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Sample records for abcc8 dna variations

  1. Complex ABCC8 DNA variations in congenital hyperinsulinism: lessons from functional studies

    Muzyamba, Morris; Farzaneh, Tabasum; Behe, Phillip;

    2007-01-01

    singly or in combination led to intracellular retention of the channel complex and loss of function. By contrast, V1572I is trafficked appropriately and is functional, consistent with a mechanism of reduction to hemizygosity of paternal ABCC8 in focal disease. V1572I is likely to be a benign DNA variant...

  2. Hyperinsulinaemic hypoglycaemia and diabetes mellitus due to dominant ABCC8/KCNJ11 mutations.

    Kapoor, R R

    2011-10-01

    Dominantly acting loss-of-function mutations in the ABCC8\\/KCNJ11 genes can cause mild medically responsive hyperinsulinaemic hypoglycaemia (HH). As controversy exists over whether these mutations predispose to diabetes in adulthood we investigated the prevalence of diabetes in families with dominantly inherited ATP-sensitive potassium (K(ATP)) channel mutations causing HH in the proband.

  3. Familial mild hyperglycemia associated with a novel ABCC8-V84I mutation within three generations

    Gonsorcikova, Lucie; Vaxillaire, Martine; Pruhova, Stepanka;

    2011-01-01

    of the young genes (MODY1-4 and 6), we identified a novel ABCC8 V84I mutation, which segregated with autosomal dominant transmission of mild hyperglycemia within three generations. This mutation that is located in a conserved area of transmembrane domain TMD0 seems to be a rare cause of clinical phenotype...

  4. Permanent Neonatal Diabetes Mellitus Due to an ABCC8 Mutation: A Case Report

    Nithya Abraham

    2014-03-01

    Full Text Available Context Neonatal diabetes is a rare disorder with an incidence of about 1 in 100,000 live births. It is defined as diabetesdiagnosed in the first 6 months of life and it is vital to differentiate this entity from type 1 diabetes to enable accuratediagnosis, prognosis, genetic counseling and treatment. Case report We describe a case of permanent neonatal diabetesmellitus due to a novel mutation affecting the ABCC8 gene that encodes the SUR1 subunit of potassium ATP channel (KATP.Conclusion This genetic diagnosis has therapeutic implications as patients can switch from insulin therapy to sulphonylurea,as described in this case report.

  5. ABCC8-Related Maturity-Onset Diabetes of the Young (MODY12): Clinical Features and Treatment Perspective.

    Ovsyannikova, Alla K; Rymar, Oksana D; Shakhtshneider, Elena V; Klimontov, Vadim V; Koroleva, Elena A; Myakina, Natalya E; Voevoda, Mikhail I

    2016-09-01

    Maturity-onset diabetes of the young (MODY) is a heterogeneous group of diseases associated with gene mutations leading to dysfunction of pancreatic β-cells. Thirteen identified MODY variants differ from each other by the clinical course and treatment requirement. Currently, MODY subtypes 1-5 are best-studied, descriptions of the other forms are sporadic. This article reports a MODY12 clinical case, caused by a mutation in the gene of the ATP-binding cassette transporter sub-family C member 8 (ABCC8), encoding sulfonylurea receptor 1. Diabetes manifested in a 27-year-old non-obese man with epilepsy in anamnesis. No evidence of ketosis was present, pancreatic antibodies were undetectable, and C-peptide remained within the reference range. During the initial investigation, non-proliferative diabetic retinopathy and elevated albumin excretion rate was revealed. After 4 months, diabetes was complicated by pre-proliferative retinopathy and diabetic macular edema. Recurrent hypoglycemia and an increase in body weight was observed on moderate and even small insulin doses. Taking into account the clinical features and the presence of diabetes in four generations on the maternal side, screening for all MODY subtypes was performed. A mutation in the ABCC8 gene was found in proband and in his mother. After the insulin discontinuation, gliclazide modified release combined with sodium/glucose cotransporter 2 (SGLT2) inhibitors was started. This treatment eliminated hypoglycemia and improved glycemic variability parameters. A decrease in the amplitude of glucose excursions was documented by continuous glucose monitoring. After 3 months of treatment, glycemic control was still optimal, and no hypoglycemic episodes were observed. The case report demonstrates the clinical features of ABCC8-associated MODY and the therapeutic potential of a combination of sulfonylurea with SGLT2 inhibitor in this disease. PMID:27538677

  6. Effect of genetic variants in KCNJ11, ABCC8, PPARG and HNF4A loci on the susceptibility of type 2 diabetes in Chinese Han population

    WANG Fang; HAN Xue-yao; REN Qian; ZHANG Xiu-ying; HAN Ling-chuan; LUO Ying-ying; ZHOU Xiang-hai; JI Li-nong

    2009-01-01

    Background KCNJ11, ABCC8, PPARG, and HNF4A have been found to be associated with type 2 diabetes in populations with different genetic backgrounds. The aim of this study was to test, in a Chinese Han population from Beijing, whether the genetic variants in these four genes were associated with genetic predisposition to type 2 diabetes.Methods We studied the association of four representative SNPs in KCNJ11, ABCC8, PPARG and HNF4A by genotyping them using ABI SnaPshot(R) Multiplex System in 400 unrelated type 2 diabetic patients and 400 unrelated normoglycaemic subjects. Results rs5219(E23K) in KCNJ11 was associated with genetic susceptibility to type 2 diabetes (OR=1.400 with 95% Cl 1.117 1.755, P=0.004 under an additive model, OR=-1.652 with 95% Cl 1.086 2.513, P=0.019 under a recessive model,and OR=1.521 with 95% Cl 1.089 2.123, P=0.014 under a dominant model) after adjusting for sex and body mass index (BMI). We did not find evidence of association for ABCC8 rs1799854, PPARG rs1801282 (Pro12Ala) and HNF4A rs2144908. Genotype-phenotype correlation analysis revealed that rs1799854 in ABCC8 was associated with 2-hour postprandial insulin secretion (P=0.005) after adjusting for sex, age and BMI. Although no interactions between the four variants on the risk of type 2 diabetes were detected, the multiplicative interaction between PPARG Pro12Ala and HNF4A rs2144908 was found to be associated with 2-hour postprandial insulin (P=-0.004 under an additive model for rs2144908;and P=0.001 under a dominant model for rs2144908) after adjusting for age, sex and BMI, assuming a dominant model for PPARG Pro12Ala.Conclusions Our study replicated the association of rs5219 in KCNJ11 with type 2 diabetes in Chinese Han population in Beijing. And we also observed that ABCC8 as well as the interaction between PPARG and HNF4A may contribute to post-challenge insulin secretion.

  7. Lack of association between KCNJ11 (rs5219 and ABCC8 (rs757110 polymorphisms and sulphonylurea treatment response in type 2 diabetes patients in Novosibirsk region

    Irina Arkadyevna Bondar

    2015-03-01

    Full Text Available AimSulfonylureas (SU are widely used in everyday clinical practice in treatment of patients with type 2 diabetes mellitus (T2DM. There is a considerable variability in SU effects, which may be caused by psychological, social, biological and genetic factors. The aim of the study was to investigate the association between rs5219 KCNJ11 gene and rs757110 ABCC8 gene polymorphism and long-term response to SU-drugs of second and third generation in the Novosibirsk region.Materials and Methods326 patients with type 2 diabetes in the Novosibirsk region were examined. Patients were divided into 2 groups, depending on HbA1c level. The first group included patients with target HbA1c levels on SU monotherapy. The second group included patients who did not reach target HbA1c levels on the highest dose of SU. Genotyping of KCNJ11 (rs5219 and ABCC8 (rs757110 was performed by TaqMan real-time PCR (ICBFM SB RAS, Novosibirsk, Russia.ResultsPatients with type 2 diabetes with a good response to SU-therapy compared to the group of patients with a poor response to SU-therapy were older (65.8±9.1 years vs. 61.6±7.9 years, p<0.01, had later onset of type 2 diabetes (59.7±9.2 years vs. 48.3±9.3 years, p <0.01, shorter duration of type 2 diabetes (6.1±4.8 years vs. 13.2±7.3 years, p<0.01 and weak insulin resistance: fasting insulin 9.7±6.9 mU/ml vs. 13.6±12.7 mU/ml (p<0.05, HOMA-IR 3.1±2.2 vs. 6.2±6.0 (p<0.01, triglycerides 1.76±0.83 mmol/l vs. 2.42±1.97 mmol/l (p <0.01. Statistically significant differences between KCNJ11 (rs5219 and ABCC8 (rs757110 genotypes and response to SU-therapy was not found. The frequency of risk allele T polymorphism rs5219 KCNG11 gene in patients with a good response to SU was 0.38 and in the patients with a poor response to SU -0.38 (χ2=0.02, р=0.89. The frequency of the risk allele G polymorphism rs757110 ABCC8 gene in patients with a good response to SU was 0.40 and in the patients with poor response to SU -0.37 (χ2

  8. Mitochondrial DNA variation analysis in cervical cancer.

    Kabekkodu, Shama Prasada; Bhat, Samatha; Mascarenhas, Roshan; Mallya, Sandeep; Bhat, Manoj; Pandey, Deeksha; Kushtagi, Pralhad; Thangaraj, Kumarasamy; Gopinath, P M; Satyamoorthy, Kapaettu

    2014-05-01

    This study was undertaken to investigate the mitochondrial DNA (mtDNA) variation in non-malignant and malignant cervical tissue samples. We have identified 229 and 739 variations non-malignant and malignant tissues respectively distributed over 321 locations in the D-loop (50 in non-malignant and 166 in malignant; 216 variations), coding region (139 in non-malignant and 455 in malignant; 594 variations) tRNA and rRNA genes (39 in non-malignant and 119 in malignant; 158 variations). Besides, 77 novel and 34 various other disease associated variations were identified in non-malignant and malignant samples. A total of 236 tumor specific variations in 201 locations representing 30.1% in D-loop, 59.3% in coding regions and 10.6% in RNA genes were also identified. Our study shows that D loop (in 67 locations) is highly altered followed by ND5 (35 locations) region. Moreover, mtDNA alterations were significantly higher in malignant samples by two tailed Fisher's exact test (P≤0.05) with decreased mtDNA copy numbers. Bioinformatic analysis of 59 non-synonymous changes predicted several variations as damaging leading to decreased stability of the proteins. Taken together, mtDNA is highly altered in cervical cancer and functional studies are needed to be investigated to understand the consequence of these variations in cervical carcinogenesis and their potential application as biomarkers. PMID:23851045

  9. DNA fingerprinting and minisatellite variation of swans

    Meng, Anming

    1990-01-01

    Genetic variation in natural populations of four species of swans (Cygnus bewickii, Cygnus olor, Cygnus buccinator and Cygnus cygnus) has been investigated by examining minisatellite loci using human DNA fingerprinting probes pSPT19.6 and pSPT18.15. It has been found that swan minisatellites are highly variable. However, the degree of variation depends on the population structure and species. Bewick's Swans at Slimbridge have the highest degree of minisatellite variation, Whooper Swans at Cae...

