in the natural world. Further to this, experimental evolution studies allow for tests of theories that may be difficult or impossible to test in natural populations for logistical and methodological reasons and can even generate new insights......, suggesting further refinement of existing theories. However, as experimental evolution studies often take place in a very particular set of controlled conditions – that is simple environments, a small range of usually asexual species, relatively short timescales – the question remains as to how applicable...... natural population studies. We finish by making suggestions for future work in particular a need for natural population genomic time series data, as well as the necessity for studies that combine both experimental evolution and natural population approaches....

  13. Increased fire frequency promotes stronger spatial genetic structure and natural selection at regional and local scales in Pinus halepensis Mill.

    Science.gov (United States)

    Budde, Katharina B; González-Martínez, Santiago C; Navascués, Miguel; Burgarella, Concetta; Mosca, Elena; Lorenzo, Zaida; Zabal-Aguirre, Mario; Vendramin, Giovanni G; Verdú, Miguel; Pausas, Juli G; Heuertz, Myriam

    2017-04-01

    The recurrence of wildfires is predicted to increase due to global climate change, resulting in severe impacts on biodiversity and ecosystem functioning. Recurrent fires can drive plant adaptation and reduce genetic diversity; however, the underlying population genetic processes have not been studied in detail. In this study, the neutral and adaptive evolutionary effects of contrasting fire regimes were examined in the keystone tree species Pinus halepensis Mill. (Aleppo pine), a fire-adapted conifer. The genetic diversity, demographic history and spatial genetic structure were assessed at local (within-population) and regional scales for populations exposed to different crown fire frequencies. Eight natural P. halepensis stands were sampled in the east of the Iberian Peninsula, five of them in a region exposed to frequent crown fires (HiFi) and three of them in an adjacent region with a low frequency of crown fires (LoFi). Samples were genotyped at nine neutral simple sequence repeats (SSRs) and at 251 single nucleotide polymorphisms (SNPs) from coding regions, some of them potentially important for fire adaptation. Fire regime had no effects on genetic diversity or demographic history. Three high-differentiation outlier SNPs were identified between HiFi and LoFi stands, suggesting fire-related selection at the regional scale. At the local scale, fine-scale spatial genetic structure (SGS) was overall weak as expected for a wind-pollinated and wind-dispersed tree species. HiFi stands displayed a stronger SGS than LoFi stands at SNPs, which probably reflected the simultaneous post-fire recruitment of co-dispersed related seeds. SNPs with exceptionally strong SGS, a proxy for microenvironmental selection, were only reliably identified under the HiFi regime. An increasing fire frequency as predicted due to global change can promote increased SGS with stronger family structures and alter natural selection in P. halepensis and in plants with similar life history traits

  14. Genetic origin and composition of a natural hybrid poplar Populus × jrtyschensis from two distantly related species.

    Science.gov (United States)

    Jiang, Dechun; Feng, Jianju; Dong, Miao; Wu, Guili; Mao, Kangshan; Liu, Jianquan

    2016-04-18

    The factors that contribute to and maintain hybrid zones between distinct species are highly variable, depending on hybrid origins, frequencies and fitness. In this study, we aimed to examine genetic origins, compositions and possible maintenance of Populus × jrtyschensis, an assumed natural hybrid between two distantly related species. This hybrid poplar occurs mainly on the floodplains along the river valleys between the overlapping distributions of the two putative parents. We collected 566 individuals from 45 typical populations of P. × jrtyschensis, P. nigra and P. laurifolia. We genotyped them based on the sequence variations of one maternally inherited chloroplast DNA (cpDNA) fragment and genetic polymorphisms at 20 SSR loci. We further sequenced eight nuclear genes for 168 individuals from 31 populations. Two groups of cpDNA haplotypes characteristic of P. nigra and P. laurifolia respectively were both recovered for P. × jrtyschensis. Genetic structures and coalescent tests of two sets of nuclear population genetic data suggested that P. × jrtyschensis originated from hybridizations between the two assumed parental species. All examined populations of P. × jrtyschensis comprise mainly F1 hybrids from interspecific hybridizations between P. nigra and P. laurifolia. In the habitats of P. × jrtyschensis, there are lower concentrations of soil nitrogen than in the habitats occupied by the other two species. Our extensive examination of the genetic composition of P. × jrtyschensis suggested that it is typical of F1-dominated hybrid zones. This finding plus the low concentration of soil nitrogen in the floodplain soils support the F1-dominated bounded hybrid superiority hypothesis of hybrid zone maintenance for this particular hybrid poplar.

  15. Genetic Divergence and signatures of natural election in marginal populations of a Keystone, long-lived conifer, Eastern White Pine (Pinus strobus) from Northern Ontario

    Science.gov (United States)

    Vikram E. Chhatre; Om P. Rajora

    2014-01-01

    Marginal populations are expected to provide the frontiers for adaptation, evolution and range shifts of plant species under the anticipated climate change conditions. Marginal populations are predicted to show genetic divergence from central populations due to their isolation, and divergent natural selection and genetic drift operating therein. Marginal populations...

  16. Genetic and Cytological Analyses of the Natural Variation of Seed Number per Pod in Rapeseed (Brassica napus L.

    Directory of Open Access Journals (Sweden)

    Yuhua Yang

    2017-11-01

    Full Text Available Seed number is one of the key traits related to plant evolution/domestication and crop improvement/breeding. In rapeseed germplasm, the seed number per pod (SNPP shows a very wide variation from several to nearly 30; however, the underlying causations/mechanisms for this variation are poorly known. In the current study, the genetic and cytological bases for the natural variation of SNPP in rapeseed was firstly and systematically investigated using the representative four high-SNPP and five low-SNPP lines. The results of self- or cross-pollination experiment between the high- and low-SNPP lines showed that the natural variation of SNPP was mainly controlled by maternal effect (mean = 0.79, followed by paternal effect (mean = 0.21. Analysis of the data using diploid seed embryo–cytoplasmic–maternal model further showed that the maternal genotype, embryo, and cytoplasm effects, respectively, explained 47.6, 35.2, and 7.5% of the genetic variance. In addition, the analysis of combining ability showed that for the SNPP of hybrid F1 was mainly determined by the general combining ability of parents (63.0%, followed by special combining ability of parental combination (37.0%. More importantly, the cytological observation showed that the SNPP difference between the high- and low-SNPP lines was attributable to the accumulative differences in its components. Of which, the number of ovules, the proportion of fertile ovules, the proportion of fertile ovules to be fertilized, and the proportion of fertilized ovules to develop into seeds accounted for 30.7, 18.2, 7.1, and 43.9%, respectively. The accordant results of both genetic and cytological analyses provide solid evidences and systematic insights to further understand the mechanisms underlying the natural variation of SNPP, which will facilitate the development of high-yield cultivars in rapeseed.

  17. Genetic architecture of natural variation in cuticular hydrocarbon composition in Drosophila melanogaster.

    Science.gov (United States)

    Dembeck, Lauren M; Böröczky, Katalin; Huang, Wen; Schal, Coby; Anholt, Robert R H; Mackay, Trudy F C

    2015-11-14

    Insect cuticular hydrocarbons (CHCs) prevent desiccation and serve as chemical signals that mediate social interactions. Drosophila melanogaster CHCs have been studied extensively, but the genetic basis for individual variation in CHC composition is largely unknown. We quantified variation in CHC profiles in the D. melanogaster Genetic Reference Panel (DGRP) and identified novel CHCs. We used principal component (PC) analysis to extract PCs that explain the majority of CHC variation and identified polymorphisms in or near 305 and 173 genes in females and males, respectively, associated with variation in these PCs. In addition, 17 DGRP lines contain the functional Desat2 allele characteristic of African and Caribbean D. melanogaster females (more 5,9-C27:2 and less 7,11-C27:2, female sex pheromone isomers). Disruption of expression of 24 candidate genes affected CHC composition in at least one sex. These genes are associated with fatty acid metabolism and represent mechanistic targets for individual variation in CHC composition.

  18. An investigation of natural genetic variation in the circadian system of Drosophila melanogaster: rhythm characteristics and methods of quantification.

    Science.gov (United States)

    Emery, P T; Morgan, E; Birley, A J

    1994-04-01

    Variation in four characteristics of the circadian locomotor activity rhythm was investigated in 24 true-breeding strains of Drosophila melanogaster with a view to establishing methods of phenotypic measurement sufficiently robust to allow subsequent biometric analysis. Between them, these strains formed a representative sample of the genetic variability of a natural population. Period, phase, definition (the degree to which a rhythmic signal was obscured by noise), and rhythm waveform were all found to vary continuously among the strains, although within each strain the rhythm phenotype was remarkably consistent. Each characteristic was found to be sufficiently robust to permit objective measurement using several different methods of quantification, which were then compared.

  19. Genetic diversity in natural populations of Buriti (Mauritia flexuosa L. f.

    Directory of Open Access Journals (Sweden)

    Liene Rocha Picanço Gomes

    2011-01-01

    Full Text Available This study aimed to characterize the genetic diversity of buriti populations by AFLP (Amplified Fragment LengthPolymorphism markers. The analysis was performed in four populations used by traditional communities in the state of Amazonia(Bom Jesus do Anamã, Lauro Sodré, Santa Luzia do Buiçuzinho, and Esperança II. From each population 30 plants wererandomly selected. To obtain the markers four primer combinations were used. The percentage of polymorphic loci was estimated,the molecular variance among and within populations analyzed and a dendrogram constructed. The primers detected 339 polymorphicloci ranging from 81.1 % to 91.1 % among populations. Analysis of molecular variance attributed 77.18 % to variation within and22.8 % to variation between populations. The dendrogram indicated the formation of two groups, showing that the populations ofBom Jesus do Anamã and Lauro Sodré are genetically most similar and thet the genetic and geographical distances are notcorrelated.

  20. Biogenesis of natural substances - chemistry, metabolism, genetics. Part of a coordinated programme on radiation microbiology

    International Nuclear Information System (INIS)

    Vanek, Z.

    1975-10-01

    Research on the following main topics is reported: applied genetics in antibiotic drug production (tetracycline); formation of ergot alkaloids by saprophytic cultures of Claviceps paspali and C. purpurea; genetic studies of bacidiomycetes (Oudemansiella mucida). In the antibiotic drug production, the effect of mutagenic factors on biosynthetic activity of S. aureofaciens was studied. UV-light and N-methyl-N'-nitro-N-nitrosoguanidine (NMG) were the most effective mutagens. The genetic and metabolic regulation of biosynthesis of tetracycline was studied by using 14 C and 32 P labelled compounds. The formation of ergot alkaloids was found to take place only at a certain stage of development of cultures of Claviceps paspali and C. purpurea. It was found that the ergot alkaloids influence the primary metabolism of the producing cell. Experiments with spores of Oudemansiella mucida showed that the spores are very resistant to UV light (lethal dose 43.000 erg/mm 2 ). The effect of gamma rays and NMG was also studied and the biosynthesis of mucidin was followed using 14 C labelled compounds

  1. Natural genetic variation in Arabidopsis thaliana defense metabolism genes modulates field fitness.

    Science.gov (United States)

    Kerwin, Rachel; Feusier, Julie; Corwin, Jason; Rubin, Matthew; Lin, Catherine; Muok, Alise; Larson, Brandon; Li, Baohua; Joseph, Bindu; Francisco, Marta; Copeland, Daniel; Weinig, Cynthia; Kliebenstein, Daniel J

    2015-04-13

    Natural populations persist in complex environments, where biotic stressors, such as pathogen and insect communities, fluctuate temporally and spatially. These shifting biotic pressures generate heterogeneous selective forces that can maintain standing natural variation within a species. To directly test if genes containing causal variation for the Arabidopsis thaliana defensive compounds, glucosinolates (GSL) control field fitness and are therefore subject to natural selection, we conducted a multi-year field trial using lines that vary in only specific causal genes. Interestingly, we found that variation in these naturally polymorphic GSL genes affected fitness in each of our environments but the pattern fluctuated such that highly fit genotypes in one trial displayed lower fitness in another and that no GSL genotype or genotypes consistently out-performed the others. This was true both across locations and within the same location across years. These results indicate that environmental heterogeneity may contribute to the maintenance of GSL variation observed within Arabidopsis thaliana.

  2. Introducing ZBrush 4

    CERN Document Server

    Keller, Eric

    2011-01-01

    Introducing ZBrush 4 launches readers head-on into fulfilling their artistic potential for sculpting realistic creature, cartoon, and hard surface models in ZBrush. ZBrush's innovative technology and interface can be intimidating to both digital-art beginners as well as veterans who are used to a more conventional modeling environment. This book dispels myths about the difficulty of ZBrush with a thorough tour and exploration of the program's interface. Engaging projects also allow the reader to become comfortable with digital sculpting in with a relaxed and fun book atmosphere. Introducing ZB

  3. Aquaporins in the wild: natural genetic diversity and selective pressure in the PIP gene family in five Neotropical tree species

    Directory of Open Access Journals (Sweden)

    Vendramin Giovanni G

    2010-06-01

    Full Text Available Abstract Background Tropical trees undergo severe stress through seasonal drought and flooding, and the ability of these species to respond may be a major factor in their survival in tropical ecosystems, particularly in relation to global climate change. Aquaporins are involved in the regulation of water flow and have been shown to be involved in drought response; they may therefore play a major adaptive role in these species. We describe genetic diversity in the PIP sub-family of the widespread gene family of Aquaporins in five Neotropical tree species covering four botanical families. Results PIP Aquaporin subfamily genes were isolated, and their DNA sequence polymorphisms characterised in natural populations. Sequence data were analysed with statistical tests of standard neutral equilibrium and demographic scenarios simulated to compare with the observed results. Chloroplast SSRs were also used to test demographic transitions. Most gene fragments are highly polymorphic and display signatures of balancing selection or bottlenecks; chloroplast SSR markers have significant statistics that do not conform to expectations for population bottlenecks. Although not incompatible with a purely demographic scenario, the combination of all tests tends to favour a selective interpretation of extant gene diversity. Conclusions Tropical tree PIP genes may generally undergo balancing selection, which may maintain high levels of genetic diversity at these loci. Genetic variation at PIP genes may represent a response to variable environmental conditions.

  4. Condition dependence and the nature of genetic variation for male sex comb bristle number in Drosophila melanogaster.

    Science.gov (United States)

    Ahuja, Abha; De Vito, Scott; Singh, Rama S

    2011-04-01

    Genetic architecture of variation underlying male sex comb bristle number, a rapidly evolving secondary sexual character of Drosophila, was examined. First, in order to test for condition dependence, diet was manipulated in a set of ten Drosophila melanogaster full-sib families. We confirmed heightened condition dependent expression of sex comb bristle number and its female homologue (distal transverse row bristles) as compared to non-sex sternopleural bristles. Significant genotype by environment effects were detected for the sex traits indicating a genetic basis for condition dependence. Next we measured sex comb bristle number and sternopleural bristle number, as well as residual mass, a commonly used condition index, in a set of thirty half-sib families. Sire effect was not significant for sex comb and sternopleural bristle number, and we detected a strong dominance and/or maternal effect or X chromosome effect for both traits. A strong sire effect was detected for condition and its heritability was the highest as compared to sex comb and sternopleural bristles. We discuss our results in light of the rapid response to divergent artificial selection for sex comb bristle number reported previously. The nature of genetic variation for male sex traits continues to be an important unresolved issue in evolutionary biology.

  5. Introducing Business English

    NARCIS (Netherlands)

    Nickerson, C.; Planken, B.C.

    2015-01-01

    Introducing Business English provides a comprehensive overview of this topic, situating the concepts of Business English and English for Specific Business Purposes within the wider field of English for Special Purposes. This book draws on contemporary teaching and research contexts to demonstrate

  6. Population-genetic nature of copy number variations in the human genome.

    Science.gov (United States)

    Kato, Mamoru; Kawaguchi, Takahisa; Ishikawa, Shumpei; Umeda, Takayoshi; Nakamichi, Reiichiro; Shapero, Michael H; Jones, Keith W; Nakamura, Yusuke; Aburatani, Hiroyuki; Tsunoda, Tatsuhiko

    2010-03-01

    Copy number variations (CNVs) are universal genetic variations, and their association with disease has been increasingly recognized. We designed high-density microarrays for CNVs, and detected 3000-4000 CNVs (4-6% of the genomic sequence) per population that included CNVs previously missed because of smaller sizes and residing in segmental duplications. The patterns of CNVs across individuals were surprisingly simple at the kilo-base scale, suggesting the applicability of a simple genetic analysis for these genetic loci. We utilized the probabilistic theory to determine integer copy numbers of CNVs and employed a recently developed phasing tool to estimate the population frequencies of integer copy number alleles and CNV-SNP haplotypes. The results showed a tendency toward a lower frequency of CNV alleles and that most of our CNVs were explained only by zero-, one- and two-copy alleles. Using the estimated population frequencies, we found several CNV regions with exceptionally high population differentiation. Investigation of CNV-SNP linkage disequilibrium (LD) for 500-900 bi- and multi-allelic CNVs per population revealed that previous conflicting reports on bi-allelic LD were unexpectedly consistent and explained by an LD increase correlated with deletion-allele frequencies. Typically, the bi-allelic LD was lower than SNP-SNP LD, whereas the multi-allelic LD was somewhat stronger than the bi-allelic LD. After further investigation of tag SNPs for CNVs, we conclude that the customary tagging strategy for disease association studies can be applicable for common deletion CNVs, but direct interrogation is needed for other types of CNVs.

  7. Human genetics studies in areas of high natural radiation. IV. Research in radioactive areas

    Energy Technology Data Exchange (ETDEWEB)

    Freire-Maia, A [Faculdade de Ciencias Medicas e Biologicas de Botucatu (Brazil). Departamento de Genetica

    1974-01-01

    A review is made on researches performed in areas with high levels of natural radioactivity. Some considerations are made on the importance and difficulties involved in projects of this kind. Although there is no doubt that natural radioactivity is one of the causes of the so-called spontaneous mutations, the practical demonstration of this assertion is extremely complex. Projects trying to correlate high levels of natural radioactivity with the occurrence of cancer (in general, or specific), leukemia, congenital malformations (in general or specific), neuro-vegetative disturbs, sex ratio, mortality, and physical development, as well as other characteristics. Some researches with animals are also mentioned, and references are given for plant studies. A critical analysis is made of some works relating to human populations.

  8. Human genetics studies in areas of high natural radiation.IV. Research in radioactive areas

    International Nuclear Information System (INIS)

    Freire-Maia, A.

    1974-01-01

    A review is made on researches performed in areas with high levels of natural radioactivity. Some considerations are made on the importance and difficulties involved in projects of this kind. Although there is no doubt that natural radioactivity is one of the causes of the so-called spontaneous mutations, the practical demonstration of this assertion is extremely complex. Projects trying to correlate high levels of natural radioactivity with the occurrence of cancer (in general, or specific), leukemia, congenital malformations (in general or specific), neuro-vegetative disturbs, sex ratio, mortality, and physical development, as well as other characteristics. Some researches with animals are also mentioned, and references are given for plant studies. A critical analysis is made of some works relating to human populations [pt

  9. A population genetic analysis of the potential for a crude oil spill to induce heritable mutations and impact natural populations

    Energy Technology Data Exchange (ETDEWEB)

    Cronin, M.A. [LGL Alaska Research Associates Inc., Anchorage, AK (United States); Bickham, J.W. [Texas A and M University, College Station, TX (United States). Dept. of Wildlife and Fisheries Sciences; LGL Ecological Genetics Inc., Bryan, TX (United States)

    1998-07-01

    The primary environmental impact following an oil spill typically is acute toxicity to fish and wildlife. However, multigenerational effects through toxicant-induced heritable mutations might also occur. Some polycyclic aromatic hydrocarbon (PAH) components of crude oil are potentially mutagenic, although specific components and doses that induce mutations are poorly known. We applied population genetics concepts to assess the extent of mortality and the persistence of deleterious heritable mutations resulting from exposure to potential mutagens, such as crude oil. If lethal mutations are induced, the population will experience some mortality, but the mutations are quickly removed or reduced to low frequency by natural selection. This occurs within one or a few generations when mutations are dominant or partially recessive. Totally recessive alleles persist in low frequency for many generations, but result in relatively little impact on the population, depending on the number of mutated loci. We also applied population genetics concepts to assess the potential for heritable mutations induced by the Exxon Valdez oil spill in Prince William Sound, Alaska, to affect pink salmon populations. We stress that breeding units (e.g., streams with distinct spawning populations of salmon) must be considered individually to assess heritable genetic effects. For several streams impacted by the oil spill, there is inconsistency between observed egg mortality and that expected if lethal heritable mutations had been induced by exposure to crude oil. Observed mortality was either higher or lower than expected depending on the spawning population, year, and cohort considered. Any potential subtle effect of lethal mutations induced by the Exxon Valdez oil spill is overridden by natural environmental variation among spawning areas. We discuss the need to focus on population-level effects in toxicological assessments because fish and wildlife management focuses on populations, not

  10. The roles of genetic drift and natural selection in quantitative trait divergence along an altitudinal gradient in Arabidopsis thaliana.

    Science.gov (United States)

    Luo, Y; Widmer, A; Karrenberg, S

    2015-02-01

    Understanding how natural selection and genetic drift shape biological variation is a central topic in biology, yet our understanding of the agents of natural selection and their target traits is limited. We investigated to what extent selection along an altitudinal gradient or genetic drift contributed to variation in ecologically relevant traits in Arabidopsis thaliana. We collected seeds from 8 to 14 individuals from each of 14 A. thaliana populations originating from sites between 800 and 2700 m above sea level in the Swiss Alps. Seed families were grown with and without vernalization, corresponding to winter-annual and summer-annual life histories, respectively. We analyzed putatively neutral genetic divergence between these populations using 24 simple sequence repeat markers. We measured seven traits related to growth, phenology and leaf morphology that are rarely reported in A. thaliana and performed analyses of altitudinal clines, as well as overall QST-FST comparisons and correlation analyses among pair-wise QST, FST and altitude of origin differences. Multivariate analyses suggested adaptive differentiation along altitude in the entire suite of traits, particularly when expressed in the summer-annual life history. Of the individual traits, a decrease in rosette leaf number in the vegetative state and an increase in leaf succulence with increasing altitude could be attributed to adaptive divergence. Interestingly, these patterns relate well to common within- and between-species trends of smaller plant size and thicker leaves at high altitude. Our results thus offer exciting possibilities to unravel the underlying mechanisms for these conspicuous trends using the model species A. thaliana.

  11. Genetic and biochemical analysis reveals linked QTLs determining natural variation for fruit post-harvest water loss in pepper (Capsicum).

    Science.gov (United States)

    Popovsky-Sarid, Sigal; Borovsky, Yelena; Faigenboim, Adi; Parsons, Eugene P; Lohrey, Gregory T; Alkalai-Tuvia, Sharon; Fallik, Elazar; Jenks, Matthew A; Paran, Ilan

    2017-02-01

    Molecular markers linked to QTLs controlling post-harvest fruit water loss in pepper may be utilized to accelerate breeding for improved shelf life and inhibit over-ripening before harvest. Bell pepper (Capsicum annuum L.) is an important vegetable crop world-wide. However, marketing is limited by the relatively short shelf life of the fruit due to water loss and decay that occur during prolonged storage. Towards breeding pepper with reduced fruit post-harvest water loss (PWL), we studied the genetic, physiological and biochemical basis for natural variation of PWL. We performed quantitative trait locus (QTL) mapping of fruit PWL in multiple generations of an interspecific cross of pepper, which resulted in the identification of two linked QTLs on chromosome 10 that control the trait. We further developed near-isogenic lines (NILs) for characterization of the QTL effects. Transcriptome analysis of the NILs allowed the identification of candidate genes associated with fruit PWL-associated traits such as cuticle biosynthesis, cell wall metabolism and fruit ripening. Significant differences in PWL between the NILs in the immature fruit stage, differentially expressed cuticle-associated genes and differences in the content of specific chemical constituents of the fruit cuticle, indicated a likely influence of cuticle composition on the trait. Reduced PWL in the NILs was associated with delayed over-ripening before harvest, low total soluble solids before storage, and reduced fruit softening after storage. Our study enabled a better understanding of the genetic and biological processes controlling natural variation in fruit PWL in pepper. Furthermore, the genetic materials and molecular markers developed in this study may be utilized to breed peppers with improved shelf life and inhibited over-ripening before harvest.

  12. Genetically distinct isolates of Spirocerca sp. from a naturally infected red fox (Vulpes vulpes) from Denmark.

    Science.gov (United States)

    Al-Sabi, Mohammad Nafi Solaiman; Hansen, Mette Sif; Chriél, Mariann; Holm, Elisabeth; Larsen, Gitte; Enemark, Heidi Larsen

    2014-09-15

    Spirocerca lupi causes formation of nodules that may transform into sarcoma in the walls of aorta, esophagus and stomach of infected canids. In February 2013, post mortem examination of a red fox (Vulpes vulpes) hunted in Denmark revealed the presence of several nodules containing adult worms of Spirocerca sp. in the stomach and the omentum. The nodules largely consisted of fibrous tissue with infiltration of mononuclear cells, neutrophilic granulocytes and macrophages with hemosiderin deposition. Parasitological examination by three copromicroscopic methods, sedimentation, flotation with saturated sugar-salt solution, and sieving failed to detect eggs of Spirocerca sp. in feces collected from the colon. This is the first report of spirocercosis in Denmark, and may have been caused by a recent introduction by migrating paratenic or definitive host. Analysis of two overlapping partial sequences of the cox1 gene, from individual worms, revealed distinct genetic variation (7-9%) between the Danish worms and isolates of S. lupi from Europe, Asia and Africa. This was confirmed by phylogenetic analysis that clearly separated the Danish worms from other isolates of S. lupi. The distinct genetic differences of the current worms compared to other isolates of S. lupi may suggest the presence of a cryptic species within Spirocerca. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Peer Influence, Genetic Propensity, and Binge Drinking: A Natural Experiment and a Replication.

    Science.gov (United States)

    Guo, Guang; Li, Yi; Wang, Hongyu; Cai, Tianji; Duncan, Greg J

    2015-11-01

    The authors draw data from the College Roommate Study (ROOM) and the National Longitudinal Study of Adolescent Health to investigate gene-environment interaction effects on youth binge drinking. In ROOM, the environmental influence was measured by the precollege drinking behavior of randomly assigned roommates. Random assignment safeguards against friend selection and removes the threat of gene-environment correlation that makes gene-environment interaction effects difficult to interpret. On average, being randomly assigned a drinking peer as opposed to a nondrinking peer increased college binge drinking by 0.5-1.0 episodes per month, or 20%-40% the average amount of binge drinking. However, this peer influence was found only among youths with a medium level of genetic propensity for alcohol use; those with either a low or high genetic propensity were not influenced by peer drinking. A replication of the findings is provided in data drawn from Add Health. The study shows that gene-environment interaction analysis can uncover social-contextual effects likely to be missed by traditional sociological approaches.

  14. Disentangling the roles of natural selection and genetic drift in shaping variation at MHC immunity genes.

    Science.gov (United States)

    Sutton, Jolene T; Nakagawa, Shinichi; Robertson, Bruce C; Jamieson, Ian G

    2011-11-01

    The major histocompatibility complex (MHC) forms an integral component of the vertebrate immune response and, due to strong selection pressures, is one of the most polymorphic regions of the entire genome. Despite over 15 years of research, empirical studies offer highly contradictory explanations of the relative roles of different evolutionary forces, selection and genetic drift, acting on MHC genes during population bottlenecks. Here, we take a meta-analytical approach to quantify the results of studies into the effects of bottlenecks on MHC polymorphism. We show that the consequences of selection acting on MHC loci prior to a bottleneck event, combined with drift during the bottleneck, will result in overall loss of MHC polymorphism that is ∼15% greater than loss of neutral genetic diversity. These results are counter to general expectations that selection should maintain MHC polymorphism, but do agree with the results of recent simulation models and at least two empirical studies. Notably, our results suggest that negative frequency-dependent selection could be more important than overdominance for maintaining high MHC polymorphism in pre-bottlenecked populations. © 2011 Blackwell Publishing Ltd.

  15. Expression weighted cell type enrichments reveal genetic and cellular nature of major brain disorders

    Directory of Open Access Journals (Sweden)

    Nathan Gerald Skene

    2016-01-01

    Full Text Available The cell types that trigger the primary pathology in many brain diseases remain largely unknown. One route to understanding the primary pathological cell type for a particular disease is to identify the cells expressing susceptibility genes. Although this is straightforward for monogenic conditions where the causative mutation may alter expression of a cell type specific marker, methods are required for the common polygenic disorders. We developed the Expression Weighted Cell Type Enrichment (EWCE method that uses single cell transcriptomes to generate the probability distribution associated with a gene list having an average level of expression within a cell type. Following validation, we applied EWCE to human genetic data from cases of epilepsy, Schizophrenia, Autism, Intellectual Disability, Alzheimer’s disease, Multiple Sclerosis and anxiety disorders. Genetic susceptibility primarily affected microglia in Alzheimer’s and Multiple Sclerosis; was shared between interneurons and pyramidal neurons in Autism and Schizophrenia; while intellectual disabilities and epilepsy were attributable to a range of cell-types, with the strongest enrichment in interneurons. We hypothesised that the primary cell type pathology could trigger secondary changes in other cell types and these could be detected by applying EWCE to transcriptome data from diseased tissue. In Autism, Schizophrenia and Alzheimer’s disease we find evidence of pathological changes in all of the major brain cell types. These findings give novel insight into the cellular origins and progression in common brain disorders. The methods can be applied to any tissue and disorder and have applications in validating mouse models.

  16. Genetic structuring and fixed polymorphisms in the gene period among natural populations of Lutzomyia longipalpis in Brazil.

    Science.gov (United States)

    Lima Costa, César Raimundo; Freitas, Moises Thiago de Souza; Santiago Figueirêdo, Carlos Alberto; Aragão, Nádia Consuelo; da Silva, Lidiane Gomes; Marcondes, Carlos Brisola; Dias, Raimundo Vieira; Leal-Balbino, Tereza Cristina; Souza, Manuela Barbosa Rodrigues; Ramalho-Ortigão, Marcelo; Balbino, Valdir de Queiroz

    2015-04-01

    Even one hundred years after being originally identified, aspects of the taxonomy of the sand fly Lutzomyia longipalpis, the principal vector of Leishmania infantum in the Americas, remain unresolved for Brazilian populations of this vector. The diversity of morphological, behavioral, biochemical, and ethological characters, as well as the genetic variability detected by molecular markers are indicative of the presence of a complex of species. In this study, a 525 bp fragment of the period gene was used to evaluate sympatric populations of L. longipalpis. A combination of probabilistic methods such as maximum likelihood and genetic assignment approach to investigate sympatric species of L. longipalpis were applied in three populations of Northeast Brazil. Fixed polymorphisms in geographically isolated populations of L. longipalpis from two localities in the state of Ceará and one in the state of Pernambuco, Brazil, was identified in a 525 bp fragment of the gene period (per). Our results suggest a direct relationship between the number of spots found in males' tergites and the genetic variation in cryptic species of L. longipalpis. The fragment used in this study revealed the nature of the ancestral morphotype 1S. New polymorphisms were identified in the gene per which can be used as a genetic barcode to sympatric taxonomy of L. longipalpis. The per gene fragment confirmed the presence of two siblings species of L. longipalpis in Sobral and showed that these same species are present in two other localities, representing an expansion within the L. longipalpis species complex with regards to the states of Ceará and Pernambuco.

  17. Spatial genetic structure in natural populations of Phragmites australis in a mosaic of saline habitats in the Yellow River Delta, China.

    Directory of Open Access Journals (Sweden)

    Lexuan Gao

    Full Text Available Determination of spatial genetic structure (SGS in natural populations is important for both theoretical aspects of evolutionary genetics and their application in species conservation and ecological restoration. In this study, we examined genetic diversity within and among the natural populations of a cosmopolitan grass Phragmites australis (common reed in the Yellow River Delta (YRD, China, where a mosaic of habitat patches varying in soil salinity was detected. We demonstrated that, despite their close geographic proximity, the common reed populations in the YRD significantly diverged at six microsatellite loci, exhibiting a strong association of genetic variation with habitat heterogeneity. Genetic distances among populations were best explained as a function of environmental difference, rather than geographical distance. Although the level of genetic divergence among populations was relatively low (F'(ST =0.073, weak but significant genetic differentiation, as well as the concordance between ecological and genetic landscapes, suggests spatial structuring of genotypes in relation to patchy habitats. These findings not only provided insights into the population dynamics of common reed in changing environments, but also demonstrated the feasibility of using habitat patches in a mosaic landscape as test systems to identify appropriate genetic sources for ecological restoration.

  18. Back to America: tracking the origin of European introduced populations of Quercus rubra L.

    Science.gov (United States)

    Merceron, Nastasia R; Leroy, Thibault; Chancerel, Emilie; Romero-Severson, Jeanne; Borkowski, Daniel S; Ducousso, Alexis; Monty, Arnaud; Porté, Annabel J; Kremer, Antoine

    2017-09-01

    Quercus rubra has been introduced in Europe since the end of the 17th century. It is widely distributed today across this continent and considered invasive in some countries. Here, we investigated the distribution of genetic diversity of both native and introduced populations with the aim of tracing the origin of introduced populations. A large sampling of 883 individuals from 73 native and 38 European locations were genotyped at 69 SNPs. In the natural range, we found a continuous geographic gradient of variation with a predominant latitudinal component. We explored the existence of ancestral populations by performing Bayesian clustering analysis and found support for two or three ancestral genetic clusters. Approximate Bayesian Computations analyses based on these two or three clusters support recent extensive secondary contacts between them, suggesting that present-day continuous genetic variation resulted from recent admixture. In the introduced range, one main genetic cluster was not recovered in Europe, suggesting that source populations were preferentially located in the northern part of the natural distribution. However, our results cannot refute the introduction of populations from the southern states that did not survive in Europe.

  19. Natural genetic variation in Arabidopsis thaliana defense metabolism genes modulates field fitness

    Science.gov (United States)

    Kerwin, Rachel; Feusier, Julie; Corwin, Jason; Rubin, Matthew; Lin, Catherine; Muok, Alise; Larson, Brandon; Li, Baohua; Joseph, Bindu; Francisco, Marta; Copeland, Daniel; Weinig, Cynthia; Kliebenstein, Daniel J

    2015-01-01

    Natural populations persist in complex environments, where biotic stressors, such as pathogen and insect communities, fluctuate temporally and spatially. These shifting biotic pressures generate heterogeneous selective forces that can maintain standing natural variation within a species. To directly test if genes containing causal variation for the Arabidopsis thaliana defensive compounds, glucosinolates (GSL) control field fitness and are therefore subject to natural selection, we conducted a multi-year field trial using lines that vary in only specific causal genes. Interestingly, we found that variation in these naturally polymorphic GSL genes affected fitness in each of our environments but the pattern fluctuated such that highly fit genotypes in one trial displayed lower fitness in another and that no GSL genotype or genotypes consistently out-performed the others. This was true both across locations and within the same location across years. These results indicate that environmental heterogeneity may contribute to the maintenance of GSL variation observed within Arabidopsis thaliana. DOI: http://dx.doi.org/10.7554/eLife.05604.001 PMID:25867014

  20. The Use of Genetic Mechanisms and Behavioral Characteristics to Control Natural Populations of the German Cockroach.

    Science.gov (United States)

    1981-03-01

    release of sterile males into natural populations of the German cockroach. Submitted to Entomologia exp. & Appl. Feb., 1981. A first draft was...populations of the German cockroach. Subm. Entomologia Exp. & Appl. Feb., 1981. aEight other publications of earlier research on this Contract have

  1. Introducing English grammar

    CERN Document Server

    Borjars, Kersti

    2013-01-01

    Answering key questions such as 'Why study grammar?' and 'What is standard English?', Introducing English Grammar guides readers through the practical analysis of the syntax of English sentences. With all special terms carefully explained as they are introduced, the book is written for readers with no previous experience of grammatical analysis. It is ideal for all those beginning their study of linguistics, English language or speech pathology, as well as students with primarily literary interests who need to cover the basics of linguistic analysis. The approach taken is in line with current research in grammar, a particular advantage for students who may go on to study syntax in more depth. All the examples and exercises use real language taken from newspaper articles, non-standard dialects and include excerpts from studies of patients with language difficulties. Students are encouraged to think about the terminology as a tool kit for studying language and to test what can and cannot be described using thes...

  2. Genetic characterization of Trypanosoma cruzi natural clones from the state of Paraíba, Brazil

    Directory of Open Access Journals (Sweden)

    Christian Barnabé

    2005-05-01

    Full Text Available Eighteen Trypanosoma cruzi stocks from the state of Paraíba, Brazil, isolated from man, wild mammals, and triatomine bugs were studied by multilocus enzyme electrophoresis and random primed amplified polymorphic DNA. Despite the low number of stocks, a notable genetic, genotypic, and phylogenetic diversity was recorded. The presence of the two main phylogenetic subdivisions, T. cruzi I and II, was recorded. The strong linkage disequilibrium observed in the population under survey suggests that T. cruzi undergoes predominant clonal evolution in this area too, although this result should be confirmed by a broader sample. The pattern of clonal variation does not suggests a recent origin by founder effect with a limited number of different genotypes.

  3. Nature, Nurture, and Cancer Risks: Genetic and Nutritional Contributions to Cancer.

    Science.gov (United States)

    Theodoratou, Evropi; Timofeeva, Maria; Li, Xue; Meng, Xiangrui; Ioannidis, John P A

    2017-08-21

    It is speculated that genetic variants are associated with differential responses to nutrients (known as gene-diet interactions) and that these variations may be linked to different cancer risks. In this review, we critically evaluate the evidence across 314 meta-analyses of observational studies and randomized controlled trials of dietary risk factors and the five most common cancers (breast, lung, prostate, colorectal, and stomach). We also critically evaluate the evidence across 13 meta-analyses of observational studies of gene-diet interactions for the same cancers. Convincing evidence for association was found only for the intake of alcohol and whole grains in relation to colorectal cancer risk. Three nutrient associations had highly suggestive evidence and another 15 associations had suggestive evidence. Among the examined gene-diet interactions, only one had moderately strong evidence.

  4. Disentangling Genetic and Environmental Influences on Children's Development:Introducing A Novel Methodology%分离遗传与环境对儿童发展的影响:介绍一个新颖的研究方法

    Institute of Scientific and Technical Information of China (English)

    Gordon T. Harold; Katherine H. Shelton; Frances Rice; Jacky Boivin; Dale Hay; Marianne Van Den Bree; Anita Thapar

    2008-01-01

    本文介绍一个可以用于研究遗传与环境互动的新颖方法.此研究收集了上千个4~10岁儿童的数据.这些儿童的出生都借助于不同的辅助受孕技术(Assisted Reproductive Technologies),包括试管婴儿、精子捐赠、卵子捐赠、胚胎捐赠及代孕技术.本项目通过妇科(助孕)医院收集被试的行为数据,包括家庭互动、养育方式、父母婚姻质量、家庭成员的心理健康及经济状况等.本文选择性地介绍一些分析的结果,以彰显这种设计在分离遗传和产前产后环境对儿童发展的贡献.首先,我们比较了"助孕"儿童与"自然孕"儿童在父母冲突、父母对子女敌意以及儿童抑郁症状之间关系的异同.其次,我们比较了这两组儿童在父母抑郁症状、家庭关系质量以及儿童抑郁症状之间关系的异同.再次,本文介绍了这一可分离遗传与环境因素的研究设计.最后,我们讨论了这一设计对发展心理病干预及预防的意义.%The present study describes a novel methodology to examine the interplay between genetic and environmental influences on children's development. Families of children aged 4 - 10 years born by one of five methods of assisted reproductive technologies, specifically homologous in vitro fertilization (IVF), sperm donation, egg donation, embryo donation, and gestational surrogacy, were contacted through fertility clinics and mailed a set of questionnaires focusing on the quality of family interaction, parenting, marital satisfaction, parent and child psychological health, economic conditions and family demographics. Analyses are described that highlight the novelty of this research design to disentangle genetic, intrauterine and early social environmental influences on children's development. First, results are described whereby comparisons were made between children born through assisted reproductive technologies and children conceived naturally in relation to patterns of

  5. Novel methods for genetic transformation of natural Bacillus subtilis isolates used to study the regulation of the mycosubtilin and surfactin synthetases

    NARCIS (Netherlands)

    Duitman, Erwin H.; Wyczawski, Dobek; Boven, Ludolf G.; Venema, Gerard; Kuipers, Oscar P.; Hamoen, Leendert W.

    Natural isolates of Bacillus subtilis are often difficult to transform due to their low genetic competence levels. Here we describe two methods that stimulate natural transformation. The first method uses plasmid pGSP12, which expresses the competence transcription factor ComK and stimulates

  6. Genetic complexity and multiple infections with more Parvovirus species in naturally infected cats

    Directory of Open Access Journals (Sweden)

    Battilani Mara

    2011-03-01

    Full Text Available Abstract Parvoviruses of carnivores include three closely related autonomous parvoviruses: canine parvovirus (CPV, feline panleukopenia virus (FPV and mink enteritis virus (MEV. These viruses cause a variety of serious diseases, especially in young patients, since they have a remarkable predilection for replication in rapidly dividing cells. FPV is not the only parvovirus species which infects cats; in addition to MEV, the new variants of canine parvovirus, CPV-2a, 2b and 2c have also penetrated the feline host-range, and they are able to infect and replicate in cats, causing diseases indistinguishable from feline panleukopenia. Furthermore, as cats are susceptible to both CPV-2 and FPV viruses, superinfection and co-infection with multiple parvovirus strains may occur, potentially facilitating recombination and high genetic heterogeneity. In the light of the importance of cats as a potential source of genetic diversity for parvoviruses and, since feline panleukopenia virus has re-emerged as a major cause of mortality in felines, the present study has explored the molecular characteristics of parvovirus strains circulating in cat populations. The most significant findings reported in this study were (a the detection of mixed infection FPV/CPV with the presence of one parvovirus variant which is a true intermediate between FPV/CPV and (b the quasispecies cloud size of one CPV sample variant 2c. In conclusion, this study provides new important results about the evolutionary dynamics of CPV infections in cats, showing that CPV has presumably started a new process of readaptation in feline hosts.

  7. Introducing Program Evaluation Models

    Directory of Open Access Journals (Sweden)

    Raluca GÂRBOAN

    2008-02-01

    Full Text Available Programs and project evaluation models can be extremely useful in project planning and management. The aim is to set the right questions as soon as possible in order to see in time and deal with the unwanted program effects, as well as to encourage the positive elements of the project impact. In short, different evaluation models are used in order to minimize losses and maximize the benefits of the interventions upon small or large social groups. This article introduces some of the most recently used evaluation models.

  8. Hybridisation between native Oreochromis species and introduced ...

    African Journals Online (AJOL)

    The Nile tilapia Oreochromis niloticus has been introduced throughout Africa outside its native range for aquaculture purposes. Hybridisation between escaped O. niloticus and native Oreochromis species is of concern due to potential negative effects on wild genetic resources for conservation, aquaculture and capture ...

  9. Identifying Genetic Signatures of Natural Selection Using Pooled Population Sequencing in Picea abies.

    Science.gov (United States)

    Chen, Jun; Källman, Thomas; Ma, Xiao-Fei; Zaina, Giusi; Morgante, Michele; Lascoux, Martin

    2016-07-07

    The joint inference of selection and past demography remain a costly and demanding task. We used next generation sequencing of two pools of 48 Norway spruce mother trees, one corresponding to the Fennoscandian domain, and the other to the Alpine domain, to assess nucleotide polymorphism at 88 nuclear genes. These genes are candidate genes for phenological traits, and most belong to the photoperiod pathway. Estimates of population genetic summary statistics from the pooled data are similar to previous estimates, suggesting that pooled sequencing is reliable. The nonsynonymous SNPs tended to have both lower frequency differences and lower FST values between the two domains than silent ones. These results suggest the presence of purifying selection. The divergence between the two domains based on synonymous changes was around 5 million yr, a time similar to a recent phylogenetic estimate of 6 million yr, but much larger than earlier estimates based on isozymes. Two approaches, one of them novel and that considers both FST and difference in allele frequencies between the two domains, were used to identify SNPs potentially under diversifying selection. SNPs from around 20 genes were detected, including genes previously identified as main target for selection, such as PaPRR3 and PaGI. Copyright © 2016 Chen et al.

  10. Patterns of ancestry, signatures of natural selection, and genetic association with stature in Western African pygmies.

    Directory of Open Access Journals (Sweden)

    Joseph P Jarvis

    Full Text Available African Pygmy groups show a distinctive pattern of phenotypic variation, including short stature, which is thought to reflect past adaptation to a tropical environment. Here, we analyze Illumina 1M SNP array data in three Western Pygmy populations from Cameroon and three neighboring Bantu-speaking agricultural populations with whom they have admixed. We infer genome-wide ancestry, scan for signals of positive selection, and perform targeted genetic association with measured height variation. We identify multiple regions throughout the genome that may have played a role in adaptive evolution, many of which contain loci with roles in growth hormone, insulin, and insulin-like growth factor signaling pathways, as well as immunity and neuroendocrine signaling involved in reproduction and metabolism. The most striking results are found on chromosome 3, which harbors a cluster of selection and association signals between approximately 45 and 60 Mb. This region also includes the positional candidate genes DOCK3, which is known to be associated with height variation in Europeans, and CISH, a negative regulator of cytokine signaling known to inhibit growth hormone-stimulated STAT5 signaling. Finally, pathway analysis for genes near the strongest signals of association with height indicates enrichment for loci involved in insulin and insulin-like growth factor signaling.

  11. Bacteria are small but not stupid: cognition, natural genetic engineering and socio-bacteriology.

    Science.gov (United States)

    Shapiro, J A

    2007-12-01

    Forty years' experience as a bacterial geneticist has taught me that bacteria possess many cognitive, computational and evolutionary capabilities unimaginable in the first six decades of the twentieth century. Analysis of cellular processes such as metabolism, regulation of protein synthesis, and DNA repair established that bacteria continually monitor their external and internal environments and compute functional outputs based on information provided by their sensory apparatus. Studies of genetic recombination, lysogeny, antibiotic resistance and my own work on transposable elements revealed multiple widespread bacterial systems for mobilizing and engineering DNA molecules. Examination of colony development and organization led me to appreciate how extensive multicellular collaboration is among the majority of bacterial species. Contemporary research in many laboratories on cell-cell signaling, symbiosis and pathogenesis show that bacteria utilise sophisticated mechanisms for intercellular communication and even have the ability to commandeer the basic cell biology of 'higher' plants and animals to meet their own needs. This remarkable series of observations requires us to revise basic ideas about biological information processing and recognise that even the smallest cells are sentient beings.

  12. Genetic Diversity of a Natural Population of Apple stem pitting virus Isolated from Apple in Korea

    Directory of Open Access Journals (Sweden)

    Ju Yeon Yoon

    2014-06-01

    Full Text Available Apple stem pitting virus (ASPV, of the Foveavirus genus in the family Betaflexiviridae, is one of the most common viruses of apple and pear trees. To examine variability of the coat protein (CP gene from ASPV, eight isolates originating from 251 apple trees, which were collected from 22 apple orchards located in intensive apple growing areas of the North Gyeongsang and North Jeolla Provinces in Korea, were sequenced and compared. The nucleotide sequence identity of the CP gene of eight ASPV isolates ranged from 77.0 to 97.0%, while the amino acid sequence identity ranged from 87.7 to 98.5%. The N-terminal region of the viral CP gene was highly variable, whereas the C-terminal region was conserved. Genetic algorithm recombination detection (GARD and single breakpoint recombination (SBP analyses identified base substitutions between eight ASPV isolates at positions 54 and 57 and position 771, respectively. GABranch analysis was used to determine whether the eight isolates evolved due to positive selection. All values in the GABranch analysis showed a ratio of substitution rates at non-synonymous and synonymous sites (dNS/dS below 1, suggestive of strong negative selection forces during ASPV CP history. Although negative selection dominated CP evolution in the eight ASPV isolates, SLAC and FEL tests identified four possible positive selection sites at codons 10, 22, 102, and 158. This is the first study of the ASPV genome in Korea.

  13. Detection of PrPres in genetically susceptible fetuses from sheep with natural scrapie.

    Directory of Open Access Journals (Sweden)

    María Carmen Garza

    Full Text Available Scrapie is a transmissible spongiform encephalopathy with a wide PrPres dissemination in many non-neural tissues and with high levels of transmissibility within susceptible populations. Mechanisms of transmission are incompletely understood. It is generally assumed that it is horizontally transmitted by direct contact between animals or indirectly through the environment, where scrapie can remain infectious for years. In contrast, in utero vertical transmission has never been demonstrated and has rarely been studied. Recently, the use of the protein misfolding cyclic amplification technique (PMCA has allowed prion detection in various tissues and excretions in which PrPres levels have been undetectable by traditional assays. The main goal of this study was to detect PrPres in fetal tissues and the amniotic fluid from natural scrapie infected ewes using the PMCA technique. Six fetuses from three infected pregnant ewes in an advanced clinical stage of the disease were included in the study. From each fetus, amniotic fluid, brain, spleen, ileo-cecal valve and retropharyngeal lymph node samples were collected and analyzed using Western blotting and PMCA. Although all samples were negative using Western blotting, PrPres was detected after in vitro amplification. Our results represent the first time the biochemical detection of prions in fetal tissues, suggesting that the in utero transmission of scrapie in natural infected sheep might be possible.

  14. A short-term load forecasting model of natural gas based on optimized genetic algorithm and improved BP neural network

    International Nuclear Information System (INIS)

    Yu, Feng; Xu, Xiaozhong

    2014-01-01

    Highlights: • A detailed data processing will make more accurate results prediction. • Taking a full account of more load factors to improve the prediction precision. • Improved BP network obtains higher learning convergence. • Genetic algorithm optimized by chaotic cat map enhances the global search ability. • The combined GA–BP model improved by modified additional momentum factor is superior to others. - Abstract: This paper proposes an appropriate combinational approach which is based on improved BP neural network for short-term gas load forecasting, and the network is optimized by the real-coded genetic algorithm. Firstly, several kinds of modifications are carried out on the standard neural network to accelerate the convergence speed of network, including improved additional momentum factor, improved self-adaptive learning rate and improved momentum and self-adaptive learning rate. Then, it is available to use the global search capability of optimized genetic algorithm to determine the initial weights and thresholds of BP neural network to avoid being trapped in local minima. The ability of GA is enhanced by cat chaotic mapping. In light of the characteristic of natural gas load for Shanghai, a series of data preprocessing methods are adopted and more comprehensive load factors are taken into account to improve the prediction accuracy. Such improvements facilitate forecasting efficiency and exert maximum performance of the model. As a result, the integration model improved by modified additional momentum factor gets more ideal solutions for short-term gas load forecasting, through analyses and comparisons of the above several different combinational algorithms

  15. Metabolome-genome-wide association study dissects genetic architecture for generating natural variation in rice secondary metabolism

    Science.gov (United States)

    Matsuda, Fumio; Nakabayashi, Ryo; Yang, Zhigang; Okazaki, Yozo; Yonemaru, Jun-ichi; Ebana, Kaworu; Yano, Masahiro; Saito, Kazuki

    2015-01-01

    Plants produce structurally diverse secondary (specialized) metabolites to increase their fitness for survival under adverse environments. Several bioactive compounds for new drugs have been identified through screening of plant extracts. In this study, genome-wide association studies (GWAS) were conducted to investigate the genetic architecture behind the natural variation of rice secondary metabolites. GWAS using the metabolome data of 175 rice accessions successfully identified 323 associations among 143 single nucleotide polymorphisms (SNPs) and 89 metabolites. The data analysis highlighted that levels of many metabolites are tightly associated with a small number of strong quantitative trait loci (QTLs). The tight association may be a mechanism generating strains with distinct metabolic composition through the crossing of two different strains. The results indicate that one plant species produces more diverse phytochemicals than previously expected, and plants still contain many useful compounds for human applications. PMID:25267402

  16. Molecular ecology of the big brown bat (Eptesicus fuscus): Genetic and natural history variation in a hybrid zone

    Science.gov (United States)

    Neubaum, M.A.; Douglas, M.R.; Douglas, M.E.; O'Shea, T.J.

    2007-01-01

    Several geographically distinct mitochondrial DNA (mtDNA) lineages of the big brown bat (Eptesicus fuscus) have been documented in North America. Individuals from 2 of these lineages, an eastern and a western form, co-occur within maternity colonies in Colorado. The discovery of 2 divergent mtDNA lineages in sympatry prompted a set of questions regarding possible biological differences between haplotypes. We captured big brown bats at maternity roosts in Colorado and recorded data on body size, pelage color, litter size, roosting and overwintering behaviors, and local distributions. Wing biopsies were collected for genetic analysis. The ND2 region of the mtDNA molecule was used to determine lineage of the bats. In addition, nuclear DNA (nDNA) intron 1 of the ??-globin gene was used to determine if mtDNA lineages are hybridizing. Eastern and western mtDNA lineages differed by 10.3% sequence divergence and examination of genetic data suggests recent population expansion for both lineages. Differences in distribution occur along the Colorado Front Range, with an increasing proportion of western haplotypes farther south. Results from nDNA analyses demonstrated hybridization between the 2 lineages. Additionally, no outstanding distinctiveness was found between the mtDNA lineages in natural history characters examined. We speculate that historical climate changes separated this species into isolated eastern and western populations, and that secondary contact with subsequent interbreeding was facilitated by European settlement. ?? 2007 American Society of Mammalogists.

  17. Genetic diversity/impurity estimation in sources of natural resistance against cotton leaf curl disease in pakistan

    International Nuclear Information System (INIS)

    Sarwar, G.

    2007-01-01

    Cotton accounts for more than 60% of Pakistan's export earnings through the export of both raw cotton and cotton products. An epidemic of cotton leaf curl disease (CLCuD) in Pakistan during the 1990s led to the withdrawal of high yielding cotton cultivars. Due of their susceptibility to the disease. The identification of natural resistance in some genotypes provided a means to manage reduce losses due to the disease. But it has been an adversity that almost all these resistant varieties have ultimately 'lost' their resistance. There are also reports that the original sources of resistance, as well as the varieties developed from them, are now susceptible to the disease when grafted with infected scion. For the present studies. Seed of two resistant varieties (LRA-5166 and (CP-152) was obtained from six different research organizations. Plants raised from these seed were grafted with symptomatic scion and used for morphological comparisons. Our results indicated that the genetic pool of these cultivars is not well maintained and that an unacceptable diversity impurity is present within and among the genetic stock of both these lines. There is thus a requirement for screening of these elite lines at the molecular level to ensure the purity of these varieties for future development. The virus causing CLCuD showed change by recombination making the search for new sources of resistance, as well as the maintenance of established sources, indispensable for the sustainable cotton production in Pakistan. (author)

  18. Genetic Architecture of Natural Variation Underlying Adult Foraging Behavior That Is Essential for Survival of Drosophila melanogaster.

    Science.gov (United States)

    Lee, Yuh Chwen G; Yang, Qian; Chi, Wanhao; Turkson, Susie A; Du, Wei A; Kemkemer, Claus; Zeng, Zhao-Bang; Long, Manyuan; Zhuang, Xiaoxi

    2017-05-01

    Foraging behavior is critical for the fitness of individuals. However, the genetic basis of variation in foraging behavior and the evolutionary forces underlying such natural variation have rarely been investigated. We developed a systematic approach to assay the variation in survival rate in a foraging environment for adult flies derived from a wild Drosophila melanogaster population. Despite being such an essential trait, there is substantial variation of foraging behavior among D. melanogaster strains. Importantly, we provided the first evaluation of the potential caveats of using inbred Drosophila strains to perform genome-wide association studies on life-history traits, and concluded that inbreeding depression is unlikely a major contributor for the observed large variation in adult foraging behavior. We found that adult foraging behavior has a strong genetic component and, unlike larval foraging behavior, depends on multiple loci. Identified candidate genes are enriched in those with high expression in adult heads and, demonstrated by expression knock down assay, are involved in maintaining normal functions of the nervous system. Our study not only identified candidate genes for foraging behavior that is relevant to individual fitness, but also shed light on the initial stage underlying the evolution of the behavior. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  19. Genetic stability of foot-and-mouth disease virus during long-term infections in natural hosts.

    Science.gov (United States)

    Ramirez-Carvajal, Lisbeth; Pauszek, Steven J; Ahmed, Zaheer; Farooq, Umer; Naeem, Khalid; Shabman, Reed S; Stockwell, Timothy B; Rodriguez, Luis L

    2018-01-01

    Foot-and-mouth disease (FMD) is a severe infection caused by a picornavirus that affects livestock and wildlife. Persistence in ruminants is a well-documented feature of Foot-and-mouth disease virus (FMDV) pathogenesis and a major concern for disease control. Persistently infected animals harbor virus for extended periods, providing a unique opportunity to study within-host virus evolution. This study investigated the genetic dynamics of FMDV during persistent infections of naturally infected Asian buffalo. Using next-generation sequencing (NGS) we obtained 21 near complete FMDV genome sequences from 12 sub-clinically infected buffalo over a period of one year. Four animals yielded only one virus isolate and one yielded two isolates of different serotype suggesting a serial infection. Seven persistently infected animals yielded more than one virus of the same serotype showing a long-term intra-host viral genetic divergence at the consensus level of less than 2.5%. Quasi-species analysis showed few nucleotide variants and non-synonymous substitutions of progeny virus despite intra-host persistence of up to 152 days. Phylogenetic analyses of serotype Asia-1 VP1 sequences clustered all viruses from persistent animals with Group VII viruses circulating in Pakistan in 2011, but distinct from those circulating on 2008-2009. Furthermore, signature amino acid (aa) substitutions were found in the antigenically relevant VP1 of persistent viruses compared with viruses from 2008-2009. Intra-host purifying selective pressure was observed, with few codons in structural proteins undergoing positive selection. However, FMD persistent viruses did not show a clear pattern of antigenic selection. Our findings provide insight into the evolutionary dynamics of FMDV populations within naturally occurring subclinical and persistent infections that may have implications to vaccination strategies in the region.

  20. Genetic stability of foot-and-mouth disease virus during long-term infections in natural hosts.

    Directory of Open Access Journals (Sweden)

    Lisbeth Ramirez-Carvajal

    Full Text Available Foot-and-mouth disease (FMD is a severe infection caused by a picornavirus that affects livestock and wildlife. Persistence in ruminants is a well-documented feature of Foot-and-mouth disease virus (FMDV pathogenesis and a major concern for disease control. Persistently infected animals harbor virus for extended periods, providing a unique opportunity to study within-host virus evolution. This study investigated the genetic dynamics of FMDV during persistent infections of naturally infected Asian buffalo. Using next-generation sequencing (NGS we obtained 21 near complete FMDV genome sequences from 12 sub-clinically infected buffalo over a period of one year. Four animals yielded only one virus isolate and one yielded two isolates of different serotype suggesting a serial infection. Seven persistently infected animals yielded more than one virus of the same serotype showing a long-term intra-host viral genetic divergence at the consensus level of less than 2.5%. Quasi-species analysis showed few nucleotide variants and non-synonymous substitutions of progeny virus despite intra-host persistence of up to 152 days. Phylogenetic analyses of serotype Asia-1 VP1 sequences clustered all viruses from persistent animals with Group VII viruses circulating in Pakistan in 2011, but distinct from those circulating on 2008-2009. Furthermore, signature amino acid (aa substitutions were found in the antigenically relevant VP1 of persistent viruses compared with viruses from 2008-2009. Intra-host purifying selective pressure was observed, with few codons in structural proteins undergoing positive selection. However, FMD persistent viruses did not show a clear pattern of antigenic selection. Our findings provide insight into the evolutionary dynamics of FMDV populations within naturally occurring subclinical and persistent infections that may have implications to vaccination strategies in the region.

  1. Selection for long and short sleep duration in Drosophila melanogaster reveals the complex genetic network underlying natural variation in sleep.

    Science.gov (United States)

    Harbison, Susan T; Serrano Negron, Yazmin L; Hansen, Nancy F; Lobell, Amanda S

    2017-12-01

    Why do some individuals need more sleep than others? Forward mutagenesis screens in flies using engineered mutations have established a clear genetic component to sleep duration, revealing mutants that convey very long or short sleep. Whether such extreme long or short sleep could exist in natural populations was unknown. We applied artificial selection for high and low night sleep duration to an outbred population of Drosophila melanogaster for 13 generations. At the end of the selection procedure, night sleep duration diverged by 9.97 hours in the long and short sleeper populations, and 24-hour sleep was reduced to 3.3 hours in the short sleepers. Neither long nor short sleeper lifespan differed appreciably from controls, suggesting little physiological consequences to being an extreme long or short sleeper. Whole genome sequence data from seven generations of selection revealed several hundred thousand changes in allele frequencies at polymorphic loci across the genome. Combining the data from long and short sleeper populations across generations in a logistic regression implicated 126 polymorphisms in 80 candidate genes, and we confirmed three of these genes and a larger genomic region with mutant and chromosomal deficiency tests, respectively. Many of these genes could be connected in a single network based on previously known physical and genetic interactions. Candidate genes have known roles in several classic, highly conserved developmental and signaling pathways-EGFR, Wnt, Hippo, and MAPK. The involvement of highly pleiotropic pathway genes suggests that sleep duration in natural populations can be influenced by a wide variety of biological processes, which may be why the purpose of sleep has been so elusive.

  2. Selection for long and short sleep duration in Drosophila melanogaster reveals the complex genetic network underlying natural variation in sleep.

    Directory of Open Access Journals (Sweden)

    Susan T Harbison

    2017-12-01

    Full Text Available Why do some individuals need more sleep than others? Forward mutagenesis screens in flies using engineered mutations have established a clear genetic component to sleep duration, revealing mutants that convey very long or short sleep. Whether such extreme long or short sleep could exist in natural populations was unknown. We applied artificial selection for high and low night sleep duration to an outbred population of Drosophila melanogaster for 13 generations. At the end of the selection procedure, night sleep duration diverged by 9.97 hours in the long and short sleeper populations, and 24-hour sleep was reduced to 3.3 hours in the short sleepers. Neither long nor short sleeper lifespan differed appreciably from controls, suggesting little physiological consequences to being an extreme long or short sleeper. Whole genome sequence data from seven generations of selection revealed several hundred thousand changes in allele frequencies at polymorphic loci across the genome. Combining the data from long and short sleeper populations across generations in a logistic regression implicated 126 polymorphisms in 80 candidate genes, and we confirmed three of these genes and a larger genomic region with mutant and chromosomal deficiency tests, respectively. Many of these genes could be connected in a single network based on previously known physical and genetic interactions. Candidate genes have known roles in several classic, highly conserved developmental and signaling pathways-EGFR, Wnt, Hippo, and MAPK. The involvement of highly pleiotropic pathway genes suggests that sleep duration in natural populations can be influenced by a wide variety of biological processes, which may be why the purpose of sleep has been so elusive.

  3. IR and Raman studies of oil and seedcake extracts from natural and genetically modified flax seeds

    Science.gov (United States)

    Żuk, M.; Dymińska, L.; Kulma, A.; Boba, A.; Prescha, A.; Szopa, J.; Mączka, M.; Zając, A.; Szołtysek, K.; Hanuza, J.

    2011-03-01

    Flax plant of the third generation (F3) overexpressing key genes of flavonoid pathway cultivated in field in 2008 season was used as the plant material throughout this study. The biochemical properties of seed, oil and seedcake extracts from natural and transgenic flax plants were compared. Overproduction of flavonoids (kaempferol), phenolic acids (coumaric, ferulic/synapic) and lignan-secoisolariciresinol diglucoside (SDG) in oil and extracts from transgenic seeds has been revealed providing a valuable source of these compounds for biotechnological application. The changes in fatty acids composition and increase in their stability against oxidation along three plant generations were also detected. The analysis of oil and seedcake extracts was performed using Raman and IR spectroscopy. The wavenumbers and integral intensities of Raman and IR bands were used to identify the components of phenylpropanoid pathway in oil and seedcake extracts from control and transgenic flax seeds. The spectroscopic data were compared to those obtained from biochemical analysis.

  4. Mexico introduces pentavalent vaccine.

    Science.gov (United States)

    1999-08-01

    Combination vaccines have been introduced in Mexico. The national immunization program has incorporated the measles-mumps-rubella (MMR) vaccines in 1998, and the pentavalent vaccine in 1999. The two categories of antigen composition in combination vaccines are: 1) multiple different antigenic types of a single pathogen, such as the 23 valent pneumococcal polysaccharide vaccine, and 2) antigens from different pathogens causing different diseases, such as the DPT and MMR vaccines. Pentavalent vaccines are included in the second category. The vaccine protects against diphtheria, tetanus, pertussis, hepatitis B, and other diseases produced by Haemophilus influenzae type b (Hib). Combined diphtheria, tetanus, pertussis, hepatitis B, and Haemophilus influenza type b (DTP-HB/Hib) vaccine has been distributed to 87% of Mexican children under 1 year of age. Over 800,000 doses of pentavalent vaccine have been administered.

  5. Genetic diversity and natural selection of Plasmodium vivax multi-drug resistant gene (pvmdr1) in Mesoamerica.

    Science.gov (United States)

    González-Cerón, Lilia; Montoya, Alberto; Corzo-Gómez, Josselin C; Cerritos, Rene; Santillán, Frida; Sandoval, Marco A

    2017-07-01

    The Plasmodium vivax multidrug resistant 1 gene (pvmdr1) codes for a transmembrane protein of the parasite's digestive vacuole. It is likely that the pvmdr1 gene mutations occur at different sites by convergent evolution. In here, the genetic variation of pvmdr1 at three sites of the Mesoamerican region was studied. Since 1950s, malarious patients of those areas have been treated only with chloroquine and primaquine. Blood samples from patients infected with P. vivax were obtained in southern Mexico (SMX), in the Northwest (NIC-NW) and in the northeast (NIC-NE) of Nicaragua. Genomic DNA was obtained and fragments of pvmdr1 were amplified and sequenced. The nucleotide and amino acid changes as well as the haplotype frequency in pvmdr1 were determined per strain and per geographic site. The sequences of pvmdr1 obtained from the studied regions were compared with homologous sequences from the GenBank database to explore the P. vivax genetic structure. In 141 parasites, eight nucleotide changes (two changes were synonymous and other six were nonsynonymous) were detected in 1536 bp. The PvMDR1 amino acid changes Y976F, F1076FL were predominant in endemic parasites from NIC-NE and outbreak parasites in NIC-NW but absent in SMX. Thirteen haplotypes were resolved, and found to be closely related, but their frequency at each geographic site was different (P = 0.0001). The pvmdr1 codons 925-1083 gene fragment showed higher genetic and haplotype diversity in parasites from NIC-NE than the other areas outside Latin America. The haplotype networks suggested local diversification of pvmdr1 and no significant departure from neutrality. The F ST values were low to moderate regionally, but high between NIC-NE or NIC-NW and other regions inside and outside Latin America. The pvmdr1 gene might have diversified recently at regional level. In the absence of significant natural, genetic drift might have caused differential pvmdr1 haplotype frequencies at different geographic sites

  6. Human Inspired Self-developmental Model of Neural Network (HIM): Introducing Content/Form Computing

    Science.gov (United States)

    Krajíček, Jiří

    This paper presents cross-disciplinary research between medical/psychological evidence on human abilities and informatics needs to update current models in computer science to support alternative methods for computation and communication. In [10] we have already proposed hypothesis introducing concept of human information model (HIM) as cooperative system. Here we continue on HIM design in detail. In our design, first we introduce Content/Form computing system which is new principle of present methods in evolutionary computing (genetic algorithms, genetic programming). Then we apply this system on HIM (type of artificial neural network) model as basic network self-developmental paradigm. Main inspiration of our natural/human design comes from well known concept of artificial neural networks, medical/psychological evidence and Sheldrake theory of "Nature as Alive" [22].

  7. Natural micropolymorphism in human leukocyte antigens provides a basis for genetic control of antigen recognition

    Energy Technology Data Exchange (ETDEWEB)

    Archbold, Julia K.; Macdonald, Whitney A.; Gras, Stephanie; Ely, Lauren K.; Miles, John J.; Bell, Melissa J.; Brennan, Rebekah M.; Beddoe, Travis; Wilce, Matthew C.J.; Clements, Craig S.; Purcell, Anthony W.; McCluskey, James; Burrows, Scott R.; Rossjohn, Jamie; (Monash); (Queensland Inst. of Med. Rsrch.); (Melbourne)

    2009-07-10

    Human leukocyte antigen (HLA) gene polymorphism plays a critical role in protective immunity, disease susceptibility, autoimmunity, and drug hypersensitivity, yet the basis of how HLA polymorphism influences T cell receptor (TCR) recognition is unclear. We examined how a natural micropolymorphism in HLA-B44, an important and large HLA allelic family, affected antigen recognition. T cell-mediated immunity to an Epstein-Barr virus determinant (EENLLDFVRF) is enhanced when HLA-B*4405 was the presenting allotype compared with HLA-B*4402 or HLA-B*4403, each of which differ by just one amino acid. The micropolymorphism in these HLA-B44 allotypes altered the mode of binding and dynamics of the bound viral epitope. The structure of the TCR-HLA-B*4405EENLLDFVRF complex revealed that peptide flexibility was a critical parameter in enabling preferential engagement with HLA-B*4405 in comparison to HLA-B*4402/03. Accordingly, major histocompatibility complex (MHC) polymorphism can alter the dynamics of the peptide-MHC landscape, resulting in fine-tuning of T cell responses between closely related allotypes.

  8. Davies, Florence (1995. Introducing Reading. Davies, Florence (1995. Introducing Reading.

    Directory of Open Access Journals (Sweden)

    Sonia Maria Gomes Ferreira

    2008-04-01

    Full Text Available Arising at a time of unprecedented growth of interest in fostering critical thinking, Introducing Reading offers a clear introduction and thorough account of contemporary developments in the field of reading. While overtly focusing on the special demands of social and human aspects of the reading practice, the issues raised have crucial resonance in the sphere of critical reading. Explicitly addressed to teachers of mother tongue and foreign language contexts, the book claims to elaborate on aspects of reading which have received meager attention to date: individual readers engaged in different real-world reading tasks, the social contexts where such readers engage and interact with texts, and the nature and variety of texts, here regarded as “participants” in the interaction between reader and writer. To this extent, the book successfully reaches the ambitious aim of “socializing and humanizing reading and the teaching of reading” (p. xi. Arising at a time of unprecedented growth of interest in fostering critical thinking, Introducing Reading offers a clear introduction and thorough account of contemporary developments in the field of reading. While overtly focusing on the special demands of social and human aspects of the reading practice, the issues raised have crucial resonance in the sphere of critical reading. Explicitly addressed to teachers of mother tongue and foreign language contexts, the book claims to elaborate on aspects of reading which have received meager attention to date: individual readers engaged in different real-world reading tasks, the social contexts where such readers engage and interact with texts, and the nature and variety of texts, here regarded as “participants” in the interaction between reader and writer. To this extent, the book successfully reaches the ambitious aim of “socializing and humanizing reading and the teaching of reading” (p. xi.

  9. [Research progress in chemical communication among insect-resistant genetically modified plants, insect pests and natural enemies].

    Science.gov (United States)

    Liu, Qing-Song; Li, Yun-He; Chen, Xiu-Ping; Peng, Yu-Fa

    2014-08-01

    Semiochemicals released by plants or insects play an important role in the communication among plants, phytophagous insects and their natural enemies. They thus form a chemical information network which regulates intra- and inter-specific behaviors and sustains the composition and structure of plant and insect communities. The application of insect-resistant genetically modified (IRGM) crops may affect the chemical communication within and among the tritrophic levels, and thus cause disturbances to the biotic community structure and the stability of the farmland ecosystem. This has raised concerns about the environmental safety of IRGM crops and triggered research worldwide. In the current article we provided a brief summary of the chemical communication among plants, herbivores and natural enemies; analyzed the potential of IRGM crops to affect the chemical communication between plants and arthropods and the related mechanisms; and discussed the current research progress and the future prospects in this field. We hope that this will promote the research in this field by Chinese scientists and increase our understanding of the potential effects of growing of IRGM crops on the arthropod community structure.

  10. An investigation of genetic algorithms

    International Nuclear Information System (INIS)

    Douglas, S.R.

    1995-04-01

    Genetic algorithms mimic biological evolution by natural selection in their search for better individuals within a changing population. they can be used as efficient optimizers. This report discusses the developing field of genetic algorithms. It gives a simple example of the search process and introduces the concept of schema. It also discusses modifications to the basic genetic algorithm that result in species and niche formation, in machine learning and artificial evolution of computer programs, and in the streamlining of human-computer interaction. (author). 3 refs., 1 tab., 2 figs

  11. Introducing International Geneva

    CERN Multimedia

    2015-01-01

    Geneva is variously known as the city of peace, the world’s smallest metropolis and a place where great ideas have taken form. It has been the home to philosophers such as Rousseau and Voltaire. It was the centre of the Calvinist reformation and birthplace of the Red Cross.   I hardly need to tell you that it is also a city of great international collaboration in science. Little wonder, then, that over the years, Geneva has developed into the world’s capital of internationalism in the broadest sense of the word. Yet while we all know of the existence of modern day International Geneva, how many of us really know what it does? Here at CERN, we’re about to find out. Next week sees the first in a series of talks at the Laboratory from the heads of some of the institutions that make up International Geneva. On Friday, 20 February, it will be my pleasure to introduce you to Michael Møller, Acting Director-General of the United Nations Office at Geneva (UNO...

  12. Introducing the new EDMS

    CERN Multimedia

    The EDMS Team

    2014-01-01

    We are very pleased to announce the arrival of a brand new EDMS: EDMS 6. The CERN Engineering and Equipment Data Management Service just got better than ever! EDMS is the de facto interface for all engineering related data and more. Currently there are more than 1.2 million documents and nearly 2 million files stored in EDMS.   What’s new? The first thing you will notice is the look and feel of EDMS 6; the new design not only makes it more modern but also more intuitive, so that the system is easier to use, regardless of your experience with EDMS. Whilst we have kept the key concepts, we have introduced more functionality and improved navigation within the interface, allowing for better performance to help you in your daily work. We have also added a personal slant to EDMS 6 so that you can now customise your list of favourite objects. Modifying data in EDMS is much simpler, allowing you to view all object data in a single window.  More functionality will be added in the ...

  13. Genetic variability and natural selection at the ligand domain of the Duffy binding protein in brazilian Plasmodium vivax populations

    Directory of Open Access Journals (Sweden)

    Gil Luiz HS

    2010-11-01

    Full Text Available Abstract Background Plasmodium vivax malaria is a major public health challenge in Latin America, Asia and Oceania, with 130-435 million clinical cases per year worldwide. Invasion of host blood cells by P. vivax mainly depends on a type I membrane protein called Duffy binding protein (PvDBP. The erythrocyte-binding motif of PvDBP is a 170 amino-acid stretch located in its cysteine-rich region II (PvDBPII, which is the most variable segment of the protein. Methods To test whether diversifying natural selection has shaped the nucleotide diversity of PvDBPII in Brazilian populations, this region was sequenced in 122 isolates from six different geographic areas. A Bayesian method was applied to test for the action of natural selection under a population genetic model that incorporates recombination. The analysis was integrated with a structural model of PvDBPII, and T- and B-cell epitopes were localized on the 3-D structure. Results The results suggest that: (i recombination plays an important role in determining the haplotype structure of PvDBPII, and (ii PvDBPII appears to contain neutrally evolving codons as well as codons evolving under natural selection. Diversifying selection preferentially acts on sites identified as epitopes, particularly on amino acid residues 417, 419, and 424, which show strong linkage disequilibrium. Conclusions This study shows that some polymorphisms of PvDBPII are present near the erythrocyte-binding domain and might serve to elude antibodies that inhibit cell invasion. Therefore, these polymorphisms should be taken into account when designing vaccines aimed at eliciting antibodies to inhibit erythrocyte invasion.