  10. Physical activity modifies the effect of SNPs in the SLC2A2 (GLUT2) and ABCC8 (SUR1) genes on the risk of developing type 2 diabetes

    Oskari Kilpeläinen, Tuomas; Lakka, T A; Laaksonen, D E;

    2007-01-01

    Single nucleotide polymorphisms (SNPs) in two genes regulating insulin secretion, SLC2A2 (encoding GLUT2) and ABCC8 (encoding SUR1), were associated with the conversion from impaired glucose tolerance (IGT) to type 2 diabetes (T2D) in the Finnish Diabetes Prevention Study (DPS). We determined...... interaction of the SNPs with the change in PA on the conversion to T2D was assessed using Cox regression with adjustments for the other components of the intervention (dietary changes, weight reduction). The carriers of the common homozygous genotype of rs5393, rs5394, or rs5404 of SLC2A2 and rs3758947 of...

  11. Mitochondrial DNA sequence variation and risk of pancreatic cancer

    Lam, Ernest T.; Bracci, Paige M.; Holly, Elizabeth A; Chu, Catherine; Poon, Annie; Wan, Eunice; White, Krystal; Kwok, Pui-Yan; Pawlikowska, Ludmila; Tranah, Gregory J

    2011-01-01

    Although the mitochondrial genome exhibits high mutation rates, common mitochondrial DNA (mtDNA) variation has not been consistently associated with pancreatic cancer. Here, we comprehensively examined mitochondrial genomic variation by sequencing the mtDNA of participants (cases=286, controls=283) in a San Francisco Bay Area pancreatic cancer case-control study. Five common variants were associated with pancreatic cancer at nominal statistical significance (p

  12. mtDNA Variation and Analysis Using MITOMAP and MITOMASTER

    Lott, Marie T.; Leipzig, Jeremy N.; Derbeneva, Olga; Xie, H. Michael; Chalkia, Dimitra; Sarmady, Mahdi; Procaccio, Vincent; Wallace, Douglas C.

    2013-01-01

    The MITOMAP database of human mitochondrial DNA (mtDNA) information has been an important compilation of mtDNA variation for researchers, clinicians and genetic counselors for the past twenty-five years. The MITOMAP protocol shows how users may look up human mitochondrial gene loci, search for public mitochondrial sequences, and browse or search for reported general population nucleotide variants as well as those reported in clinical disease. Within MITOMAP is the powerful s...

  13. Reduced Variation in Drosophila Simulans Mitochondrial DNA

    Ballard, JWO.; Hatzidakis, J.; Karr, T L; Kreitman, M

    1996-01-01

    We investigated the evolutionary dynamics of infection of a Drosophila simulans population by a maternally inherited insect bacterial parasite, Wolbachia, by analyzing nucleotide variability in three regions of the mitochondrial genome in four infected and 35 uninfected lines. Mitochondrial variability is significantly reduced compared to a noncoding region of a nuclear-encoded gene in both uninfected and pooled samples of flies, indicating a sweep of genetic variation. The selective sweep of...

  14. Mitochondrial DNA copy number variation across human cancers.

    Reznik, Ed; Miller, Martin L; Şenbabaoğlu, Yasin; Riaz, Nadeem; Sarungbam, Judy; Tickoo, Satish K; Al-Ahmadie, Hikmat A; Lee, William; Seshan, Venkatraman E; Hakimi, A Ari; Sander, Chris

    2016-01-01

    Mutations, deletions, and changes in copy number of mitochondrial DNA (mtDNA), are observed throughout cancers. Here, we survey mtDNA copy number variation across 22 tumor types profiled by The Cancer Genome Atlas project. We observe a tendency for some cancers, especially of the bladder, breast, and kidney, to be depleted of mtDNA, relative to matched normal tissue. Analysis of genetic context reveals an association between incidence of several somatic alterations, including IDH1 mutations in gliomas, and mtDNA content. In some but not all cancer types, mtDNA content is correlated with the expression of respiratory genes, and anti-correlated to the expression of immune response and cell-cycle genes. In tandem with immunohistochemical evidence, we find that some tumors may compensate for mtDNA depletion to sustain levels of respiratory proteins. Our results highlight the extent of mtDNA copy number variation in tumors and point to related therapeutic opportunities. PMID:26901439

  15. Mitochondrial DNA sequence variation in single cells from leukemia patients

    Yao, Yong-Gang; Ogasawara, Yoji; Kajigaya, Sachiko; Molldrem, Jeffrey J.; Falcão, Roberto P; Pintão, Maria-Carolina; McCoy, J. Philip; Rizzatti, Edgar Gil; Young, Neal S

    2007-01-01

    A high frequency of mtDNA somatic mutation has been observed in many tumors as well as in aging tissues. In this study, we analyzed the mtDNA control region sequence variation in 3534 single normal cells and individual blasts from 18 patients with leukemia and 10 healthy donors, to address the mutation process in leukemic cells. We found significant differences in mtDNA sequence, as represented by the number of haplotypes and the mean number of cells with each nonaggregate haplotype in a popu...

  16. Microbial antigenic variation mediated by homologous DNA recombination.

    Vink, Cornelis; Rudenko, Gloria; Seifert, H Steven

    2012-09-01

    Pathogenic microorganisms employ numerous molecular strategies in order to delay or circumvent recognition by the immune system of their host. One of the most widely used strategies of immune evasion is antigenic variation, in which immunogenic molecules expressed on the surface of a microorganism are continuously modified. As a consequence, the host is forced to constantly adapt its humoral immune response against this pathogen. An antigenic change thus provides the microorganism with an opportunity to persist and/or replicate within the host (population) for an extended period of time or to effectively infect a previously infected host. In most cases, antigenic variation is caused by genetic processes that lead to the modification of the amino acid sequence of a particular antigen or to alterations in the expression of biosynthesis genes that induce changes in the expression of a variant antigen. Here, we will review antigenic variation systems that rely on homologous DNA recombination and that are found in a wide range of cellular, human pathogens, including bacteria (such as Neisseria spp., Borrelia spp., Treponema pallidum, and Mycoplasma spp.), fungi (such as Pneumocystis carinii) and parasites (such as the African trypanosome Trypanosoma brucei). Specifically, the various DNA recombination-based antigenic variation systems will be discussed with a focus on the employed mechanisms of recombination, the DNA substrates, and the enzymatic machinery involved. PMID:22212019

  17. Plant genome size variation: bloating and purging DNA.

    Michael, Todd P

    2014-07-01

    Plant genome size variation is a dynamic process of bloating and purging DNA. While it was thought plants were on a path to obesity through continual DNA bloating, recent research supports that most plants activity purge DNA. Plant genome size research has greatly benefited from the cataloguing of genome size estimates at the Kew Plant DNA C-values Database, and the recent availability of over 50 fully sequenced and published plant genomes. The emerging trend is that plant genomes bloat due to the copy-and-paste proliferation of a few long terminal repeat retrotransposons (LTRs) and aggressively purge these proliferating LTRs through several mechanisms including illegitimate and incomplete recombination, and double-strand break repair through non-homologous end joining. However, ultra-small genomes such as Utricularia gibba (Bladderwort), which is 82 megabases (Mb), purge excess DNA through genome fractionation and neofunctionalization during multiple rounds of whole genome duplication (WGD). In contrast, the largest published genome, Picea abies (Norway Spruce) at 19 800 Mb, has no detectable WGD but has bloated with diverse and diverged LTRs that either have evaded purging mechanisms or these purging mechanism are absent in gymnosperms. Finally, advances in DNA methylation studies suggest that smaller genomes have a more aggressive epigenomic surveillance system to purge young LTR retrotransposons, which is less active or missing in larger genomes like the bloated gymnosperms. While genome size may not reflect genome complexity, evidence is mounting that genome size may reflect evolutionary status. PMID:24651721

  18. Patterns of DNA Barcode Variation in Canadian Marine Molluscs

    Layton, Kara K.S.; Martel, André L.; Hebert, Paul DN.

    2014-01-01

    Background Molluscs are the most diverse marine phylum and this high diversity has resulted in considerable taxonomic problems. Because the number of species in Canadian oceans remains uncertain, there is a need to incorporate molecular methods into species identifications. A 648 base pair segment of the cytochrome c oxidase subunit I gene has proven useful for the identification and discovery of species in many animal lineages. While the utility of DNA barcoding in molluscs has been demonstrated in other studies, this is the first effort to construct a DNA barcode registry for marine molluscs across such a large geographic area. Methodology/Principal Findings This study examines patterns of DNA barcode variation in 227 species of Canadian marine molluscs. Intraspecific sequence divergences ranged from 0–26.4% and a barcode gap existed for most taxa. Eleven cases of relatively deep (>2%) intraspecific divergence were detected, suggesting the possible presence of overlooked species. Structural variation was detected in COI with indels found in 37 species, mostly bivalves. Some indels were present in divergent lineages, primarily in the region of the first external loop, suggesting certain areas are hotspots for change. Lastly, mean GC content varied substantially among orders (24.5%–46.5%), and showed a significant positive correlation with nearest neighbour distances. Conclusions/Significance DNA barcoding is an effective tool for the identification of Canadian marine molluscs and for revealing possible cases of overlooked species. Some species with deep intraspecific divergence showed a biogeographic partition between lineages on the Atlantic, Arctic and Pacific coasts, suggesting the role of Pleistocene glaciations in the subdivision of their populations. Indels were prevalent in the barcode region of the COI gene in bivalves and gastropods. This study highlights the efficacy of DNA barcoding for providing insights into sequence variation across a broad

  19. Variation of DNA Methylome of Zebrafish Cells under Cold Pressure

    Xu, Qiongqiong; Luo, Juntao; Shi, Yingdi; Li, Xiaoxia; Yan, Xiaonan; Zhang, Junfang

    2016-01-01

    DNA methylation is an essential epigenetic mechanism involved in multiple biological processes. However, the relationship between DNA methylation and cold acclimation remains poorly understood. In this study, Methylated DNA Immunoprecipitation Sequencing (MeDIP-seq) was performed to reveal a genome-wide methylation profile of zebrafish (Danio rerio) embryonic fibroblast cells (ZF4) and its variation under cold pressure. MeDIP-seq assay was conducted with ZF4 cells cultured at appropriate temperature of 28°C and at low temperature of 18°C for 5 (short-term) and 30 (long-term) days, respectively. Our data showed that DNA methylation level of whole genome increased after a short-term cold exposure and decreased after a long-term cold exposure. It is interesting that metabolism of folate pathway is significantly hypomethylated after short-term cold exposure, which is consistent with the increased DNA methylation level. 21% of methylation peaks were significantly altered after cold treatment. About 8% of altered DNA methylation peaks are located in promoter regions, while the majority of them are located in non-coding regions. Methylation of genes involved in multiple cold responsive biological processes were significantly affected, such as anti-oxidant system, apoptosis, development, chromatin modifying and immune system suggesting that those processes are responsive to cold stress through regulation of DNA methylation. Our data indicate the involvement of DNA methylation in cellular response to cold pressure, and put a new insight into the genome-wide epigenetic regulation under cold pressure. PMID:27494266

  20. Nonneutral mitochondrial DNA variation in humans and chimpanzees

    Nachman, M.W.; Aquadro, C.F. [Cornell Univ., Ithaca, NY (United States); Brown, W.M. [Univ. of Michigan, Ann Arbor, MI (United States)] [and others

    1996-03-01

    We sequenced the NADH dehydrogenase subunit 3 (ND3) gene from a sample of 61 humans, five common chimpanzees, and one gorilla to test whether patterns of mitochondrial DNA (mtDNA) variation are consistent with a neutral model of molecular evolution. Within humans and within chimpanzees, the ratio of replacement to silent nucleotide substitutions was higher than observed in comparisons between species, contrary to neutral expectations. To test the generality of this result, we reanalyzed published human RFLP data from the entire mitochondrial genome. Gains of restriction sites relative to a known human mtDNA sequence were used to infer unambiguous nucleotide substitutions. We also compared the complete mtDNA sequences of three humans. Both the RFLP data and the sequence data reveal a higher ratio of replacement to silent nucleotide substitutions within humans than is seen between species. This pattern is observed at most or all human mitochondrial genes and is inconsistent with a strictly neutral model. These data suggest that many mitochondrial protein polymorphisms are slightly deleterious, consistent with studies of human mitochondrial diseases. 59 refs., 2 figs., 8 tabs.

  1. Minifish shows high genetic variation in mtDNA size.

    Chen, X-W; Li, Q-L; Hu, X-J; Yuan, Y-M; Wen, M; Peng, L-Y; Liu, S-J; Hong, Y-H

    2014-01-01

    The genus Paedocypris is a newly described taxon of minifish species that are characterized by extensive chromosome evolution and one of the smallest known vertebrate nuclear genomes. Paedocypris features a tiny adult size, a short generation time, low fecundity and fragmented tropical habitats, which are factors that favor rapid speciation. Most recently, we have revealed that P. progenetica (Pp), the type species of the genus Paedocypris, has an unusual mtDNA bearing - within its D-loop - a tandem array of a 34-bp repeat sequence called the minifish repeat, which shows compromised replication efficiency in vitro. Here we report that Pp exhibits high genetic variation in mtDNA size. The efficiency of D-loop amplification was found to depend upon primers. Interestingly, Pp individuals of one and the same population differed drastically in mtDNA size resulting from varying copy numbers of the minifish repeat. We conclude that minifish has a high mutation rate and perhaps represents a rapidly evolving taxon of vertebrates. PMID:25470287

  2. Mitochondrial DNA sequence variation in the Anatolian Peninsula (Turkey)

    Hatice Mergen; Reyhan Öner; Cihan Öner

    2004-04-01

    Throughout human history, the region known today as the Anatolian peninsula (Turkey) has served as a junction connecting the Middle East, Europe and Central Asia, and, thus, has been subject to major population movements. The present study is undertaken to obtain information about the distribution of the existing mitochondrial D-loop sequence variations in the Turkish population of Anatolia. A few studies have previously reported mtDNA sequences in Turks. We attempted to extend these results by analysing a cohort that is not only larger, but also more representative of the Turkish population living in Anatolia. In order to obtain a descriptive picture for the phylogenetic distribution of the mitochondrial genome within Turkey, we analysed mitochondrial D-loop region sequence variations in 75 individuals from different parts of Anatolia by direct sequencing. Analysis of the two hypervariable segments within the noncoding region of the mitochondrial genome revealed the existence of 81 nucleotide mutations at 79 sites. The neighbour-joining tree of Kimura’s distance matrix has revealed the presence of six main clusters, of which H and U are the most common. The data obtained are also compared with several European and Turkic Central Asian populations.

  3. Thermal adaptation and clinal mitochondrial DNA variation of European anchovy.

    Silva, Gonçalo; Lima, Fernando P; Martel, Paulo; Castilho, Rita

    2014-10-01

    Natural populations of widely distributed organisms often exhibit genetic clinal variation over their geographical ranges. The European anchovy, Engraulis encrasicolus, illustrates this by displaying a two-clade mitochondrial structure clinally arranged along the eastern Atlantic. One clade has low frequencies at higher latitudes, whereas the other has an anti-tropical distribution, with frequencies decreasing towards the tropics. The distribution pattern of these clades has been explained as a consequence of secondary contact after an ancient geographical isolation. However, it is not unlikely that selection acts on mitochondria whose genes are involved in relevant oxidative phosphorylation processes. In this study, we performed selection tests on a fragment of 1044 bp of the mitochondrial cytochrome b gene using 455 individuals from 18 locations. We also tested correlations of six environmental features: temperature, salinity, apparent oxygen utilization and nutrient concentrations of phosphate, nitrate and silicate, on a compilation of mitochondrial clade frequencies from 66 sampling sites comprising 2776 specimens from previously published studies. Positive selection in a single codon was detected predominantly (99%) in the anti-tropical clade and temperature was the most relevant environmental predictor, contributing with 59% of the variance in the geographical distribution of clade frequencies. These findings strongly suggest that temperature is shaping the contemporary distribution of mitochondrial DNA clade frequencies in the European anchovy. PMID:25143035

  4. Molecular detection of genomic dna variation induced by space environment in sweet pepper (Capsicum annuum L.)

    To study effects of space environment on genomic DNA variation in the offsprings of sweet pepper, the 4th offspring and its ground control were used as materials. The genomic DNA variation was detected by random amplified polymprphic DNA (RAPD), parts of the different fragments were sequenced. The results showed that the genomic DNA of SP4 after space mutation changed compared to the ground control. Eight polymorphic bands were detected. Four polymorphic bands were amplified in the ground control and variant separately. Two special fragments were sequenced and sequence homology was 97%. So space environment could induce the changes of the genomic DNA in the offsprings of sweet pepper. (authors)

  5. Analysis of mitochondrial DNA variations in Indian patients with congenital cataract

    Roshan, Mascarenhas; Kabekkodu, Shama Prasada; Vijaya, Pai H.; Manjunath, Kamath; Graw, Jochen; Gopinath, PM.; Satyamoorthy, Kapeattu

    2012-01-01

    Purpose Identification of mitochondrial DNA (mtDNA) variations in the inherited cataract patients from south India. Methods Three families with inherited cataract of maternal origin were evaluated. Clinical and ophthalmologic examinations were performed on available affected as well as unaffected family members. Samples of mtDNA were amplified using 24 pairs of overlapping primers to analyze the entire mitochondrial genome to screen for variations and analyzed for both coding and non-coding r...

  6. Association of DNA sequence variation in mitochondrial DNA polymerase with mitochondrial DNA synthesis and risk of oral cancer.

    Datta, Sayantan; Ray, Anindita; Roy, Roshni; Roy, Bidyut

    2016-01-10

    Enzymes responsible for mitochondrial (mt) DNA synthesis and transcription are encoded by nuclear genome and inherited mutations in these genes may play important roles in enhancing risk of precancer and cancer. Here, genetic variations in 23 functionally relevant tagSNPs in 6 genes responsible for mtDNA synthesis and transcription were studied in 522 cancer and 241 precancer (i.e. leukoplakia) patients and 525 healthy controls using Illumina Golden Gate assay to explore association with risk of oral precancer and cancer. Two SNPs, rs41553913 at POLRMT and rs9905016 at POLG2, significantly increased risk of oral leukoplakia and cancer, respectively, at both genotypic and allelic levels. Gene-environment interaction models also revealed that tobacco habits and SNPs at POLG2 and TFAM may modulate risk of both leukoplakia and cancer. In silico analysis of published data-set also revealed that variant heterozygote (TC) significantly increased transcription of POLG2 compared to wild genotype (p=0.03). Cancer tissues having variant allele genotypes (TC+CC) at POLG2 contained 1.6 times (pcancer tissues having wild genotype (TT). In conclusion, polymorphisms at POLG2 and POLRMT increased risk of oral cancer and leukoplakia, respectively, probably modulating synthesis and activity of the enzymes. Enhanced synthesis of mtDNA in cancer tissues may have implication in carcinogenesis, but the mechanism is yet to be explored. PMID:26403317

  7. Human Papillomavirus-16 and 18 in Penile Carcinomas: DNA Methylation, Chromosomal Recombination, and Genomic Variation

    Kalantari, Mina; Villa, Luisa L.; Calleja-Macias, Itzel E.; Bernard, Hans-Ulrich

    2008-01-01

    Penile carcinomas are frequently associated with high-risk human papillomavirus (HPV) types. Since little is known about the molecular biology of this association, we investigated three properties of HPV genomes in penile carcinomas from Brazilian patients: (i) HPV DNA methylation, (ii) junctions between HPV and cellular DNA, and (iii) genomic variation. In cervical carcinogenesis, recombination between HPV and chromosomal DNA is frequent and likely necessary for progression, and DNA hypermet...