  14. Genetic diversity and structure of managed and semi-natural populations of cocoa (Theobroma cacao) in the Huallaga and Ucayali Valleys of Peru.

    Science.gov (United States)

    Zhang, Dapeng; Arevalo-Gardini, Enrique; Mischke, Sue; Zúñiga-Cernades, Luis; Barreto-Chavez, Alejandro; Del Aguila, Jorge Adriazola

    2006-09-01

    Cocoa (Theobroma cacao) is indigenous to the Amazon region of South America, and it is well known that the Peruvian Amazon harbours a large number of diverse cocoa populations. A small fraction of the diversity has been collected and maintained as an ex-situ germplasm repository in Peru. However, incorrect labelling of accessions and lack of information on genetic diversity have hindered efficient conservation and use of this germplasm. This study targeted assessment of genetic diversity and population structure in a managed and a semi-natural population. Using a capillary electrophoresis genotyping system, 105 cocoa accessions collected from the Huallaga and Ucayali valleys of Peru were fingerprinted. Based on 15 loci SSR profiles, genetic identity was examined for each accession and duplicates identified, population structure assessed and genetic diversity analysed in these two populations. Ten synonymous mislabelled groups were identified among the 105 accessions. The germplasm group in the Huallaga valley was clearly separated from the group in Ucayali valley by the Bayesian assignment test. The Huallaga group has lower genetic diversity, both in terms of allelic richness and of gene diversity, than the Ucayali group. Analysis of molecular variance suggested genetic substructure in the Ucayali group. Significant spatial correlation between genetic distance and geographical distances was detected in the Ucayali group by Mantel tests. These results substantiate the hypothesis that the Peruvian Amazon hosts a high level of cocoa genetic diversity, and the diversity has a spatial structure. The introduction of exotic seed populations into the Peruvian Amazon is changing the cocoa germplasm spectrum in this region. The spatial structure of cocoa diversity recorded here highlights the need for additional collecting and conservation measures for natural and semi-natural cocoa populations.

  15. natural

    Directory of Open Access Journals (Sweden)

    Elías Gómez Macías

    2006-01-01

    Full Text Available Partiendo de óxido de magnesio comercial se preparó una suspensión acuosa, la cual se secó y calcinó para conferirle estabilidad térmica. El material, tanto fresco como usado, se caracterizó mediante DRX, área superficial BET y SEM-EPMA. El catalizador mostró una matriz de MgO tipo periclasa con CaO en la superficie. Las pruebas de actividad catalítica se efectuaron en lecho fijo empacado con partículas obtenidas mediante prensado, trituración y clasificación del material. El flujo de reactivos consistió en mezclas gas natural-aire por debajo del límite inferior de inflamabilidad. Para diferentes flujos y temperaturas de entrada de la mezcla reactiva, se midieron las concentraciones de CH4, CO2 y CO en los gases de combustión con un analizador de gases tipo infrarrojo no dispersivo (NDIR. Para alcanzar conversión total de metano se requirió aumentar la temperatura de entrada al lecho a medida que se incrementó el flujo de gases reaccionantes. Los resultados obtenidos permiten desarrollar un sistema de combustión catalítica de bajo costo con un material térmicamente estable, que promueva la alta eficiencia en la combustión de gas natural y elimine los problemas de estabilidad, seguridad y de impacto ambiental negativo inherentes a los procesos de combustión térmica convencional.

  16. Genetic investigation of natural hybridization between rainbow and coastal cutthroat trout in the copper River Delta, Alaska

    Science.gov (United States)

    Williams, I.; Reeves, G.H.; Graziano, S.L.; Nielsen, J.L.

    2007-01-01

    Molecular genetic methods were used to quantify natural hybridization between rainbow trout Oncorhynchus mykiss or steelhead (anadromous rainbow trout) and coastal cutthroat trout O. clarkii clarkii collected in the Copper River delta, Southeast Alaska. Eleven locations were sampled to determine the extent of hybridization and the distribution of hybrids. Four diagnostic nuclear microsatellite loci and four species-specific simple sequence repeat markers were used in combination with restriction fragment length polymorphism analyses of NADH dehydrogenase 5/6 (ND5/6) mitochondrial DNA (mtDNA) to investigate the genetic structure of trout from both species and identify putative interspecific hybrids. Hybrids were found in 7 of the 11 streams sampled in the Copper River delta, the extent of hybridization across all streams varying from 0% to 58%. Hybrid trout distribution appeared to be nonrandom, most individuals of mixed taxonomic ancestry being detected in streams containing rainbow trout rather than in streams containing coastal cutthroat trout. Genotypic disequilibrium was observed among microsatellite loci in populations with high levels of hybridization. We found no significant correlation between unique stream channel process groups and the number of hybrid fish sampled. Eighty-eight percent of fish identified as first-generation hybrids (F1) in two populations contained coastal cutthroat trout mtDNA, suggesting directionality in hybridization. However, dominance of coastal cutthroat trout mtDNA was not observed at a third location containing F1 hybrids, indicating that interspecific mating behavior varied among locations. Backcrossed individuals were found in drainages lacking F1 hybrids and in populations previously thought to contain a single species. The extent and distribution of backcrossed individuals suggested that at least some hybrids are reproductively viable and backcrossed hybrid offspring move throughout the system.

  17. Toward a Predictive Framework for Convergent Evolution: Integrating Natural History, Genetic Mechanisms, and Consequences for the Diversity of Life.

    Science.gov (United States)

    Agrawal, Anurag A

    2017-08-01

    A charm of biology as a scientific discipline is the diversity of life. Although this diversity can make laws of biology challenging to discover, several repeated patterns and general principles govern evolutionary diversification. Convergent evolution, the independent evolution of similar phenotypes, has been at the heart of one approach to understand generality in the evolutionary process. Yet understanding when and why organismal traits and strategies repeatedly evolve has been a central challenge. These issues were the focus of the American Society of Naturalists Vice Presidential Symposium in 2016 and are the subject of this collection of articles. Although naturalists have long made inferences about convergent evolution and its importance, there has been confusion in the interpretation of the pattern of convergence. Does convergence primarily indicate adaptation or constraint? How often should convergence be expected? Are there general principles that would allow us to predict where and when and by what mechanisms convergent evolution should occur? What role does natural history play in advancing our understanding of general evolutionary principles? In this introductory article, I address these questions, review several generalizations about convergent evolution that have emerged over the past 15 years, and present a framework for advancing the study and interpretation of convergence. Perhaps the most important emerging conclusion is that the genetic mechanisms of convergent evolution are phylogenetically conserved; that is, more closely related species tend to share the same genetic basis of traits, even when independently evolved. Finally, I highlight how the articles in this special issue further develop concepts, methodologies, and case studies at the frontier of our understanding of the causes and consequences of convergent evolution.

  18. Arthropod Genetics.

    Science.gov (United States)

    Zumwalde, Sharon

    2000-01-01

    Introduces an activity on arthropod genetics that involves phenotype and genotype identification of the creature and the construction process. Includes a list of required materials and directions to build a model arthropod. (YDS)

  19. Adaptive major histocompatibility complex (MHC) and neutral genetic variation in two native Baltic Sea fishes (perch Perca fluviatilis and zander Sander lucioperca) with comparisons to an introduced and disease susceptible population in Australia (P. fluviatilis): assessing the risk of disease epidemics.

    Science.gov (United States)

    Faulks, L K; Östman, Ö

    2016-04-01

    This study assessed the major histocompatibility complex (MHC) and neutral genetic variation and structure in two percid species, perch Perca fluviatilis and zander Sander lucioperca, in a unique brackish ecosystem, the Baltic Sea. In addition, to assess the importance of MHC diversity to disease susceptibility in these populations, comparisons were made to an introduced, disease susceptible, P. fluviatilis population in Australia. Eighty-three MHC class II B exon 2 variants were amplified: 71 variants from 92 P. fluviatilis samples, and 12 variants from 82 S. lucioperca samples. Microsatellite and MHC data revealed strong spatial genetic structure in S. lucioperca, but not P. fluviatilis, across the Baltic Sea. Both microsatellite and MHC data showed higher levels of genetic diversity in P. fluviatilis from the Baltic Sea compared to Australia, which may have facilitated the spread of an endemic virus, EHNV in the Australian population. The relatively high levels of genetic variation in the Baltic Sea populations, together with spatial genetic structure, however, suggest that there currently seems to be little risk of disease epidemics in this system. To ensure this remains the case in the face of ongoing environmental changes, fisheries and habitat disturbance, the conservation of local-scale genetic variation is recommended. © 2016 The Fisheries Society of the British Isles.

  20. Natural Competence Is Common among Clinical Isolates of Veillonella parvula and Is Useful for Genetic Manipulation of This Key Member of the Oral Microbiome

    Directory of Open Access Journals (Sweden)

    Justin Merritt

    2017-04-01

    Full Text Available The six Veillonella species found in the human oral cavity are among the most abundant members of the oral flora, occurring in both supra- and subgingival dental plaque as well as on the oral mucosa. Epidemiological data have also implicated these species in the development of the most common oral diseases. Despite their ubiquity, abundance, and ecological significance, surprisingly little is known about Veillonella biology, largely due to the difficulties associated with their genetic manipulation. In an effort to improve genetic analyses of Veillonella species, we isolated a collection of veillonellae from clinical plaque samples and screened for natural competence using a newly developed transformation protocol. Numerous strains of V. parvula were found to exhibit a natural competence ability that was highly influenced by growth medium composition. By exploiting this ability, we were able to utilize cloning-independent allelic exchange mutagenesis to identify the likely source of DNA uptake machinery within a locus homologous to type II secretion systems (T2SS. Interestingly, V. parvula natural competence was found to exhibit a clear hierarchy of preference for different sources of DNA (plasmid < PCR product < genomic DNA, which is unlike most naturally competent species. Genomic comparisons with other members of the Veillonellaceae family suggest that natural competence is likely to be widely distributed within this group. To the best of our knowledge, this study is the first demonstration of natural competence and targeted allelic exchange mutagenesis within the entire Veillonellaceae family and demonstrates a simple and rapid method to study Veillonella genetics.

  1. Natural genetic resources of Arabidopsis thaliana reveal a high prevalence and unexpected phenotypic plasticity of RPW8-mediated powdery mildew resistance

    NARCIS (Netherlands)

    Gollner, K.; Schweizer, P.; Bai, Y.; Panstruga, R.

    2008-01-01

    Here, an approach based on natural genetic variation was adopted to analyse powdery mildew resistance in Arabidopsis thaliana. ¿ Accessions resistant to multiple powdery mildew species were crossed with the susceptible Col-0 ecotype and inheritance of resistance was analysed. Histochemical staining

  2. Genetic Divergence and Signatures of Natural Selection in Marginal Populations of a Keystone, Long-Lived Conifer, Eastern White Pine (Pinus strobus) from Northern Ontario

    Science.gov (United States)

    Chhatre, Vikram E.; Rajora, Om P.

    2014-01-01

    Marginal populations are expected to provide the frontiers for adaptation, evolution and range shifts of plant species under the anticipated climate change conditions. Marginal populations are predicted to show genetic divergence from central populations due to their isolation, and divergent natural selection and genetic drift operating therein. Marginal populations are also expected to have lower genetic diversity and effective population size (N e) and higher genetic differentiation than central populations. We tested these hypotheses using eastern white pine (Pinus strobus) as a model for keystone, long-lived widely-distributed plants. All 614 eastern white pine trees, in a complete census of two populations each of marginal old-growth, central old-growth, and central second-growth, were genotyped at 11 microsatellite loci. The central populations had significantly higher allelic and genotypic diversity, latent genetic potential (LGP) and N e than the marginal populations. However, heterozygosity and fixation index were similar between them. The marginal populations were genetically diverged from the central populations. Model testing suggested predominant north to south gene flow in the study area with curtailed gene flow to northern marginal populations. Signatures of natural selection were detected at three loci in the marginal populations; two showing divergent selection with directional change in allele frequencies, and one balancing selection. Contrary to the general belief, no significant differences were observed in genetic diversity, differentiation, LGP, and N e between old-growth and second-growth populations. Our study provides information on the dynamics of migration, genetic drift and selection in central versus marginal populations of a keystone long-lived plant species and has broad evolutionary, conservation and adaptation significance. PMID:24859159

  3. Genetic divergence and signatures of natural selection in marginal populations of a keystone, long-lived conifer, Eastern White Pine (Pinus strobus) from Northern Ontario.

    Science.gov (United States)

    Chhatre, Vikram E; Rajora, Om P

    2014-01-01

    Marginal populations are expected to provide the frontiers for adaptation, evolution and range shifts of plant species under the anticipated climate change conditions. Marginal populations are predicted to show genetic divergence from central populations due to their isolation, and divergent natural selection and genetic drift operating therein. Marginal populations are also expected to have lower genetic diversity and effective population size (Ne) and higher genetic differentiation than central populations. We tested these hypotheses using eastern white pine (Pinus strobus) as a model for keystone, long-lived widely-distributed plants. All 614 eastern white pine trees, in a complete census of two populations each of marginal old-growth, central old-growth, and central second-growth, were genotyped at 11 microsatellite loci. The central populations had significantly higher allelic and genotypic diversity, latent genetic potential (LGP) and Ne than the marginal populations. However, heterozygosity and fixation index were similar between them. The marginal populations were genetically diverged from the central populations. Model testing suggested predominant north to south gene flow in the study area with curtailed gene flow to northern marginal populations. Signatures of natural selection were detected at three loci in the marginal populations; two showing divergent selection with directional change in allele frequencies, and one balancing selection. Contrary to the general belief, no significant differences were observed in genetic diversity, differentiation, LGP, and Ne between old-growth and second-growth populations. Our study provides information on the dynamics of migration, genetic drift and selection in central versus marginal populations of a keystone long-lived plant species and has broad evolutionary, conservation and adaptation significance.

  4. Assessment of the genetic diversity of natural rubber tree clones of the SINCHI Institutes clone collection, using of morphological descriptors

    International Nuclear Information System (INIS)

    Quesada Mendez, Isaac; Quintero Barrera, Lorena; Aristizabal, Fabio A; Rodriguez Acuna, Olga

    2011-01-01

    Genetic diversity of natural rubber clones of the in SINCHI Institute’s clone collection was assessed. Clones of Hevea brasiliensis (Willd. ex Adr. De Juss.) Muell.Arg., Hevea spp. (H. brasiliensis x H. benthamiana), and three more species of Hevea genus are a part of the collection. Seventy-two materials were characterized with twenty-eight morphological descriptors. They were later used to generate a similarity matrix through the analysis of multi-categorical variables, and to obtain clusters based on the matrix. A low variability between clones of H. brasiliensis and H. spp. was observed, presumably because of the direct descendants of most of the materials from crosses of parental PB 80, PB 5/51, PB 49 and Tjir, exception made of clone GU 1410. Clustering between some materials product of exclusive cross of PB series, a group between clones descendants of parental clones PB 86, and clustering between descendants of parental clones PB 5/51, were observed. Clones from other species of Hevea differ from this big group.

  5. Steelhead Supplementation Studies in Idaho Rivers: To evaluate the feasibility of using artificial production to increase natural steelhead populations and to collect baseline life history, genetic, and disease data from natural steelhead populations. 1993 Annual report

    International Nuclear Information System (INIS)

    Byrne, A.

    1996-01-01

    The Steelhead Supplementation Study was designed to evaluate the feasibility of using artificial production to increase natural steelhead Oncorhynchus mykiss populations and to collect baseline life history, genetic, and disease data from natural steelhead populations. To evaluate supplementation, the authors focused their experimental design on post-release survival, reproductive success, long-term fitness, and ecological interactions. They began field experiments in 1993 by outplanting hatchery adults and fingerlings to assess reproductive fitness and long-term survival. They snorkeled eight streams to estimate juvenile steelhead densities, recorded temperatures in 17 streams, and tagged natural steelhead in six streams with Passive Integrated Transponder (PIT) tags

  6. The genetics and conservation of Araucaria angustifolia: I. Genetic structure and diversity of natural populations by means of non-adaptive variation in the state of Santa Catarina, Brazil

    Directory of Open Access Journals (Sweden)

    Neiva Maria Frizon Auler

    2002-01-01

    Full Text Available The objective of this study was to generate information relative to the allele distribution and dynamics within and among populations of Araucaria angustifolia, a naturally-occurring conifer in the south of Brazil, being known popularly as "pinheiro-do-Paraná", "araucaria" or pine tree. In order to elucidate the levels and the distribution of the genetic variability, the population's genetic structure and the genetic distance among natural populations of this species with different levels of disturbance in different geographical areas were studied in detail. For this, samples of leaf tissue were collected from 328 adult individuals in nine natural populations in Santa Catarina State. To analyze the samples, the allozyme technique was applied in starch gel electrophoresis (penetrose 13%, with citrate/morfholine buffer. Nine enzymatic systems (PGM, PGI MDH, PRX, SKDH, 6PGDH, ACP, IDH and G6PDH revealed 15 loci. The analysis provided values for He and Ho of 0.084 and 0.072, respectively. The general average of polymorphic loci was 73% in the species and 26.6% in the studied populations and the allele number per locus was 1.6. Wright's F-statistical estimates indicated the existence of inbreeding in populations (F IS= 0.148 and a low divergence among populations (F ST = 0.044. However, the inbreeding values were variable in different populations. Taken together, the results indicated that the greater part of the genetic variability is contained within populations. The working hypothesis that originally there was greater genetic diversity can be supported by these results which indicate that in the degraded populations the diversity indexes are lower in the degraded populations than those found in better-conserved populations. Thus the fragmentation of the forest followed by "araucaria" exploitation could have contributed to the genetic differentiation expressed through the allele frequency of the studied population.

  7. High Prevalence and Genetic Polymorphisms of Legionella in Natural and Man-Made Aquatic Environments in Wenzhou, China

    Directory of Open Access Journals (Sweden)

    Leyi Zhang

    2017-02-01

    Full Text Available Natural and engineered water systems are the main sources of Legionnaires’ disease. It is essential from a public health perspective to survey water environments for the existence of Legionella. To analyze the main serogroups, genotypes and pathogenicity of the pathogen, a stratified sampling method was adopted to collect water samples randomly from shower water, cooling tower water, and local public hot springs in Wenzhou, China. Suspected strains were isolated from concentrated water samples. Serum agglutination assay and real-time PCR (Polymerase chain reaction were used to identify L. pneumophila. Sequence-based typing (SBT and pulsed-field gel electrophoresis (PFGE were used to elucidate the genetic polymorphisms in the collected isolates. The intracellular growth ability of the isolates was determined through their interaction with J774 cells and plating them onto BCYE (Buffered Charcoal Yeast Extract agar plates. Overall, 25.56% (46/180 of water samples were Legionella-positive; fifty-two strains were isolated and two kinds of serogroups were co-detected from six water samples from 2015 to 2016. Bacterial concentrations ranged from 20 CFU/100 mL to 10,720 CFU/100 mL. In detail, the Legionella-positive rates of shower water, cooling tower water and hot springs water were 15.45%, 13.33%, and 62.5%, respectively. The main serogroups were LP1 (30.69% and LP3 (28.85% and all strains carried the dot gene. Among them, 52 isolates and another 10 former isolates were analyzed by PFGE. Nineteen distinct patterns were observed in 52 strains isolated from 2015 to 2016 with three patterns being observed in 10 strains isolated from 2009 to 2014. Seventy-three strains containing 52 from this study and 21 former isolates were selected for SBT analysis and divided into 25 different sequence types in 4 main clonal groups belonging to 4 homomorphic types. Ten strains were chosen to show their abilities to grow and multiply in J744 cells. Taken together

  8. Untangling individual variation in natural populations: ecological, genetic and epigenetic correlates of long-term inequality in herbivory.

    Science.gov (United States)

    Herrera, C M; Bazaga, P

    2011-04-01

    Individual variation in ecologically important features of organisms is a crucial element in ecology and evolution, yet disentangling its underlying causes is difficult in natural populations. We applied a genomic scan approach using amplified fragment length polymorphism (AFLP) markers to quantify the genetic basis of long-term individual differences in herbivory by mammals at a wild population of the violet Viola cazorlensis monitored for two decades. In addition, methylation-sensitive amplified polymorphism (MSAP) analyses were used to investigate the association between browsing damage and epigenetic characteristics of individuals, an aspect that has been not previously explored for any wild plant. Structural equation modelling was used to identify likely causal structures linking genotypes, epigenotypes and herbivory. Individuals of V. cazorlensis differed widely in the incidence of browsing mammals over the 20-year study period. Six AFLP markers (1.6% of total) were significantly related to herbivory, accounting altogether for 44% of population-wide variance in herbivory levels. MSAP analyses revealed considerable epigenetic variation among individuals, and differential browsing damage was significantly related to variation in multilocus epigenotypes. In addition, variation across plants in epigenetic characteristics was related to variation in several herbivory-related AFLP markers. Statistical comparison of alternative causal models suggested that individual differences in herbivory are the outcome of a complex causal structure where genotypes and epigenotypes are interconnected and have direct and indirect effects on herbivory. Insofar as methylation states of MSAP markers influential on herbivory are transgenerationally heritable, herbivore-driven evolutionary changes at the study population will involve correlated changes in genotypic and epigenotypic distributions. © 2011 Blackwell Publishing Ltd.

  9. Natural selection causes adaptive genetic resistance in wild emmer wheat against powdery mildew at "Evolution Canyon" microsite, Mt. Carmel, Israel.

    Science.gov (United States)

    Yin, Huayan; Ben-Abu, Yuval; Wang, Hongwei; Li, Anfei; Nevo, Eviatar; Kong, Lingrang

    2015-01-01

    "Evolution Canyon" (ECI) at Lower Nahal Oren, Mount Carmel, Israel, is an optimal natural microscale model for unraveling evolution in action highlighting the basic evolutionary processes of adaptation and speciation. A major model organism in ECI is wild emmer, Triticum dicoccoides, the progenitor of cultivated wheat, which displays dramatic interslope adaptive and speciational divergence on the tropical-xeric "African" slope (AS) and the temperate-mesic "European" slope (ES), separated on average by 250 m. We examined 278 single sequence repeats (SSRs) and the phenotype diversity of the resistance to powdery mildew between the opposite slopes. Furthermore, 18 phenotypes on the AS and 20 phenotypes on the ES, were inoculated by both Bgt E09 and a mixture of powdery mildew races. In the experiment of genetic diversity, very little polymorphism was identified intra-slope in the accessions from both the AS or ES. By contrast, 148 pairs of SSR primers (53.23%) amplified polymorphic products between the phenotypes of AS and ES. There are some differences between the two wild emmer wheat genomes and the inter-slope SSR polymorphic products between genome A and B. Interestingly, all wild emmer types growing on the south-facing slope (SFS=AS) were susceptible to a composite of Blumeria graminis, while the ones growing on the north-facing slope (NFS=ES) were highly resistant to Blumeria graminis at both seedling and adult stages. Remarkable inter-slope evolutionary divergent processes occur in wild emmer wheat, T. dicoccoides at EC I, despite the shot average distance of 250 meters. The AS, a dry and hot slope, did not develop resistance to powdery mildew, whereas the ES, a cool and humid slope, did develop resistance since the disease stress was strong there. This is a remarkable demonstration in host-pathogen interaction on how resistance develops when stress causes an adaptive result at a micro-scale distance.

  10. Natural selection causes adaptive genetic resistance in wild emmer wheat against powdery mildew at "Evolution Canyon" microsite, Mt. Carmel, Israel.

    Directory of Open Access Journals (Sweden)

    Huayan Yin

    Full Text Available "Evolution Canyon" (ECI at Lower Nahal Oren, Mount Carmel, Israel, is an optimal natural microscale model for unraveling evolution in action highlighting the basic evolutionary processes of adaptation and speciation. A major model organism in ECI is wild emmer, Triticum dicoccoides, the progenitor of cultivated wheat, which displays dramatic interslope adaptive and speciational divergence on the tropical-xeric "African" slope (AS and the temperate-mesic "European" slope (ES, separated on average by 250 m.We examined 278 single sequence repeats (SSRs and the phenotype diversity of the resistance to powdery mildew between the opposite slopes. Furthermore, 18 phenotypes on the AS and 20 phenotypes on the ES, were inoculated by both Bgt E09 and a mixture of powdery mildew races.In the experiment of genetic diversity, very little polymorphism was identified intra-slope in the accessions from both the AS or ES. By contrast, 148 pairs of SSR primers (53.23% amplified polymorphic products between the phenotypes of AS and ES. There are some differences between the two wild emmer wheat genomes and the inter-slope SSR polymorphic products between genome A and B. Interestingly, all wild emmer types growing on the south-facing slope (SFS=AS were susceptible to a composite of Blumeria graminis, while the ones growing on the north-facing slope (NFS=ES were highly resistant to Blumeria graminis at both seedling and adult stages.Remarkable inter-slope evolutionary divergent processes occur in wild emmer wheat, T. dicoccoides at EC I, despite the shot average distance of 250 meters. The AS, a dry and hot slope, did not develop resistance to powdery mildew, whereas the ES, a cool and humid slope, did develop resistance since the disease stress was strong there. This is a remarkable demonstration in host-pathogen interaction on how resistance develops when stress causes an adaptive result at a micro-scale distance.

  11. Crumbling Diversity: Comparison of Historical Archived and Contemporary Natural Populations Indicate Reduced Genetic Diversity and Increasing Genetic Differentiation in the Golden-Cheeked Warbler

    Science.gov (United States)

    2011-06-01

    clavata. Heredity 101:120–126 Crow JF, Denniston C (1988) Inbreeding and variance effective population numbers. Evolution 42:482–495 Dixo M, Metzger JP...University Press, Cambridge, pp 361–366 Young A, Boyle T, Brown T (1996) The population genetic consequences of habitat fragmentation for plants . Trends

  12. The Genetic Basis of Natural Variation in Kernel Size and Related Traits Using a Four-Way Cross Population in Maize.

    Science.gov (United States)

    Chen, Jiafa; Zhang, Luyan; Liu, Songtao; Li, Zhimin; Huang, Rongrong; Li, Yongming; Cheng, Hongliang; Li, Xiantang; Zhou, Bo; Wu, Suowei; Chen, Wei; Wu, Jianyu; Ding, Junqiang

    2016-01-01

    Kernel size is an important component of grain yield in maize breeding programs. To extend the understanding on the genetic basis of kernel size traits (i.e., kernel length, kernel width and kernel thickness), we developed a set of four-way cross mapping population derived from four maize inbred lines with varied kernel sizes. In the present study, we investigated the genetic basis of natural variation in seed size and other components of maize yield (e.g., hundred kernel weight, number of rows per ear, number of kernels per row). In total, ten QTL affecting kernel size were identified, three of which (two for kernel length and one for kernel width) had stable expression in other components of maize yield. The possible genetic mechanism behind the trade-off of kernel size and yield components was discussed.

  13. Introducing particle physics a graphic guide

    CERN Document Server

    AUTHOR|(CDS)2071677

    2013-01-01

    What really happens at the most fundamental levels of nature? Introducing Particle Physics explores the very frontiers of our knowledge, even showing how particle physicists are now using theory and experiment to probe our very concept of what is real. From the earliest history of the atomic theory through to supersymmetry, micro-black holes, dark matter, the Higgs boson, and the possibly mythical graviton, practising physicist and CERN contributor Tom Whyntie gives us a mind-expanding tour of cutting-edge science. Featuring brilliant illustrations from Oliver Pugh, Introducing Particle Physics is a unique tour through the most astonishing and challenging science being undertaken today.

  14. Genetic Diversity, Natural Selection and Haplotype Grouping of Plasmodium knowlesi Gamma Protein Region II (PkγRII): Comparison with the Duffy Binding Protein (PkDBPαRII).

    Science.gov (United States)

    Fong, Mun Yik; Rashdi, Sarah A A; Yusof, Ruhani; Lau, Yee Ling

    2016-01-01

    Plasmodium knowlesi is a simian malaria parasite that has been reported to cause malaria in humans in Southeast Asia. This parasite invades the erythrocytes of humans and of its natural host, the macaque Macaca fascicularis, via interaction between the Duffy binding protein region II (PkDBPαRII) and the Duffy antigen receptor on the host erythrocytes. In contrast, the P. knowlesi gamma protein region II (PkγRII) is not involved in the invasion of P. knowlesi into humans. PkγRII, however, mediates the invasion of P. knowlesi into the erythrocytes of M. mulata, a non-natural host of P. knowlesi via a hitherto unknown receptor. The haplotypes of PkDBPαRII in P. knowlesi isolates from Peninsular Malaysia and North Borneo have been shown to be genetically distinct and geographically clustered. Also, the PkDBPαRII was observed to be undergoing purifying (negative) selection. The present study aimed to determine whether similar phenomena occur in PkγRII. Blood samples from 78 knowlesi malaria patients were used. Forty-eight of the samples were from Peninsular Malaysia, and 30 were from Malaysia Borneo. The genomic DNA of the samples was extracted and used as template for the PCR amplification of the PkγRII. The PCR product was cloned and sequenced. The sequences obtained were analysed for genetic diversity and natural selection using MEGA6 and DnaSP (version 5.10.00) programmes. Genetic differentiation between the PkγRII of Peninsular Malaysia and North Borneo isolates was estimated using the Wright's FST fixation index in DnaSP (version 5.10.00). Haplotype analysis was carried out using the Median-Joining approach in NETWORK (version 4.6.1.3). A total of 78 PkγRII sequences was obtained. Comparative analysis showed that the PkγRII have similar range of haplotype (Hd) and nucleotide diversity (π) with that of PkDBPαRII. Other similarities between PkγRII and PkDBPαRII include undergoing purifying (negative) selection, geographical clustering of haplotypes

  15. Genetic Diversity, Natural Selection and Haplotype Grouping of Plasmodium knowlesi Gamma Protein Region II (PkγRII: Comparison with the Duffy Binding Protein (PkDBPαRII.

    Directory of Open Access Journals (Sweden)

    Mun Yik Fong

    Full Text Available Plasmodium knowlesi is a simian malaria parasite that has been reported to cause malaria in humans in Southeast Asia. This parasite invades the erythrocytes of humans and of its natural host, the macaque Macaca fascicularis, via interaction between the Duffy binding protein region II (PkDBPαRII and the Duffy antigen receptor on the host erythrocytes. In contrast, the P. knowlesi gamma protein region II (PkγRII is not involved in the invasion of P. knowlesi into humans. PkγRII, however, mediates the invasion of P. knowlesi into the erythrocytes of M. mulata, a non-natural host of P. knowlesi via a hitherto unknown receptor. The haplotypes of PkDBPαRII in P. knowlesi isolates from Peninsular Malaysia and North Borneo have been shown to be genetically distinct and geographically clustered. Also, the PkDBPαRII was observed to be undergoing purifying (negative selection. The present study aimed to determine whether similar phenomena occur in PkγRII.Blood samples from 78 knowlesi malaria patients were used. Forty-eight of the samples were from Peninsular Malaysia, and 30 were from Malaysia Borneo. The genomic DNA of the samples was extracted and used as template for the PCR amplification of the PkγRII. The PCR product was cloned and sequenced. The sequences obtained were analysed for genetic diversity and natural selection using MEGA6 and DnaSP (version 5.10.00 programmes. Genetic differentiation between the PkγRII of Peninsular Malaysia and North Borneo isolates was estimated using the Wright's FST fixation index in DnaSP (version 5.10.00. Haplotype analysis was carried out using the Median-Joining approach in NETWORK (version 4.6.1.3.A total of 78 PkγRII sequences was obtained. Comparative analysis showed that the PkγRII have similar range of haplotype (Hd and nucleotide diversity (π with that of PkDBPαRII. Other similarities between PkγRII and PkDBPαRII include undergoing purifying (negative selection, geographical clustering of

  16. Nature Versus Nurture: Does Proteostasis Imbalance Underlie the Genetic, Environmental, and Age-Related Risk Factors for Alzheimer's Disease?

    Science.gov (United States)

    Kikis, Elise A

    2017-08-22

    Aging is a risk factor for a number of "age-related diseases", including Alzheimer's disease (AD). AD affects more than a third of all people over the age of 85, and is the leading cause of dementia worldwide. Symptoms include forgetfulness, memory loss, and cognitive decline, ultimately resulting in the need for full-time care. While there is no cure for AD, pharmacological approaches to alleviate symptoms and target underlying causes of the disease have been developed, albeit with limited success. This review presents the age-related, genetic, and environmental risk factors for AD and proposes a hypothesis for the mechanistic link between genetics and the environment. In short, much is known about the genetics of early-onset familial AD (EO-FAD) and the central role played by the Aβ peptide and protein misfolding, but late-onset AD (LOAD) is not thought to have direct genetic causes. Nonetheless, genetic risk factors such as isoforms of the protein ApoE have been identified. Additional findings suggest that air pollution caused by the combustion of fossil fuels may be an important environmental risk factor for AD. A hypothesis suggesting that poor air quality might act by disrupting protein folding homeostasis (proteostasis) is presented.

  17. Virus fitness differences observed between two naturally occurring isolates of Ebola virus Makona variant using a reverse genetics approach.

    Science.gov (United States)

    Albariño, César G; Guerrero, Lisa Wiggleton; Chakrabarti, Ayan K; Kainulainen, Markus H; Whitmer, Shannon L M; Welch, Stephen R; Nichol, Stuart T

    2016-09-01

    During the large outbreak of Ebola virus disease that occurred in Western Africa from late 2013 to early 2016, several hundred Ebola virus (EBOV) genomes have been sequenced and the virus genetic drift analyzed. In a previous report, we described an efficient reverse genetics system designed to generate recombinant EBOV based on a Makona variant isolate obtained in 2014. Using this system, we characterized the replication and fitness of 2 isolates of the Makona variant. These virus isolates are nearly identical at the genetic level, but have single amino acid differences in the VP30 and L proteins. The potential effects of these differences were tested using minigenomes and recombinant viruses. The results obtained with this approach are consistent with the role of VP30 and L as components of the EBOV RNA replication machinery. Moreover, the 2 isolates exhibited clear fitness differences in competitive growth assays. Published by Elsevier Inc.

  18. Genetic basis for spontaneous hybrid genome doubling during allopolyploid speciation of common wheat shown by natural variation analyses of the paternal species.

    Directory of Open Access Journals (Sweden)

    Yoshihiro Matsuoka

    Full Text Available The complex process of allopolyploid speciation includes various mechanisms ranging from species crosses and hybrid genome doubling to genome alterations and the establishment of new allopolyploids as persisting natural entities. Currently, little is known about the genetic mechanisms that underlie hybrid genome doubling, despite the fact that natural allopolyploid formation is highly dependent on this phenomenon. We examined the genetic basis for the spontaneous genome doubling of triploid F1 hybrids between the direct ancestors of allohexaploid common wheat (Triticum aestivum L., AABBDD genome, namely Triticumturgidum L. (AABB genome and Aegilopstauschii Coss. (DD genome. An Ae. tauschii intraspecific lineage that is closely related to the D genome of common wheat was identified by population-based analysis. Two representative accessions, one that produces a high-genome-doubling-frequency hybrid when crossed with a T. turgidum cultivar and the other that produces a low-genome-doubling-frequency hybrid with the same cultivar, were chosen from that lineage for further analyses. A series of investigations including fertility analysis, immunostaining, and quantitative trait locus (QTL analysis showed that (1 production of functional unreduced gametes through nonreductional meiosis is an early step key to successful hybrid genome doubling, (2 first division restitution is one of the cytological mechanisms that cause meiotic nonreduction during the production of functional male unreduced gametes, and (3 six QTLs in the Ae. tauschii genome, most of which likely regulate nonreductional meiosis and its subsequent gamete production processes, are involved in hybrid genome doubling. Interlineage comparisons of Ae. tauschii's ability to cause hybrid genome doubling suggested an evolutionary model for the natural variation pattern of the trait in which non-deleterious mutations in six QTLs may have important roles. The findings of this study demonstrated

  19. Hybridization and adaptation to introduced balloon vines in an Australian soapberry bug.

    Science.gov (United States)

    Andres, J A; Thampy, P R; Mathieson, M T; Loye, J; Zalucki, M P; Dingle, H; Carroll, S P

    2013-12-01

    Contemporary adaptation of plant feeding insects to introduced hosts provides clear cases of ecologically based population divergence. In most cases the mechanisms permitting rapid differentiation are not well known. Here we study morphological and genetic variation associated with recent shifts by the Australian soapberry bug Leptocoris tagalicus onto two naturalized Neotropical balloon vines, Cardiospermum halicacabum and C. grandiflorum that differ in time since introduction. Our results show that these vines have much larger fruits than the native hosts (Whitewood tree -Atalaya hemiglauca- and Woolly Rambutan -Alectryon tomentosus-) and that bugs living on them have evolved significantly longer beaks and new allometries. Genetic analyses of mitochondrial haplotypes and amplified fragment length polymorphic (AFLP) markers indicate that the lineage of bugs on the annual vine C. halicacabum, the older introduction, is intermediate between the two subspecies of L. tagalicus found on native hosts. Moreover, where the annual vine and Whitewood tree co-occur, the morphology and genomic composition of the bugs are similar to those occurring in allopatry. These results show that hybridization provided the genetic elements underlying the strongly differentiated 'Halicacabum bugs'. In contrast, the bugs feeding on the recently introduced perennial balloon vine (C. grandiflorum) showed no evidence of admixture, and are genetically indistinguishable from the nearby populations on a native host. © 2013 John Wiley & Sons Ltd.

  20. Introduced Terrestrial Species Richness (Future)

    Data.gov (United States)

    U.S. Environmental Protection Agency — These data represent predicted current distributions of all introduced fish in the Middle-Atlantic region. These data are available for both 8-digit HUCs and EMAP...