  8. Genomic profiling of plastid DNA variation in the Mediterranean olive tree

    Dorado Gabriel; Khadari Bouchaib; Hernández Pilar; Besnard Guillaume; Savolainen Vincent

    2011-01-01

    Abstract Background Characterisation of plastid genome (or cpDNA) polymorphisms is commonly used for phylogeographic, population genetic and forensic analyses in plants, but detecting cpDNA variation is sometimes challenging, limiting the applications of such an approach. In the present study, we screened cpDNA polymorphism in the olive tree (Olea europaea L.) by sequencing the complete plastid genome of trees with a distinct cpDNA lineage. Our objective was to develop new markers for a rapid...

  9. Variation of DNA damage levels in peripheral blood mononuclear cells isolated in different laboratories

    Godschalk, Roger W L; Ersson, Clara; Stępnik, Maciej;

    2014-01-01

    This study investigated the levels of DNA strand breaks and formamidopyrimidine DNA glycosylase (FPG) sensitive sites, as assessed by the comet assay, in peripheral blood mononuclear cells (PBMC) from healthy women from five different countries in Europe. The laboratory in each country (referred to...... as 'centre') collected and cryopreserved PBMC samples from three donors, using a standardised cell isolation protocol. The samples were analysed in 13 different laboratories for DNA damage, which is measured by the comet assay. The study aim was to assess variation in DNA damage in PBMC samples that...... were collected in the same way and processed using the same blood isolation procedure. The inter-laboratory variation was the prominent contributor to the overall variation. The inter-laboratory coefficient of variation decreased for both DNA strand breaks (from 68 to 26%) and FPG sensitive sites (from...

  10. Genomic profiling of plastid DNA variation in the Mediterranean olive tree

    Dorado Gabriel

    2011-05-01

    Full Text Available Abstract Background Characterisation of plastid genome (or cpDNA polymorphisms is commonly used for phylogeographic, population genetic and forensic analyses in plants, but detecting cpDNA variation is sometimes challenging, limiting the applications of such an approach. In the present study, we screened cpDNA polymorphism in the olive tree (Olea europaea L. by sequencing the complete plastid genome of trees with a distinct cpDNA lineage. Our objective was to develop new markers for a rapid genomic profiling (by Multiplex PCRs of cpDNA haplotypes in the Mediterranean olive tree. Results Eight complete cpDNA genomes of Olea were sequenced de novo. The nucleotide divergence between olive cpDNA lineages was low and not exceeding 0.07%. Based on these sequences, markers were developed for studying two single nucleotide substitutions and length polymorphism of 62 regions (with variable microsatellite motifs or other indels. They were then used to genotype the cpDNA variation in cultivated and wild Mediterranean olive trees (315 individuals. Forty polymorphic loci were detected on this sample, allowing the distinction of 22 haplotypes belonging to the three Mediterranean cpDNA lineages known as E1, E2 and E3. The discriminating power of cpDNA variation was particularly low for the cultivated olive tree with one predominating haplotype, but more diversity was detected in wild populations. Conclusions We propose a method for a rapid characterisation of the Mediterranean olive germplasm. The low variation in the cultivated olive tree indicated that the utility of cpDNA variation for forensic analyses is limited to rare haplotypes. In contrast, the high cpDNA variation in wild populations demonstrated that our markers may be useful for phylogeographic and populations genetic studies in O. europaea.

  11. Mitochondrial DNA T4216C and A4917G variations in multiple sclerosis

    Andalib, Sasan; Talebi, Mahnaz; Sakhinia, Ebrahim;

    2015-01-01

    focuses on the neurogenetics of the complex pathogenesis of MS in relation to factors such as mitochondrial DNA (mtDNA) variations. T4216C and A4917G are common mitochondrial gene variations associated with MS. The present study tested whether mtDNA T4216C variation in the NADH Dehydrogenase 1 (ND1) mtDNA...... gene and A4917G variation in the mtDNA NADH Dehydrogenase 2 (ND2) gene are associated with MS in an Iranian population. MATERIAL AND METHODS: Blood samples were collected from 100 patients with MS and 100 unrelated healthy controls, and DNA extraction was performed by salting-out. By means of...... appropriate primers, polymerase chain reaction (PCR) amplification was carried out for the mtDNA fragment. Afterwards, the PCR products were digested using Nla III and Acc I restriction endonuclease enzymes for analysis of Restriction Fragment Length polymorphism (RFLP) in mtDNA T4216C and A4917G variations...

  12. Mitochondrial DNA Variation in Southeastern Pre-Columbian Canids.

    Brzeski, Kristin E; DeBiasse, Melissa B; Rabon, David R; Chamberlain, Michael J; Taylor, Sabrina S

    2016-05-01

    The taxonomic status of the red wolf (Canis rufus) is heavily debated, but could be clarified by examining historic specimens from the southeastern United States. We analyzed mitochondrial DNA (mtDNA) from 3 ancient (350-1900 year olds) putative wolf samples excavated from middens and sinkholes within the historic red wolf range. We detected 3 unique mtDNA haplotypes, which grouped with the coyote mtDNA clade, suggesting that the canids inhabiting southeastern North America prior to human colonization from Europe were either coyotes, which would vastly expand historic coyote distributions, an ancient coyote-wolf hybrid, or a North American evolved red wolf lineage related to coyotes. Should the red wolf prove to be a distinct species, our results support the idea of either an ancient hybrid origin for red wolves or a shared common ancestor between coyotes and red wolves. PMID:26774058

  13. DNA content variation and its significance in the evolution of the genus Micrasterias (Desmidiales, Streptophyta.

    Aloisie Poulíčková

    Full Text Available It is now clear that whole genome duplications have occurred in all eukaryotic evolutionary lineages, and that the vast majority of flowering plants have experienced polyploidisation in their evolutionary history. However, study of genome size variation in microalgae lags behind that of higher plants and seaweeds. In this study, we have addressed the question whether microalgal phylogeny is associated with DNA content variation in order to evaluate the evolutionary significance of polyploidy in the model genus Micrasterias. We applied flow-cytometric techniques of DNA quantification to microalgae and mapped the estimated DNA content along the phylogenetic tree. Correlations between DNA content and cell morphometric parameters were also tested using geometric morphometrics. In total, DNA content was successfully determined for 34 strains of the genus Micrasterias. The estimated absolute 2C nuclear DNA amount ranged from 2.1 to 64.7 pg; intraspecific variation being 17.4-30.7 pg in M. truncata and 32.0-64.7 pg in M. rotata. There were significant differences between DNA contents of related species. We found strong correlation between the absolute nuclear DNA content and chromosome numbers and significant positive correlation between the DNA content and both cell size and number of terminal lobes. Moreover, the results showed the importance of cell/life cycle studies for interpretation of DNA content measurements in microalgae.

  14. Fully Streched Single DNA Molecules in a Nanofluidic Chip Show Large-Scale Structural Variation

    Pedersen, Jonas Nyvold; Marie, Rodolphe; Bauer, D. L.;

    2013-01-01

    When stretching and imaging DNA molecules in nanofluidic devices, it is important to know the relation between the physical length as measured in the lab and the distance along the contour of the DNA. Here a single DNA molecule longer than 1 Mbp is loaded into a nanofluidic device consisting of two...... the contour length of the DNA, and (iii) without having the full DNA molecule inside the field-of-view. The analysis is based on the transverse motion of the DNA due its Brownian motion, i.e. the DNA's response to the thermal fluctuations of the liquid surrounding it. The parameter values obtained by fitting...... reflects the local AT/GC-content. Single molecules are loaded into the chip and imaged. Due to the almost complete stretching of the DNA, structural variations in the size range from kbp to Mbp can be detected and quantified from the melting pattern alone....

  15. Modeling kinetic rate variation in third generation DNA sequencing data to detect putative modifications to DNA bases.

    Schadt, Eric E; Banerjee, Onureena; Fang, Gang; Feng, Zhixing; Wong, Wing H; Zhang, Xuegong; Kislyuk, Andrey; Clark, Tyson A; Luong, Khai; Keren-Paz, Alona; Chess, Andrew; Kumar, Vipin; Chen-Plotkin, Alice; Sondheimer, Neal; Korlach, Jonas; Kasarskis, Andrew

    2013-01-01

    Current generation DNA sequencing instruments are moving closer to seamlessly sequencing genomes of entire populations as a routine part of scientific investigation. However, while significant inroads have been made identifying small nucleotide variation and structural variations in DNA that impact phenotypes of interest, progress has not been as dramatic regarding epigenetic changes and base-level damage to DNA, largely due to technological limitations in assaying all known and unknown types of modifications at genome scale. Recently, single-molecule real time (SMRT) sequencing has been reported to identify kinetic variation (KV) events that have been demonstrated to reflect epigenetic changes of every known type, providing a path forward for detecting base modifications as a routine part of sequencing. However, to date no statistical framework has been proposed to enhance the power to detect these events while also controlling for false-positive events. By modeling enzyme kinetics in the neighborhood of an arbitrary location in a genomic region of interest as a conditional random field, we provide a statistical framework for incorporating kinetic information at a test position of interest as well as at neighboring sites that help enhance the power to detect KV events. The performance of this and related models is explored, with the best-performing model applied to plasmid DNA isolated from Escherichia coli and mitochondrial DNA isolated from human brain tissue. We highlight widespread kinetic variation events, some of which strongly associate with known modification events, while others represent putative chemically modified sites of unknown types. PMID:23093720

  16. Length Variation, Heteroplasmy and Sequence Divergence in the Mitochondrial DNA of Four Species of Sturgeon (Acipenser)

    Brown, J R; Beckenbach, K.; Beckenbach, A. T.; Smith, M.J

    1996-01-01

    The extent of mtDNA length variation and heteroplasmy as well as DNA sequences of the control region and two tRNA genes were determined for four North American sturgeon species: Acipenser transmontanus, A. medirostris, A. fulvescens and A. oxyrhnychus. Across the Continental Divide, a division in the occurrence of length variation and heteroplasmy was observed that was concordant with species biogeography as well as with phylogenies inferred from restriction fragment length polymorphisms (RFL...