  1. Genetic relationship between wool shedding in ewe-lambs and ewes

    Science.gov (United States)

    Interest in reducing labor costs related to shearing has led to the development of breeds that naturally shed their wool annually. This goal has been achieved by introducing hair-sheep genetics. These developments are relatively recent and thus the genetic underpinnings of wool shedding (WS) are not...

  2. Coping with the abstract and complex nature of genetics in biology education : The yo-yo learning and teaching strategy

    NARCIS (Netherlands)

    Knippels, M.C.P.J.

    2002-01-01

    This thesis describes a research project that was carried out at the Centre for Science and Mathematics Education at Utrecht University between 1998 and 2002. The study addresses problems in learning and teaching genetics in upper secondary biology education. The aim of the study is to develop a

  3. Genetic diversity and population structure of Chinese natural bermudagrass [Cynodon dactylon (L.) Pers.] germplasm based on SRAP markers.

    Science.gov (United States)

    Zheng, Yiqi; Xu, Shaojun; Liu, Jing; Zhao, Yan; Liu, Jianxiu

    2017-01-01

    Bermudagrass [Cynodon dactylon (L.) Pers.], an important turfgrass used in public parks, home lawns, golf courses and sports fields, is widely distributed in China. In the present study, sequence-related amplified polymorphism (SRAP) markers were used to assess genetic diversity and population structure among 157 indigenous bermudagrass genotypes from 20 provinces in China. The application of 26 SRAP primer pairs produced 340 bands, of which 328 (96.58%) were polymorphic. The polymorphic information content (PIC) ranged from 0.36 to 0.49 with a mean of 0.44. Genetic distance coefficients among accessions ranged from 0.04 to 0.61, with an average of 0.32. The results of STRUCTURE analysis suggested that 157 bermudagrass accessions can be grouped into three subpopulations. Moreover, according to clustering based on the unweighted pair-group method of arithmetic averages (UPGMA), accessions were divided into three major clusters. The UPGMA dendrogram revealed that accessions from identical or adjacent areas were generally, but not entirely, clustered into the same cluster. Comparison of the UPGMA dendrogram and the Bayesian STRUCTURE analysis showed general agreement between the population subdivisions and the genetic relationships among accessions. Principal coordinate analysis (PCoA) with SRAP markers revealed a similar grouping of accessions to the UPGMA dendrogram and STRUCTUE analysis. Analysis of molecular variance (AMOVA) indicated that 18% of total molecular variance was attributed to diversity among subpopulations, while 82% of variance was associated with differences within subpopulations. Our study represents the most comprehensive investigation of the genetic diversity and population structure of bermudagrass in China to date, and provides valuable information for the germplasm collection, genetic improvement, and systematic utilization of bermudagrass.

  4. Genetic Diversity and Natural Selection in 42 kDa Region of Plasmodium vivax Merozoite Surface Protein-1 from China-Myanmar Endemic Border.

    Science.gov (United States)

    Zhou, Xia; Tambo, Ernest; Su, Jing; Fang, Qiang; Ruan, Wei; Chen, Jun-Hu; Yin, Ming-Bo; Zhou, Xiao-Nong

    2017-10-01

    Plasmodium vivax merozoite surface protein-1 (PvMSP1) gene codes for a major malaria vaccine candidate antigen. However, its polymorphic nature represents an obstacle to the design of a protective vaccine. In this study, we analyzed the genetic polymorphism and natural selection of the C-terminal 42 kDa fragment within PvMSP1 gene (Pv MSP142) from 77 P. vivax isolates, collected from imported cases of China-Myanmar border (CMB) areas in Yunnan province and the inland cases from Anhui, Yunnan, and Zhejiang province in China during 2009-2012. Totally, 41 haplotypes were identified and 30 of them were new haplotypes. The differences between the rates of non-synonymous and synonymous mutations suggest that PvMSP142 has evolved under natural selection, and a high selective pressure preferentially acted on regions identified of PvMSP133. Our results also demonstrated that PvMSP142 of P. vivax isolates collected on China-Myanmar border areas display higher genetic polymorphisms than those collected from inland of China. Such results have significant implications for understanding the dynamic of the P. vivax population and may be useful information towards China malaria elimination campaign strategies.

  5. Qualitative analysis of mouse specific-locus mutations: information on genetic organization, gene expression, and the chromosomal nature of induced lesions

    International Nuclear Information System (INIS)

    Russell, L.B.

    1982-01-01

    Analysis of mouse specific-locus (SL) mutations at three loci has identified over 33 distinct complementation groups - most of which are probably overlapping deficiencies - and 13 to 14 new functional units. The complementation maps that have been generated for the d-se and c regions include numerous vital functions; however, some of the genes in these regions are non-vital. At such loci, hypomorphic mutants must represent intragenic alterations, and some viable nulls could conceivably be intragenic lesions also. Analysis of SL mutations has provided information on genetic expression. Homozygous deficiencies can be completely viable or can kill at any one of a range of developmental stages. Heterozygonus deficiencies of up to 6 cM or more in genetic length have been recovered and propagated. The time of death of homozygous and the degree of inviability of heterozygous deficiencies are related more to specific content of the missing segment than to its length. Combinations of deficiencies with x-autosome translocations that inactivate the homologous region in a mosaic fashion have shown that organismic lethals are not necessarily cell lethal. The spectrum of mutations induced depends on the nature of the mutagen and the type of germ cell exposed. Radiation of spermatogonia produces intragenic as well as null mutations. Spontaneous mutations have an admixture of types not present in populations of mutations induced in germ cells, and this raises doubts concerning the accuracy of doubling-dose calculations in genetic risk estimation. The analysis of SL mutations has yielded genetic tools for the construction of detailed gene-dosage series, cis-trans comparisons, the mapping of known genes and identification of new genes, genetic rescue of various types, and the identification and isolation of DNA sequences

  6. Game Design to Introduce Pets

    Directory of Open Access Journals (Sweden)

    Wahyu Febriyanto

    2017-02-01

    Full Text Available Introduction of animals from an early age can make children to love animals, especially pets. Children are the easiest group to receive stimulation, such as for example the stimulation of introducing children to the pet. Various media are used by parents to introduce pet. For examplle, by the media of books, multimedia, etc. One of the interesting media to introduce pet is with game. Of these problems then need to know how to make concept and design game to introduced pets for children age 3-6 years. In this paper, author formulate how to make pet game design include game genre, user interface design, image model selection, game characters, and game engine. The expected design of this game can be formulation of learning through proper game as a learning tool children. Game design derived from this writing by using model 2-dimensional images are funny and interesting coloring. And combines several game genres into one, or use the mini games that children do not get bored quickly. Design of GUI (Graphical User Interface is made as simple as possible so that children easily understand in playing this game, but also must use an interesting image

  7. Introducing Positive Psychology to SLA

    Science.gov (United States)

    MacIntyre, Peter D.; Mercer, Sarah

    2014-01-01

    Positive psychology is a rapidly expanding subfield in psychology that has important implications for the field of second language acquisition (SLA). This paper introduces positive psychology to the study of language by describing its key tenets. The potential contributions of positive psychology are contextualized with reference to prior work,…

  8. An Exercise to Introduce Power

    Science.gov (United States)

    Seier, Edith; Liu, Yali

    2013-01-01

    In introductory statistics courses, the concept of power is usually presented in the context of testing hypotheses about the population mean. We instead propose an exercise that uses a binomial probability table to introduce the idea of power in the context of testing a population proportion. (Contains 2 tables, and 2 figures.)

  9. Introducing Group Theory through Music

    Science.gov (United States)

    Johnson, Craig M.

    2009-01-01

    The central ideas of postcalculus mathematics courses offered in college are difficult to introduce in middle and secondary schools, especially through the engineering and sciences examples traditionally used in algebra, geometry, and trigonometry textbooks. However, certain concepts in music theory can be used to expose students to interesting…

  10. Introducing Ethics Using Structured Controversies

    Science.gov (United States)

    Wareham, David; Elefsiniotis, Takis P.; Elms, David

    2006-01-01

    This paper describes a method of introducing ethics to a second-year class of civil engineering students. The method, known as a "structured controversy", takes the form of a workshop where the students assume the identity of stakeholders having an interest in a proposed development in an environmentally sensitive region. The instructor…

  11. Five Perspectives for Introducing Hemingway.

    Science.gov (United States)

    Tillinghast, B. S., Jr.

    1983-01-01

    Suggests that the works of Ernest Hemingway can introduce young readers to (1) an intense expression of the joy of life, (2) heroic models, (3) original use of language, (4) a sharp sense of time and place, and (5) literature that can be understood at many levels. (MM)

  12. Preimplantation Genetic Diagnosis and Natural Conception: A Comparison of Live Birth Rates in Patients with Recurrent Pregnancy Loss Associated with Translocation.

    Directory of Open Access Journals (Sweden)

    Shinichiro Ikuma

    Full Text Available Established causes of recurrent pregnancy loss (RPL include antiphospholipid syndrome, uterine anomalies, parental chromosomal abnormalities, particularly translocations, and abnormal embryonic karyotypes. The number of centers performing preimplantation genetic diagnosis (PGD for patients with translocations has steadily increased worldwide. The live birth rate with PGD was reported to be 27-54%. The live birth rate with natural conception was reported to be 37-63% on the first trial and 65-83% cumulatively. To date, however, there has been no cohort study comparing age and the number of previous miscarriages in matched patients undergoing or not undergoing PGD. Thus, we compared the live birth rate of patients with RPL associated with a translocation undergoing PGD with that of patients who chose natural conception.After genetic counseling, 52 patients who desired natural conception and 37 patients who chose PGD were matched for age and number of previous miscarriages and these comprised the subjects of our study. PGD was performed by means of fluorescence in situ hybridization analysis. The live birth rates on the first PGD trial and the first natural pregnancy after ascertainment of the carrier status were 37.8% and 53.8%, respectively (odds ratio 0.52, 95% confidence interval 0.22-1.23. Cumulative live birth rates were 67.6% and 65.4%, respectively, in the groups undergoing and not undergoing PGD. The time required to become pregnancy was similar in both groups. PGD was found to reduce the miscarriage rate significantly. The prevalence of twin pregnancies was significantly higher in the PGD group. The cost of PGD was $7,956 U.S. per patient.While PGD significantly prevented further miscarriages, there was no difference in the live birth rate. Couples should be fully informed of the similarity in the live birth rate, the similarity in time to become pregnancy, the advantages of PGD, such as the reduction in the miscarriage rate, as well as

  13. Natural genetic variation in transcriptome reflects network structure inferred with major effect mutations: insulin/TOR and associated phenotypes in Drosophila melanogaster

    Directory of Open Access Journals (Sweden)

    Harshman Lawrence G

    2009-03-01

    Full Text Available Abstract Background A molecular process based genotype-to-phenotype map will ultimately enable us to predict how genetic variation among individuals results in phenotypic alterations. Building such a map is, however, far from straightforward. It requires understanding how molecular variation re-shapes developmental and metabolic networks, and how the functional state of these networks modifies phenotypes in genotype specific way. We focus on the latter problem by describing genetic variation in transcript levels of genes in the InR/TOR pathway among 72 Drosophila melanogaster genotypes. Results We observe tight co-variance in transcript levels of genes not known to influence each other through direct transcriptional control. We summarize transcriptome variation with factor analyses, and observe strong co-variance of gene expression within the dFOXO-branch and within the TOR-branch of the pathway. Finally, we investigate whether major axes of transcriptome variation shape phenotypes expected to be influenced through the InR/TOR pathway. We find limited evidence that transcript levels of individual upstream genes in the InR/TOR pathway predict fly phenotypes in expected ways. However, there is no evidence that these effects are mediated through the major axes of downstream transcriptome variation. Conclusion In summary, our results question the assertion of the 'sparse' nature of genetic networks, while validating and extending candidate gene approaches in the analyses of complex traits.

  14. The genetic basis of Haldane's rule and the nature of asymmetric hybrid male sterility among Drosophila simulans, Drosophila mauritiana and Drosophila sechellia.

    Science.gov (United States)

    Zeng, L W; Singh, R S

    1993-05-01

    Haldane's rule (i.e., the preferential hybrid sterility and inviability of heterogametic sex) has been known for 70 years, but its genetic basis, which is crucial to the understanding of the process of species formation, remains unclear. In the present study, we have investigated the genetic basis of hybrid male sterility using Drosophila simulans, Drosophila mauritiana and Drosophila sechellia. An introgression of D. sechellia Y chromosome into a fairly homogenous background of D. simulans did not show any effect of the introgressed Y on male sterility. The substitution of D. simulans Y chromosome into D. sechellia, and both reciprocal Y chromosome substitutions between D. simulans and D. mauritiana were unsuccessful. Introgressions of cytoplasm between D. simulans and D. mauritiana (or D. sechellia) also did not have any effect on hybrid male sterility. These results rule out the X-Y interaction hypothesis as a general explanation of Haldane's rule in this species group and indicate an involvement of an X-autosome interaction. Models of symmetrical and asymmetrical X-autosome interaction have been developed which explain the Y chromosome substitution results and suggest that evolution of interactions between different genetic elements in the early stages of speciation is more likely to be of an asymmetrical nature. The model of asymmetrical X-autosome interaction also predicts that different sets of interacting genes may be involved in different pairs of related species and can account for the observation that hybrid male sterility in many partially isolated species is often nonreciprocal or unidirectional.

  15. Fossil and Genetic Evidence for the Polyphyletic Nature of the Planktonic Foraminifera "Globigerinoides", and Description of the New Genus Trilobatus

    Science.gov (United States)

    Spezzaferri, Silvia; Kucera, Michal; Pearson, Paul Nicholas; Wade, Bridget Susan; Rappo, Sacha; Poole, Christopher Robert; Morard, Raphaël; Stalder, Claudio

    2015-01-01

    Planktonic foraminifera are one of the most abundant and diverse protists in the oceans. Their utility as paleo proxies requires rigorous taxonomy and comparison with living and genetically related counterparts. We merge genetic and fossil evidence of “Globigerinoides”, characterized by supplementary apertures on spiral side, in a new approach to trace their “total evidence phylogeny” since their first appearance in the latest Paleogene. Combined fossil and molecular genetic data indicate that this genus, as traditionally understood, is polyphyletic. Both datasets indicate the existence of two distinct lineages that evolved independently. One group includes “Globigerinoides” trilobus and its descendants, the extant “Globigerinoides” sacculifer, Orbulina universa and Sphaeroidinella dehiscens. The second group includes the Globigerinoides ruber clade with the extant G. conglobatus and G. elongatus and ancestors. In molecular phylogenies, the trilobus group is not the sister taxon of the ruber group. The ruber group clusters consistently together with the modern Globoturborotalita rubescens as a sister taxon. The re-analysis of the fossil record indicates that the first “Globigerinoides” in the late Oligocene are ancestral to the trilobus group, whereas the ruber group first appeared at the base of the Miocene with representatives distinct from the trilobus group. Therefore, polyphyly of the genus "Globigerinoides" as currently defined can only be avoided either by broadening the genus concept to include G. rubescens and a large number of fossil species without supplementary apertures, or if the trilobus group is assigned to a separate genus. Since the former is not feasible due to the lack of a clear diagnosis for such a broad genus, we erect a new genus Trilobatus for the trilobus group (type species Globigerina triloba Reuss) and amend Globoturborotalita and Globigerinoides to clarify morphology and wall textures of these genera. In the new

  16. Verification of genetic identity of introduced cacao germplasm in ...

    African Journals Online (AJOL)

    In the present study, high-throughput genotyping with SNP markers was used to fingerprint 160 cacao trees in the germplasm collection at the Cocoa Research Institute of Ghana (CRIG). ... Keywords: Cacao, conservation, chocolate, DNA fingerprint, molecular marker, tropical plant, off-type, true-to-type, West Africa.

  17. 40 CFR 725.421 - Introduced genetic material.

    Science.gov (United States)

    2010-07-01

    ... fever toxins, pyrogenic exotoxins) Yersinia enterocolitica Heat-stable enterotoxins (ST) ... Neurotoxin Staphylococcus aureus Alpha toxin (alpha lysin) Yersinia pestis Murine toxin Snake toxins Bungarus...

  18. Genetic versus rearing-environment effects on phenotype: hatchery and natural rearing effects on hatchery- and wild-born coho salmon.

    Directory of Open Access Journals (Sweden)

    Cedar M Chittenden

    Full Text Available With the current trends in climate and fisheries, well-designed mitigative strategies for conserving fish stocks may become increasingly necessary. The poor post-release survival of hatchery-reared Pacific salmon indicates that salmon enhancement programs require assessment. The objective of this study was to determine the relative roles that genotype and rearing environment play in the phenotypic expression of young salmon, including their survival, growth, physiology, swimming endurance, predator avoidance and migratory behaviour. Wild- and hatchery-born coho salmon adults (Oncorhynchus kisutch returning to the Chehalis River in British Columbia, Canada, were crossed to create pure hatchery, pure wild, and hybrid offspring. A proportion of the progeny from each cross was reared in a traditional hatchery environment, whereas the remaining fry were reared naturally in a contained side channel. The resulting phenotypic differences between replicates, between rearing environments, and between cross types were compared. While there were few phenotypic differences noted between genetic groups reared in the same habitat, rearing environment played a significant role in smolt size, survival, swimming endurance, predator avoidance and migratory behaviour. The lack of any observed genetic differences between wild- and hatchery-born salmon may be due to the long-term mixing of these genotypes from hatchery introgression into wild populations, or conversely, due to strong selection in nature--capable of maintaining highly fit genotypes whether or not fish have experienced part of their life history under cultured conditions.

  19. Emphasizing the History of Genetics in an Explicit and Reflective Approach to Teaching the Nature of Science: A Pilot Study

    Science.gov (United States)

    Williams, Cody Tyler; Rudge, David Wÿss

    2016-01-01

    Science education researchers have long advocated the central role of the nature of science (NOS) for our understanding of scientific literacy. NOS is often interpreted narrowly to refer to a host of epistemological issues associated with the process of science and the limitations of scientific knowledge. Despite its importance, practitioners and…

  20. Reproductive fitness and dietary choice behavior of the genetic model organism Caenorhabditis elegans under semi-natural conditions.

    Science.gov (United States)

    Freyth, Katharina; Janowitz, Tim; Nunes, Frank; Voss, Melanie; Heinick, Alexander; Bertaux, Joanne; Scheu, Stefan; Paul, Rüdiger J

    2010-10-01

    Laboratory breeding conditions of the model organism C. elegans do not correspond with the conditions in its natural soil habitat. To assess the consequences of the differences in environmental conditions, the effects of air composition, medium and bacterial food on reproductive fitness and/or dietary-choice behavior of C. elegans were investigated. The reproductive fitness of C. elegans was maximal under oxygen deficiency and not influenced by a high fractional share of carbon dioxide. In media approximating natural soil structure, reproductive fitness was much lower than in standard laboratory media. In seminatural media, the reproductive fitness of C. elegans was low with the standard laboratory food bacterium E. coli (γ-Proteobacteria), but significantly higher with C. arvensicola (Bacteroidetes) and B. tropica (β-Proteobacteria) as food. Dietary-choice experiments in semi-natural media revealed a low preference of C. elegans for E. coli but significantly higher preferences for C. arvensicola and B. tropica (among other bacteria). Dietary-choice experiments under quasi-natural conditions, which were feasible by fluorescence in situ hybridization (FISH) of bacteria, showed a high preference of C. elegans for Cytophaga-Flexibacter-Bacteroides, Firmicutes, and β-Proteobacteria, but a low preference for γ-Proteobacteria. The results show that data on C. elegans under standard laboratory conditions have to be carefully interpreted with respect to their biological significance.

  1. The Labyrinth of Time Introducing the Universe

    CERN Document Server

    Lockwood, Michael

    2007-01-01

    Modern physics has revealed the universe as a much stranger place than we could have imagined. The puzzle at the centre of our knowledge of the universe is time. Michael Lockwood takes the reader on a fascinating journey into the nature of things. He investigates philosophical questions about past, present, and future, our experience of time, and the possibility of time travel. And he provides the most careful, lively, and up-to-date introduction to the physics of time and thestructure of the universe. He guides us step by step through relativity theory and quantum physics, introducing and exp

  2. Genetically Engineering Entomopathogenic Fungi.

    Science.gov (United States)

    Zhao, H; Lovett, B; Fang, W

    2016-01-01

    Entomopathogenic fungi have been developed as environmentally friendly alternatives to chemical insecticides in biocontrol programs for agricultural pests and vectors of disease. However, mycoinsecticides currently have a small market share due to low virulence and inconsistencies in their performance. Genetic engineering has made it possible to significantly improve the virulence of fungi and their tolerance to adverse conditions. Virulence enhancement has been achieved by engineering fungi to express insect proteins and insecticidal proteins/peptides from insect predators and other insect pathogens, or by overexpressing the pathogen's own genes. Importantly, protein engineering can be used to mix and match functional domains from diverse genes sourced from entomopathogenic fungi and other organisms, producing insecticidal proteins with novel characteristics. Fungal tolerance to abiotic stresses, especially UV radiation, has been greatly improved by introducing into entomopathogens a photoreactivation system from an archaean and pigment synthesis pathways from nonentomopathogenic fungi. Conversely, gene knockout strategies have produced strains with reduced ecological fitness as recipients for genetic engineering to improve virulence; the resulting strains are hypervirulent, but will not persist in the environment. Coupled with their natural insect specificity, safety concerns can also be mitigated by using safe effector proteins with selection marker genes removed after transformation. With the increasing public concern over the continued use of synthetic chemical insecticides and growing public acceptance of genetically modified organisms, new types of biological insecticides produced by genetic engineering offer a range of environmentally friendly options for cost-effective control of insect pests. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Combining high-throughput phenotyping and genome-wide association studies to reveal natural genetic variation in rice

    Science.gov (United States)

    Yang, Wanneng; Guo, Zilong; Huang, Chenglong; Duan, Lingfeng; Chen, Guoxing; Jiang, Ni; Fang, Wei; Feng, Hui; Xie, Weibo; Lian, Xingming; Wang, Gongwei; Luo, Qingming; Zhang, Qifa; Liu, Qian; Xiong, Lizhong

    2014-01-01

    Even as the study of plant genomics rapidly develops through the use of high-throughput sequencing techniques, traditional plant phenotyping lags far behind. Here we develop a high-throughput rice phenotyping facility (HRPF) to monitor 13 traditional agronomic traits and 2 newly defined traits during the rice growth period. Using genome-wide association studies (GWAS) of the 15 traits, we identify 141 associated loci, 25 of which contain known genes such as the Green Revolution semi-dwarf gene, SD1. Based on a performance evaluation of the HRPF and GWAS results, we demonstrate that high-throughput phenotyping has the potential to replace traditional phenotyping techniques and can provide valuable gene identification information. The combination of the multifunctional phenotyping tools HRPF and GWAS provides deep insights into the genetic architecture of important traits. PMID:25295980

  4. Ancestral seed zones and genetic mixture of tanoak

    Science.gov (United States)

    Richard Dodd; Zara Rafii; Wasima Mayer

    2010-01-01

    Understanding the genetic structure of tanoak (Lithocarpus densiflorus) is necessary to pathologists seeking natural variation in resistance to Phytophthora ramorum, cause of sudden oak death (SOD), and to resource managers who need indications of conservation priorities for this species now threatened by this introduced pathogen. We investigated...

  5. Natural Selection Causes Adaptive Genetic Resistance in Wild Emmer Wheat against Powdery Mildew at ?Evolution Canyon? Microsite, Mt. Carmel, Israel

    OpenAIRE

    Yin, Huayan; Ben-Abu, Yuval; Wang, Hongwei; Li, Anfei; Nevo, Eviatar; Kong, Lingrang

    2015-01-01

    Background ?Evolution Canyon? (ECI) at Lower Nahal Oren, Mount Carmel, Israel, is an optimal natural microscale model for unraveling evolution in action highlighting the basic evolutionary processes of adaptation and speciation. A major model organism in ECI is wild emmer, Triticum dicoccoides, the progenitor of cultivated wheat, which displays dramatic interslope adaptive and speciational divergence on the tropical-xeric ?African? slope (AS) and the temperate-mesic ?European? slope (ES), sep...

  6. Increased natural reproduction and genetic diversity one generation after cessation of a steelhead trout (Oncorhynchus mykiss) conservation hatchery program.

    Science.gov (United States)

    Berejikian, Barry A; Van Doornik, Donald M

    2018-01-01

    Spatial and temporal fluctuations in productivity and abundance confound assessments of captive propagation programs aimed at recovery of Threatened and Endangered populations. We conducted a 17 year before-after-control-impact experiment to determine the effects of a captive rearing program for anadromous steelhead trout (Oncorhynchus mykiss) on a key indicator of natural spawner abundance (naturally produced nests or 'redds'). The supplemented population exhibited a significant (2.6-fold) increase in redd abundance in the generation following supplementation. Four non-supplemented (control) populations monitored over the same 17 year period exhibited stable or decreasing trends in redd abundance. Expected heterozygosity in the supplemented population increased significantly. Allelic richness increased, but to a lesser (non-significant) degree. Estimates of the effective number of breeders increased from a harmonic mean of 24.4 in the generation before supplementation to 38.9 after supplementation. Several non-conventional aspects of the captive rearing program may have contributed to the positive response in the natural population.

  7. Increased natural reproduction and genetic diversity one generation after cessation of a steelhead trout (Oncorhynchus mykiss conservation hatchery program.

    Directory of Open Access Journals (Sweden)

    Barry A Berejikian

    Full Text Available Spatial and temporal fluctuations in productivity and abundance confound assessments of captive propagation programs aimed at recovery of Threatened and Endangered populations. We conducted a 17 year before-after-control-impact experiment to determine the effects of a captive rearing program for anadromous steelhead trout (Oncorhynchus mykiss on a key indicator of natural spawner abundance (naturally produced nests or 'redds'. The supplemented population exhibited a significant (2.6-fold increase in redd abundance in the generation following supplementation. Four non-supplemented (control populations monitored over the same 17 year period exhibited stable or decreasing trends in redd abundance. Expected heterozygosity in the supplemented population increased significantly. Allelic richness increased, but to a lesser (non-significant degree. Estimates of the effective number of breeders increased from a harmonic mean of 24.4 in the generation before supplementation to 38.9 after supplementation. Several non-conventional aspects of the captive rearing program may have contributed to the positive response in the natural population.

  8. Introducing ZBrush 3rd Edition

    CERN Document Server

    Keller, Eric

    2012-01-01

    Learn ZBrush inside and out with this updated new edition Get totally comfortable sculpting in a digital environment with the latest edition of this bestselling beginner's guide to ZBrush. Fully updated for the newest version of the software, ZBrush 4R3, this book dispels any fears you might have about the difficulty of using ZBrush and soon has you creating realistic, cartoon, and organic models with flair. Learn all the essentials, as you complete fun tutorials on painting, meshes, organic scripting, hard surface sculpting, lighting, rendering, and more. Introduces you to ZBrush, the sculpt

  9. Introducing time a graphic guide

    CERN Document Server

    Callender, Craig

    2010-01-01

    What is time? The 5th-century philosopher St Augustine famously said that he knew what time was, so long as no one asked him. Is time a fourth dimension similar to space or does it flow in some sense? And if it flows, does it make sense to say how fast? Does the future exist? Is time travel possible? Why does time seem to pass in only one direction?These questions and others are among the deepest and most subtle that one can ask, but "Introducing Time" presents them - many for the first time - in an easily accessible, lucid and engaging manner, wittily illustrated by Ralph Edney.

  10. Introduced species as evolutionary traps

    Science.gov (United States)

    Schlaepfer, Martin A.; Sherman, P.W.; Blossey, B.; Runge, M.C.

    2005-01-01

    Invasive species can alter environments in such a way that normal behavioural decision-making rules of native species are no longer adaptive. The evolutionary trap concept provides a useful framework for predicting and managing the impact of harmful invasive species. We discuss how native species can respond to changes in their selective regime via evolution or learning. We also propose novel management strategies to promote the long-term co-existence of native and introduced species in cases where the eradication of the latter is either economically or biologically unrealistic.

  11. Introducing Character Animation with Blender

    CERN Document Server

    Mullen, Tony

    2011-01-01

    Introducing Character Animation with Blender, 2nd Edition is written in a friendly but professional tone, with clear descriptions and numerous illustrative screenshots. Throughout the book, tutorials focus on how to accomplish actual animation goals, while illustrating the necessary technical methods along the way. These are reinforced by clear descriptions of how each specific aspect of Blender works and fits together with the rest of the package. By following all the tutorials, the reader will gain all the skills necessary to build and animate a well-modeled, fully-rigged character of their

  12. Introducing the Medical Ethics Bowl.

    Science.gov (United States)

    Merrick, Allison; Green, Rochelle; Cunningham, Thomas V; Eisenberg, Leah R; Hester, D Micah

    2016-01-01

    Although ethics is an essential component of undergraduate medical education, research suggests that current medical ethics curricula face considerable challenges in improving students' ethical reasoning. This article discusses these challenges and introduces a promising new mode of graduate and professional ethics instruction for overcoming them. We begin by describing common ethics curricula, focusing in particular on established problems with current approaches. Next, we describe a novel method of ethics education and assessment for medical students that we have devised: the Medical Ethics Bowl (MEB). Finally, we suggest the pedagogical advantages of the MEB when compared to other ethics curricula.

  13. Inspirations in medical genetics.

    Science.gov (United States)

    Asadollahi, Reza

    2016-02-01

    There are abundant instances in the history of genetics and medical genetics to illustrate how curiosity, charisma of mentors, nature, art, the saving of lives and many other matters have inspired great discoveries. These achievements from deciphering genetic concepts to characterizing genetic disorders have been crucial for management of the patients. There remains, however, a long pathway ahead. © The Author(s) 2014.

  14. [Evaluation of modern epizootic activity of natural tularemia foci in Voronezh region using immune-serological and molecular-genetic study of main carriers of the disease].

    Science.gov (United States)

    Meshcheriakova, I S; Trankvilevskiĭ, D V; Kvasov, D A; Mikhaĭlova, T V; Kormilitsina, M I; Demidova, T N; Stepkin, Iu I; Zhukov, V I

    2015-01-01

    Improvement of monitoring and prognosis of epidemic manifestations of natural foci of tularemia on the territory of Voronezh region using immune-serological and molecular-genetic study of main carriers of the disease. 539 small mammals captured during summer period of 2011 in 4 districts of North-Eastern part of Voronezh region were studied. Animal organs were studied by serologic (search for Francisella tularensis antigens) and molecular-biologic (detection of F. tularensis DNA) methods. Tularemia antigen was detected using passive hemagglutination reaction (PHAR) with erythrocytic tularemia immunoglobulin diagnosticum. Real-time polymerase chain reaction (RT-PCR) was applied for detection of tularemia causative agent DNA. Complex study revealed epizootic activity of natural foci of tularemia in the examined territory. F. tularensis antigen and/or DNA were detected in 82 objects (15.2%). Use of RT-PCR allowed to additionally detect samples with relatively low content of F. tularensis DNA substrate, when antigen was not detected in samples. High sensitivity and specificity of the RT-PCR was ensured by inclusion of specific probes (tu14-PR2 and ISFTu2P). The results obtained give evidence on functioning and epizootic activity of natural foci of tularemia in Voronezh region that requires constant monitoring of the territory and prophylaxis measures, first of all vaccination of risk groups by live tularemia vaccine.

  15. Genetic and phenotypic diversity of naturally isolated wild strains of Aspergillus niger with hyper glucose oxidase production

    Directory of Open Access Journals (Sweden)

    MAHMOUD EL-HARIRI

    2015-12-01

    Full Text Available Glucose oxidase (GOx is the basic stone for many of biological industry worldwide. The improvement of GOx production basically depends on selection of hyper producer strain of Aspergillus niger. Selective isolation and screening for natural hyper producer strains of A. niger and sequence analysis of the GOD gene, which is responsible for production of the enzyme, are very effective approaches to investigate the naturally modified strains of A. niger with hyper productive capacity of GOx enzyme. The aims of the current study were selective isolation of naturally hyper GOx producing strains of A. niger and evaluation of their GOx activities under optimized parameters in the laboratory. Five wild Egyptian isolates of A. niger were screened for GOx and catalase activity using two types of modified basal liquid media. The GOx activity was evaluated by high throughout liquid phase system. The isolates showed a variable activity for GOx production ranged from 0 to 28.7 U.ml-1. One isolate coded Strain 7 was negative GOx producer on Vogel's broth medium in comparison to other isolates, while its GOx activity on Cazpek Dox was considered as positive (7.28 U.ml-1. It was concluded that GOx production is affected by three controllable factors – the basal media components, time of incubation, and the strain with its adaption to the media components‎. Also, the catalase activity was tested and it was produced with a different degree of variability, which may be reflected on GOx stability. GOD genes of these wild variant of A. niger were cloned and sequenced to determine intraspecies diversity of GOD between the wild variants. The comparison of isolated wild variants to other reference hyper GOx producer strains of A. niger was performed to determine if the GOD sequence analysis of these strains can be distinguished based on their GOx activity. This is the first report for isolation and detection of naturally A. niger hyper GOx-producer strains with

  16. Genetic Architecture of Natural Variation in Rice Chlorophyll Content Revealed by a Genome-Wide Association Study.

    Science.gov (United States)

    Wang, Quanxiu; Xie, Weibo; Xing, Hongkun; Yan, Ju; Meng, Xiangzhou; Li, Xinglei; Fu, Xiangkui; Xu, Jiuyue; Lian, Xingming; Yu, Sibin; Xing, Yongzhong; Wang, Gongwei

    2015-06-01

    Chlorophyll content is one of the most important physiological traits as it is closely related to leaf photosynthesis and crop yield potential. So far, few genes have been reported to be involved in natural variation of chlorophyll content in rice (Oryza sativa) and the extent of variations explored is very limited. We conducted a genome-wide association study (GWAS) using a diverse worldwide collection of 529 O. sativa accessions. A total of 46 significant association loci were identified. Three F2 mapping populations with parents selected from the association panel were tested for validation of GWAS signals. We clearly demonstrated that Grain number, plant height, and heading date7 (Ghd7) was a major locus for natural variation of chlorophyll content at the heading stage by combining evidence from near-isogenic lines and transgenic plants. The enhanced expression of Ghd7 decreased the chlorophyll content, mainly through down-regulating the expression of genes involved in the biosynthesis of chlorophyll and chloroplast. In addition, Narrow leaf1 (NAL1) corresponded to one significant association region repeatedly detected over two years. We revealed a high degree of polymorphism in the 5' UTR and four non-synonymous SNPs in the coding region of NAL1, and observed diverse effects of the major haplotypes. The loci or candidate genes identified would help to fine-tune and optimize the antenna size of canopies in rice breeding. Copyright © 2015 The Author. Published by Elsevier Inc. All rights reserved.

  17. Invariant natural killer T-cell control of type 1 diabetes: a dendritic cell genetic decision of a silver bullet or Russian roulette.

    Science.gov (United States)

    Driver, John P; Scheuplein, Felix; Chen, Yi-Guang; Grier, Alexandra E; Wilson, S Brian; Serreze, David V

    2010-02-01

    In part, activation of invariant natural killer T (iNKT)-cells with the superagonist alpha-galactosylceramide (alpha-GalCer) inhibits the development of T-cell-mediated autoimmune type 1 diabetes in NOD mice by inducing the downstream differentiation of antigen-presenting dendritic cells (DCs) to an immunotolerogenic state. However, in other systems iNKT-cell activation has an adjuvant-like effect that enhances rather than suppresses various immunological responses. Thus, we tested whether in some circumstances genetic variation would enable activated iNKT-cells to support rather than inhibit type 1 diabetes development. We tested whether iNKT-conditioned DCs in NOD mice and a major histocompatibility complex-matched C57BL/6 (B6) background congenic stock differed in capacity to inhibit type 1 diabetes induced by the adoptive transfer of pathogenic AI4 CD8 T-cells. Unlike those of NOD origin, iNKT-conditioned DCs in the B6 background stock matured to a state that actually supported rather than inhibited AI4 T-cell-induced type 1 diabetes. The induction of a differing activity pattern of T-cell costimulatory molecules varying in capacity to override programmed death-ligand-1 inhibitory effects contributes to the respective ability of iNKT-conditioned DCs in NOD and B6 background mice to inhibit or support type 1 diabetes development. Genetic differences inherent to both iNKT-cells and DCs contribute to their varying interactions in NOD and B6.H2(g7) mice. This great variability in the interactions between iNKT-cells and DCs in two inbred mouse strains should raise a cautionary note about considering manipulation of this axis as a potential type 1 diabetes prevention therapy in genetically heterogeneous humans.

  18. The role of natural selection in shaping genetic variation in a promising Chagas disease drug target: Trypanosoma cruzi trans-sialidase.