  17. Interindividual variation in binding of benzo[a]pyrene to DNA in cultured human Bronchi

    Harris, C.C.; Autrup, Herman; Connor, R.;

    1976-01-01

    The binding of benzo[a]pyrene to DNA in cultured human bronchus was measured in specimens from 37 patients. The binding values ranged from 2 to 151 picomoles of benzo[a]pyrene per milligram of DNA with an overall mean +/- standard error of 34.2 +/- 5.2. This 75-fold interindividual variation in t...

  18. Chloroplast DNA variation of oaks in western Central Europe and genetic consequences of human influences

    König, A.O.; Ziegenhagen, B.; Dam, van B.C.; Csaikl, U.M.; Coart, E.; Degen, B.; Burg, K.; Vries, de S.M.G.; Petit, R.J.

    2002-01-01

    Oak chloroplast DNA (cpDNA) variation was studied in a grid-based inventory in western Central Europe, including Belgium, The Netherlands, Luxembourg, Germany, the Czech Republic, and the northern parts of Upper and Lower Austria. A total of 2155 trees representing 426 populations of Quercus robur L

  19. Genetic variations of East Kalimantan Orangutan based on D-Loop mitochondria DNA

    DIDIK PRASETYO; JITO SUGARDJITO

    2007-01-01

    Analysis of the variation of D-Loop mtDNA of East Kalimantan orangutan was done to provided the genetic information data from endangerd species in order to support their population conservation efforts. The reason using mtDNA in this research is caused by higher level of mutation ( 5 – 10 trimes) when compared with nuclear DNA and it enable to transmited via maternal transmission without experience in recombination. From the analysis conducted on 38 samples resulting eight types of haplotype...

  20. Human longevity and variation in DNA damage response and repair

    Debrabant, Birgit; Soerensen, Mette; Flachsbart, Friederike;

    2014-01-01

    others. Data were applied on 592 SNPs from 77 genes involved in nine sub-processes: DNA-damage response, base excision repair (BER), nucleotide excision repair, mismatch repair, non-homologous end-joining, homologous recombinational repair (HRR), RecQ helicase activities (RECQ), telomere functioning...... and mitochondrial DNA processes. The study population was 1089 long-lived and 736 middle-aged Danes. A self-contained set-based test of all SNPs displayed association with longevity (P-value=9.9 × 10-5), supporting that the overall pathway could affect longevity. Investigation of the nine sub-processes using...

  1. Geographic variation of chloroplast DNA in Platycarya strobilacea (Juglandaceae)

    Shi-Chao CHEN; Li ZHANG; Jie ZENG; Fei SHI; Hong YANG; Yun-Rui MAO; Cheng-Xin FU

    2012-01-01

    The monotypic genus Platycarya (Juglandaceae) is one of the most widespread temperate tree species in East Asia.In this research,we implemented a phylogeographical study using chloroplast DNA (cpDNA) (psbA-trnH and atpB-rbcL intergenic spacer) sequences on Platycarya strobilacea,in order to identify the locations of the species' main refugia and migration routes.A total of 180 individuals of P.stobilacea from 27 populations from China and Jeju Island (Korea) were collected.The results revealed that P.strobilacea had 35 haplotypes for the two intergenic spacers and high genetic diversity (hT =0.926).This surprisingly high diversity ofhaplotypes indicates its long evolutionary history,which is in agreement with previous phylogenetic analyses and fossil records.Significant cpDNA population subdivision was detected (GST =0.720; NST =0.862),suggesting low levels of recurrent gene flow through seeds among populations and significant phylogeographical structure (NST > GST,P < 0.05).The construction of phylogenetic relationships of the 35 chlorotypes detected four major cpDNA clades.Divergence dating analyses using BEAST suggest that the divergence of the major cpDNA clades occurred before the Miocene.Demographic analysis indicated that the Eastern clade underwent localized demographic expansions.The molecular phylogenetic data,together with the geographic distribution of the haplotypes,suggest the existence of multiple glacial refugia in most of its current range in China through Quaternary climatic oscillations.

  2. Patterns of DNA Barcode Variation in Canadian Marine Molluscs

    Layton, Kara K. S.; Martel, André L.; Hebert, Paul D. N.

    2014-01-01

    BACKGROUND: Molluscs are the most diverse marine phylum and this high diversity has resulted in considerable taxonomic problems. Because the number of species in Canadian oceans remains uncertain, there is a need to incorporate molecular methods into species identifications. A 648 base pair segment of the cytochrome c oxidase subunit I gene has proven useful for the identification and discovery of species in many animal lineages. While the utility of DNA barcoding in molluscs has been demonst...

  3. Large scale variation in DNA copy number in chicken breeds

    Background Detecting genetic variation is a critical step in elucidating the molecular mechanisms underlying phenotypic diversity. Until recently, such detection has mostly focused on single nucleotide polymorphisms (SNPs) because of the ease in screening complete genomes. Another type of variant, c...

  4. Thermal adaptation and clinal mitochondrial DNA variation of European anchovy

    Silva, Gonçalo; Lima, Fernando P.; Martel, Paulo; Castilho, Rita

    2014-01-01

    Natural populations of widely distributed organisms often exhibit genetic clinal variation over their geographical ranges. The European anchovy, Engraulis encrasicolus, illustrates this by displaying a two-clade mitochondrial structure clinally arranged along the eastern Atlantic. One clade has low frequencies at higher latitudes, whereas the other has an anti-tropical distribution, with frequencies decreasing towards the tropics. The distribution pattern of these clades has been explained as...

  5. Mitochondrial DNA variation of domestic sheep (Ovis aries) in Kenya.

    Resende, Adriana; Gonçalves, Joana; Muigai, Anne W T; Pereira, Filipe

    2016-06-01

    The history of domestic sheep (Ovis aries) in Africa remains largely unknown. After being first introduced from the Near East, sheep gradually spread through the African continent with pastoral societies. The eastern part of Africa was important either for the first diffusion of sheep southward or for putative secondary introductions from the Arabian Peninsula or southern Asia. We analysed mitochondrial DNA control region sequences of 91 domestic sheep from Kenya and found a high diversity of matrilines from the widespread haplogroup B, whereas only a single individual from haplogroup A was detected. Our phylogeography analyses of more than 500 available mitochondrial DNA sequences also identified ancestral haplotypes that were probably first introduced in Africa and are now widely distributed. Moreover, we found no evidence of an admixture between East and West African sheep. The presence of shared haplotypes in eastern and ancient southern African sheep suggests the possible southward movement of sheep along the eastern part of Africa. Finally, we found no evidence of an extensive introduction of sheep from southern Asia into Africa via the Indian Ocean trade. The overall findings on the phylogeography of East African domestic sheep set the grounds for understanding the origin and subsequent movements of sheep in Africa. The richness of maternal lineages in Kenyan breeds is of prime importance for future conservation and breeding programmes. PMID:26765790

  6. Role of mitochondrial DNA variation in the pathogenesis of diabetes mellitus.

    Kwak, Soo Heon; Park, Kyong Soo

    2016-01-01

    Mitochondria are crucial intracellular organelles where ATP and reactive oxygen species are generated via the electron transport chain. They are also where cellular fate is determined. There is a growing body of evidence that mitochondrial dysfunction plays an important role in the pathogenesis of type 2 diabetes. Mitochondrial dysfunction in pancreatic beta-cells results in impaired glucose-stimulated insulin secretion. It is also associated with decreased oxidative phosphorylation and fatty acid oxidation in insulin sensitive tissues. Variation in mitochondrial DNA (mtDNA) quantity and quality are reported to be associated with the risk of developing diabetes. A rare variant, mtDNA 3243 A>G, is well known to cause maternally inherited diabetes. Common mtDNA variants, such as mtDNA 16189 T>C and several mtDNA haplogroups, are also associated with an increased risk of diabetes, especially in Asians. The variant load, known as heteroplasmy, in a specific tissue is thought to modulate the phenotypic expression of these mtDNA variants. In this article, we review the role of mitochondrial dysfunction in the pathogenesis of diabetes and the association between mtDNA variations and risk of diabetes. PMID:27100497

  7. Mitochondrial DNA sequence variation in Finnish patients with matrilineal diabetes mellitus

    Soini Heidi K

    2012-07-01

    Full Text Available Abstract Background The genetic background of type 2 diabetes is complex involving contribution by both nuclear and mitochondrial genes. There is an excess of maternal inheritance in patients with type 2 diabetes and, furthermore, diabetes is a common symptom in patients with mutations in mitochondrial DNA (mtDNA. Polymorphisms in mtDNA have been reported to act as risk factors in several complex diseases. Findings We examined the nucleotide variation in complete mtDNA sequences of 64 Finnish patients with matrilineal diabetes. We used conformation sensitive gel electrophoresis and sequencing to detect sequence variation. We analysed the pathogenic potential of nonsynonymous variants detected in the sequences and examined the role of the m.16189 T>C variant. Controls consisted of non-diabetic subjects ascertained in the same population. The frequency of mtDNA haplogroup V was 3-fold higher in patients with diabetes. Patients harboured many nonsynonymous mtDNA substitutions that were predicted to be possibly or probably damaging. Furthermore, a novel m.13762 T>G in MTND5 leading to p.Ser476Ala and several rare mtDNA variants were found. Haplogroup H1b harbouring m.16189 T > C and m.3010 G > A was found to be more frequent in patients with diabetes than in controls. Conclusions Mildly deleterious nonsynonymous mtDNA variants and rare population-specific haplotypes constitute genetic risk factors for maternally inherited diabetes.

  8. Terminal region sequence variations in variola virus DNA.

    Massung, R F; Loparev, V N; Knight, J C; Totmenin, A V; Chizhikov, V E; Parsons, J M; Safronov, P F; Gutorov, V V; Shchelkunov, S N; Esposito, J J

    1996-07-15

    Genome DNA terminal region sequences were determined for a Brazilian alastrim variola minor virus strain Garcia-1966 that was associated with an 0.8% case-fatality rate and African smallpox strains Congo-1970 and Somalia-1977 associated with variola major (9.6%) and minor (0.4%) mortality rates, respectively. A base sequence identity of > or = 98.8% was determined after aligning 30 kb of the left- or right-end region sequences with cognate sequences previously determined for Asian variola major strains India-1967 (31% death rate) and Bangladesh-1975 (18.5% death rate). The deduced amino acid sequences of putative proteins of > or = 65 amino acids also showed relatively high identity, although the Asian and African viruses were clearly more related to each other than to alastrim virus. Alastrim virus contained only 10 of 70 proteins that were 100% identical to homologs in Asian strains, and 7 alastrim-specific proteins were noted. PMID:8661439

  9. Inter-laboratory variation in DNA damage using a standard comet assay protocol

    Forchhammer, Lykke; Ersson, Clara; Loft, Steffen;

    2012-01-01

    There are substantial inter-laboratory variations in the levels of DNA damage measured by the comet assay. The aim of this study was to investigate whether adherence to a standard comet assay protocol would reduce inter-laboratory variation in reported values of DNA damage. Fourteen laboratories......, which were not related to the level of experience. Therefore, the inter-laboratory variation in DNA damage was only analysed using the results from laboratories that had obtained complete data with the standard comet assay protocol. This analysis showed that the differences between reported levels of...... poor results using the standard procedure. This study indicates that future comet assay validation trials should take steps to evaluate the implementation of standard procedures in participating laboratories....