    Science.gov (United States)

    Gallant, Joseph P; Lima-Cordón, Raquel Asunción; Justi, Silvia A; Monroy, Maria Carlota; Viola, Toni; Stevens, Lori

    2018-04-21

    Rational drug design creates innovative therapeutics based on knowledge of the biological target to provide more effective and responsible therapeutics. Chagas disease, endemic throughout Latin America, is caused by Trypanosoma cruzi, a protozoan parasite. Current therapeutics are problematic with widespread calls for new approaches. Researchers are using rational drug design for Chagas disease and one target receiving considerable attention is the T. cruzi trans-sialidase protein (TcTS). In T. cruzi, trans-sialidase catalyzes the transfer of sialic acid from a mammalian host to coat the parasite surface membrane and avoid immuno-detection. However, the role of TcTS in pathology variance among and within genetic variants of the parasite is not well understood despite numerous studies. Previous studies reported the crystalline structure of TcTS and the TS protein structure in other trypanosomes where the enzyme is often inactive. However, no study has examined the role of natural selection in genetic variation in TcTS. To understand the role of natural selection in TcTS DNA sequence and protein variation, we examined a 471 bp portion of the TcTS gene from 48 T. cruzi samples isolated from insect vectors. Because there may be multiple parasite genotypes infecting one insect and there are multiple copies of TcTS per parasite genome, all 48 sequences had multiple polymorphic bases. To resolve these polymorphisms, we examined cloned sequences from two insect vectors. The data are analyzed to understand the role of natural selection in shaping genetic variation in TcTS and interpreted in light of the possible role of TcTS as a drug target. The analysis highlights negative or purifying selection on three amino acids previously shown to be important in TcTS transfer activity. One amino acid in particular, Tyr342, is a strong candidate for a drug target because it is under negative selection and amino acid substitutions inactivate TcTS transfer activity. Chagas disease

  19. Preliminary analysis of the genetic variability of two natural beds of the Scallop Euvola ziczac (Linnaeus, 1758 in Brazil

    Directory of Open Access Journals (Sweden)

    Mercedes Gonzalez Wangüemert

    2000-01-01

    Full Text Available Euvola ziczac (formerly Pecten ziczac, a simultaneous hermaphroditic scallop was heavily fished in Brazil between 1972 and 1980. The production peaked in 1980 with 8,800 tons and was followed by the total collapse of the resource. In order to investigate the possible loss of genetic variability of the stock associated to overfishing and self-fertilization, the polymorphism of phosphoglucomutase (PGM and glucose phosphate isomerase (GPI was analyzed by electrophoresis of the adductor muscle of scallops from São Francisco (26° 20.583’S; 48° 16.507’W and Bom Abrigo (25° 28.735’S; 47° 37.621’W beds; the southern and northern extremes of the scallop fishing ground, respectively. Animals from São Francisco showed a strong deficiency of heterozygosity for GPI and PGM. In addition, PGM showed *exclusive alleles for each bed. Such results coupled with other information about the species suggested the following hypothesis: a the stock was a metapopulation with at least two populations; b some reproductive isolation might be occurring which might be influenced by conditions of larval transport and by the extremely low densities of scallops; c presently, the stock seemed to be mostly maintained through self-fertilization; d São Francisco could constitute a source-area, contributing with larvae and recruits to Bom Abrigo and other areas; e both beds were suffering a genetic homogenization more evident in São Francisco. Such hypothesis needed to be investigated in order to furnish guidelines for future programs of recovery and management of the resource.A vieira hermafrodita simultânea Euvola ziczac (anteriormente Pecten ziczac, foi intensamente explotada no Brasil entre os anos de 1972 e 1980. O máximo de produção foi atingido em 1980, com 8800 toneladas desembarcadas, após o qual ocorreu o total colapso do recurso. Com o objetivo de reconhecer uma possível perda de variabilidade genética do estoque associada à sobrepesca e

  20. Genetics, receptor binding property, and transmissibility in mammals of naturally isolated H9N2 Avian Influenza viruses.

    Directory of Open Access Journals (Sweden)

    Xuyong Li

    2014-11-01

    Full Text Available H9N2 subtype influenza viruses have been detected in different species of wild birds and domestic poultry in many countries for several decades. Because these viruses are of low pathogenicity in poultry, their eradication is not a priority for animal disease control in many countries, which has allowed them to continue to evolve and spread. Here, we characterized the genetic variation, receptor-binding specificity, replication capability, and transmission in mammals of a series of H9N2 influenza viruses that were detected in live poultry markets in southern China between 2009 and 2013. Thirty-five viruses represented 17 genotypes on the basis of genomic diversity, and one specific "internal-gene-combination" predominated among the H9N2 viruses. This gene combination was also present in the H7N9 and H10N8 viruses that have infected humans in China. All of the 35 viruses preferentially bound to the human-like receptor, although two also retained the ability to bind to the avian-like receptor. Six of nine viruses tested were transmissible in ferrets by respiratory droplet; two were highly transmissible. Some H9N2 viruses readily acquired the 627K or 701N mutation in their PB2 gene upon infection of ferrets, further enhancing their virulence and transmission in mammals. Our study indicates that the widespread dissemination of H9N2 viruses poses a threat to human health not only because of the potential of these viruses to cause an influenza pandemic, but also because they can function as "vehicles" to deliver different subtypes of influenza viruses from avian species to humans.

  1. Genetic structure and natural variation associated with host of origin in Penicillium expansum strains causing blue mould.

    Science.gov (United States)

    Sanzani, S M; Montemurro, C; Di Rienzo, V; Solfrizzo, M; Ippolito, A

    2013-07-15

    Blue mould, caused by Penicillium expansum, is one of the most economically damaging postharvest diseases of pome fruits, although it may affect a wider host range, including sweet cherries and table grapes. Several reports on the role of mycotoxins in plant pathogenesis have been published, but few focussed on the influence of mycotoxins on the variation in host preference amongst producing fungi. In the present study the influence of the host on P. expansum pathogenicity/virulence was investigated, focussing mainly on the relationship with patulin production. Three P. expansum strain groups, originating from apples, sweet cherries, and table grapes (7 strains per host) were grown on their hosts of isolation and on artificial media derived from them. Strains within each P. expansum group proved to be more aggressive and produced more patulin than the other two groups under evaluation when grown on the host from which they originated. Table grape strains were the most aggressive (81% disease incidence) and strongest patulin producers (up to 554μg/g). The difference in aggressiveness amongst strains was appreciable only in the presence of a living host, suggesting that the complex pathogen-host interaction significantly influenced the ability of P. expansum to cause the disease. Incidence/severity of the disease and patulin production proved to be positively correlated, supporting the role of patulin as virulence/pathogenicity factor. The existence of genetic variation amongst isolates was confirmed by the High Resolution Melting method that was set up herein, which permitted discrimination of P. expansum from other species (P. chrysogenum and P. crustosum) and, within the same species, amongst the host of origin. Host effect on toxin production appeared to be exerted at a transcriptional level. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. Introducing Newton and classical physics

    CERN Document Server

    Rankin, William

    2002-01-01

    The rainbow, the moon, a spinning top, a comet, the ebb and flood of the oceans ...a falling apple. There is only one universe and it fell to Isaac Newton to discover its secrets. Newton was arguably the greatest scientific genius of all time, and yet he remains a mysterious figure. Written and illustrated by William Rankin, "Introducting Newton and Classical Physics" explains the extraordinary ideas of a man who sifted through the accumulated knowledge of centuries, tossed out mistaken beliefs, and single-handedly made enormous advances in mathematics, mechanics and optics. By the age of 25, entirely self-taught, he had sketched out a system of the world. Einstein's theories are unthinkable without Newton's founding system. He was also a secret heretic, a mystic and an alchemist, the man of whom Edmund Halley said "Nearer to the gods may no man approach!". This is an ideal companion volume to "Introducing Einstein".

  3. Introducing positive psychology to SLA

    Directory of Open Access Journals (Sweden)

    Sarah Mercer

    2014-01-01

    Full Text Available Positive psychology is a rapidly expanding subfield in psychology that has important implications for the field of second language acquisition (SLA. This paper introduces positive psychology to the study of language by describing its key tenets. The potential contributions of positive psychology are contextualized with reference to prior work, including the humanistic movement in language teaching, models of motivation, the concept of an affective filter, studies of the good language learner, and the concepts related to the self. There are reasons for both encouragement and caution as studies inspired by positive psychology are undertaken. Papers in this special issue of SSLLT cover a range of quantitative and qualitative methods with implications for theory, research, and teaching practice. The special issue serves as a springboard for future research in SLA under the umbrella of positive psychology.

  4. Natural radiation

    International Nuclear Information System (INIS)

    Feliciano, Vanusa Maria Delage

    2016-01-01

    Cosmic radiation, as well as cosmogenic radiation, terrestrial radiation, radon and thorium are introduced in this chapter 3. The distribution of natural radiation sources is treated, where the percentage distribution of the contribution relative to exposure to radiation from natural and artificial sources is also included

  5. Low genetic diversity and local adaptive divergence of Dracaena cambodiana (Liliaceae) populations associated with historical population bottlenecks and natural selection: an endangered long-lived tree endemic to Hainan Island, China.

    Science.gov (United States)

    Zheng, D-J; Xie, L-S; Zhu, J-H; Zhang, Z-L

    2012-09-01

    Historical population bottlenecks and natural selection have important effects on the current genetic diversity and structure of long-lived trees. Dracaena cambodiana is an endangered, long-lived tree endemic to Hainan Island, China. Our field investigations showed that only 10 populations remain on Hainan Island and that almost all have been seriously isolated and grow in distinct habitats. A considerable amount of genetic variation at the species level, but little variation at the population level, and a high level of genetic differentiation among the populations with limited gene flow in D. cambodiana were detected using inter-simple sequence repeat (ISSR) and random amplified polymorphic DNA (RAPD) analyses. No significant correlation was found between genetic diversity and actual population size, as the genetic diversities were similar regardless of population size. The Mantel test revealed that there was no correlation between genetic and geographic distances among the 10 populations. The UPGMA, PCoA and Bayesian analyses showed that local adaptive divergence has occurred among the D. cambodiana populations, which was further supported by habitat-private fragments. We suggest that the current genetic diversity and population differentiation of D. cambodiana resulted from historical population bottlenecks and natural selection followed by historical isolation. However, the lack of natural regeneration of D. cambodiana indicates that former local adaptations with low genetic diversity may have been genetically weak and are unable to adapt to the current ecological environments. © 2012 German Botanical Society and The Royal Botanical Society of the Netherlands.

  6. In vivo tracking of genetically engineered, anti-HER2/neu directed natural killer cells to HER2/neu positive mammary tumors with magnetic resonance imaging

    International Nuclear Information System (INIS)

    Daldrup-Link, Heike E.; Meier, Reinhardt; Metz, Stephan; Settles, Marcus; Rummeny, Ernst J.; Rudelius, Martina; Piontek, Guido; Schlegel, Juergen; Piert, Morand; Uherek, Christoph; Wels, Winfried

    2005-01-01

    The purpose of this study is to optimize labeling of the human natural killer (NK) cell line NK-92 with iron-oxide-based contrast agents and to monitor the in vivo distribution of genetically engineered NK-92 cells, which are directed against HER2/neu receptors, to HER2/neu positive mammary tumors with magnetic resonance (MR) imaging. Parental NK-92 cells and genetically modified HER2/neu specific NK-92-scFv(FRP5)-zeta cells, expressing a chimeric antigen receptor specific to the tumor-associated ErbB2 (HER2/neu) antigen, were labeled with ferumoxides and ferucarbotran using simple incubation, lipofection and electroporation techniques. Labeling efficiency was evaluated by MR imaging, Prussian blue stains and spectrometry. Subsequently, ferucarbotran-labeled NK-92-scFv(FRP5)-zeta (n=3) or parental NK-92 cells were intravenously injected into the tail vein of six mice with HER2/neu-positive NIH 3T3 mammary tumors, implanted in the mammary fat pad. The accumulation of the cells in the tumors was monitored by MR imaging before and 12 and 24 h after cell injection (p.i.). MR data were correlated with histopathology. Both the parental NK-92 and the genetically modified NK-92-scFv(FRP5)-zeta cells could be labeled with ferucarbotran and ferumoxides by lipofection and electroporation, but not by simple incubation. The intracellular cytoplasmatic iron-oxide uptake was significantly higher after labeling with ferucarbotran than ferumoxides (P 6 NK-92-scFv(FRP5)-zeta cells into tumor-bearing mice, MR showed a progressive signal decline in HER2/neu-positive mammary tumors at 12 and 24 h (p.i.). Conversely, injection of 5 x 10 6 parental NK-92 control cells, not directed against HER2/neu receptors, did not cause significant signal intensity changes of the tumors. Histopathology confirmed an accumulation of the former, but not the latter cells in tumor tissue. The human natural killer cell line NK-92 can be efficiently labeled with clinically applicable iron-oxide contrast

  7. In vivo tracking of genetically engineered, anti-HER2/neu directed natural killer cells to HER2/neu positive mammary tumors with magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Daldrup-Link, Heike E. [UCSF Medical Center, Department of Radiology, San Francisco, CA (United States); Meier, Reinhardt; Metz, Stephan; Settles, Marcus; Rummeny, Ernst J. [Technical University Munich, Department of Radiology, Munich (Germany); Rudelius, Martina; Piontek, Guido; Schlegel, Juergen [Technical University Munich, Institute of Pathology, Division of Neuropathology, Munich (Germany); Piert, Morand [Technical University Munich, Department of Nuclear Medicine, Munich (Germany); Uherek, Christoph; Wels, Winfried [University of Frankfurt, Georg Speyer House, Frankfurt (Germany)

    2005-01-01

    The purpose of this study is to optimize labeling of the human natural killer (NK) cell line NK-92 with iron-oxide-based contrast agents and to monitor the in vivo distribution of genetically engineered NK-92 cells, which are directed against HER2/neu receptors, to HER2/neu positive mammary tumors with magnetic resonance (MR) imaging. Parental NK-92 cells and genetically modified HER2/neu specific NK-92-scFv(FRP5)-zeta cells, expressing a chimeric antigen receptor specific to the tumor-associated ErbB2 (HER2/neu) antigen, were labeled with ferumoxides and ferucarbotran using simple incubation, lipofection and electroporation techniques. Labeling efficiency was evaluated by MR imaging, Prussian blue stains and spectrometry. Subsequently, ferucarbotran-labeled NK-92-scFv(FRP5)-zeta (n=3) or parental NK-92 cells were intravenously injected into the tail vein of six mice with HER2/neu-positive NIH 3T3 mammary tumors, implanted in the mammary fat pad. The accumulation of the cells in the tumors was monitored by MR imaging before and 12 and 24 h after cell injection (p.i.). MR data were correlated with histopathology. Both the parental NK-92 and the genetically modified NK-92-scFv(FRP5)-zeta cells could be labeled with ferucarbotran and ferumoxides by lipofection and electroporation, but not by simple incubation. The intracellular cytoplasmatic iron-oxide uptake was significantly higher after labeling with ferucarbotran than ferumoxides (P<0.05). After intravenous injection of 5 x 10{sup 6} NK-92-scFv(FRP5)-zeta cells into tumor-bearing mice, MR showed a progressive signal decline in HER2/neu-positive mammary tumors at 12 and 24 h (p.i.). Conversely, injection of 5 x 10{sup 6} parental NK-92 control cells, not directed against HER2/neu receptors, did not cause significant signal intensity changes of the tumors. Histopathology confirmed an accumulation of the former, but not the latter cells in tumor tissue. The human natural killer cell line NK-92 can be efficiently

  8. Genetic characterization of natural variants of Vpu from HIV-1 infected individuals from Northern India and their impact on virus release and cell death.

    Directory of Open Access Journals (Sweden)

    Sachin Verma

    Full Text Available BACKGROUND: Genetic studies reveal that vpu is one of the most variable regions in HIV-1 genome. Functional studies have been carried out mostly with Vpu derived from laboratory adapted subtype B pNL 4-3 virus. The rationale of this study was to characterize genetic variations that are present in the vpu gene from HIV-1 infected individuals from North-India (Punjab/Haryana and determine their functional relevance. METHODS: Functionally intact vpu gene variants were PCR amplified from genomic DNA of HIV-1 infected individuals. These variants were then subjected to genetic analysis and unique representative variants were cloned under CMV promoter containing expression vector as well as into pNL 4-3 HIV-1 virus for intracellular expression studies. These variants were characterized with respect to their ability to promote virus release as well as cell death. RESULTS: Based on phylogenetic analysis and extensive polymorphisms with respect to consensus Vpu B and C, we were able to arbitrarily assign variants into two major groups (B and C. The group B variants always showed significantly higher virus release activity and exhibited moderate levels of cell death. On the other hand, group C variants displayed lower virus release activity but greater cell death potential. Interestingly, Vpu variants with a natural S61A mutation showed greater intracellular stability. These variants also exhibited significant reduction in their intracellular ubiquitination and caused greater virus release. Another group C variant that possessed a non-functional β-TrcP binding motif due to two critical serine residues (S52 and S56 being substituted with isoleucine residues, showed reduced virus release activity but modest cytotoxic activity. CONCLUSIONS: The natural variations exhibited by our Vpu variants involve extensive polymorphism characterized by substitution and deletions that contribute toward positive selection. We identified two major groups and an extremely

  9. Prevalence, genetic identity and vertical transmission of Babesia microti in three naturally infected species of vole, Microtus spp. (Cricetidae).

    Science.gov (United States)

    Tołkacz, Katarzyna; Bednarska, Małgorzata; Alsarraf, Mohammed; Dwużnik, Dorota; Grzybek, Maciej; Welc-Falęciak, Renata; Behnke, Jerzy M; Bajer, Anna

    2017-02-06

    Vertical transmission is one of the transmission routes for Babesia microti, the causative agent of the zoonotic disease, babesiosis. Congenital Babesia invasions have been recorded in laboratory mice, dogs and humans. The aim of our study was to determine if vertical transmission of B. microti occurs in naturally-infected reservoir hosts of the genus Microtus. We sampled 124 common voles, Microtus arvalis; 76 root voles, M. oeconomus and 17 field voles, M. agrestis. In total, 113 embryos were isolated from 20 pregnant females. Another 11 pregnant females were kept in the animal house at the field station in Urwitałt until they had given birth and weaned their pups (n = 62). Blood smears and/or PCR targeting the 550 bp 18S rRNA gene fragment were used for the detection of B. microti. Selected PCR products, including isolates from females/dams and their embryos/pups, were sequenced. Positive PCR reactions were obtained for 41% (89/217) of the wild-caught voles. The highest prevalence of B. microti was recorded in M. arvalis (56/124; 45.2%), then in M. oeconomus (30/76; 39.5%) and the lowest in M. agrestis (3/17; 17.7%). Babesia microti DNA was detected in 61.4% (27/44) of pregnant females. Vertical transmission was confirmed in 81% (61/75) of the embryos recovered from Babesia-positive wild-caught pregnant females. The DNA of B. microti was detected in the hearts, lungs and livers of embryos from 98% of M. arvalis, 46% of M. oeconomus and 0% of M. agrestis embryos from Babesia-positive females. Of the pups born in captivity, 90% were born to Babesia-positive dams. Babesia microti DNA was detected in 70% (35/50) of M. arvalis and 83% (5/6) of M. oeconomus pups. Congenitally acquired infections had no impact on the survival of pups over a 3-week period post partum. Among 97 B. microti sequences, two genotypes were found. The IRU1 genotype (Jena-like) was dominant in wild-caught voles (49/53; 92%), pregnant females (9/11; 82%) and dams (3/5; 60%). The IRU2

  10. An engineered genetic selection for ternary protein complexes inspired by a natural three-component hitchhiker mechanism.

    Science.gov (United States)

    Lee, Hyeon-Cheol; Portnoff, Alyse D; Rocco, Mark A; DeLisa, Matthew P

    2014-12-22

    The bacterial twin-arginine translocation (Tat) pathway is well known to translocate correctly folded monomeric and dimeric proteins across the tightly sealed cytoplasmic membrane. We identified a naturally occurring heterotrimer, the Escherichia coli aldehyde oxidoreductase PaoABC, that is co-translocated by the Tat translocase according to a ternary "hitchhiker" mechanism. Specifically, the PaoB and PaoC subunits, each devoid of export signals, are escorted to the periplasm in a piggyback fashion by the Tat signal peptide-containing subunit PaoA. Moreover, export of PaoA was blocked when either PaoB or PaoC was absent, revealing a surprising interdependence for export that is not seen for classical secretory proteins. Inspired by this observation, we created a bacterial three-hybrid selection system that links the formation of ternary protein complexes with antibiotic resistance. As proof-of-concept, a bispecific antibody was employed as an adaptor that physically crosslinked one antigen fused to a Tat export signal with a second antigen fused to TEM-1 β-lactamase (Bla). The resulting non-covalent heterotrimer was exported in a Tat-dependent manner, delivering Bla to the periplasm where it hydrolyzed β-lactam antibiotics. Collectively, these results highlight the remarkable flexibility of the Tat system and its potential for studying and engineering ternary protein interactions in living bacteria.

  11. Natural genetic variation of seed micronutrients of Arabidopsis thaliana grown in zinc-deficient and zinc-amended soil

    Directory of Open Access Journals (Sweden)

    Xiaochao Chen

    2016-07-01

    Full Text Available The quality of edible seeds for human and animal nutrition is crucially dependent on high zinc (Zn and iron (Fe seed concentrations. The micronutrient bioavailability is strongly reduced by seed phytate that forms complexes with seed cations. Superior genotypes with increased seed Zn concentrations had been identified, but low micronutrient seed levels often prevail when the plants are grown in Zn-deficient soils, which are globally widespread and correlate with human Zn-deficiency. Here, seed Zn concentrations of Arabidopsis accessions grown in Zn-deficient and Zn-amended conditions were measured together with seed Fe and manganese (Mn, in a panel of 108 accessions. By applying genome-wide association, de novo candidate genes potentially involved in the seed micronutrient accumulation were identified. However, a candidate inositol 1,3,4-trisphosphate 5/6-kinase 3 gene (ITPK3, located close to a significant nucleotide polymorphism associated with relative Zn seed concentrations, was dispensable for seed micronutrients accumulation in Col-0. Loss of this gene in itpk3-1 did neither affect phytate seed levels, nor seed Zn, Fe and Mn. It is concluded that large natural variance of micronutrient seed levels is identified in the population and several accessions maintain high seed Zn despite growth in Zn-deficient conditions.

  12. Natural radiation; A radiacao natural

    Energy Technology Data Exchange (ETDEWEB)

    Feliciano, Vanusa Maria Delage

    2016-07-01

    Cosmic radiation, as well as cosmogenic radiation, terrestrial radiation, radon and thorium are introduced in this chapter 3. The distribution of natural radiation sources is treated, where the percentage distribution of the contribution relative to exposure to radiation from natural and artificial sources is also included.

  13. Quantum Genetics in terms of Quantum Reversible Automata and Quantum Computation of Genetic Codes and Reverse Transcription

    CERN Document Server

    Baianu,I C

    2004-01-01

    The concepts of quantum automata and quantum computation are studied in the context of quantum genetics and genetic networks with nonlinear dynamics. In previous publications (Baianu,1971a, b) the formal concept of quantum automaton and quantum computation, respectively, were introduced and their possible implications for genetic processes and metabolic activities in living cells and organisms were considered. This was followed by a report on quantum and abstract, symbolic computation based on the theory of categories, functors and natural transformations (Baianu,1971b; 1977; 1987; 2004; Baianu et al, 2004). The notions of topological semigroup, quantum automaton, or quantum computer, were then suggested with a view to their potential applications to the analogous simulation of biological systems, and especially genetic activities and nonlinear dynamics in genetic networks. Further, detailed studies of nonlinear dynamics in genetic networks were carried out in categories of n-valued, Lukasiewicz Logic Algebra...

  14. Accessibility and contribution to glucan masking of natural and genetically tagged versions of yeast wall protein 1 of Candida albicans.

    Science.gov (United States)

    Granger, Bruce L

    2018-01-01

    Yeast wall protein 1 (Ywp1) is an abundant glycoprotein of the cell wall of the yeast form of Candida albicans, the most prevalent fungal pathogen of humans. Antibodies that bind to the polypeptide backbone of isolated Ywp1 show little binding to intact yeast cells, presumably because the Ywp1 epitopes are masked by the polysaccharides of the mannoproteins that form the outer layer of the cell wall. Rare cells do exhibit much greater anti-Ywp1 binding, however, and one of these was isolated and characterized. No differences were seen in its Ywp1, but it exhibited greater adhesiveness, sensitivity to wall perturbing agents, and exposure of its underlying β-1,3-glucan layer to external antibodies. The molecular basis for this greater epitope accessibility has not been determined, but has facilitated exploration of how these properties change as a function of cell growth and morphology. In addition, previously engineered strains with reduced quantities of Ywp1 in their cell walls were also found to have greater β-1,3-glucan exposure, indicating that Ywp1 itself contributes to the masking of wall epitopes, which may be important for understanding the anti-adhesive effect of Ywp1. Ectopic production of Ywp1 by hyphae, which reduces the adhesivity of these filamentous forms of C. albicans, was similarly found to reduce exposure of the β-1,3-glucan in their walls. To monitor Ywp1 in the cell wall irrespective of its accessibility, green fluorescent protein (Gfp) was genetically inserted into wall-anchored Ywp1 using a bifunctional cassette that also allowed production from a single transfection of a soluble, anchor-free version. The wall-anchored Ywp1-Gfp-Ywp1 accumulated in the wall of the yeast forms but not hyphae, and appeared to have properties similar to native Ywp1, including its adhesion-inhibiting effect. Some pseudohyphal walls also detectably accumulated this probe. Strains of C. albicans with tandem hemagglutinin (HA) epitopes inserted into wall

  15. Accessibility and contribution to glucan masking of natural and genetically tagged versions of yeast wall protein 1 of Candida albicans.

    Directory of Open Access Journals (Sweden)

    Bruce L Granger

    Full Text Available Yeast wall protein 1 (Ywp1 is an abundant glycoprotein of the cell wall of the yeast form of Candida albicans, the most prevalent fungal pathogen of humans. Antibodies that bind to the polypeptide backbone of isolated Ywp1 show little binding to intact yeast cells, presumably because the Ywp1 epitopes are masked by the polysaccharides of the mannoproteins that form the outer layer of the cell wall. Rare cells do exhibit much greater anti-Ywp1 binding, however, and one of these was isolated and characterized. No differences were seen in its Ywp1, but it exhibited greater adhesiveness, sensitivity to wall perturbing agents, and exposure of its underlying β-1,3-glucan layer to external antibodies. The molecular basis for this greater epitope accessibility has not been determined, but has facilitated exploration of how these properties change as a function of cell growth and morphology. In addition, previously engineered strains with reduced quantities of Ywp1 in their cell walls were also found to have greater β-1,3-glucan exposure, indicating that Ywp1 itself contributes to the masking of wall epitopes, which may be important for understanding the anti-adhesive effect of Ywp1. Ectopic production of Ywp1 by hyphae, which reduces the adhesivity of these filamentous forms of C. albicans, was similarly found to reduce exposure of the β-1,3-glucan in their walls. To monitor Ywp1 in the cell wall irrespective of its accessibility, green fluorescent protein (Gfp was genetically inserted into wall-anchored Ywp1 using a bifunctional cassette that also allowed production from a single transfection of a soluble, anchor-free version. The wall-anchored Ywp1-Gfp-Ywp1 accumulated in the wall of the yeast forms but not hyphae, and appeared to have properties similar to native Ywp1, including its adhesion-inhibiting effect. Some pseudohyphal walls also detectably accumulated this probe. Strains of C. albicans with tandem hemagglutinin (HA epitopes inserted into

  16. Introducing Physician Assistants to Ontario

    Directory of Open Access Journals (Sweden)

    Meredith Vanstone

    2014-02-01

    Full Text Available In 2006, the Ontario Ministry of Health and Long-Term Care (MOHLTC introduced Physician Assistants (PAs through the announcement of demonstration projects, education and training programs, and subsequent funding. PAs are directly supervised by physicians and act as physician extenders by performing acts as delegated to them by their supervising physicians. PAs were proposed as a potential solution to help improve access to health care and reduce wait times throughout the province. Prior to the 2006 Ministry announcement, there was little public discussion regarding the acceptance of the PA role or its sustainability. Opposition from nursing and other groups emerged in response to the 2006 announcement and flared again when stakeholder comments were solicited in 2012 as part of the PA application for status as regulated health professionals. As a health reform, the introduction of PAs has neither succeeded nor failed. In 2013, the majority of PA funding continues to be provided by the MOHLTC, and it is unknown whether the PA role will be sustainable when the MOHTLC withdraws salary funding and health system employers must decide whether or not to continue employing PAs at their own expense.

  17. Two new pollution regulations introduced

    International Nuclear Information System (INIS)

    Anon.

    2000-01-01

    A newly proposed regulation in Ontario will require the mandatory tracking of 358 airborne pollutants by the electricity sector as well as by other large industrial facilities such as iron and steel manufacturers and petroleum refiners. If passed, the regulation would make Ontario the first jurisdiction in the world to require monitoring and reporting of a full suite of major greenhouse gases, including smog and acid-rain causing emissions. The proposed regulation also provides for immediate public access to any reported information. Ontario residents can comment on the proposed regulation through the Environmental Bill of Rights registry. A new, more severe hazardous waste regulation will also take effect on March 31, 2001, whereby testing for 88 contaminants will be done according to a new standard called the Toxicity Characteristic Leaching Procedure (TCLP). This new regulation also introduces a new 'derived from' rule which requires that a listed hazardous waste keep its classification until it can be demonstrated otherwise. Ontario's list of hazardous wastes has been updated to include 129 new chemicals and industrial processes. The Ontario Ministry has also adopted the Canada-wide Standards for Particulate Matter and Ozone, as well as the Canada-wide Standards for mercury emissions from base metal smelters as well as from incineration of sewage sludge and municipal, medical, hazardous waste

  18. The Brown-Vialetto-Van Laere and Fazio Londe syndrome revisited: natural history, genetics, treatment and future perspectives

    Directory of Open Access Journals (Sweden)

    Bosch Annet M

    2012-10-01

    Full Text Available Abstract The Brown-Vialetto-Van Laere syndrome is a rare neurological disorder which may present at all ages with sensorineural deafness, bulbar palsy and respiratory compromise. Fazio-Londe syndrome is considered to be the same disease entity. Recently it was demonstrated that in some patients the disease is caused by mutations in the SLC52A3 gene which encodes the intestinal (hRFT2 riboflavin transporter. In these patients riboflavin deficiency is the cause of the BVVL/FL syndrome and supplementation of riboflavin proved a life saving treatment. Mutations in the SLC52A2 gene and the SLC52A1 (GPR172B gene, coding for human riboflavin transporters hRFT3 and hRFT1 have been associated with the BVVL syndrome as well. We performed a review of the literature, with emphasis on the natural history and the effects of treatment in these patients. A total of 35 publications were traced reporting on the clinical presentation of 74 patients who presented before age 18. The most prevalent symptoms were bulbar palsy, hearing loss, facial weakness and respiratory compromise. Death was reported in 28 of the 61 untreated patients, with a very low survival in patients presenting before age 4. All 13 patients who were treated with riboflavin survived, with a strong clinical improvement after days to months of treatment in eight patients. Three patients demonstrated a stable clinical course and treatment was stopped early in two patients. Abnormalities in plasma flavin levels and/or plasma acylcarnitine profiles were observed in some but not in all patients, and also patients with normal plasma flavin levels and acylcarnitine profiles demonstrated a striking clinical improvement on riboflavin supplementation. It is now clear that proper diagnosis requires mutation analysis of all three transporter genes and treatment should be started immediately without first awaiting results of molecular analysis. Clinical improvement may be rapid or gradual over a period of

  19. [Ethical challenges of genetic manipulation and research with animals].

    Science.gov (United States)

    Rodríguez Yunta, Eduardo

    2012-01-01

    Research with animals presents ethical questions both for being used as models of human diseases and for being a prerequisite for trials in humans, as in the introduction of genetic modifications. Some of these questions refer to the fact that, as models, they do not fully represent the human condition; that conducting toxicity tests causes great harm to animals; that their nature is altered by genetic modifications and that introducing genetically modified organisms is a risk. The use of animals in research for the benefit of humans imposes the moral responsibility to respect them, not making them suffer unnecessarily, since they are living beings capable of feeling.

  20. Introducing quantum theory a graphic guide

    CERN Document Server

    McEvoy, J P

    2013-01-01

    Quantum theory confronts us with bizarre paradoxes which contradict the logic of classical physics. At the subatomic level, one particle seems to know what the others are doing, and according to Heisenberg's "uncertainty principle", there is a limit on how accurately nature can be observed. And yet the theory is amazingly accurate and widely applied, explaining all of chemistry and most of physics. "Introducing Quantum Theory" takes us on a step-by-step tour with the key figures, including Planck, Einstein, Bohr, Heisenberg and Schrodinger. Each contributed at least one crucial concept to the theory. The puzzle of the wave-particle duality is here, along with descriptions of the two questions raised against Bohr's "Copenhagen Interpretation" - the famous "dead and alive cat" and the EPR paradox. Both remain unresolved.

  1. Introducing the new meat. Problems and prospects

    Directory of Open Access Journals (Sweden)

    Stellan Welin

    2013-05-01

    Full Text Available Cultured meat, or in vitro meat, is one of the ideas that are being proposed to help solve the problems associated with the ever-growing global meat consumption. The prospect may bring benefit for the environment, climate, and animal ethics, but has also generated doubts and criticism. A discussion of the possible environmental benefit and of animal ethics issues in relation to cultured meat production will be given. A perceived 'unnaturalness' of cultured meat may be one of the strongest barriers for public acceptance. This will be discussed and rejected. As to our relations with nature and animals, it is plausible that cultured meat will lead to improvement rather than to deterioration. The issue of public acceptance and some of the problems of introducing this new product on the market will also be discussed.http://dx.doi.org/10.5324/eip.v7i1.1788

  2. Introducing Science to undergraduate students

    Directory of Open Access Journals (Sweden)

    P. Avila Jr

    2006-07-01

    Full Text Available The knowledge of scientific method provides stimulus and development of critical thinking and logical analysis of information besides the training of continuous formulation of hypothesis to be applied in formal scientific issues as well as in everyday facts. The scientific education, useful for all people, is indispensable for the experimental science students. Aiming at the possibility to offer a systematic learning of the scientific principles, we developed a undergraduate course designed to approximate the students to the procedures of scientific production and publication. The course was developed in a 40 hours, containing two modules: I. Introducing Scientific Articles (papers and II. Writing Research Project. The first module deals with: (1 the difference between scientific knowledge and common sense; (2 scientific methodology; (3 scientific publishing categories; (4 logical principles; (5 deduction and induction approach and (6 paper analysis. The second module includes (1 selection of problem to be solved by experimental procedures; (2 bibliography revision; (3 support agencies; (4 project writing and presentation and (5 critical analysis of experimental results. The course used a Collaborative Learning strategy with each topic being developed through activities performed by the students. Qualitative and quantitative (through Likert questionnaires evaluation were carried out in each step of the course, the results showing great appreciation by the students. This is also the opinion of the staff responsible for the planning and development of the course, which is now in its second and improved version.

  3. Development of a methodology and software for analysis of energy and economic feasibility of introducing natural gas facilities in residential an commercial sector; Desenvolvimento de metodologia e de software para analise de viabilidade energetica e economica da introducao de instalacoes para gas natural no setor residencial e comercial

    Energy Technology Data Exchange (ETDEWEB)

    Jesus, Marcos Fabio de; Torres, Ednildo Andrade [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Escola Politecnica. Lab. de Energia e Gas; Santos, Carlos Antonio Cabral dos [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil). Lab. de Energia Solar; Campos, Michel Fabianski [PETROBRAS, Rio de Janeiro, RJ (Brazil). RedeGasEnergia

    2004-07-01

    With the increasing participation of the natural gas in the world-wide and national energy matrix, beyond the constant search for an alternative source of energy that has an acceptable behavior of the ambient point of view, they become each time more necessary studies to make possible the expansion of the use of this fuel in the diverse energy sectors, such as: Industrial, advertising, residential, to propagate, among others; Of these sectors, the residential one is what more it needs innovations and/or technological adaptations to exert a massive participation in the demand of the natural gas. This work has as objective to establish a methodology adjusted for analysis of the energy and economic viability of the introduction of installations for natural gas in the residential and commercial sector, as well as the implementation of a software that will more facilitate to the taking of decisions of this the confection of the plant low of the enterprise until the choice of the adjusted material for the installation of the tubing, besides showing to the viability technique - economic of the use of the natural gas for supplying all even though the energy necessities of this construction or of its joint participation with the electric energy or with the GLP. The methodology will mainly have support in first and the second law of the thermodynamics, beyond the norms Brazilian techniques that conduct this sector of the civil construction, taking in consideration the fixed and changeable costs of the energy construction of the construction and the involved ones. One expects, on the basis of the literature, that the introduction of installations for natural gas in the residential and commercial sector presents viability economic technique and, increasing with this the demand of this fuel and consequently its participation in the national energy matrix. (author)

  4. Genetic analysis

    NARCIS (Netherlands)

    Koornneef, M.; Alonso-Blanco, C.; Stam, P.

    2006-01-01

    The Mendelian analysis of genetic variation, available as induced mutants or as natural variation, requires a number of steps that are described in this chapter. These include the determination of the number of genes involved in the observed trait's variation, the determination of dominance

  5. Introducing guidelines into clinical practice.

    Science.gov (United States)

    Fowkes, F G; Roberts, C J

    1984-04-01

    the impetus for the College to develop guidelines for the use of pre-operative chest X-rays in hospitals in the United Kingdom. Creating a change in clinical practice through the introduction of guidelines is a three stage process: Stage I: introducing the idea of a change in practice. Stage II: introduction of guidelines into clinical practice. Stage III: sustained implementation of guidelines in clinical practice.(ABSTRACT TRUNCATED AT 400 WORDS)

  6. Genetic diversity and natural selection in the rhoptry-associated protein 1 (RAP-1) of recent Plasmodium knowlesi clinical isolates from Malaysia.

    Science.gov (United States)

    Rawa, Mira Syahfriena Amir; Fong, Mun-Yik; Lau, Yee-Ling

    2016-02-05

    The Plasmodium rhoptry-associated protein 1 (RAP-1) plays a role in the formation of the parasitophorous vacuole following the parasite's invasion of red blood cells. Although there is some evidence that the protein is recognized by the host's immune system, study of Plasmodium falciparum RAP-1 (PfRAP-1) suggests that it is not under immune pressure. A previous study on five old (1953-1962) P. knowlesi strains suggested that RAP-1 has limited genetic polymorphism and might be under negative selection. In the present study, 30 recent P. knowlesi isolates were studied to obtain a better insight into the polymorphism and natural selection of PkRAP-1. Blood samples from 30 knowlesi malaria patients were used. These samples were collected between 2010 and 2014. The PkRAP-1 gene, which contains two exons, was amplified by PCR, cloned into Escherichia coli and sequenced. Genetic diversity and phylogenetic analyses were performed using MEGA6 and DnaSP ver. 5.10.00 programs. Thirty PkRAP-1 sequences were obtained. The nucleotide diversity (π) of exons 1, 2 and the total coding region (0.00915, 0.01353 and 0.01298, respectively) were higher than those of the old strains. Further analysis revealed a lower rate of non-synonymous (dN) than synonymous (dS) mutations, suggesting negative (purifying) selection of PkRAP-1. Tajima's D test and Fu and Li's D test values were not significant. At the amino acid level, 22 haplotypes were established with haplotype H7 having the highest frequency (7/34, 20.5 %). In the phylogenetic analysis, two distinct haplotype groups were observed. The first group contained the majority of the haplotypes, whereas the second had fewer haplotypes. The present study found higher genetic polymorphism in the PkRAP-1 gene than the polymorphism level reported in a previous study. This observation may stem from the difference in sample size between the present (n = 30) and the previous (n = 5) study. Synonymous and non-synonymous mutation analysis indicated

  7. Biotechnology: Two Decades of Experimentation with Genetically Modified Foods

    Directory of Open Access Journals (Sweden)

    Marjan Ajami

    2016-10-01

    Full Text Available Background and Objective: Over the recent years, genetically modified food in varieties of corn, soybeans, canola and cotton have been introduced to the global market. This study reviews the health and nutritional value of genetically modified foods in the past two decades.Results and Conclusions: Contrary to the present biotechnological claims, transgenic products did not prove to be so flawless, and actually failed to maintain social satisfaction. Genetically modified foods could not gain an increase in the yield potential. Planting natural products and genetically modified products in parallel lines will absolutely result in genetic infection from the side of genetically modified foods. One of the major anxieties of the anti- genetically modified foods activism is the claim that genetically modified crops would alter the consumable parts of the plant quality and safety. Genetically modified foods have shown to have inadequate efficiency and potential adverse effects in both fields of health and biodiversity. This review has presented studies of genetically modified foods performances in the past two decades, and concludes that the wide application and the over generalization of genetically modified foods are not fundamentally recommended.Conflict of interest: Authors declare that there is no conflict of interest.

  8. First surveys on genetic variability and structure of field maple (Acer campestre L. in natural and managed populations in the landscape of central and southern Italy

    Directory of Open Access Journals (Sweden)

    Fulvio Ducci

    2010-12-01

    Full Text Available Normal 0 14 false false false MicrosoftInternetExplorer4 Four Tuscan populations (central Italy and three Italian populations from southern Italy (Campania were sampled to compare their genetic variability and genetic structure. In each geographical area one of the sampled populations is originated naturally in forest and used as a local reference. The remaining populations were originated artificially. Indeed, field maple was traditionally used in Italy to supply fresh fodder to animals in dry summer period as tree twigs or to train up grape trees in the fields edges. This tradition initiated  at the time of Etruscans and continued throughout the Roman partitioning of agriculture landscape. Biochemical markers were used to explore variability in the examined populations (5 enzyme systems by 11 loci. Results showed that the main amount of variation is due to the individual component as for most of the scattered hardwoods in Europe and that differentiation among populations for these neutral  traits is relatively low. On the other hand, the natural populations in both the geographical areas showed a very high level of panmittic equilibrium, whilst the artificial populations were really distant from this condition showing a high probability of “founder effect”. This could be determined by the former system of self-supplying reproductive material carried out by farmers, based on the wild offspring collection growing around few mother trees. Discussion is focused also on how handling the opportunity given by many hundreds kilometers of lines  in the agriculture landscape as a way of managing diversity for this species. st1\\:*{behavior:url(#ieooui } /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tabella normale"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso

  9. Genetic data suggest a natural prehuman origin of open habitats in northern Madagascar and question the deforestation narrative in this region.

    Science.gov (United States)

    Quéméré, Erwan; Amelot, Xavier; Pierson, Julie; Crouau-Roy, Brigitte; Chikhi, Lounès

    2012-08-07

    The impact of climate change and anthropogenic deforestation on biodiversity is of growing concern worldwide. Disentangling how past anthropogenic and natural factors contributed to current biome distribution is thus a crucial issue to understand their complex interactions on wider time scales and to improve predictions and conservation strategies. This is particularly important in biodiversity hotspots, such as Madagascar, dominated by large open habitats whose origins are increasingly debated. Although a dominant narrative argues that Madagascar was originally entirely covered by woodlands, which were destroyed by humans, a number of recent studies have suggested that past climatic fluctuations played a major role in shaping current biome distributions well before humans arrived. Here, we address the question of the origin of open habitats in the Daraina region in northern Madagascar, using a multiproxy approach combining population genetics modeling and remote-sensing analyses. We show that (i) contrary to most regions of Madagascar, the forest cover in Daraina remained remarkably stable over the past 60 y, and (ii) the golden-crowned sifaka (Propithecus tattersalli), a forest-dwelling lemur, underwent a strong population contraction before the arrival of the first humans, hence excluding an anthropogenic cause. Prehuman Holocene droughts may have led to a significant increase of grasslands and a reduction in the species' habitat. This contradicts the prevailing narrative that land cover changes are necessarily anthropogenic in Madagascar but does not preclude the later role played by humans in other regions in which recent lemur bottlenecks have been observed.

  10. Prenatal screening and genetics

    DEFF Research Database (Denmark)

    Alderson, P; Aro, A R; Dragonas, T

    2001-01-01

    Although the term 'genetic screening' has been used for decades, this paper discusses how, in its most precise meaning, genetic screening has not yet been widely introduced. 'Prenatal screening' is often confused with 'genetic screening'. As we show, these terms have different meanings, and we...... examine definitions of the relevant concepts in order to illustrate this point. The concepts are i) prenatal, ii) genetic screening, iii) screening, scanning and testing, iv) maternal and foetal tests, v) test techniques and vi) genetic conditions. So far, prenatal screening has little connection...... with precisely defined genetics. There are benefits but also disadvantages in overstating current links between them in the term genetic screening. Policy making and professional and public understandings about screening could be clarified if the distinct meanings of prenatal screening and genetic screening were...

  11. Introducing DAE Systems in Undergraduate and Graduate Chemical Engineering Curriculum

    Science.gov (United States)

    Mandela, Ravi Kumar; Sridhar, L. N.; Rengaswamy, Raghunathan

    2010-01-01

    Models play an important role in understanding chemical engineering systems. While differential equation models are taught in standard modeling and control courses, Differential Algebraic Equation (DAE) system models are not usually introduced. These models appear naturally in several chemical engineering problems. In this paper, the introduction…

  12. Witnessing Evolution First Hand: A K-12 Laboratory Exercise in Genetics & Evolution Using "Drosophila"

    Science.gov (United States)

    Heil, Caiti S. S.; Manzano-Winkler, Brenda; Hunter, Mika J.; Noor, Juliet K. F.; Noor, Mohamed A. F.

    2013-01-01

    We present a laboratory exercise that leverages student interest in genetics to observe and understand evolution by natural selection. Students begin with white-eyed fruit fly populations, to which they introduce a single advantageous variant (one male with red eyes). The superior health and vision associated with having the red-eye-color allele…

  13. "DNA Re-EvolutioN": A Game for Learning Molecular Genetics and Evolution

    Science.gov (United States)

    Miralles, Laura; Moran, Paloma; Dopico, Eduardo; Garcia-Vazquez, Eva

    2013-01-01

    Evolution is a main concept in biology, but not many students understand how it works. In this article we introduce the game "DNA Re-EvolutioN" as an active learning tool that uses genetic concepts (DNA structure, transcription and translation, mutations, natural selection, etc.) as playing rules. Students will learn about molecular…

  14. Introduce of Viable But Nonculturable Bacteria

    Directory of Open Access Journals (Sweden)

    Mehdi Hassanshahian

    2008-03-01

    Full Text Available Viable-But-Nonculturable-State (VBNC is the condition in which bacteria fail to grow on their routine bacteriological media where they would normally grow and develop into colonies, but are still alive and capable of renewed metabolic activity. VBNC state is useful for evaluating public health and for ascertaining the sterility of drinking water, pharmaceuticals, and foodstuff. A number of bacteria, mostly pathogenic to humans, have been proved to enter into this state in response to natural stresses such as starvation, incubation out of optimum growth temperature, increased osmotic pressure, etc. Once in the VBNC state, they undergo various physiological, structural, and genetic alterations. These alterations result in reduced cell size, conversion from bacilli to coccid, thickened cell walls, and peptidoglycan gaining many cross links. Metabolic changes also occur that include reductions in growth, nutrient transport, and respiratory rate; biosynthesis of new protein, and ATP remaining at a constant level. It has been shown that in the VBNC state, some pathogens conserve their virulence properties. Gene expression continues in the VBNC cell. Nucleic acids remain intact in the early VBNC phase but they gradually undergo degradation with prolonged VBNC. Cytological methods such as direct viable count and reduction of tetrazolium salts, and molecular methods such as reverse transcription polymerase chain reaction and green fluorescent protein have been used for the study of VBNC. Resuscitation from VBNC state starts when the inducing factor(s is/are lifted. Factors that help the resuscitation of VBNC bacteria include addition of certain nutrients and chemicals, introduction of a few culturable cells into the VBNC cell population, and passage through the animal host. As virulence properties are sustained during the VBNC phase, special care must be paid when evaluating sterility of drinking water.

  15. Spatial variation in genetic diversity and natural selection on the thrombospondin-related adhesive protein locus of Plasmodium vivax (PvTRAP.

    Directory of Open Access Journals (Sweden)

    Rattiporn Kosuwin

    Full Text Available Thrombospondin-related adhesive protein (TRAP of malaria parasites is essential for sporozoite motility and invasions into mosquito's salivary gland and vertebrate's hepatocyte; thereby, it is a promising target for pre-erythrocytic vaccine. TRAP of Plasmodium vivax (PvTRAP exhibits sequence heterogeneity among isolates, an issue relevant to vaccine development. To gain insights into variation in the complete PvTRAP sequences of parasites in Thailand, 114 vivax malaria patients were recruited in 2006-2007 from 4 major endemic provinces bordering Myanmar (Tak in the northwest, n = 30 and Prachuap Khirikhan in the southwest, n = 25, Cambodia (Chanthaburi in the east, n = 29 and Malaysia (Yala and Narathiwat in the south, n = 30. In total, 26 amino acid substitutions were detected and 9 of which were novel, resulting in 44 distinct haplotypes. Haplotype and nucleotide diversities were lowest in southern P. vivax population while higher levels of diversities were observed in other populations. Evidences of positive selection on PvTRAP were demonstrated in domains II and IV and purifying selection in domains I, II and VI. Genetic differentiation was significant between each population except that between populations bordering Myanmar where transmigration was common. Regression analysis of pairwise linearized Fst and geographic distance suggests that P. vivax populations in Thailand have been isolated by distance. Sequence diversity of PvTRAP seems to be temporally stable over one decade in Tak province based on comparison of isolates collected in 1996 (n = 36 and 2006-2007. Besides natural selection, evidences of intragenic recombination have been supported in this study that could maintain and further generate diversity in this locus. It remains to be investigated whether amino acid substitutions in PvTRAP could influence host immune responses although several predicted variant T cell epitopes drastically altered the epitope

  16. Revealing the Diversity of Introduced Coffea canephora Germplasm in Ecuador: Towards a National Strategy to Improve Robusta

    OpenAIRE

    Loor Solórzano, Rey Gastón; De Bellis, Fabien; Leroy, Thierry; Plaza, Luis; Guerrero, Hilton; Subia, Cristian; Calderón, Darío; Fernández, Fabián; Garzón, Iván; Lopez, Diana; Vera, Danilo

    2017-01-01

    Genetic resources of Coffea canephora have been introduced in several tropical countries with potential for crop development. In Ecuador, the species has been cultivated since the mid-20th century. However, little is known about the diversity and genetic structure of introduced germplasm. This paper provides an overview of the genetic and phenotypic diversity of C. canephora in Ecuador and some proposals for implementing a breeding program. Twelve SSR markers were used to analyze 1491 plants ...

  17. Explanatory chapter: introducing exogenous DNA into cells.

    Science.gov (United States)

    Koontz, Laura

    2013-01-01

    The ability to efficiently introduce DNA into cells is essential for many experiments in biology. This is an explanatory chapter providing an overview of the various methods for introducing DNA into bacteria, yeast, and mammalian cells. Copyright © 2013 Elsevier Inc. All rights reserved.

  18. Nature-inspired computing and optimization theory and applications

    CERN Document Server

    Yang, Xin-She; Nakamatsu, Kazumi

    2017-01-01

    The book provides readers with a snapshot of the state of the art in the field of nature-inspired computing and its application in optimization. The approach is mainly practice-oriented: each bio-inspired technique or algorithm is introduced together with one of its possible applications. Applications cover a wide range of real-world optimization problems: from feature selection and image enhancement to scheduling and dynamic resource management, from wireless sensor networks and wiring network diagnosis to sports training planning and gene expression, from topology control and morphological filters to nutritional meal design and antenna array design. There are a few theoretical chapters comparing different existing techniques, exploring the advantages of nature-inspired computing over other methods, and investigating the mixing time of genetic algorithms. The book also introduces a wide range of algorithms, including the ant colony optimization, the bat algorithm, genetic algorithms, the collision-based opti...

  19. Genetic and molecular analyses of natural variation indicate CBF2 as a candidate gene for underlying a freezing tolerance quantitative trait locus in Arabidopsis

    NARCIS (Netherlands)

    Alonso-Blanco, C.; Gomez-Mena, C.; Llorente, F.; Koornneef, M.; Salinas, J.; Martinez-Zapater, J.M.

    2005-01-01

    Natural variation for freezing tolerance is a major component of adaptation and geographic distribution of plant species. However, little is known about the genes and molecular mechanisms that determine its naturally occurring diversity. We have analyzed the intraspecific freezing tolerance

  20. Disentangling the effects of evolutionary, demographic, and environmental factors influencing genetic structure of natural populations: Atlantic herring as a case study

    DEFF Research Database (Denmark)

    Gaggiotti, Oscar E.; Bekkevold, Dorte; Jørgensen, Hanne B.H.

    2009-01-01

    , on the other hand, seems to have been largely eroded, which is not surprising given the large reproductive potential and presumed enormous local effective population sizes of pelagic fish that constrain the effect of stochastic processes. The approach we used can in principle be applied to any abundant...... carried out separate analyses of neutral and selected genetic variation, which allowed us to establish that the two most important factors affecting population structure were selection due to salinity at spawning sites and feeding migrations. The genetic signal left by the demographic history of herring...

  1. Introducing Product Lines through Open Source Tools

    OpenAIRE

    Haugen, Øystein

    2008-01-01

    We present an approach to introducing product lines to companies that lower their initial risk by applying open source tools and a smooth learning curve into the use and creation of domain specific modeling combined with standardized variability modeling.

  2. Introducing Relativity: Less May Be More

    Science.gov (United States)

    Ogborn, Jon

    2005-01-01

    This article shows how relativity can be introduced in four stages, each building on those before it, but the teacher can choose to stop after whichever stage he/she believes the pupils are capable of tackling.

  3. Two colonisation stages generate two different patterns of genetic diversity within native and invasive ranges of Ulex europaeus.

    Science.gov (United States)

    Hornoy, B; Atlan, A; Roussel, V; Buckley, Y M; Tarayre, M

    2013-11-01

    Genetic diversity and the way a species is introduced influence the capacity of populations of invasive species to persist in, and adapt to, their new environment. The diversity of introduced populations affects their evolutionary potential, which is particularly important for species that have invaded a wide range of habitats and climates, such as European gorse, Ulex europaeus. This species originated in the Iberian peninsula and colonised Europe in the Neolithic; over the course of the past two centuries it was introduced to, and has become invasive in, other continents. We characterised neutral genetic diversity and its structure in the native range and in invaded regions. By coupling these results with historical data, we have identified the way in which gorse populations were introduced and the consequences of introduction history on genetic diversity. Our study is based on the genotyping of individuals from 18 populations at six microsatellite loci. As U. europaeus is an allohexaploid species, we used recently developed tools that take into account genotypic ambiguity. Our results show that genetic diversity in gorse is very high and mainly contained within populations. We confirm that colonisation occurred in two stages. During the first stage, gorse spread out naturally from Spain towards northern Europe, losing some genetic diversity. During the second stage, gorse was introduced by humans into different regions of the world, from northern Europe. These introductions resulted in the loss of rare alleles but did not significantly reduce genetic diversity and thus the evolutionary potential of this invasive species.

  4. Genetic structure of a natural oak community in central Italy: Evidence of gene flow between three sympatric white oak species (Quercus, Fagaceae

    Directory of Open Access Journals (Sweden)

    Gaby Antonecchia

    2015-12-01

    Full Text Available Incomplete reproductive barriers between species, especially in sympatric areas where several species coexist, may result in hybridization and an increase in genetic diversity. Here we assessed the amount of genetic diversity in a community of three interfertile and sympatric European oaks (Quercus frainetto Ten., Q. petraea Liebl. Matt. and Q. pubescens Willd. situated in central Italy. We used 11 microsatellite markers derived from Expressed Sequence Tag (EST-SSRs and we implemented a Bayesian clustering analysis to assign individuals to species or hybrids. All genotyped loci were polymorphic for all the species and three genetic clusters corresponding to each species were detected. Significant differences and a higher level of gene flow were observed between the three oak species. Occurrence of hybrids varied markedly within the studied area: hybrids between Q. petraea and Q, pubescens were the most frequent, while hybrids between Q. petraea and Q. frainetto were particularly rare. Q. pubescens and Q. petraea showed the highest number of alleles compared to Q. frainetto,which was characterized by a low number of private, but highly frequent, alleles. However, Q. frainetto showed a lower genetic diversity and a stronger reproductive isolation from the other two oak species.

  5. Genetic diversity and structure in natural populations of Maytenus truncata Reiss, 1861, a medicinal plant vulnerable to extractivism in Bahia State, Brazil.

    Science.gov (United States)

    Simplicio, R R; Waldschmidt, A M; Amorim, M B; Almeida, B S; Pereira, D G

    2015-12-28

    Maytenus truncata (Celastraceae) is a plant species widely used in the treatment of ulcers and tumors. Despite the intensive harvest of native specimens in the State of Bahia, northeastern Brazil, there is no information about the genetic variability or structure of this species. Therefore, the goal of this study was to estimate the genetic diversity and population structure of M. truncata based on inter simple sequence repeat (ISSR) molecular markers. The samples comprised specimens from Jequié, Contendas do Sincorá, Boa Nova, and Boa Vista do Tupim in the State of Bahia. After selection of eight ISSR primers, the percentage of polymorphic loci was equal to 96.2% and genetic diversity was 0.3581. The Mantel test revealed positive correlation among genetic and geographic distances (r = 0.5462), but it was not significant (r ≥ 0, P = 0.8365). Even though AMOVA revealed that most variation was found within populations (68%), a high structuring was detected among them (ΦST = 0.31, P extractivism of populations of this species.

  6. Complex genetics controls natural variation among seed quality phenotypes in a recombinant inbred population of an interspecific cross between Solanum lycopersicum × Solanum pimpinellifolium

    NARCIS (Netherlands)

    Kazmi, R.H.; Khan, N.; Willems, L.A.J.; Heusden, van A.W.; Ligterink, J.W.; Hilhorst, H.W.M.

    2012-01-01

    Seed quality in tomato is associated with many complex physiological and genetic traits. While plant processes are frequently controlled by the action of small- to large-effect genes that follow classic Mendelian inheritance, our study suggests that seed quality is primarily quantitative and

  7. Molecular genetics made simple

    Directory of Open Access Journals (Sweden)

    Heba Sh. Kassem

    2012-07-01

    Full Text Available Genetics have undoubtedly become an integral part of biomedical science and clinical practice, with important implications in deciphering disease pathogenesis and progression, identifying diagnostic and prognostic markers, as well as designing better targeted treatments. The exponential growth of our understanding of different genetic concepts is paralleled by a growing list of genetic terminology that can easily intimidate the unfamiliar reader. Rendering genetics incomprehensible to the clinician however, defeats the very essence of genetic research: its utilization for combating disease and improving quality of life. Herein we attempt to correct this notion by presenting the basic genetic concepts along with their usefulness in the cardiology clinic. Bringing genetics closer to the clinician will enable its harmonious incorporation into clinical care, thus not only restoring our perception of its simple and elegant nature, but importantly ensuring the maximal benefit for our patients.

  8. Molecular genetics made simple

    Science.gov (United States)

    Kassem, Heba Sh.; Girolami, Francesca; Sanoudou, Despina

    2012-01-01

    Abstract Genetics have undoubtedly become an integral part of biomedical science and clinical practice, with important implications in deciphering disease pathogenesis and progression, identifying diagnostic and prognostic markers, as well as designing better targeted treatments. The exponential growth of our understanding of different genetic concepts is paralleled by a growing list of genetic terminology that can easily intimidate the unfamiliar reader. Rendering genetics incomprehensible to the clinician however, defeats the very essence of genetic research: its utilization for combating disease and improving quality of life. Herein we attempt to correct this notion by presenting the basic genetic concepts along with their usefulness in the cardiology clinic. Bringing genetics closer to the clinician will enable its harmonious incorporation into clinical care, thus not only restoring our perception of its simple and elegant nature, but importantly ensuring the maximal benefit for our patients. PMID:25610837

  9. Ante-mortem diagnosis, diarrhea, oocyst shedding, treatment, isolation, and genetic typing of Toxoplasma gondii associated with clinical toxoplasmosis in a naturally infected cat.

    Science.gov (United States)

    Dubey, J P; Prowell, M

    2013-02-01

    Toxoplasma gondii infections are common in humans and other animals, but clinical disease is relatively rare. It is unknown whether the severity of toxoplasmosis in immunocompetent hosts is due to the parasite strain, host variability, or to other factors. Recently, attention has been focused on the genetic variability among T. gondii isolates from apparently healthy and sick hosts. Whether T. gondii genetic makeup plays a part in the pathogenesis of clinical feline toxoplasmosis is uncertain because little is known of genetic typing of strains associated with clinical feline toxoplasmosis. A 6-mo-old domestic male cat was hospitalized because of lethargy, anorexia, fever, and diarrhea. Numerous (6 million in 1 sample) T. gondii oocysts were found in feces of the cat and antibodies to T. gondii (titer 1:800) were found in its serum by the modified agglutination test. The cat was medicated orally with Clindamycin for 10 days; it became asymptomatic after 10 days and was discharged from the hospital. Viable T. gondii (designated TgCatUs9) was isolated from feces (oocysts) by bioassays in mice. Genetic typing using the DNA extracted from the brains of infected mice and 10 PCR-restriction fragment length polymorphism (RFLP) markers revealed Type II allele at the SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, and PK1 loci and Type I at the L358 and Apico loci; therefore, this isolate belongs to the ToxoDB PCR-RFLP genotype no. 4, which is grouped into the Type 12 lineage that is dominant in wildlife from North America. To our knowledge, this is the first T. gondii isolate characterized genetically from a sick cat in the USA.

  10. The genetic difference principle.

    Science.gov (United States)

    Farrelly, Colin

    2004-01-01

    In the newly emerging debates about genetics and justice three distinct principles have begun to emerge concerning what the distributive aim of genetic interventions should be. These principles are: genetic equality, a genetic decent minimum, and the genetic difference principle. In this paper, I examine the rationale of each of these principles and argue that genetic equality and a genetic decent minimum are ill-equipped to tackle what I call the currency problem and the problem of weight. The genetic difference principle is the most promising of the three principles and I develop this principle so that it takes seriously the concerns of just health care and distributive justice in general. Given the strains on public funds for other important social programmes, the costs of pursuing genetic interventions and the nature of genetic interventions, I conclude that a more lax interpretation of the genetic difference principle is appropriate. This interpretation stipulates that genetic inequalities should be arranged so that they are to the greatest reasonable benefit of the least advantaged. Such a proposal is consistent with prioritarianism and provides some practical guidance for non-ideal societies--that is, societies that do not have the endless amount of resources needed to satisfy every requirement of justice.

  11. Deep Learning for Population Genetic Inference.

    Science.gov (United States)

    Sheehan, Sara; Song, Yun S

    2016-03-01

    Given genomic variation data from multiple individuals, computing the likelihood of complex population genetic models is often infeasible. To circumvent this problem, we introduce a novel likelihood-free inference framework by applying deep learning, a powerful modern technique in machine learning. Deep learning makes use of multilayer neural networks to learn a feature-based function from the input (e.g., hundreds of correlated summary statistics of data) to the output (e.g., population genetic parameters of interest). We demonstrate that deep learning can be effectively employed for population genetic inference and learning informative features of data. As a concrete application, we focus on the challenging problem of jointly inferring natural selection and demography (in the form of a population size change history). Our method is able to separate the global nature of demography from the local nature of selection, without sequential steps for these two factors. Studying demography and selection jointly is motivated by Drosophila, where pervasive selection confounds demographic analysis. We apply our method to 197 African Drosophila melanogaster genomes from Zambia to infer both their overall demography, and regions of their genome under selection. We find many regions of the genome that have experienced hard sweeps, and fewer under selection on standing variation (soft sweep) or balancing selection. Interestingly, we find that soft sweeps and balancing selection occur more frequently closer to the centromere of each chromosome. In addition, our demographic inference suggests that previously estimated bottlenecks for African Drosophila melanogaster are too extreme.

  12. Deep Learning for Population Genetic Inference.

    Directory of Open Access Journals (Sweden)

    Sara Sheehan

    2016-03-01

    Full Text Available Given genomic variation data from multiple individuals, computing the likelihood of complex population genetic models is often infeasible. To circumvent this problem, we introduce a novel likelihood-free inference framework by applying deep learning, a powerful modern technique in machine learning. Deep learning makes use of multilayer neural networks to learn a feature-based function from the input (e.g., hundreds of correlated summary statistics of data to the output (e.g., population genetic parameters of interest. We demonstrate that deep learning can be effectively employed for population genetic inference and learning informative features of data. As a concrete application, we focus on the challenging problem of jointly inferring natural selection and demography (in the form of a population size change history. Our method is able to separate the global nature of demography from the local nature of selection, without sequential steps for these two factors. Studying demography and selection jointly is motivated by Drosophila, where pervasive selection confounds demographic analysis. We apply our method to 197 African Drosophila melanogaster genomes from Zambia to infer both their overall demography, and regions of their genome under selection. We find many regions of the genome that have experienced hard sweeps, and fewer under selection on standing variation (soft sweep or balancing selection. Interestingly, we find that soft sweeps and balancing selection occur more frequently closer to the centromere of each chromosome. In addition, our demographic inference suggests that previously estimated bottlenecks for African Drosophila melanogaster are too extreme.

  13. Deep Learning for Population Genetic Inference

    Science.gov (United States)

    Sheehan, Sara; Song, Yun S.

    2016-01-01

    Given genomic variation data from multiple individuals, computing the likelihood of complex population genetic models is often infeasible. To circumvent this problem, we introduce a novel likelihood-free inference framework by applying deep learning, a powerful modern technique in machine learning. Deep learning makes use of multilayer neural networks to learn a feature-based function from the input (e.g., hundreds of correlated summary statistics of data) to the output (e.g., population genetic parameters of interest). We demonstrate that deep learning can be effectively employed for population genetic inference and learning informative features of data. As a concrete application, we focus on the challenging problem of jointly inferring natural selection and demography (in the form of a population size change history). Our method is able to separate the global nature of demography from the local nature of selection, without sequential steps for these two factors. Studying demography and selection jointly is motivated by Drosophila, where pervasive selection confounds demographic analysis. We apply our method to 197 African Drosophila melanogaster genomes from Zambia to infer both their overall demography, and regions of their genome under selection. We find many regions of the genome that have experienced hard sweeps, and fewer under selection on standing variation (soft sweep) or balancing selection. Interestingly, we find that soft sweeps and balancing selection occur more frequently closer to the centromere of each chromosome. In addition, our demographic inference suggests that previously estimated bottlenecks for African Drosophila melanogaster are too extreme. PMID:27018908

  14. ED-XRF spectrometry-based trace element composition of genetically engineered rhizoclones vis-a-vis natural roots of a multi-medicinal plant, butterfly pea (Clitoria ternatea L.)

    International Nuclear Information System (INIS)

    Swain, S.S.; Chand, P.K.

    2012-01-01

    The energy dispersive X-ray fluorescence set-up incorporating a molybdenum secondary exciter was used for quantitative determination of major and minor elements in genetically transformed root somaclones (rhizoclones) of butterfly pea (Clitoria ternatea L.) which had been established via explant co-cultivation with Agrobacterium rhizogenes. The multi-elemental composition of these transformed rhizoclones was compared with that of the naturally grown in vivo donor plant. Trace elements namely Cr, Mn, Fe, Co, Ni, Cu, Zn, Se, Rb, Sr and Pb in addition to two macro-elements K and Ca were identified and quantified in root tissues of both sources. The elemental content of transformed root cultures was found to be at par with that of the natural roots of in vivo grown plants of the same species. These findings are implicated on the context of utilization of such Agrobacterium-mediated genetically transformed root cultures as a viable alternative to natural roots, the former being a fast-proliferating renewable resource of medicinally useful minerals essential for designing of effective drugs, besides providing an ex situ means for plant conservation. (author)

  15. A strategy for introducing hydrogen into transportation

    International Nuclear Information System (INIS)

    Farrell, A.E.; Keith, D.W.; Corbett, J.J.

    2003-01-01

    Considerable effort is being expended on research and demonstration projects aimed at introducing hydrogen into the transportation sector as a fuel, generally motivated by concerns about carbon dioxide emissions and petroleum imports (or scarcity). In this paper we focus on one aspect of strategy for introducing hydrogen--the choice of transportation mode. Our analysis suggests that cost of introducing hydrogen can be reduced by selecting a mode that uses a small number of relatively large vehicles that are operated by professional crews along a limited number of point-to-point routes or within a small geographic area. In addition, technological innovation in vehicle design will take place most quickly in modes where individual vehicles are produced to order and each receives significant engineering attention (not those manufactured in vast quantities on assembly lines). The immediate environmental benefits of introducing hydrogen fuel will occur in modes that have relatively less stringent pollution regulations applied to them. These insights, suggest that heavy-duty freight modes would be a less costly way to introduce hydrogen as a transportation fuel and a more effective way to advance hydrogen-related technologies so that they could subsequently be used more widely in light-duty vehicles

  16. Reactor controller design using genetic algorithms with simulated annealing

    International Nuclear Information System (INIS)

    Erkan, K.; Buetuen, E.

    2000-01-01

    This chapter presents a digital control system for ITU TRIGA Mark-II reactor using genetic algorithms with simulated annealing. The basic principles of genetic algorithms for problem solving are inspired by the mechanism of natural selection. Natural selection is a biological process in which stronger individuals are likely to be winners in a competing environment. Genetic algorithms use a direct analogy of natural evolution. Genetic algorithms are global search techniques for optimisation but they are poor at hill-climbing. Simulated annealing has the ability of probabilistic hill-climbing. Thus, the two techniques are combined here to get a fine-tuned algorithm that yields a faster convergence and a more accurate search by introducing a new mutation operator like simulated annealing or an adaptive cooling schedule. In control system design, there are currently no systematic approaches to choose the controller parameters to obtain the desired performance. The controller parameters are usually determined by test and error with simulation and experimental analysis. Genetic algorithm is used automatically and efficiently searching for a set of controller parameters for better performance. (orig.)

  17. Newly introduced sample preparation techniques: towards miniaturization.

    Science.gov (United States)

    Costa, Rosaria

    2014-01-01

    Sampling and sample preparation are of crucial importance in an analytical procedure, representing quite often a source of errors. The technique chosen for the isolation of analytes greatly affects the success of a chemical determination. On the other hand, growing concerns about environmental and human safety, along with the introduction of international regulations for quality control, have moved the interest of scientists towards specific needs. Newly introduced sample preparation techniques are challenged to meet new criteria: (i) miniaturization, (ii) higher sensitivity and selectivity, and (iii) automation. In this survey, the most recent techniques introduced in the field of sample preparation will be described and discussed, along with many examples of applications.

  18. Genetic diversity of Plasmodium falciparum isolates from naturally infected children in north-central Nigeria using the merozoite surface protein-2 as molecular marker.

    Science.gov (United States)

    Oyedeji, Segun Isaac; Awobode, Henrietta Oluwatoyin; Anumudu, Chiaka; Kun, Jürgen

    2013-08-01

    To characterize the genetic diversity of Plasmodium falciparum (P. falciparum) field isolates in children from Lafia, North-central Nigeria, using the highly polymorphic P. falciparum merozoite surface protein 2 (MSP-2) gene as molecular marker. Three hundred and twenty children were enrolled into the study between 2005 and 2006. These included 140 children who presented with uncomplicated malaria at the Dalhatu Araf Specialist Hospital, Lafia and another 180 children from the study area with asymptomatic infection. DNA was extracted from blood spot on filter paper and MSP-2 genes were genotyped using allele-specific nested PCR in order to analyze the genetic diversity of parasite isolates. A total of 31 and 34 distinct MSP-2 alleles were identified in the asymptomatic and uncomplicated malaria groups respectively. No difference was found between the multiplicity of infection in the asymptomatic group and that of the uncomplicated malaria group (P>0.05). However, isolates of the FC27 allele type were dominant in the asymptomatic group whereas isolates of the 3D7 allele type were dominant in the uncomplicated malaria group. This study showed a high genetic diversity of P. falciparum isolates in North-central Nigeria and is comparable to reports from similar areas with high malaria transmission intensity. Copyright © 2013 Hainan Medical College. Published by Elsevier B.V. All rights reserved.

  19. Genetic differentiation in natural populations of Lutzomyia longipalpis (Lutz & Neiva) (Diptera: Psychodidae) with different phenotypic spot patterns on tergites in males.

    Science.gov (United States)

    Silva, M H; Nascimento, M D S B; Leonardo, F S; Rebêlo, J M M; Pereira, S R F

    2011-01-01

    Entomological surveys in the state of Maranhão have recorded morphologically distinct populations of Lutzomyia longipalpis (Lutz & Neiva). Some populations have one pair of spots (1S) on the fourth tergite, while others have two pairs (2S) on the third and fourth tergites of males. In the present study we investigated the degree of genetic polymorphism among four populations in the municipalities of Caxias, Codó and Raposa, in the state of Maranhão, Brazil, by using RAPD (Random Amplified Polymorphic DNA) markers. A total of 35 loci were identified, of which 30 were polymorphic. The highest polymorphism was observed with primer OPA 4, which produced 11 different profiles. Genetic diversity was assessed using grouping methods that produced a dendrogram in which the genotypes could be clearly separated into two main clades according to the number of spots on the male abdominal tergites. One cluster contained the populations from Caxias and Codó, and the other was formed by the populations from Raposa and Codó. The results of our RAPD analysis showed a clear separation between the populations with one and two pairs of spots. The epidemiologic significance of this genetic differentiation should be investigated in future studies.

  20. Optimization of breeding methods when introducing multiple ...

    African Journals Online (AJOL)

    Academic Journals

    2011-09-28

    Sep 28, 2011 ... QU-GENE is a simulation platform developed at the University of Queensland for ... ment (GE) interaction system was not considered in QU-GENE in this study. ..... Genetics and molecular mapping of genes for race-specific ... dicoccoides is closely linked to the grain protein content locus Gpc-. B1. Theor.

  1. Diversity and genetic structure in natural populations of Hancornia speciosa var. speciosa Gomes in northeastern Brazil Diversidade e estrutura genética em populações naturais de Hancornia speciosa var. speciosa Gomes no nordeste do Brasil

    Directory of Open Access Journals (Sweden)

    Georgia Vilela Martins

    2012-12-01

    Full Text Available Hancornia speciosa Gomes is a fruit tree native from Brazil that belongs to Apocinaceae family, and is popularly known as Mangabeira. Its fruits are widely consumed raw or processed as fruit jam, juices and ice creams, which have made it a target of intense exploitation. The extractive activities and intense human activity on the environment of natural occurrence of H. speciosa has caused genetic erosion in the species and little is known about the ecology or genetic structure of natural populations. The objective of this research was the evaluation of the genetic diversity and genetic structure of H. speciosa var. speciosa. The genetic variability was assessed using 11 allozyme loci with a sample of 164 individuals distributed in six natural populations located in the States of Pernambuco and Alagoas, Northeastern Brazil. The results showed a high level of genetic diversity within the species (e= 0.36 seeing that the most of the genetic variability of H. speciosa var. speciosa is within its natural populations with low difference among populations ( or = 0.081. The inbreeding values within ( = -0.555 and among populations ( =-0.428 were low showing lacking of endogamy and a surplus of heterozygotes. The estimated gene flow ( m was high, ranging from 2.20 to 13.18, indicating to be enough to prevent the effects of genetic drift and genetic differentiation among populations. The multivariate analyses indicated that there is a relationship between genetic and geographical distances, which was confirmed by a spatial pattern analysis using Mantel test (r = 0.3598; p = 0.0920 with 1000 random permutations. The high genetic diversity index in these populations indicates potential for in situ genetic conservation.Hancornia speciosa Gomes é uma árvore frutífera nativa do Brasil, pertencente à família Apocinaceae, e é conhecida popularmente como Mangabeira. Seus frutos são amplamente consumidos in natura ou processados como sucos, sorvetes e

  2. The Applications of Genetic Algorithms in Medicine

    Directory of Open Access Journals (Sweden)

    Ali Ghaheri

    2015-11-01

    Full Text Available A great wealth of information is hidden amid medical research data that in some cases cannot be easily analyzed, if at all, using classical statistical methods. Inspired by nature, metaheuristic algorithms have been developed to offer optimal or near-optimal solutions to complex data analysis and decision-making tasks in a reasonable time. Due to their powerful features, metaheuristic algorithms have frequently been used in other fields of sciences. In medicine, however, the use of these algorithms are not known by physicians who may well benefit by applying them to solve complex medical problems. Therefore, in this paper, we introduce the genetic algorithm and its applications in medicine. The use of the genetic algorithm has promising implications in various medical specialties including radiology, radiotherapy, oncology, pediatrics, cardiology, endocrinology, surgery, obstetrics and gynecology, pulmonology, infectious diseases, orthopedics, rehabilitation medicine, neurology, pharmacotherapy, and health care management. This review introduces the applications of the genetic algorithm in disease screening, diagnosis, treatment planning, pharmacovigilance, prognosis, and health care management, and enables physicians to envision possible applications of this metaheuristic method in their medical career.