  10. Mitochondrial DNA Length Variation and Heteroplasmy in Populations of White Sturgeon (Acipenser Transmontanus)

    Brown, J R; Beckenbach, A. T.; Smith, M.J.

    1992-01-01

    Southern blot analysis was used to quantify the extent of mtDNA D-loop length variation in two populations of white sturgeon, Acipenser transmontanus. Over 42% of individuals were heteroplasmic for up to six different mtDNA length variants attributable to varying copy numbers of an 82-bp repeat sequence. Chi-square analyses revealed that the frequencies of length genotypes and the incidence of heteroplasmy were significantly different between Fraser and Columbia River sturgeon populations but...

  11. An improved method for detecting genetic variation in DNA using denaturing gradient gel electrophoresis

    We have examined the feasibility of denaturing gradient gel electrophoresis (DGGE) of RNA:DNA duplexes to detect variations in genomic and cloned DNAs. The result has demonstrated that use of RNA:DNA duplexes makes DGGE much more practical for screening a large number of samples than use of DNA:DNA heteroduplexes, because preparation of RNA probes is easier than that of DNA probes. Three different 32P-labeled RNA probes were produced. Genomic or cloned DNAs were digested with restriction enzymes and hybridized to labeled RNA probes, and resulting RNA:DNA duplexes were examined by DGGE. The presence of a mismatch(es) was detected as a difference in the mobility of bands on the gel. The experimental conditions were determined using DNA segments from cloned normal and three thalassemic human β-globin genes. The results from experiments on the cloned DNAs suggest that DGGE of RNA:DNA duplexes will detect nucleotide substitutions and deletions in DNA. In the course of these studies, a polymorphism due to a single-base substitution at position 666 of IVS2 (IVS2-666) of the human β-globin gene was directly identified using genomic DNA samples. A study of 59 unrelated Japanese from Hiroshima was undertaken in which the frequency of the allele with C at IVS2-666 was 0.48 and that of the allele with T was 0.52. This approach was found to be very effective for detecting heritable variation and should be a powerful tool for detecting fresh mutations in DNA, which occur outside the known restriction sites. (author)

  12. Genetic Variation in DNA of Coho Salmon from the Lower Columbia River : Final Report 1993.

    Fobes, Stephen; Knudsen, Kathy; Allendorf, Fred

    1993-04-01

    The goal of this project was to develop techniques to provide the information needed to determine if Lower Columbia River coho salmon represent a 'species' under the Endangered Species Act. Our report features two new nuclear DNA approaches to the improved detection of genetic variation: (1) Studies of DNA-level genetic variation for two nuclear growth hormone genes; (2) Use of arbitrary DNA primers (randomly amplified polymorphic DNA, or 'RAPD' primers) to detect variation at large numbers of nuclear genes. We used the polymerase chain reaction (PCR) to amplify variable sections (introns) of two growth hormone genes (GH-I and G/f-Z) in several salmonid species. Coho salmon had three DNA length variants for G/-I intron C. Restriction analysis and sequencing provided valuable information about the mode of evolution of these DNA sequences. We tested segregation of the variants in captive broods of coho salmon, and demonstrated that they are alleles at a single Mendelian locus. Population studies using the GH-1 alleles showed highly significant frequency differences between Lower Columbia River and Oregon Coast coho salmon, and marginal differences among stocks within these regions. These new markers are adequately defined and tested to use in coho salmon population studies of any size. The nature of the variation at GH-1 (Variable Number Tandem Repeats, or 'VNTRs') suggests that more genetic variants will be found in coho salmon from other areas. GH-2 intron C also showed length variation in coho salmon, and this variation was found to be sex-linked. Because PCR methods require minute amounts of tissue, this discovery provides a technique to determine the gender of immature coho salmon without killing them. Chinook salmon had restriction patterns and sequence divergences similar to coho salmon. Thus, we expect that sex linkage of GH-2 alleles predates the evolutionary divergence of Pacific salmon species, and that gender testing with

  13. mtDNA variation among Greenland Eskimos: the edge of the Beringian expansion

    Saillard, J; Forster, P; Lynnerup, N;

    2000-01-01

    characterization of Eskimos in general and Greenlanders in particular, we have sequenced hypervariable segment I (HVS-I) of the mitochondrial DNA (mtDNA) control region and typed relevant RFLP sites in the mtDNA of 82 Eskimos from Greenland. A comparison of our data with published sequences demonstrates major mtDNA...... types shared between Na Dene and Eskimo, indicating a common Beringian history within the Holocene. We further confirm the presence of an Eskimo-specific mtDNA subgroup characterized by nucleotide position 16265G within mtDNA group A2. This subgroup is found in all Eskimo groups analyzed so far and is...... estimated to have originated <3,000 years ago. A founder analysis of all Eskimo and Chukchi A2 types indicates that the Siberian and Greenland ancestral mtDNA pools separated around the time when the Neo-Eskimo culture emerged. The Greenland mtDNA types are a subset of the Alaskan mtDNA variation: they lack...

  14. Extensive variation in the density and distribution of DNA polymorphism in sorghum genomes.

    Joseph Evans

    Full Text Available Sorghum genotypes currently used for grain production in the United States were developed from African landraces that were imported starting in the mid-to-late 19(th century. Farmers and plant breeders selected genotypes for grain production with reduced plant height, early flowering, increased grain yield, adaptation to drought, and improved resistance to lodging, diseases and pests. DNA polymorphisms that distinguish three historically important grain sorghum genotypes, BTx623, BTx642 and Tx7000, were characterized by genome sequencing, genotyping by sequencing, genetic mapping, and pedigree-based haplotype analysis. The distribution and density of DNA polymorphisms in the sequenced genomes varied widely, in part because the lines were derived through breeding and selection from diverse Kafir, Durra, and Caudatum race accessions. Genomic DNA spanning dw1 (SBI-09 and dw3 (SBI-07 had identical haplotypes due to selection for reduced height. Lower SNP density in genes located in pericentromeric regions compared with genes located in euchromatic regions is consistent with background selection in these regions of low recombination. SNP density was higher in euchromatic DNA and varied >100-fold in contiguous intervals that spanned up to 300 Kbp. The localized variation in DNA polymorphism density occurred throughout euchromatic regions where recombination is elevated, however, polymorphism density was not correlated with gene density or DNA methylation. Overall, sorghum chromosomes contain distal euchromatic regions characterized by extensive, localized variation in DNA polymorphism density, and large pericentromeric regions of low gene density, diversity, and recombination.

  15. Meta-Analysis of Mitochondrial DNA Variation in the Iberian Peninsula.

    Barral-Arca, Ruth; Pischedda, Sara; Gómez-Carballa, Alberto; Pastoriza, Ana; Mosquera-Miguel, Ana; López-Soto, Manuel; Martinón-Torres, Federico; Álvarez-Iglesias, Vanesa; Salas, Antonio

    2016-01-01

    The Iberian Peninsula has been the focus of attention of numerous studies dealing with mitochondrial DNA (mtDNA) variation, most of them targeting the control region segment. In the present study we sequenced the control region of 3,024 Spanish individuals from areas where available data were still limited. We also compiled mtDNA haplotypes from the literature involving 4,588 sequences and 28 population groups or small regions. We meta-analyzed all these data in order to shed further light on patterns of geographic variation, taking advantage of the large sample size and geographic coverage, in contrast with the atomized sampling strategy of previous work. The results indicate that the main mtDNA haplogroups show primarily clinal geographic patterns across the Iberian geography, roughly along a North-South axis. Haplogroup HV0 (where haplogroup U is nested) is more prevalent in the Franco Cantabrian region, in good agreement with previous findings that identified this area as a climate refuge during the Last Glacial Maximum (LGM), prior to a subsequent demographic re-expansion towards Central Europe and the Mediterranean. Typical sub-Saharan and North African lineages are slightly more prevalent in South Iberia, although at low frequencies; this pattern has been shaped mainly by the transatlantic slave trade and the Arab invasion of the Iberian Peninsula. The results also indicate that summary statistics that aim to measure molecular variation, or AMOVA, have limited sensitivity to detect population substructure, in contrast to patterns revealed by phylogeographic analysis. Overall, the results suggest that mtDNA variation in Iberia is substantially stratified. These patterns might be relevant in biomedical studies given that stratification is a common cause of false positives in case-control mtDNA association studies, and should be also considered when weighting the DNA evidence in forensic casework, which is strongly dependent on haplotype frequencies. PMID

  16. Microsatellite DNA and mitochondrial DNA variation in polar bears (Ursus maritimus) from the Beaufort and Chukchi seas, Alaska

    Cronin, M.A.; Amstrup, Steven C.; Scribner, K.T.

    2006-01-01

    Radiotelemetry data have shown that polar bears (Ursus maritimus Phipps, 1774) occur in separate subpopulations in the Chukchi Sea and the southern Beaufort Sea. However, segregation is not absolute, and there is overlap of ranges of animals in each subpopulation. We used genetic variation at eight microsatellite DNA loci and mitochondrial DNA (mtDNA) to further assess the degree of spatial structure of polar bears from the Chukchi and southern Beaufort seas. Microsatellite allele frequencies and mtDNA haplotype frequencies of bears from the southern Beaufort and Chukchi seas did not differ significantly. Lack of differentiation at both maternally inherited mtDNA and bi-parentally inherited microsatellite loci suggests that gene flow between the two areas is mediated by both sexes. The genetic data indicate that polar bears in the southern Beaufort and Chukchi seas compose one interbreeding population. However, there is considerable fidelity to ranges in each area, particularly by adult females. The combined genetic and movement data suggest that polar bears could be managed as Beaufort Sea and Chukchi Sea subpopulations of a combined southern Beaufort Sea and Chukchi Sea population. ?? 2006 NRC.