  3. The Applications of Genetic Algorithms in Medicine.

    Science.gov (United States)

    Ghaheri, Ali; Shoar, Saeed; Naderan, Mohammad; Hoseini, Sayed Shahabuddin

    2015-11-01

    A great wealth of information is hidden amid medical research data that in some cases cannot be easily analyzed, if at all, using classical statistical methods. Inspired by nature, metaheuristic algorithms have been developed to offer optimal or near-optimal solutions to complex data analysis and decision-making tasks in a reasonable time. Due to their powerful features, metaheuristic algorithms have frequently been used in other fields of sciences. In medicine, however, the use of these algorithms are not known by physicians who may well benefit by applying them to solve complex medical problems. Therefore, in this paper, we introduce the genetic algorithm and its applications in medicine. The use of the genetic algorithm has promising implications in various medical specialties including radiology, radiotherapy, oncology, pediatrics, cardiology, endocrinology, surgery, obstetrics and gynecology, pulmonology, infectious diseases, orthopedics, rehabilitation medicine, neurology, pharmacotherapy, and health care management. This review introduces the applications of the genetic algorithm in disease screening, diagnosis, treatment planning, pharmacovigilance, prognosis, and health care management, and enables physicians to envision possible applications of this metaheuristic method in their medical career.].

  4. Introducing Micro-finance in Sweden

    DEFF Research Database (Denmark)

    Barinaga, Ester

    2013-01-01

    The case describes the first year of efforts to introduce microfinance as a tool to work with vulnerable groups in Sweden, more particularly ex-convicts, former drug-addicts and longterm unemployed women of immigrant background. The teaching objective is to discuss whether micro-finance can be seen...

  5. Introducing Simulation via the Theory of Records

    Science.gov (United States)

    Johnson, Arvid C.

    2011-01-01

    While spreadsheet simulation can be a useful method by which to help students to understand some of the more advanced concepts in an introductory statistics course, introducing the simulation methodology at the same time as these concepts can result in student cognitive overload. This article describes a spreadsheet model that has been…

  6. Introducing Technology Education at the Elementary Level

    Science.gov (United States)

    McKnight, Sean

    2012-01-01

    Many school districts are seeing a need to introduce technology education to students at the elementary level. Pennsylvania's Penn Manor School District is one of them. Pennsylvania has updated science and technology standards for grades 3-8, and after several conversations the author had with elementary principals and the assistant superintendent…

  7. Introducing GIS across Levels: Designing for Diversity

    Science.gov (United States)

    Barros, Joana

    2017-01-01

    The paper proposes a strategy for designing introductory GIS modules at Birkbeck, University of London. Seven design aspects or elements (content, practical exercises, assessment, pace, mode, level of support, and level of difficulty) for tailoring modules at appropriate levels and for diversity are introduced and their application in Birkbeck's…

  8. Introducing Grounded Theory into translation studies | Wehrmeyer ...

    African Journals Online (AJOL)

    This article introduces tenets of Grounded Theory into a reception-oriented model for translation studies, in which the basis of comparison (tertium comparationis) between source and target texts is constructed from target audience expectancy norms. The model is primarily designed for projects where conformity to target ...

  9. Comparing macrophyte herbivory by introduced Louisiana crayfish ...

    African Journals Online (AJOL)

    The omnivorous Louisiana crayfish, Procambarus clarkii, has caused significant changes to macrophyte communities worldwide and may have similar negative effects in Kenya if used as a biological control agent for snails harbouring human schistosomes. Here we examine how herbivory by the introduced Louisiana ...

  10. Optimization of breeding methods when introducing multiple ...

    African Journals Online (AJOL)

    Optimization of breeding methods when introducing multiple resistance genes from American to Chinese wheat. JN Qi, X Zhang, C Yin, H Li, F Lin. Abstract. Stripe rust is one of the most destructive diseases of wheat worldwide. Growing resistant cultivars with resistance genes is the most effective method to control this ...

  11. Introducing Giovanni Gentile, the "Philosopher of Fascism"

    Science.gov (United States)

    Clayton, Thomas

    2009-01-01

    This essay aims to introduce Giovanni Gentile to scholars of Gramsci studies broadly and Gramsci-education studies more specifically. The largest part of the essay explores Gentile's academic life, his philosophical agenda, and his political career. Having established a basis for understanding the educational reform Gentile enacted as Mussolini's…

  12. Genetic variation in California oaks

    Science.gov (United States)

    Constance I. Millar; Diane L. Delany; Lawrence A. Riggs

    1990-01-01

    In forestry the importance of genetic variation for successful reproduction, survival and growth has been widely documented for commercial conifers; until recently, little genetic work has been done on the California oaks. Even before the nature of genetic variation was scientifically investigated, its importance was suspected in operational forestry. Many failures of...

  13. Moral Fantasy in Genetic Engineering.

    Science.gov (United States)

    Boone, C. Keith

    1984-01-01

    Discusses the main ethical issues generated by the new genetics and suggests ways to think about them. Concerns include "playing God," violation of the natural order of the universe, and abuse of genetic technology. Critical distinctions for making difficult decisions about genetic engineering issues are noted. (DH)

  14. FY 1998 annual report on the research on the possibility of introducing a usable chemical substance manufacturing system by utilizing natural gas containing CO2; CO{sub 2} gan'yu tennen gas den katsuyo ni yoru yuyo kagaku busshitsu seizo system donyu kanosei ni kansuru chosa kenkyu 1998 nendo chosa hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-01

    The trends of effective use of gas containing CO2 from natural gas fields are surveyed, and usable chemical substance manufacturing systems which utilize natural energy are investigated, evaluated and analyzed, to extract promising systems for effective use of CO2-containing natural gas and thereby to promote its effective use. Chapter 1 outlines possibility of integrated use of gas containing CO2 from natural gas fields and natural gas energy. Chapter 2 describes the research trends in the CO2 conversion reactions for using unexploited CO2 as the carbon source. Chapter 3 describes natural energy utilization technology applicable to gas containing CO2 from natural gas fields. Chapter 4 describes performance of chemical manufacturing systems utilizing natural gas containing CO2. The energy balances and CO2 emission coefficients are estimated, based on the above. The evaluation is implemented in the order of (1) conventional steam reforming, (2) steam reforming in which heat is supplied by a solar furnace, (3) examination of the exhaust gases from a methanol synthesis process, and (4) examination of CO2-mixed reforming. Chapter 5 describes summary and proposals. (NEDO)

  15. FY 1998 annual report on the research on the possibility of introducing a usable chemical substance manufacturing system by utilizing natural gas containing CO2; CO{sub 2} gan'yu tennen gas den katsuyo ni yoru yuyo kagaku busshitsu seizo system donyu kanosei ni kansuru chosa kenkyu 1998 nendo chosa hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-01

    The trends of effective use of gas containing CO2 from natural gas fields are surveyed, and usable chemical substance manufacturing systems which utilize natural energy are investigated, evaluated and analyzed, to extract promising systems for effective use of CO2-containing natural gas and thereby to promote its effective use. Chapter 1 outlines possibility of integrated use of gas containing CO2 from natural gas fields and natural gas energy. Chapter 2 describes the research trends in the CO2 conversion reactions for using unexploited CO2 as the carbon source. Chapter 3 describes natural energy utilization technology applicable to gas containing CO2 from natural gas fields. Chapter 4 describes performance of chemical manufacturing systems utilizing natural gas containing CO2. The energy balances and CO2 emission coefficients are estimated, based on the above. The evaluation is implemented in the order of (1) conventional steam reforming, (2) steam reforming in which heat is supplied by a solar furnace, (3) examination of the exhaust gases from a methanol synthesis process, and (4) examination of CO2-mixed reforming. Chapter 5 describes summary and proposals. (NEDO)

  16. Estimation and interpretation of genetic effects with epistasis using the NOIA model.

    Science.gov (United States)

    Alvarez-Castro, José M; Carlborg, Orjan; Rönnegård, Lars

    2012-01-01

    We introduce this communication with a brief outline of the historical landmarks in genetic modeling, especially concerning epistasis. Then, we present methods for the use of genetic modeling in QTL analyses. In particular, we summarize the essential expressions of the natural and orthogonal interactions (NOIA) model of genetic effects. Our motivation for reviewing that theory here is twofold. First, this review presents a digest of the expressions for the application of the NOIA model, which are often mixed with intermediate and additional formulae in the original articles. Second, we make the required theory handy for the reader to relate the genetic concepts to the particular mathematical expressions underlying them. We illustrate those relations by providing graphical interpretations and a diagram summarizing the key features for applying genetic modeling with epistasis in comprehensive QTL analyses. Finally, we briefly review some examples of the application of NOIA to real data and the way it improves the interpretability of the results.

  17. Genetic disorders as collective phenomena

    International Nuclear Information System (INIS)

    Chela-Flores, J.

    1987-05-01

    Genetic disorders due to human chromosome aberrations in number are discussed from the point of view of Molecular Genetics. The etiology of trisomy is discussed in the light of the collective variables recently introduced and an age-dependent metabolic disorder is suggested as a possible etiological factor. (author). 11 refs

  18. Apple fruit acidity is genetically diversified by natural variations in three hierarchical epistatic genes MdSAUR37, MdPP2CH and MdALMTII.

    Science.gov (United States)

    Jia, Dongjie; Shen, Fei; Wang, Yi; Wu, Ting; Xu, Xuefeng; Zhang, Xinzhong; Han, Zhenhai

    2018-05-11

    Many efforts have been made to map quantitative trait loci (QTLs) to facilitate practical marker-assisted selection (MAS) in plants. In the present study, we identified four genome-wide major QTLs responsible for apple fruit acidity by MapQTL and BSA-seq analyses using two independent pedigree-based populations. Candidate genes were screened in major QTL regions, and three functional gene markers, including a non-synonymous A/G single nucleotide polymorphism (SNP) in the coding region of MdPP2CH, a 36-bp insertion in the promoter of MdSAUR37, and a previously reported SNP in MdALMTII, were validated to influence the malate content of apple fruits. In addition, MdPP2CH inactivated three vacuolar H + -ATPases (MdVHA-A3, MdVHA-B2 and MdVHA-D2) and one aluminium-activated malate transporter (MdALMTII) via dephosphorylation and negatively influenced fruit malate accumulation. The dephosphotase activity of MdPP2CH was suppressed by MdSAUR37, which implied a higher hierarchy of genetic interaction. Therefore, the MdSAUR37/MdPP2CH/MdALMTII chain cascaded hierarchical epistatic genetic effects to precisely determine apple fruit malate content. An A/G SNP (-1010) on MdMYB44 promoter region from a major QTL (qtl08.1) was closely associated with fruit malate content. The predicted phenotype values (PPVs) were estimated using the tentative genotype values of the gene markers, and the PPVs were significantly correlated with the observed phenotype values. Our findings provide an insight into plant genome-based selection in apples and will aid in conducting research to understand the physiological fundamentals of quantitative genetics. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  19. Analysis of Genetic Variation and Phylogeny of the Predatory Bug, Pilophorus typicus, in Japan using Mitochondrial Gene Sequences

    OpenAIRE

    Ito, Katsura; Nishikawa, Hiroshi; Shimada, Takuji; Ogawa, Kohei; Minamiya, Yukio; Tomoda, Masafumi; Nakahira, Kengo; Kodama, Rika; Fukuda, Tatsuya; Arakawa, Ryo

    2011-01-01

    Pilophorus typicus (Distant) (Heteroptera: Miridae) is a predatory bug occurring in East, Southeast, and South Asia. Because the active stages of P. typicus prey on various agricultural pest insects and mites, this species is a candidate insect as an indigenous natural enemy for use in biological control programs. However, the mass releasing of introduced natural enemies into agricultural fields may incur the risk of affecting the genetic integrity of species through hybridization with a loca...

  20. Introducing the Adherence Strategy Engineering Framework (ASEF)

    DEFF Research Database (Denmark)

    Wagner, Stefan Rahr; Toftegaard, Thomas Skjødeberg; Bertelsen, Olav W.

    2013-01-01

    . Methods: Key concepts related to self-care and adherence were defined, discussed, and implemented as part of the ASEF framework. ASEF was applied to seven self-care case studies, and the perceived usefulness and feasibility of ASEF was evaluated in a questionnaire study by the case study participants...... resulting in reduced data quality and suboptimal treatment. Objectives: The aim of this paper is to introduce the Adherence Strategy Engineering Framework (ASEF) as a method for developing novel technology-based adherence strategies to assess and improve patient adherence levels in the unsupervised setting....... Finally, we reviewed the individual case studies usage of ASEF. Results: A range of central self-care concepts were defined and the ASEF methodological framework was introduced. ASEF was successfully used in seven case studies with a total of 25 participants. Of these, 16 provided answers...

  1. Introducing the new business demography statistics

    OpenAIRE

    Karen Grierson; Andrew Allen

    2008-01-01

    Introducing the new business demography statisticsA new National Statistics series waspublished on 28 November 2008 bythe Offi ce for National Statistics (ONS),providing data on business births,deaths and survival rates, called BusinessDemography: Enterprise Births andDeaths. The Department for Business,Enterprise & Regulatory Reform (BERR)also published its series Business start upsand closures: VAT registrations andde-registrations in 2007 on the sameday. The year 2008 is the final update t...

  2. The challenges of introducing internal social media

    DEFF Research Database (Denmark)

    Madsen, Vibeke Thøis

    2017-01-01

    Purpose – The purpose of this paper is to explore the challenges associated with introducing internal social media (ISM) into organizations in order to help them reap the benefits of coworker communication on ISM. Design/methodology/approach – The paper is based on an exploratory study in ten...... facilitators and sense-givers. Keywords Organizational communication, Internal communication, Coworker, Internal social media Paper type Research paper...

  3. Introducing Emergency Preparedness in Childbirth Education Classes

    OpenAIRE

    DeWald, Lauren; Fountain, Lily

    2006-01-01

    In the wake of recent natural and man-made disasters and emergency situations, pregnant women are especially vulnerable. The authors of this column encourage childbirth educators to include disaster preparedness instruction and emergency childbirth techniques in their class content.

  4. Introduced mammals on Western Indian Ocean islands

    Directory of Open Access Journals (Sweden)

    James C. Russell

    2016-04-01

    Full Text Available The diversity of introduced mammals and their introduction history varies greatly across the Western Indian Ocean (WIO islands, from ancient introductions in the past millennia on islands off the East coast of Africa where extant terrestrial native mammal communities exist, to very recent invasions in the past decades on islands in the Mascarene archipelago. We compile the distribution of 16 introduced mammal taxa on 28 island groups comprising almost 2000 islands. Through an exhaustive literature review and expert consultation process we recorded all mammal eradications, and species recoveries which could be attributed to introduced mammal eradication or control. All island groups have been invaded by mammals, and invasive cats and rats in particular are ubiquitous, but cultural contingency has also led to regional invasions by other mammals such as lemurs, civets and tenrecs. Mammal eradications have been attempted on 45 islands in the WIO, the majority in the Seychelles and Mauritius, and where successful have resulted in spectacular recovery of species and ecosystems. Invasive mammalian predator eradication or control in association with habitat management has led to improved conservation prospects for at least 24 species, and IUCN red-list down-listing of eight species, in the Mascarene Islands. Future island conservation prioritisation in the region will need to take account of global climate change and predicted sea-level rises and coastal inundation. Greater investment and prioritisation in island conservation in the region is warranted, given its high biodiversity values and the extent of invasions.

  5. Introducing carbon taxes in South Africa

    International Nuclear Information System (INIS)

    Alton, Theresa; Arndt, Channing; Davies, Rob; Hartley, Faaiqa; Makrelov, Konstantin; Thurlow, James; Ubogu, Dumebi

    2014-01-01

    Highlights: • South Africa is considering introducing a carbon tax to reduce greenhouse gas emissions. • A phased-in tax of US$30 per ton can achieve national emissions reductions targets set for 2025. • Ignoring all potential benefits, the tax reduces national welfare by about 1.2 percent in 2025. • Border carbon adjustments reduce welfare losses while maintaining emissions reductions. • The mode for recycling carbon tax revenues strongly influences distributional outcomes. - Abstract: South Africa is considering introducing a carbon tax to reduce greenhouse gas emissions. Following a discussion of the motivations for considering a carbon tax, we evaluate potential impacts using a dynamic economywide model linked to an energy sector model including a detailed evaluation of border carbon adjustments. Results indicate that a phased-in carbon tax of US$30 per ton of CO 2 can achieve national emissions reductions targets set for 2025. Relative to a baseline with free disposal of CO 2 , constant world prices and no change in trading partner behavior, the preferred tax scenario reduces national welfare and employment by about 1.2 and 0.6 percent, respectively. However, if trading partners unilaterally impose a carbon consumption tax on South African exports, then welfare/employment losses exceed those from a domestic carbon tax. South Africa can lessen welfare/employment losses by introducing its own border carbon adjustments. The mode for recycling carbon tax revenues strongly influences distributional outcomes, with tradeoffs between growth and equity

  6. The role of philosophy in global bioethics: introducing four trends.

    Science.gov (United States)

    Hellsten, Sirkku K

    2015-04-01

    This article examines the relationship between philosophy and culture in global bioethics. First, it studies what is meant by the term "global" in global bioethics. Second, the author introduces four different types, or recognizable trends, in philosophical inquiry in bioethics today. The main argument is that, in order to make better sense of the complexity of the ethical questions and challenges we face today across the globe, we need to embrace the universal nature of self-critical and analytical philosophical analysis and argumentation, rather than using seemingly philosophical approaches to give unjustified normative emphasis on different cultural approaches to bioethics.

  7. Molecular Population Genetics.

    Science.gov (United States)

    Casillas, Sònia; Barbadilla, Antonio

    2017-03-01

    Molecular population genetics aims to explain genetic variation and molecular evolution from population genetics principles. The field was born 50 years ago with the first measures of genetic variation in allozyme loci, continued with the nucleotide sequencing era, and is currently in the era of population genomics. During this period, molecular population genetics has been revolutionized by progress in data acquisition and theoretical developments. The conceptual elegance of the neutral theory of molecular evolution or the footprint carved by natural selection on the patterns of genetic variation are two examples of the vast number of inspiring findings of population genetics research. Since the inception of the field, Drosophila has been the prominent model species: molecular variation in populations was first described in Drosophila and most of the population genetics hypotheses were tested in Drosophila species. In this review, we describe the main concepts, methods, and landmarks of molecular population genetics, using the Drosophila model as a reference. We describe the different genetic data sets made available by advances in molecular technologies, and the theoretical developments fostered by these data. Finally, we review the results and new insights provided by the population genomics approach, and conclude by enumerating challenges and new lines of inquiry posed by increasingly large population scale sequence data. Copyright © 2017 Casillas and Barbadilla.

  8. Naturwissenschaft und Bildung: Betrachtungen uber die Aktualitat des Genetischen Lernens (Natural Science and Education - Reflections on the Pertinence of Genetic Learning).

    Science.gov (United States)

    Ullrich, Heiner

    2000-01-01

    States that the educational mission of instruction in natural science is still not clearly defined. Explains that the unclear mission is revealed by the situation in instruction in physics today as well as by the scholastic achievement in this field. (CMK)

  9. Genetic Mapping

    Science.gov (United States)

    ... greatly advanced genetics research. The improved quality of genetic data has reduced the time required to identify a ... cases, a matter of months or even weeks. Genetic mapping data generated by the HGP's laboratories is freely accessible ...

  10. Rethinking dog domestication by integrating genetics, archeology, and biogeography

    DEFF Research Database (Denmark)

    Larson, Greger; Karlsson, Elinor K.; Perri, Angela

    2012-01-01

    The dog was the first domesticated animal but it remains uncertain when the domestication process began and whether it occurred just once or multiple times across the Northern Hemisphere. To ascertain the value of modern genetic data to elucidate the origins of dog domestication, we analyzed 49......,024 autosomal SNPs in 1,375 dogs (representing 35 breeds) and 19 wolves. After combining our data with previously published data, we contrasted the genetic signatures of 121 breeds with a worldwide archeological assessment of the earliest dog remains. Correlating the earliest archeological dogs......, and New Guinea Singing Dogs) come from regions outside the natural range of Canis lupus (the dog's wild ancestor) and where dogs were introduced more than 10,000 y after domestication. These results demonstrate that the unifying characteristic among all genetically distinct so-called ancient breeds...

  11. European Union definitely introduces common taxes on energy

    International Nuclear Information System (INIS)

    Schoenweisner, R.

    2003-01-01

    In this paper taxes of the European Union on energy are reviewed. European Union Ministers of environment Council definitely ratified new common system of minimal energy taxes in last week. Council introduces par excellence minimal all-European size of an electricity, coal and natural gas consumption tax. New directive according to European Commission will improve operation of internal market and eliminate deformation of competitive environment among individual members as well as among mineral oils and the other energy sources. Slovak Republic taxes all motor fuel types by higher charge as is minimal level demanded by EU according to new directive after rising of consumable tax from mineral oils in August 2003. According to Minister of Finances Slovak Republic demanded European Union for a temporary 10-year period for utilizing electricity, coal, coke, and natural gas consumption tax. According to Ministry, Utilizing new taxes and rising of tax load is not in interest of started tax reform in Slovak Republic

  12. Breed-specific hematological phenotypes in the dog: a natural resource for the genetic dissection of hematological parameters in a mammalian species.

    Directory of Open Access Journals (Sweden)

    Jennifer Lawrence

    Full Text Available Remarkably little has been published on hematological phenotypes of the domestic dog, the most polymorphic species on the planet. Information on the signalment and complete blood cell count of all dogs with normal red and white blood cell parameters judged by existing reference intervals was extracted from a veterinary database. Normal hematological profiles were available for 6046 dogs, 5447 of which also had machine platelet concentrations within the reference interval. Seventy-five pure breeds plus a mixed breed control group were represented by 10 or more dogs. All measured parameters except mean corpuscular hemoglobin concentration (MCHC varied with age. Concentrations of white blood cells (WBCs, neutrophils, monocytes, lymphocytes, eosinophils and platelets, but not red blood cell parameters, all varied with sex. Neutering status had an impact on hemoglobin concentration, mean corpuscular hemoglobin (MCH, MCHC, and concentrations of WBCs, neutrophils, monocytes, lymphocytes and platelets. Principal component analysis of hematological data revealed 37 pure breeds with distinctive phenotypes. Furthermore, all hematological parameters except MCHC showed significant differences between specific individual breeds and the mixed breed group. Twenty-nine breeds had distinctive phenotypes when assessed in this way, of which 19 had already been identified by principal component analysis. Tentative breed-specific reference intervals were generated for breeds with a distinctive phenotype identified by comparative analysis. This study represents the first large-scale analysis of hematological phenotypes in the dog and underlines the important potential of this species in the elucidation of genetic determinants of hematological traits, triangulating phenotype, breed and genetic predisposition.

  13. Genetic privacy.

    Science.gov (United States)

    Sankar, Pamela

    2003-01-01

    During the past 10 years, the number of genetic tests performed more than tripled, and public concern about genetic privacy emerged. The majority of states and the U.S. government have passed regulations protecting genetic information. However, research has shown that concerns about genetic privacy are disproportionate to known instances of information misuse. Beliefs in genetic determinacy explain some of the heightened concern about genetic privacy. Discussion of the debate over genetic testing within families illustrates the most recent response to genetic privacy concerns.

  14. Re-colonization by common eiders Somateria mollissima in the Aleutian Archipelago following removal of introduced arctic foxes Vulpes lagopus

    Science.gov (United States)

    Petersen, Margaret R.; Sonsthagen, Sarah A.; Sexson, Matthew G.

    2015-01-01

    Islands provide refuges for populations of many species where they find safety from predators, but the introduction of predators frequently results in elimination or dramatic reductions in island-dwelling organisms. When predators are removed, re-colonization for some species occurs naturally, and inter-island phylogeographic relationships and current movement patterns can illuminate processes of colonization. We studied a case of re-colonization of common eiders Somateria mollissima following removal of introduced arctic foxes Vulpes lagopus in the Aleutian Archipelago, Alaska. We expected common eiders to resume nesting on islands cleared of foxes and to re-colonize from nearby islets, islands, and island groups. We thus expected common eiders to show limited genetic structure indicative of extensive mixing among island populations. Satellite telemetry was used to record current movement patterns of female common eiders from six islands across three island groups. We collected genetic data from these and other nesting common eiders at 14 microsatellite loci and the mitochondrial DNA control region to examine population genetic structure, historical fluctuations in population demography, and gene flow. Our results suggest recent interchange among islands. Analysis of microsatellite data supports satellite telemetry data of increased dispersal of common eiders to nearby areas and little between island groups. Although evidence from mtDNA is suggestive of female dispersal among island groups, gene flow is insufficient to account for recolonization and rapid population growth. Instead, near-by remnant populations of common eiders contributed substantially to population expansion, without which re-colonization would have likely occurred at a much lower rate. Genetic and morphometric data of common eiders within one island group two and three decades after re-colonization suggests reduced movement of eiders among islands and little movement between island groups after

  15. Introducing advanced nuclear fuel cycles in Canada

    International Nuclear Information System (INIS)

    Duret, M.F.

    1978-05-01

    The ability of several different advanced fuel cycles to provide energy for a range of energy growth scenarios has been examined for a few special situations of interest in Canada. Plutonium generated from the CANDU-PHW operating on natural uranium is used to initiate advanced fuel cycles in the year 2000. The four fuel cycles compared are: 1) natural uranium in the CANDU-PHW; 2) high burnup thorium cycle in the CANDU-PHW; 3) self-sufficient thorium cycle in the CANDU-PHW; 4) plutonium-uranium cycle in a fast breeder reactor. The general features of the results are quite clear. While any plutonium generated prior to the introduction of the advanced fuel cycle remains, system requirements for natural uranium for each of the advanced fuel cycles are the same and are governed by the rate at which plants operating on natural uranium can be retired. When the accumulated plutonium inventory has been entirely used, natural uranium is again required to provide inventory for the advanced fuel cycle reactors. The time interval during which no uranium is required varies only from about 25 to 40 years for both thorium cycles, depending primarily on the energy growth rate. The breeder does not require the entire plutonium inventory produced and so would call for less processing of fuel from the PHW reactors. (author)

  16. Natural hybridization between Vanilla claviculata (W. Wright) Sw. and V. barbellata Rchb.f. (Orchidaceae): genetic, morphological, and pollination experimental data

    DEFF Research Database (Denmark)

    NIELSEN, LENE ROSTGAARD

    2000-01-01

    Vanilla claviculata (W. Wright) Sw. and V. barbellata Rchb.f. grow sympatrically in the southwestern part of herto Rico. At three localities in the range of the two species, individuals with flowers that appeared different from previously known species were found. To test whether these were hybrids...... the hypothesis that the individuals are hybrids, which is further augmented by interspecific pollination experiments between the putative parental species. This is the first case of natural hybridization reported in the genus Vanilla....

  17. Simulating and Optimizing Hydrogen Production by Low-pressure Autothermal Reforming of Natural Gas using Non-dominated Sorting Genetic Algorithm-II

    OpenAIRE

    Azarhoosh, M. J.; Ale Ebrahim, H.; Pourtarah, S. H.

    2016-01-01

    Conventional hydrogen production plants consist of natural gas steam reforming to CO+3H2 on Ni catalysts in a furnace, water-gas shift reaction for converting CO into CO2 and CO2 absorption. A new alternative method for highly endothermic steam reforming is autothermal reforming (steam reforming with air input to the reactor) without the need for external heating. In this study, hydrogen production by autothermal reforming for fuel cells (base case) was simulated based on a heterogeneous and ...

  18. Introducing Pharmacogenetics and Personalized Medicine via a Weblog

    Directory of Open Access Journals (Sweden)

    Kaitlin Bova

    2014-01-01

    Full Text Available Objectives: To evaluate a weblog (blog-based course introducing pharmacogenetics (PGt and personalized medicine (PM relative to freshmen pharmacy students' knowledge base. Methods: Incoming freshmen pharmacy students were invited by email to enroll in a one semester-hour, elective, on-line blog-based course entitled "Personal Genome Evaluation". The course was offered during the students' first semester in college. A topic list related to PGt and PM was developed by a group of faculty with topics being presented via the blog once or twice weekly through week 14 of the 15 week semester. A pre-course and post-course survey was sent to the students to compare their knowledge base relative to general information, drug response related to PGt, and PM. Results: Fifty-one freshmen pharmacy students enrolled in the course and completed the pre-course survey and 49 of the 51 students completed the post-course survey. There was an increase in the students' general, PGt and PM knowledge base as evidenced by a statistically significant higher number of correct responses for 17 of 21 questions on the post-course survey as compared to the pre-course survey. Notably, following the course, students had an increased knowledge base relative to "genetic privacy", drug dosing based on metabolizer phenotype, and the breadth of PM, among other specific points. Conclusions: The study indicated that introducing PGt and PM via a blog format was feasible, increasing the students' knowledge of these emerging areas. The blog format is easily transferable and can be adopted by colleges/schools to introduce PGt and PM.   Type: Case Study

  19. Molecular genetics

    International Nuclear Information System (INIS)

    Kubitschek, H.E.

    1975-01-01

    Progress is reported on studies on the nature and action of lethal and mutagenic lesions in DNA and the mechanisms by which these are produced in bacteria by ionizing radiation or by decay of radioisotopes incorporated in DNA. Studies of radioisotope decay provide the advantages that the original lesion is localized in the genetic material and the immediate physical and chemical changes that occur at decay are known. Specific types of DNA damage were related to characteristic decay properties of several radioisotopes. Incorporated 125 I, for example, induces a double-stranded break in DNA with almost every decay, but causes remarkably little damage of any other kind to the DNA. (U.S.)

  20. Genetic diversity, structure, and demographic change in tanoak, Lithocarpus densiflorus (Fagaceae), the most susceptible species to sudden oak death in California

    Science.gov (United States)

    A. Nettel; R. S. Dodd; Z. Afzal-Rafii

    2009-01-01

    Knowledge of population genetic structure of tanoak (Lithocarpus densiflorus) is of interest to pathologists seeking natural variation in resistance to sudden oak death disease, to resource managers who need indications of conservation priorities in this species now threatened by the introduced pathogen (Phytophthora ramorum),...

  1. How to introduce the magnetic dipole moment

    International Nuclear Information System (INIS)

    Bezerra, M; Kort-Kamp, W J M; Cougo-Pinto, M V; Farina, C

    2012-01-01

    We show how the concept of the magnetic dipole moment can be introduced in the same way as the concept of the electric dipole moment in introductory courses on electromagnetism. Considering a localized steady current distribution, we make a Taylor expansion directly in the Biot-Savart law to obtain, explicitly, the dominant contribution of the magnetic field at distant points, identifying the magnetic dipole moment of the distribution. We also present a simple but general demonstration of the torque exerted by a uniform magnetic field on a current loop of general form, not necessarily planar. For pedagogical reasons we start by reviewing briefly the concept of the electric dipole moment. (paper)

  2. Introducing NET 40 With Visual Studio 2010

    CERN Document Server

    Mackey, A

    2010-01-01

    Microsoft is introducing a large number of changes to the way that the .NET Framework operates. Familiar technologies are being altered, best practices replaced, and developer methodologies adjusted. Many developers find it hard to keep up with the pace of change across .NET's ever-widening array of technologies. You may know what's happening in C#, but how about the Azure cloud? How is that going to affect your work? What are the limitations of the new pLINQ syntax? What you need is a roadmap. A guide to help you see the innovations that matter and to give you a head start on the opportunitie

  3. Toxicological evaluation of proteins introduced into food crops

    Science.gov (United States)

    Kough, John; Herouet-Guicheney, Corinne; Jez, Joseph M.

    2013-01-01

    This manuscript focuses on the toxicological evaluation of proteins introduced into GM crops to impart desired traits. In many cases, introduced proteins can be shown to have a history of safe use. Where modifications have been made to proteins, experience has shown that it is highly unlikely that modification of amino acid sequences can make a non-toxic protein toxic. Moreover, if the modified protein still retains its biological function, and this function is found in related proteins that have a history of safe use (HOSU) in food, and the exposure level is similar to functionally related proteins, then the modified protein could also be considered to be “as-safe-as” those that have a HOSU. Within nature, there can be considerable evolutionary changes in the amino acid sequence of proteins within the same family, yet these proteins share the same biological function. In general, food crops such as maize, soy, rice, canola etc. are subjected to a variety of processing conditions to generate different food products. Processing conditions such as cooking, modification of pH conditions, and mechanical shearing can often denature proteins in these crops resulting in a loss of functional activity. These same processing conditions can also markedly lower human dietary exposure to (functionally active) proteins. Safety testing of an introduced protein could be indicated if its biological function was not adequately characterized and/or it was shown to be structurally/functionally related to proteins that are known to be toxic to mammals. PMID:24164515

  4. Introducing passive matched field acoustic tomography

    International Nuclear Information System (INIS)

    Gasparini, O.; Camporeale, C.; Crise, A.

    1997-01-01

    In acoustic tomography sea-basin environmental parameters such as temperature profiles and current-velocities are derived, when ray propagation models are adopted, by the travel time estimates relative to the identifiable ray paths. The transmitted signals are either single frequency, or impulsive, or intermittent and deterministic. When the wavelength is comparable with the scale lengths present in the propagation scenario, Matched Field Tomography (MFT) is used, entailing the consideration of waveguide modes instead of rays. A new concept in tomography is introduced in the paper, that employs passively the noise emitted by ships of opportunity (cargoes, ferries) as source signals. The passive technique is acoustic-pollution-free, and if a basin is selected in which a regular ship traffic occurs data can be received on a regular schedule, with no transmission cost. A novel array pre-processor for passive tomography is introduced, such that the signal structure at the pre-processor output in nearly the same as that obtainable in the case of single-frequency source signals

  5. [Financial impact of introducing filmless CRT diagnosis].

    Science.gov (United States)

    Kusakabe, Yukihiro

    2002-09-01

    There has been a great deal of discussion as to the cost and benefit of introducing filmless CRT diagnosis for radiological exams. Although the various advantages of the filmless system tend to be highlighted, very few studies have attempted to provide a quantitative estimate of the degree of impact. We analyzed the potential financial impact on the cost of film management (film development, maintenance, and transportation) if CRT diagnosis were to be introduced in Seirei Hamamatsu Hospital. In conducting this analysis, we assumed that CRT diagnosis initially would be limited to CT and MR. The analysis demonstrated that the actual yearly cost of managing films amounts to about 240 million yen. As individual items, the cost of film materials, labor, and depreciation of assets were the three largest cost sectors, with the cost of film accounting for more than 30% of the total. The expense attributable to CT and MR exams was roughly half of the total cost. Against this level of expense, the expected savings in the first year after shifting to the filmless system would be 100 million yen, or a 36% reduction in current expenses. This savings reflects various effects of system change, including lack of need for related materials, reduction in staff workload, elimination of unnecessary equipment, etc. Under the simulation we conducted, 70% of savings occurred in the area of variable costs and 30% in the area of fixed costs.

  6. Genetic diversity among endangered rare Dalbergia cochinchinensis

    African Journals Online (AJOL)

    hocvan

    Experimental Taxonomy and Genetic Diversity, Vietnam National Museum of Nature, Vietnam Academy for Science and ... Genetic diversity of the 35 genotypes of D. cochinchinensis species were evaluated by ...... Dalbergia genus at the population level of genetic .... Population genetic software for teaching and research.

  7. Introducing Generation Y to the Wilderness

    Science.gov (United States)

    Taylor, Nicole; Gray, Tonia; Birrell, Carol

    2012-01-01

    Today's Western culture is characterized by high technology, time compression and a disconnection from the natural world. What happens when a group of young adult students who are firmly embedded within this world, embark on a 6-day unassisted wilderness experience? When divorced from the structural support of the everyday, and placed in an…

  8. Genetic characterization of natural reassortant H4 subtype avian influenza viruses isolated from domestic ducks in Zhejiang province in China from 2013 to 2014.

    Science.gov (United States)

    Wu, Haibo; Peng, Xiuming; Peng, Xiaorong; Cheng, Linfang; Lu, Xiangyun; Jin, Changzhong; Xie, Tiansheng; Yao, Hangping; Wu, Nanping

    2015-12-01

    The H4 subtype of the influenza virus was first isolated in 1999 from pigs with pneumonia in Canada. H4 avian influenza viruses (AIVs) are able to cross the species barrier to infect humans. In order to better understand the genetic relationships between H4 AIV strains circulating in Eastern China and other AIV strains from Asia, a survey of domestic ducks in live poultry markets was undertaken in Zhejiang province from 2013 to 2014. In this study, 23 H4N2 (n = 14) and H4N6 (n = 9) strains were isolated from domestic ducks, and all eight gene segments of these strains were sequenced and compared to reference AIV strains available in GenBank. The isolated strains clustered primarily within the Eurasian lineage. No mutations associated with adaption to mammalian hosts or drug resistance was observed. The H4 reassortant strains were found to be of low pathogenicity in mice and able to replicate in the lung of the mice without prior adaptation. Continued surveillance is required, given the important role of domestic ducks in reassortment events leading to new AIVs.

  9. Root-specific expression of opine genes and opine accumulation in some cultivars of the naturally occurring genetically modified organism Nicotiana tabacum.