  17. Estimation Of The Proportion Of Variation Accounted For By DNA Tests. II: Phenotypic Variance

    The proportion of phenotypic variation accounted for (Rp2) is an important characteristic of a DNA test. Therefore, several estimators of this quantity were evaluated by simulation of 500 replicates of a population of 1000 progeny of 100 sires (3 levels of narrow sense heritability and 4 levels of ...

  18. Estimation of the Proportion of Variation Accounted for by DNA Tests. I: Genetic Variance

    The proportion of genetic variation accounted for (Rg2) is an important characteristic of a DNA test. For each of 3 levels of narrow sense heritability of the observed trait (h2gy) and 4 levels of Rg2, 500 independent replicates of an observed trait and a molecular breeding value (MBV) for 1000 offs...

  19. Estimation of the Proportion of Genetic Variation Accounted for by DNA Tests

    An increasingly relevant question in evaluating commercial DNA tests is "What proportion of the additive genetic variation in the target trait is accounted for by the test?" Therefore, several estimators of this quantity were evaluated by simulation of a population of 1000 animals with 100 sires, ea...

  20. Genetic variation in Phoca vitulina (the harbour seal) revealed by DNA fingerprinting and RAPDs

    Kappe, A.L.; van de Zande, L.; Vedder, E.J.; Bijlsma, R.; van Delden, Wilke

    1995-01-01

    Genetic variation in two harbour seal (Phoca vitulina) populations from the Dutch Wadden Sea and Scotland was examined by RAPD analysis and DNA fingerprinting. For comparison a population of grey seals (Halichoerus grypus) was studied. The RAPD method revealed a very low number of polymorphic bands.

  1. DNA methylation variations of TVB in ALV-resistant and -susceptible chickens

    Epigenetic variations can convey gene expression patterns critical for neoplastic disease initiation, progression or regression. DNA methylation is one of the main components of epigenetic modification. The tumor virus B (TVB) locus, which encodes the cellular receptors for subgroups B, D, and E of ...

  2. Comprehensive view of the population history of Arabia as inferred by mtDNA variation

    Černý, Viktor; Čížková, M.; Poloni, E. S.; Al-Meeri, A.; Mulligan, C. J.

    2016-01-01

    Roč. 159, č. 4 (2016), s. 607-616. ISSN 0002-9483 R&D Projects: GA ČR GA13-37998S Institutional support: RVO:67985912 Keywords : mtDNA variation * Arabian Peninsula * migrations Subject RIV: AC - Archeology, Anthropology, Ethnology Impact factor: 2.379, year: 2014

  3. Differential DNA mismatch repair underlies mutation rate variation across the human genome

    Supek, Fran; Lehner, Ben

    2015-01-01

    Cancer genome sequencing has revealed considerable variation in somatic mutation rates across the human genome, with mutation rates elevated in heterochromatic late replicating regions and reduced in early replicating euchromatin1-5. Multiple mechanisms have been suggested to underlie this2,6-10, but the actual cause is unknown. Here we identify variable DNA mismatch repair (MMR) as the basis of this variation. Analysing ~17 million single nucleotide variants from the genomes of 652 tumours, we show that regional autosomal mutation rates at megabase resolution are largely stable across cancer types, with differences related to changes in replication timing and gene expression. However, mutations arising after the inactivation of MMR are no longer enriched in early replicating euchromatin relative to late replicating heterochromatin. Thus, differential DNA repair and not differential mutation supply is the primary cause of the large-scale regional mutation rate variation across the human genome. PMID:25707793

  4. Temporal stability of epigenetic markers: sequence characteristics and predictors of short-term DNA methylation variations.

    Hyang-Min Byun

    Full Text Available BACKGROUND: DNA methylation is an epigenetic mechanism that has been increasingly investigated in observational human studies, particularly on blood leukocyte DNA. Characterizing the degree and determinants of DNA methylation stability can provide critical information for the design and conduction of human epigenetic studies. METHODS: We measured DNA methylation in 12 gene-promoter regions (APC, p16, p53, RASSF1A, CDH13, eNOS, ET-1, IFNγ, IL-6, TNFα, iNOS, and hTERT and 2 of non-long terminal repeat elements, i.e., L1 and Alu in blood samples obtained from 63 healthy individuals at baseline (Day 1 and after three days (Day 4. DNA methylation was measured by bisulfite-PCR-Pyrosequencing. We calculated intraclass correlation coefficients (ICCs to measure the within-individual stability of DNA methylation between Day 1 and 4, subtracted of pyrosequencing error and adjusted for multiple covariates. RESULTS: Methylation markers showed different temporal behaviors ranging from high (IL-6, ICC = 0.89 to low stability (APC, ICC = 0.08 between Day 1 and 4. Multiple sequence and marker characteristics were associated with the degree of variation. Density of CpG dinucleotides nearby the sequence analyzed (measured as CpG(o/e or G+C content within ±200 bp was positively associated with DNA methylation stability. The 3' proximity to repeat elements and range of DNA methylation on Day 1 were also positively associated with methylation stability. An inverted U-shaped correlation was observed between mean DNA methylation on Day 1 and stability. CONCLUSIONS: The degree of short-term DNA methylation stability is marker-dependent and associated with sequence characteristics and methylation levels.

  5. Varietal tracing of virgin olive oils based on plastid DNA variation profiling.

    Marga Pérez-Jiménez

    Full Text Available Olive oil traceability remains a challenge nowadays. DNA analysis is the preferred approach to an effective varietal identification, without any environmental influence. Specifically, olive organelle genomics is the most promising approach for setting up a suitable set of markers as they would not interfere with the pollinator variety DNA traces. Unfortunately, plastid DNA (cpDNA variation of the cultivated olive has been reported to be low. This feature could be a limitation for the use of cpDNA polymorphisms in forensic analyses or oil traceability, but rare cpDNA haplotypes may be useful as they can help to efficiently discriminate some varieties. Recently, the sequencing of olive plastid genomes has allowed the generation of novel markers. In this study, the performance of cpDNA markers on olive oil matrices, and their applicability on commercial Protected Designation of Origin (PDO oils were assessed. By using a combination of nine plastid loci (including multi-state microsatellites and short indels, it is possible to fingerprint six haplotypes (in 17 Spanish olive varieties, which can discriminate high-value commercialized cultivars with PDO. In particular, a rare haplotype was detected in genotypes used to produce a regional high-value commercial oil. We conclude that plastid haplotypes can help oil traceability in commercial PDO oils and set up an experimental methodology suitable for organelle polymorphism detection in the complex olive oil matrices.

  6. Exploration of methods to identify polymorphisms associated with variation in DNA repair capacity phenotypes

    Jones, I M; Thomas, C B; Xi, T; Mohrenweiser, H W; Nelson, D O

    2006-07-03

    Elucidating the relationship between polymorphic sequences and risk of common disease is a challenge. For example, although it is clear that variation in DNA repair genes is associated with familial cancer, aging and neurological disease, progress toward identifying polymorphisms associated with elevated risk of sporadic disease has been slow. This is partly due to the complexity of the genetic variation, the existence of large numbers of mostly low frequency variants and the contribution of many genes to variation in susceptibility. There has been limited development of methods to find associations between genotypes having many polymorphisms and pathway function or health outcome. We have explored several statistical methods for identifying polymorphisms associated with variation in DNA repair phenotypes. The model system used was 80 cell lines that had been resequenced to identify variation; 191 single nucleotide substitution polymorphisms (SNPs) are included, of which 172 are in 31 base excision repair pathway genes, 19 in 5 anti-oxidation genes, and DNA repair phenotypes based on single strand breaks measured by the alkaline Comet assay. Univariate analyses were of limited value in identifying SNPs associated with phenotype variation. Of the multivariable model selection methods tested: the easiest that provided reduced error of prediction of phenotype was simple counting of the variant alleles predicted to encode proteins with reduced activity, which led to a genotype including 52 SNPs; the best and most parsimonious model was achieved using a two-step analysis without regard to potential functional relevance: first SNPs were ranked by importance determined by Random Forests Regression (RFR), followed by cross-validation in a second round of RFR modeling that included ever more SNPs in declining order of importance. With this approach 6 SNPs were found to minimize prediction error. The results should encourage research into utilization of multivariate

  7. Epigenetic Switch Driven by DNA Inversions Dictates Phase Variation in Streptococcus pneumoniae

    Wang, Juanjuan; An, Haoran; Liu, Yanni; Wang, Kailing; Miao, Zhun; Liang, Wenbo; Sebra, Robert; Wang, Guilin; Wang, Wen-Ching; Zhang, Jing-Ren

    2016-01-01

    DNA methylation is an important epigenetic mechanism for phenotypic diversification in all forms of life. We previously described remarkable cell-to-cell heterogeneity in epigenetic pattern within a clonal population of Streptococcus pneumoniae, a leading human pathogen. We here report that the epigenetic diversity is caused by extensive DNA inversions among hsdSA, hsdSB, and hsdSC, three methyltransferase hsdS genes in the Spn556II type-I restriction modification (R-M) locus. Because hsdSA encodes the sequence recognition subunit of this type-I R-M DNA methyltransferase, these site-specific recombinations generate pneumococcal cells with variable HsdSA alleles and thereby diverse genome methylation patterns. Most importantly, the DNA methylation pattern specified by the HsdSA1 allele leads to the formation of opaque colonies, whereas the pneumococci lacking HsdSA1 produce transparent colonies. Furthermore, this HsdSA1-dependent phase variation requires intact DNA methylase activity encoded by hsdM in the Spn556II (renamed colony opacity determinant or cod) locus. Thus, the DNA inversion-driven ON/OFF switch of the hsdSA1 allele in the cod locus and resulting epigenetic switch dictate the phase variation between the opaque and transparent phenotypes. Phase variation has been well documented for its importance in pneumococcal carriage and invasive infection, but its molecular basis remains unclear. Our work has discovered a novel epigenetic cause for this significant pathobiology phenomenon in S. pneumoniae. Lastly, our findings broadly represents a significant advancement in our understanding of bacterial R-M systems and their potential in shaping epigenetic and phenotypic diversity of the prokaryotic organisms because similar site-specific recombination systems widely exist in many archaeal and bacterial species. PMID:27427949