    Science.gov (United States)

    Chen, Ke; de Borne, François Dorlhac; Julio, Emilie; Obszynski, Julie; Pale, Patrick; Otten, Léon

    2016-08-01

    Previous studies have shown that Nicotiana tabacum contains three Agrobacterium-derived T-DNA sequences inherited from its paternal ancestor Nicotiana tomentosiformis. Among these, the TB locus carries an intact mannopine synthase 2' gene (TB-mas2'). This gene is similar to the Agrobacterium rhizogenes A4-mas2' gene that encodes the synthesis of the Amadori compound deoxyfructosyl-glutamine (DFG or santhopine). In this study we show that TB-mas2' is expressed at very low levels in N. tomentosiformis and in most N. tabacum cultivars; however, some cultivars show high TB-mas2' expression levels. The TB-mas2' promoter sequences of low- and high-expressing cultivars are identical. The low/high level of expression segregates as a single Mendelian factor in a cross between a low- and a high-expression cultivar. pTB-mas2'-GUS and pA4-mas2'-GUS reporter genes were stably introduced in N. benthamiana. Both were mainly expressed in the root expansion zone and leaf vasculature. Roots of tobacco cultivars with high TB-mas2' expression contain detectable levels of DFG. © 2016 The Authors The Plant Journal © 2016 John Wiley & Sons Ltd.

  10. sGD: software for estimating spatially explicit indices of genetic diversity.

    Science.gov (United States)

    Shirk, A J; Cushman, S A

    2011-09-01

    Anthropogenic landscape changes have greatly reduced the population size, range and migration rates of many terrestrial species. The small local effective population size of remnant populations favours loss of genetic diversity leading to reduced fitness and adaptive potential, and thus ultimately greater extinction risk. Accurately quantifying genetic diversity is therefore crucial to assessing the viability of small populations. Diversity indices are typically calculated from the multilocus genotypes of all individuals sampled within discretely defined habitat patches or larger regional extents. Importantly, discrete population approaches do not capture the clinal nature of populations genetically isolated by distance or landscape resistance. Here, we introduce spatial Genetic Diversity (sGD), a new spatially explicit tool to estimate genetic diversity based on grouping individuals into potentially overlapping genetic neighbourhoods that match the population structure, whether discrete or clinal. We compared the estimates and patterns of genetic diversity using patch or regional sampling and sGD on both simulated and empirical populations. When the population did not meet the assumptions of an island model, we found that patch and regional sampling generally overestimated local heterozygosity, inbreeding and allelic diversity. Moreover, sGD revealed fine-scale spatial heterogeneity in genetic diversity that was not evident with patch or regional sampling. These advantages should provide a more robust means to evaluate the potential for genetic factors to influence the viability of clinal populations and guide appropriate conservation plans. © 2011 Blackwell Publishing Ltd.

  11. Assessing Genetic Diversity after Mangrove Restoration in Brazil: Why Is It So Important?

    Directory of Open Access Journals (Sweden)

    Renan Granado

    2018-04-01

    Full Text Available Vital for many marine and terrestrial species, and several other environmental services, such as carbon sink areas, the mangrove ecosystem is highly threatened due to the proximity of large urban centers and climate change. The forced fragmentation of this ecosystem affects the genetic diversity distribution among natural populations. Moreover, while restoration efforts have increased, few studies have analyzed how recently-planted areas impact the original mangrove genetic diversity. We analyzed the genetic diversity of two mangroves species (Laguncularia racemosa and Avicennia schaueriana in three areas in Brazil, using inter-simple sequence repeat (ISSR markers. Using the local approach, we identified the genetic diversity pool of a restored area compared to nearby areas, including the remnant plants inside the restored area, one well-conserved population at the shore of Guanabara Bay, and one impacted population in Araçá Bay. The results for L. racemosa showed that the introduced population has lost genetic diversity by drift, but remnant plants with high genetic diversity or incoming propagules could help improve overall genetic diversity. Avicennia schaueriana showed similar genetic diversity, indicating an efficient gene flow. The principal component analysis showing different connections between both species indicate differences in gene flow and dispersal efficiencies, highlighting the needed for further studies. Our results emphasize that genetic diversity knowledge and monitoring associated with restoration actions can help avoid bottlenecks and other pitfalls, especially for the mangrove ecosystem.

  12. Similaridade genética de populações naturais de pimenta-de-macaco por análise RAPD Genetic similarity of natural populations of pimenta-de-macaco (Piper aduncum L. obtained throug RAPD analysis

    Directory of Open Access Journals (Sweden)

    José Maria D. Gaia

    2004-12-01

    Full Text Available A espécie conhecida como pimenta-de-macaco (Piper aduncum L. possui grande potencial para exploração econômica em função da comprovada utilidade do seu óleo essencial na agricultura e saúde humana. O objetivo deste trabalho foi caracterizar a diversidade genética de populações naturais dessa planta. Um total de dezoito acessos da planta, provenientes de quatro procedências da Amazônia Brasileira, foi examinado por meio de locos de DNA, gerados por análise RAPD (polimorfismo de DNA amplificado ao acaso. O estudo evidenciou a existência de real diversidade entre as populações examinadas, sendo provável que dentro das localidades investigadas, os padrões da diversidade genética acompanhem os padrões de distribuição geográfica.The species known as pimenta-de-macaco (Piper aduncum L. has great economic explotation potential based on the proved usefulness of the essential oil in agriculture and human health. The genetic diversity of their natural populations was characterized. A total of eighteen accessions of the plant, obtained from four different origins in the Brazilian Amazon, was examined by means of DNA loci, generated by RAPD analysis. Real genetic diversity was observed between the analyzed populations and it appear that the patterns of the genetic diversity follow the patterns of the geographical distribution.

  13. Introducing Spoken Dialogue Systems into Intelligent Environments

    CERN Document Server

    Heinroth, Tobias

    2013-01-01

    Introducing Spoken Dialogue Systems into Intelligent Environments outlines the formalisms of a novel knowledge-driven framework for spoken dialogue management and presents the implementation of a model-based Adaptive Spoken Dialogue Manager(ASDM) called OwlSpeak. The authors have identified three stakeholders that potentially influence the behavior of the ASDM: the user, the SDS, and a complex Intelligent Environment (IE) consisting of various devices, services, and task descriptions. The theoretical foundation of a working ontology-based spoken dialogue description framework, the prototype implementation of the ASDM, and the evaluation activities that are presented as part of this book contribute to the ongoing spoken dialogue research by establishing the fertile ground of model-based adaptive spoken dialogue management. This monograph is ideal for advanced undergraduate students, PhD students, and postdocs as well as academic and industrial researchers and developers in speech and multimodal interactive ...

  14. Introducing disability studies to occupational therapy students.

    Science.gov (United States)

    Block, Pamela; Ricafrente-Biazon, Melissa; Russo, Ann; Chu, Ke Yun; Sud, Suman; Koerner, Lori; Vittoria, Karen; Landgrover, Alyssa; Olowu, Tosin

    2005-01-01

    This article is a work of collaborative ethnography about teaching and learning disability studies within the context of an occupational therapy graduate program. In spring 2004,14 occupational therapy students were introduced to disability studies by their cultural anthropologist (nonoccupational therapist) course instructor. During the one-credit course, they were expected to complete readings, watch films, attend guest lectures, and make a site visit. The occupational therapy students were required to write a journal to record personal reactions and new insights gained from these experiences. This article focuses on a thematic analysis of the students' journaled responses to the film "Dance Me to My Song," and a site visit to a local Independent Living Center. Students were expected to analyze these experiences from both disability studies and occupational therapy perspectives. The article addresses philosophical and practical differences between occupational therapy and disability studies and identifies opportunities for collaboration between occupational therapists and independent living specialists.

  15. Genetic polymorphisms of the CYP1A1, GSTM1, and GSTT1 enzymes and their influence on cardiovascular risk and lipid profile in people who live near a natural gas plant.

    Science.gov (United States)

    Pašalić, Daria; Marinković, Natalija

    2017-03-01

    The aim of this cross-sectional study was to see whether genetic polymorphisms of the enzymes CYP1A1, GSTM1, and GSTT1 are associated with higher risk of coronary artery disease (CAD) and whether they affect lipid profile in 252 subjects living near a natural gas plant, who are likely to be exposed to polycyclic aromatic hydrocarbons (PAHs). Fasting serum concentrations of biochemical parameters were determined with standard methods. Genetic polymorphisms of CYP 1A1 rs4646903, rs1048943, rs4986883, and rs1799814 were genotyped with polymerase chain reaction-restriction fragment length polymorphism (PCR-RFPL), while GSTM1 and GSTT1 deletions were detected with multiplex PCR. Cardiovascular risk was assessed with Framingham risk score, and the subjects divided in two groups: >10% risk and ≤10% risk. The two groups did not differ in the genotype frequencies. MANCOVA analysis, which included lipid parameters, glucose, and BMI with sex, age, hypertension and smoking status as covariates, showed a significant difference between the GSTT1*0 and GSTT1*1 allele carriers (p=0.001). UNIANCOVA with same covariates showed that total cholesterol and triglyceride levels were significantly higher in GSTT1*1 allele carriers than in GSTT1*0 carriers (prisk of CAD, but that GSTT1 affects lipid profile.

  16. Biofilms for Babies: Introducing Microbes and Biofilms to Preschool-Aged Children

    Directory of Open Access Journals (Sweden)

    Jillian M. Couto

    2017-05-01

    Full Text Available Microbes are beneficial to life on our planet as they facilitate natural processes such as global nutrient cycling in our environment. This article details a 30-minute activity to introduce pre-school children ranging from 3 to 5 years of age to microbes and biofilms in the natural environment.

  17. Genetic diversity in Chilean populations of rainbow trout, Oncorhynchus mykiss

    Directory of Open Access Journals (Sweden)

    Claudia B Cárcamo

    2015-03-01

    Full Text Available The rainbow trout Oncorhynchus mykiss, was first introduced in Chile between 1905 and 1920 and is currently widely distributed in Chile from Antofagasta (23°S to Patagonia (55°S. The broad range of the geographic and climatic distributions of this species in Chile offers a unique opportunity to study the effect of naturalization of an introduced species on its genetic variability. It is of particular importance to observe the genetic variability of populations in the northern range of this species distribution, in a transition zone where a Mediterranean-type climate changes to an arid climate. The present study analyzed allozymic variability and distribution within and between populations of O. mykiss from the river basins of Elqui and Limari rivers, and six culture strains, using starch-gel protein electrophoresis. Populations were found to be in Hardy-Weinberg equilibrium and the average values of He (0.045, polymorphism (13.9% and allele per locus (1.19 are similar to rainbow trout in its native distributional range. About 77.8% of the genetic variability was within population, similar to the variability reported for wild populations in the northern hemisphere. However, a marked genetic differentiation between wild populations was also found. This is likely to be the consequence of initial founder effects followed by subsequent introgression of resident populations caused by reseeding with trout of different origins in both basins.

  18. Influence of gamma irradiation on natural mycoflora of poultry feed and effect on morphology, physiology and genetic of strains Aspergillus spp

    International Nuclear Information System (INIS)

    Ribeiro, Jessika Mara Martins

    2008-01-01

    Maize flour samples, soy crumb and feed were collected directly from the production line of a poultry farm in Avelar, RJ, and exposed to doses of 0,3.5, 0,8 and 15 kGy of gamma irradiation. Counting, isolation and identification of the contaminant mycoflora were performed before and after irradiation. The radiosensitivity of strains of reference of Aspergillus spp. was determined in CYA medium and in corn for doses ranging from 0 to 8 kGy. Comparison between the morphologies of control and irradiated strains were performed by using macroscopy, optical microscopy and transmission electron microscopy. Toxigenic profile determination and genetic evaluation by RAPD were also carried out. Higher doses have been found to reduce the number of active colonies, causing elimination of the mycoflora at 8 kGy. A larger radiosensitivity of yeasts was observed in comparison with filamentous fungi. A significant reduction in fungi population occurred at 3.5 kGy to levels below the limit that ensures the hygienic quality of ingredients and poultry feeds. The residual mycoflora was found to decrease with post-irradiation time and included mostly Cladosporium spp., Curvularia spp., Fusarium spp. and Aspergillus spp. and sterility of mycelium prevented further identification of the surviving species of Aspergillus spp. Differences in radioresistance were found among species of Aspergillus and the highest tolerance to radiation was observed for A. parasiticus. Initial morphologic changes were found to be more severe during the first isolation after irradiation than in later ones, with the fungi gradually recovering their normal growth rate. Ultrastructural changes in the irradiated strains were observed mostly in the plasmatic membrane and membranous organelles of nuclei and mitochondria. An increase in the rate of production of toxins by the irradiated strains has been found, however no significant alterations have been observed in their genotypes. Such findings apparently indicate

  19. Introducing Python tools for magnetotellurics: MTpy

    Science.gov (United States)

    Krieger, L.; Peacock, J.; Inverarity, K.; Thiel, S.; Robertson, K.

    2013-12-01

    Within the framework of geophysical exploration techniques, the magnetotelluric method (MT) is relatively immature: It is still not as widely spread as other geophysical methods like seismology, and its processing schemes and data formats are not thoroughly standardized. As a result, the file handling and processing software within the academic community is mainly based on a loose collection of codes, which are sometimes highly adapted to the respective local specifications. Although tools for the estimation of the frequency dependent MT transfer function, as well as inversion and modelling codes, are available, the standards and software for handling MT data are generally not unified throughout the community. To overcome problems that arise from missing standards, and to simplify the general handling of MT data, we have developed the software package "MTpy", which allows the handling, processing, and imaging of magnetotelluric data sets. It is written in Python and the code is open-source. The setup of this package follows the modular approach of successful software packages like GMT or Obspy. It contains sub-packages and modules for various tasks within the standard MT data processing and handling scheme. Besides pure Python classes and functions, MTpy provides wrappers and convenience scripts to call external software, e.g. modelling and inversion codes. Even though still under development, MTpy already contains ca. 250 functions that work on raw and preprocessed data. However, as our aim is not to produce a static collection of software, we rather introduce MTpy as a flexible framework, which will be dynamically extended in the future. It then has the potential to help standardise processing procedures and at same time be a versatile supplement for existing algorithms. We introduce the concept and structure of MTpy, and we illustrate the workflow of MT data processing utilising MTpy on an example data set collected over a geothermal exploration site in South

  20. Questionnaire discrimination: (re-introducing coefficient δ

    Directory of Open Access Journals (Sweden)

    Hankins Matthew

    2007-05-01

    Full Text Available Abstract Background Questionnaires are used routinely in clinical research to measure health status and quality of life. Questionnaire measurements are traditionally formally assessed by indices of reliability (the degree of measurement error and validity (the extent to which the questionnaire measures what it is supposed to measure. Neither of these indices assesses the degree to which the questionnaire is able to discriminate between individuals, an important aspect of measurement. This paper introduces and extends an existing index of a questionnaire's ability to distinguish between individuals, that is, the questionnaire's discrimination. Methods Ferguson (1949 1 derived an index of test discrimination, coefficient δ, for psychometric tests with dichotomous (correct/incorrect items. In this paper a general form of the formula, δG, is derived for the more general class of questionnaires allowing for several response choices. The calculation and characteristics of δG are then demonstrated using questionnaire data (GHQ-12 from 2003–2004 British Household Panel Survey (N = 14761. Coefficients for reliability (α and discrimination (δG are computed for two commonly-used GHQ-12 coding methods: dichotomous coding and four-point Likert-type coding. Results Both scoring methods were reliable (α > 0.88. However, δG was substantially lower (0.73 for the dichotomous coding of the GHQ-12 than for the Likert-type method (δG = 0.96, indicating that the dichotomous coding, although reliable, failed to discriminate between individuals. Conclusion Coefficient δG was shown to have decisive utility in distinguishing between the cross-sectional discrimination of two equally reliable scoring methods. Ferguson's δ has been neglected in discussions of questionnaire design and performance, perhaps because it has not been implemented in software and was restricted to questionnaires with dichotomous items, which are rare in health care research. It is

  1. ‘Soglitude’- introducing a method of thinking thresholds

    Directory of Open Access Journals (Sweden)

    Tatjana Barazon

    2010-04-01

    Full Text Available ‘Soglitude’ is an invitation to acknowledge the existence of thresholds in thought. A threshold in thought designates the indetermination, the passage, the evolution of every state the world is in. The creation we add to it, and the objectivity we suppose, on the border of those two ideas lies our perceptive threshold. No state will ever be permanent, and in order to stress the temporary, fluent character of the world and our perception of it, we want to introduce a new suitable method to think change and transformation, when we acknowledge our own threshold nature. The contributions gathered in this special issue come from various disciplines: anthropology, philosophy, critical theory, film studies, political science, literature and history. The variety of these insights shows the resonance of the idea of threshold in every category of thought. We hope to enlarge the notion in further issues on physics and chemistry, as well as mathematics. The articles in this issue introduce the method of threshold thinking by showing the importance of the in-between, of the changing of perspective in their respective domain. The ‘Documents’ section named INTERSTICES, includes a selection of poems, two essays, a philosophical-artistic project called ‘infraphysique’, a performance on thresholds in the soul, and a dialogue with Israel Rosenfield. This issue presents a kaleidoscope of possible threshold thinking and hopes to initiate new ways of looking at things.For every change that occurs in reality there is a subjective counterpart in our perception and this needs to be acknowledged as such. What we name objective is reflected in our own personal perception in its own personal manner, in such a way that the objectivity of an event might altogether be questioned. The absolute point of view, the view from “nowhere”, could well be the projection that causes dogmatism. By introducing the method of thinking thresholds into a system, be it

  2. Quo Vadis, Medical Genetics?

    Science.gov (United States)

    Czeizel, Andrew E.

    The beginning of human genetics and its medical part: medical genetics was promising in the early decades of this century. Many genetic diseases and defects with Mendelian origin were identified and it helped families with significant genetic burden to limit their child number. Unfortunately this good start was shadowed by two tragic events. On the one hand, in the 1930s and early 1940s the German fascism brought about the dominance of an unscientific eugenics to mask vile political crimes. People with genetic diseases-defects were forced to sterilisation and several of them were killed. On the other hand, in the 1950s lysenkoism inhibitied the evolution of genetics in the Soviet Union and their satelite countries. Lysenko's doctrine declared genetics as a product of imperialism and a guilty science, therefore leading geneticists were ousted form their posts and some of them were executed or put in prison. Past decades genetics has resulted fantastic new results and achieved a leading position within the natural sciences. To my mind, however, the expected wider use of new eugenics indicates a new tragedy and this Cassandra's prediction is the topic of this presentation.

  3. On Introducing Asymmetry into Circular Distributions

    Directory of Open Access Journals (Sweden)

    Dale Umbach

    2012-07-01

    Full Text Available Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman","serif";} We give a brief history of the results which led to the introduction of asymmetry into symmetric circular distributions. This is followed by the presentation of another method of introducing asymmetry. Some properties of the induced distributions are studied. Finally, this new distribution is shown to be a reasonable fit to the Jander ant data as presented in Fisher (1993.

  4. Introducing Stable Radicals into Molecular Machines.

    Science.gov (United States)

    Wang, Yuping; Frasconi, Marco; Stoddart, J Fraser

    2017-09-27

    Ever since their discovery, stable organic radicals have received considerable attention from chemists because of their unique optical, electronic, and magnetic properties. Currently, one of the most appealing challenges for the chemical community is to develop sophisticated artificial molecular machines that can do work by consuming external energy, after the manner of motor proteins. In this context, radical-pairing interactions are important in addressing the challenge: they not only provide supramolecular assistance in the synthesis of molecular machines but also open the door to developing multifunctional systems relying on the various properties of the radical species. In this Outlook, by taking the radical cationic state of 1,1'-dialkyl-4,4'-bipyridinium (BIPY •+ ) as an example, we highlight our research on the art and science of introducing radical-pairing interactions into functional systems, from prototypical molecular switches to complex molecular machines, followed by a discussion of the (i) limitations of the current systems and (ii) future research directions for designing BIPY •+ -based molecular machines with useful functions.

  5. Introducing Waqf Based Takaful Model in India

    Directory of Open Access Journals (Sweden)

    Syed Ahmed Salman

    2014-03-01

    Full Text Available Objective – Waqf is a unique feature of the socioeconomic system of Islam in a multi- religious and developing country like India. India is a rich country with waqf assets. The history of waqf in India can be traced back to 800 years ago. Most of the researchers, suggest how waqf can be used a tool to mitigate the poverty of Muslims. India has the third highest Muslim population after Indonesia and Pakistan. However, the majority of Muslims belong to the low income group and they are in need of help. It is believed that waqf can be utilized for the betterment of Indian Muslim community. Among the available uses of waqf assets, the main objective of this paper is to introduce waqf based takaful model in India. In addition, how this proposed model can be adopted in India is highlighted.Methods – Library research is applied since this paper relies on secondary data by thoroughlyreviewing the most relevant literature.Result – India as a rich country with waqf assets should fully utilize the resources to help the Muslims through takaful.Conclusion – In this study, we have proposed waqf based takaful model with the combination of the concepts mudarabah and wakalah for India. We recommend this model based on the background of the  country and situations. Since we have not tested the viability of this model in India, future research should be continued on this testing.Keywords : Wakaf, Takaful, Kemiskinan dan India

  6. Genetic diversity of the HLA-G coding region in Amerindian populations from the Brazilian Amazon: a possible role of natural selection.

    Science.gov (United States)

    Mendes-Junior, C T; Castelli, E C; Meyer, D; Simões, A L; Donadi, E A

    2013-12-01

    HLA-G has an important role in the modulation of the maternal immune system during pregnancy, and evidence that balancing selection acts in the promoter and 3'UTR regions has been previously reported. To determine whether selection acts on the HLA-G coding region in the Amazon Rainforest, exons 2, 3 and 4 were analyzed in a sample of 142 Amerindians from nine villages of five isolated tribes that inhabit the Central Amazon. Six previously described single-nucleotide polymorphisms (SNPs) were identified and the Expectation-Maximization (EM) and PHASE algorithms were used to computationally reconstruct SNP haplotypes (HLA-G alleles). A new HLA-G allele, which originated in Amerindian populations by a crossing-over event between two widespread HLA-G alleles, was identified in 18 individuals. Neutrality tests evidenced that natural selection has a complex part in the HLA-G coding region. Although balancing selection is the type of selection that shapes variability at a local level (Native American populations), we have also shown that purifying selection may occur on a worldwide scale. Moreover, the balancing selection does not seem to act on the coding region as strongly as it acts on the flanking regulatory regions, and such coding signature may actually reflect a hitchhiking effect.

  7. Global phylogeography of the widely introduced North West Pacific ascidian Styela clava.

    Science.gov (United States)

    Goldstien, Sharyn J; Dupont, Lise; Viard, Frédérique; Hallas, Paul J; Nishikawa, Teruaki; Schiel, David R; Gemmell, Neil J; Bishop, John D D

    2011-02-22

    The solitary ascidian Styela clava Herdman, 1882 is considered to be native to Japan, Korea, northern China and the Russian Federation in the NW Pacific, but it has spread globally over the last 80 years and is now established as an introduced species on the east and west coasts of North America, Europe, Australia and New Zealand. In eastern Canada it reaches sufficient density to be a serious pest to aquaculture concerns. We sequenced a fragment of the cytochrome oxidase subunit I mitochondrial gene (COI) from a total of 554 individuals to examine the genetic relationships of 20 S. clava populations sampled throughout the introduced and native ranges, in order to investigate invasive population characteristics. The data presented here show a moderate level of genetic diversity throughout the northern hemisphere. The southern hemisphere (particularly New Zealand) displays a greater amount of haplotype and nucleotide diversity in comparison. This species, like many other invasive species, shows a range of genetic diversities among introduced populations independent of the age of incursion. The successful establishment of this species appears to be associated with multiple incursions in many locations, while other locations appear to have experienced rapid expansion from a potentially small population with reduced genetic diversity. These contrasting patterns create difficulties when attempting to manage and mitigate a species that continues to spread among ports and marinas around the world.

  8. Complete Genome Analysis of Thermus parvatiensis and Comparative Genomics of Thermus spp. Provide Insights into Genetic Variability and Evolution of Natural Competence as Strategic Survival Attributes

    Directory of Open Access Journals (Sweden)

    Charu Tripathi

    2017-07-01

    Full Text Available Thermophilic environments represent an interesting niche. Among thermophiles, the genus Thermus is among the most studied genera. In this study, we have sequenced the genome of Thermus parvatiensis strain RL, a thermophile isolated from Himalayan hot water springs (temperature >96°C using PacBio RSII SMRT technique. The small genome (2.01 Mbp comprises a chromosome (1.87 Mbp and a plasmid (143 Kbp, designated in this study as pTP143. Annotation revealed a high number of repair genes, a squeezed genome but containing highly plastic plasmid with transposases, integrases, mobile elements and hypothetical proteins (44%. We performed a comparative genomic study of the group Thermus with an aim of analysing the phylogenetic relatedness as well as niche specific attributes prevalent among the group. We compared the reference genome RL with 16 Thermus genomes to assess their phylogenetic relationships based on 16S rRNA gene sequences, average nucleotide identity (ANI, conserved marker genes (31 and 400, pan genome and tetranucleotide frequency. The core genome of the analyzed genomes contained 1,177 core genes and many singleton genes were detected in individual genomes, reflecting a conserved core but adaptive pan repertoire. We demonstrated the presence of metagenomic islands (chromosome:5, plasmid:5 by recruiting raw metagenomic data (from the same niche against the genomic replicons of T. parvatiensis. We also dissected the CRISPR loci wide all genomes and found widespread presence of this system across Thermus genomes. Additionally, we performed a comparative analysis of competence loci wide Thermus genomes and found evidence for recent horizontal acquisition of the locus and continued dispersal among members reflecting that natural competence is a beneficial survival trait among Thermus members and its acquisition depicts unending evolution in order to accomplish optimal fitness.

  9. Genetic conservation and paddlefish propagation

    Science.gov (United States)

    Sloss, Brian L.; Klumb, Robert A.; Heist, Edward J.

    2009-01-01

    The conservation of genetic diversity of our natural resources is overwhelmingly one of the central foci of 21st century management practices. Three recommendations related to the conservation of paddlefish Polyodon spathula genetic diversity are to (1) identify genetic diversity at both nuclear and mitochondrial DNA loci using a suggested list of 20 sampling locations, (2) use genetic diversity estimates to develop genetic management units, and (3) identify broodstock sources to minimize effects of supplemental stocking on the genetic integrity of native paddlefish populations. We review previous genetic work on paddlefish and described key principles and concepts associated with maintaining genetic diversity within and among paddlefish populations and also present a genetic case study of current paddlefish propagation at the U.S. Fish and Wildlife Service Gavins Point National Fish Hatchery. This study confirmed that three potential sources of broodfish were genetically indistinguishable at the loci examined, allowing the management agencies cooperating on this program flexibility in sampling gametes. This study also showed significant bias in the hatchery occurred in terms of male reproductive contribution, which resulted in a shift in the genetic diversity of progeny compared to the broodfish. This shift was shown to result from differential male contributions, partially attributed to the mode of egg fertilization. Genetic insights enable implementation of a paddlefish propagation program within an adaptive management strategy that conserves inherent genetic diversity while achieving demographic goals.

  10. Introducing small modular reactors into Canada

    International Nuclear Information System (INIS)

    Humphries, J.R.

    2012-01-01

    In recent years there has been a growing interest in smaller, simpler reactors for generating electricity and process heat. This is evidenced in the growing body of literature and the increasingly frequent meetings and conferences on the subject. The interest in Small Modular Reactors (SMRs) is driven to a large extent by the desire to reduce capital costs, to reduce greenhouse gas emissions, to replace retiring fossil plants that do not meet today's environmental standards, and to provide power in locations away from large electrical grids. These drivers are as important in Canada as they are in the U.S., where the design and licensing of SMRs is being most vigorously pursued. They have led to a growing interest in Canada as a potentially significant market for SMRs, particularly in the Western Provinces of Alberta and Saskatchewan and in the remote First Nations communities of Northern Canada. There is a growing body of literature addressing the regulation and licensing of Small Modular Reactors in the U.S. Issues being identified in there can generally be categorized as licensing framework issues, licensing application issues, and design and manufacturing issues. Many of these issues are embedded in the US regulatory framework and can only be resolved through changes in the regulations. For the most part these issues are equally applicable in Canada and will need to be addressed in introducing SMRs here. A significant difference, however, is that these issues can be addressed within the Canadian regulatory framework without requiring changes in the regulations. The CNSC has taken a very proactive stance regarding the licensing of small reactors in Canada. They have published two new Regulatory Documents stipulating the requirements for licensing small reactors. A key feature is that they allow the application of a 'graded approach' in which the stringency of the design measures and analyses applied are commensurate with the level of risk posed by

  11. A PLEA FOR INTRODUCING CONSPIRATORIAL REASONING IN ECONOMICS

    Directory of Open Access Journals (Sweden)

    Mădălina CALANCE

    2014-04-01

    Full Text Available Along with the economic globalization, economics must decode a more complex reality, to which classical answers are no longer helpful. Due to excessive abstraction and mathematical representation, the economic and social phenomena are partially analyzed and understood - after the delimitation from the political context that has driven and maintained them. We notice that, throughout history, global economic relations have always been altered by the achievement instinct or by the desire for power; that markets and natural order had been violated due to the interventionist factor which takes various forms: the state, the elites or groups animated by particular interests. That is why conspiracy theories can be starting points in analyzing our world, by underlying specific political and economic interests that govern the public decision system. This paper aims to plead for introducing conspiratorial reasoning in economics; a reasoning that rejects total hazard and the limits imposed by the study of unintended consequences of economic phenomena.

  12. Genetic modification and genetic determinism

    Science.gov (United States)

    Resnik, David B; Vorhaus, Daniel B

    2006-01-01

    In this article we examine four objections to the genetic modification of human beings: the freedom argument, the giftedness argument, the authenticity argument, and the uniqueness argument. We then demonstrate that each of these arguments against genetic modification assumes a strong version of genetic determinism. Since these strong deterministic assumptions are false, the arguments against genetic modification, which assume and depend upon these assumptions, are therefore unsound. Serious discussion of the morality of genetic modification, and the development of sound science policy, should be driven by arguments that address the actual consequences of genetic modification for individuals and society, not by ones propped up by false or misleading biological assumptions. PMID:16800884

  13. Introducing Biological Microdosimetry for Ionising Radiation

    International Nuclear Information System (INIS)

    Scott, B.R.; Schoellnberger, H.

    2000-01-01

    Microdosimetry is important for radiation protection, for understanding mechanisms of radiation action, and for radiation risk assessment. This article introduces a generic, Monte Carlo based approach to biological microdosimetry for ionising radiation. Our Monte Carlo analyses are carried out with a widely used Crystal Ball software. The approach to biological microdosimetry presented relates to quantal biological effects data (e.g. cell survival, mutagenesis, neoplastic transformation) for which there is an initial linear segment to the dose-response curve. The macroscopic dose data considered were selected such that is could be presumed that the vast majority of cells at risk have radiation dose delivered to their critical target. For cell killing, neoplastic transformation, and mutagenesis, the critical biological target for radiation is presumed to be DNA. Our approach to biological microdosimetry does not require detailed information about the mass, volume, and shape of the critical biological target. Further, one does not have to know what formal distribution function applies to the microdose distribution. However, formal distributions are required for the biological data used to derive the non-parametric microdose distributions. Here, we use the binomial distribution to characterise the variability in the number of cells affected by a fixed macroscopic dose. Assuming this variability to arise from variability in the microscopic dose to the critical biological target, a non-parametric microdose distribution is generated by the standard Monte Carlo method. The non-parametric distribution is then fitted using a set of formal distributions (beta, exponential, extreme value, gamma, logistic, log-normal, normal, Pareto, triangular, uniform, and Weibull). The best fit is then evaluated based on statistical criteria (chi-square test). To demonstrate the application of biological microdosimetry, the standard Monte Carlo method is used with radiobiological data for

  14. Introducing Biological Microdosimetry for Ionising Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Scott, B.R.; Schoellnberger, H

    2000-07-01

    Microdosimetry is important for radiation protection, for understanding mechanisms of radiation action, and for radiation risk assessment. This article introduces a generic, Monte Carlo based approach to biological microdosimetry for ionising radiation. Our Monte Carlo analyses are carried out with a widely used Crystal Ball software. The approach to biological microdosimetry presented relates to quantal biological effects data (e.g. cell survival, mutagenesis, neoplastic transformation) for which there is an initial linear segment to the dose-response curve. The macroscopic dose data considered were selected such that is could be presumed that the vast majority of cells at risk have radiation dose delivered to their critical target. For cell killing, neoplastic transformation, and mutagenesis, the critical biological target for radiation is presumed to be DNA. Our approach to biological microdosimetry does not require detailed information about the mass, volume, and shape of the critical biological target. Further, one does not have to know what formal distribution function applies to the microdose distribution. However, formal distributions are required for the biological data used to derive the non-parametric microdose distributions. Here, we use the binomial distribution to characterise the variability in the number of cells affected by a fixed macroscopic dose. Assuming this variability to arise from variability in the microscopic dose to the critical biological target, a non-parametric microdose distribution is generated by the standard Monte Carlo method. The non-parametric distribution is then fitted using a set of formal distributions (beta, exponential, extreme value, gamma, logistic, log-normal, normal, Pareto, triangular, uniform, and Weibull). The best fit is then evaluated based on statistical criteria (chi-square test). To demonstrate the application of biological microdosimetry, the standard Monte Carlo method is used with radiobiological data for

  15. Chemical implications for the presence of introduced materials in the post-emplacement environment

    International Nuclear Information System (INIS)

    Meike, A.

    1993-11-01

    This paper addresses our ability to predict the chemical consequences of the presence of introduced materials, many of them man-made, in a radioactive waste repository. The chemical modeling ability required to describe this environment over a 10,000 year period is unique and unprecedented. It requires knowledge of parameters that have never been measured, many of them with respect to introduced materials. This paper discusses considerations that are required to establish the potential significance of introduced materials, especially those that could compromise the lifetime of the waste packages or affect the transport of radionuclides from breached containers. The paper presents issues related to the stability of individual compounds, the potential alteration of predicted natural chemical reactions, the potential moderation of those effects by natural zeolites, and the potential for interactions at elevated temperatures between rock, water, water vapor, radiation, waste package, and introduced materials

  16. Safe genetically engineered plants

    Energy Technology Data Exchange (ETDEWEB)

    Rosellini, D; Veronesi, F [Dipartimento di Biologia Vegetale e Biotecnologie Agroambientali e Zootecniche, Universita degli Studi di Perugia, Borgo XX giugno 74, 06121 Perugia (Italy)

    2007-10-03

    The application of genetic engineering to plants has provided genetically modified plants (GMPs, or transgenic plants) that are cultivated worldwide on increasing areas. The most widespread GMPs are herbicide-resistant soybean and canola and insect-resistant corn and cotton. New GMPs that produce vaccines, pharmaceutical or industrial proteins, and fortified food are approaching the market. The techniques employed to introduce foreign genes into plants allow a quite good degree of predictability of the results, and their genome is minimally modified. However, some aspects of GMPs have raised concern: (a) control of the insertion site of the introduced DNA sequences into the plant genome and of its mutagenic effect; (b) presence of selectable marker genes conferring resistance to an antibiotic or an herbicide, linked to the useful gene; (c) insertion of undesired bacterial plasmid sequences; and (d) gene flow from transgenic plants to non-transgenic crops or wild plants. In response to public concerns, genetic engineering techniques are continuously being improved. Techniques to direct foreign gene integration into chosen genomic sites, to avoid the use of selectable genes or to remove them from the cultivated plants, to reduce the transfer of undesired bacterial sequences, and make use of alternative, safer selectable genes, are all fields of active research. In our laboratory, some of these new techniques are applied to alfalfa, an important forage plant. These emerging methods for plant genetic engineering are briefly reviewed in this work.

  17. Safe genetically engineered plants

    International Nuclear Information System (INIS)

    Rosellini, D; Veronesi, F

    2007-01-01

    The application of genetic engineering to plants has provided genetically modified plants (GMPs, or transgenic plants) that are cultivated worldwide on increasing areas. The most widespread GMPs are herbicide-resistant soybean and canola and insect-resistant corn and cotton. New GMPs that produce vaccines, pharmaceutical or industrial proteins, and fortified food are approaching the market. The techniques employed to introduce foreign genes into plants allow a quite good degree of predictability of the results, and their genome is minimally modified. However, some aspects of GMPs have raised concern: (a) control of the insertion site of the introduced DNA sequences into the plant genome and of its mutagenic effect; (b) presence of selectable marker genes conferring resistance to an antibiotic or an herbicide, linked to the useful gene; (c) insertion of undesired bacterial plasmid sequences; and (d) gene flow from transgenic plants to non-transgenic crops or wild plants. In response to public concerns, genetic engineering techniques are continuously being improved. Techniques to direct foreign gene integration into chosen genomic sites, to avoid the use of selectable genes or to remove them from the cultivated plants, to reduce the transfer of undesired bacterial sequences, and make use of alternative, safer selectable genes, are all fields of active research. In our laboratory, some of these new techniques are applied to alfalfa, an important forage plant. These emerging methods for plant genetic engineering are briefly reviewed in this work

  18. From Genetics to Genetic Algorithms

    Indian Academy of Sciences (India)

    Genetic algorithms (GAs) are computational optimisation schemes with an ... The algorithms solve optimisation problems ..... Genetic Algorithms in Search, Optimisation and Machine. Learning, Addison-Wesley Publishing Company, Inc. 1989.

  19. From Genetics to Genetic Algorithms

    Indian Academy of Sciences (India)

    artificial genetic system) string feature or ... called the genotype whereas it is called a structure in artificial genetic ... assigned a fitness value based on the cost function. Better ..... way it has produced complex, intelligent living organisms capable of ...

  20. Genetics Home Reference: Danon disease

    Science.gov (United States)

    ... are compartments in the cell that digest and recycle materials. The role the LAMP-2 protein plays ... Page Boucek D, Jirikowic J, Taylor M. Natural history of Danon disease. Genet Med. 2011 Jun;13( ...