  8. Epigenetic Switch Driven by DNA Inversions Dictates Phase Variation in Streptococcus pneumoniae.

    Li, Jing; Li, Jing-Wen; Feng, Zhixing; Wang, Juanjuan; An, Haoran; Liu, Yanni; Wang, Yang; Wang, Kailing; Zhang, Xuegong; Miao, Zhun; Liang, Wenbo; Sebra, Robert; Wang, Guilin; Wang, Wen-Ching; Zhang, Jing-Ren

    2016-07-01

    DNA methylation is an important epigenetic mechanism for phenotypic diversification in all forms of life. We previously described remarkable cell-to-cell heterogeneity in epigenetic pattern within a clonal population of Streptococcus pneumoniae, a leading human pathogen. We here report that the epigenetic diversity is caused by extensive DNA inversions among hsdSA, hsdSB, and hsdSC, three methyltransferase hsdS genes in the Spn556II type-I restriction modification (R-M) locus. Because hsdSA encodes the sequence recognition subunit of this type-I R-M DNA methyltransferase, these site-specific recombinations generate pneumococcal cells with variable HsdSA alleles and thereby diverse genome methylation patterns. Most importantly, the DNA methylation pattern specified by the HsdSA1 allele leads to the formation of opaque colonies, whereas the pneumococci lacking HsdSA1 produce transparent colonies. Furthermore, this HsdSA1-dependent phase variation requires intact DNA methylase activity encoded by hsdM in the Spn556II (renamed colony opacity determinant or cod) locus. Thus, the DNA inversion-driven ON/OFF switch of the hsdSA1 allele in the cod locus and resulting epigenetic switch dictate the phase variation between the opaque and transparent phenotypes. Phase variation has been well documented for its importance in pneumococcal carriage and invasive infection, but its molecular basis remains unclear. Our work has discovered a novel epigenetic cause for this significant pathobiology phenomenon in S. pneumoniae. Lastly, our findings broadly represents a significant advancement in our understanding of bacterial R-M systems and their potential in shaping epigenetic and phenotypic diversity of the prokaryotic organisms because similar site-specific recombination systems widely exist in many archaeal and bacterial species. PMID:27427949

  9. Variation in rDNA locus number and position among legume species and detection of 2 linked rDNA loci in the model Medicago truncatula by FISH.

    Abirached-Darmency, Mona; Prado-Vivant, Emilce; Chelysheva, Liudmila; Pouthier, Thomas

    2005-06-01

    Within Fabaceae, legume species have a variable genome size, chromosome number, and ploidy level. The genome distribution of ribosomal genes, easily detectable by fluorescent in situ hybridization (FISH), is a good tool for anchoring physical and genetic comparative maps. The organisation of 45S rDNA and 5S loci was analysed by FISH in the 4 closely related species: Pisum sativum, Medicago truncatula, Medicago sativa (2 diploid taxa), and Lathyrus sativus. The 2 types of rDNA arrays displayed interspecific variation in locus number and location, but little intraspecific variation was detected. In the model legume, M. truncatula, the presence of 2 adjacent 45S rDNA loci was demonstrated, and the location of the rDNA loci was independent of the general evolution of the genome DNA. The different parameters relative to clustering of the rDNA loci in specific chromosome regions and the possible basis of rDNA instability are discussed. PMID:16121252

  10. Evaluating variation in human gut microbiota profiles due to DNA extraction method and inter-subject differences.

    Wagner Mackenzie, Brett; Waite, David W; Taylor, Michael W

    2015-01-01

    The human gut contains dense and diverse microbial communities which have profound influences on human health. Gaining meaningful insights into these communities requires provision of high quality microbial nucleic acids from human fecal samples, as well as an understanding of the sources of variation and their impacts on the experimental model. We present here a systematic analysis of commonly used microbial DNA extraction methods, and identify significant sources of variation. Five extraction methods (Human Microbiome Project protocol, MoBio PowerSoil DNA Isolation Kit, QIAamp DNA Stool Mini Kit, ZR Fecal DNA MiniPrep, phenol:chloroform-based DNA isolation) were evaluated based on the following criteria: DNA yield, quality and integrity, and microbial community structure based on Illumina amplicon sequencing of the V4 region of bacterial and archaeal 16S rRNA genes. Our results indicate that the largest portion of variation within the model was attributed to differences between subjects (biological variation), with a smaller proportion of variation associated with DNA extraction method (technical variation) and intra-subject variation. A comprehensive understanding of the potential impact of technical variation on the human gut microbiota will help limit preventable bias, enabling more accurate diversity estimates. PMID:25741335

  11. DNA Conformational Variations Induced by Stretching 3'5'-Termini Studied by Molecular Dynamics Simulations

    Investigating the interaction between protein and stretched DNA molecules has become a new way to study the protein DNA interaction. The conformations from different stretching methods give us a further understanding of the interaction between protein and DNA. We study the conformational variations of a 22-mer DNA caused by stretching both 3'- and 5'-termini by molecular dynamics simulations. It requires 250 kJ/mol to stretch the DNA molecule by 3'5'-termini for 3.5 nm and the force plateau is at 123.8 pN. The stretching 3'5'-termini leads to large values of the angle opening and the dihedral propeller between bases in one base pair, the double helix untwists from 34° to 20° and the successive base pairs rolls to the side of the DNA major groove. The distances between successive base pairs increases from 3.2 Å to 5.6 Å. (cross-disciplinary physics and related areas of science and technology)

  12. Quality standards for DNA sequence variation databases to improve clinical management under development in Australia

    B. Bennetts

    2014-09-01

    Full Text Available Despite the routine nature of comparing sequence variations identified during clinical testing to database records, few databases meet quality requirements for clinical diagnostics. To address this issue, The Royal College of Pathologists of Australasia (RCPA in collaboration with the Human Genetics Society of Australasia (HGSA, and the Human Variome Project (HVP is developing standards for DNA sequence variation databases intended for use in the Australian clinical environment. The outputs of this project will be promoted to other health systems and accreditation bodies by the Human Variome Project to support the development of similar frameworks in other jurisdictions.

  13. Application of the adductome approach to assess intertissue DNA damage variations in human lung and esophagus

    Methods for determining the differential susceptibility of human organs to DNA damage have not yet been explored to any large extent due to technical constraints. The development of comprehensive analytical approaches by which to detect intertissue variations in DNA damage susceptibility may advance our understanding of the roles of DNA adducts in cancer etiology and as exposure biomarkers at least. A strategy designed for the detection and comparison of multiple DNA adducts from different tissue samples was applied to assess esophageal and peripherally- and centrally-located lung tissue DNA obtained from the same person. This adductome approach utilized LC/ESI-MS/MS analysis methods designed to detect the neutral loss of 2'-deoxyribose from positively ionized 2'-deoxynucleoside adducts transmitting the [M+H]+ > [M+H-116]+ transition over 374 transitions. In the final analyses, adductome maps were produced which facilitated the visualization of putative DNA adducts and their relative levels of occurrence and allowed for comprehensive comparisons between samples, including a calf thymus DNA negative control. The largest putative adducts were distributed similarly across the samples, however, differences in the relative amounts of putative adducts in lung and esophagus tissue were also revealed. The largest-occurring lung tissue DNA putative adducts were 90% similar (n = 50), while putative adducts in esophagus tissue DNA were shown to be 80 and 84% similar to central and peripheral lung tissue DNA respectively. Seven DNA adducts, N2-ethyl-2'-deoxyguanosine (N2-ethyl-dG), 1,N6-etheno-2'-deoxyadenosine (εdA), α-S- and α-R-methyl-γ-hydroxy-1,N2-propano-2'-deoxyguanosine (1,N2-PdG1, 1,N2-PdG2), 3-(2'-deoxyribosyl)-5,6,7,8-tetrahydro-8-hydroxy-pyrimido[1,2-a] purine-(3H)-one (8-OH-PdG) and the two stereoisomers of 3-(2'-deoxyribosyl)-5,6,7,8-tetrahydro-6-hydroxypyrimido[1,2-a] purine-(3H)-one (6-OH-PdG) were unambiguously detected in all tissue DNA samples by

  14. A genetic basis for the variation in the vulnerability of cancer to DNA damage

    Yard, Brian D.; Adams, Drew J.; Chie, Eui Kyu; Tamayo, Pablo; Battaglia, Jessica S.; Gopal, Priyanka; Rogacki, Kevin; Pearson, Bradley E.; Phillips, James; Raymond, Daniel P.; Pennell, Nathan A.; Almeida, Francisco; Cheah, Jaime H.; Clemons, Paul A.; Shamji, Alykhan

    2016-01-01

    Radiotherapy is not currently informed by the genetic composition of an individual patient's tumour. To identify genetic features regulating survival after DNA damage, here we conduct large-scale profiling of cellular survival after exposure to radiation in a diverse collection of 533 genetically annotated human tumour cell lines. We show that sensitivity to radiation is characterized by significant variation across and within lineages. We combine results from our platform with genomic featur...

  15. Taiwan Y-chromosomal DNA variation and its relationship with Island Southeast Asia

    Trejaut, Jean A; Poloni, Estella S.; Yen, Ju-Chen; Lai, Ying-Hui; Loo, Jun-Hun; Lee, Chien-Liang; He, Chun-Lin; Lin, Marie

    2014-01-01

    BACKGROUND: Much of the data resolution of the haploid non-recombining Y chromosome (NRY) haplogroup O in East Asia are still rudimentary and could be an explanatory factor for current debates on the settlement history of Island Southeast Asia (ISEA). Here, 81 slowly evolving markers (mostly SNPs) and 17 Y-chromosomal short tandem repeats were used to achieve higher level molecular resolution. Our aim is to investigate if the distribution of NRY DNA variation in Taiwan and ISEA is consistent ...

  16. A genetic basis for the variation in the vulnerability of cancer to DNA damage

    Yard, Brian D.; Adams, Drew J.; Chie, Eui Kyu; Tamayo, Pablo; Battaglia, Jessica S.; Gopal, Priyanka; Rogacki, Kevin; Pearson, Bradley E.; Phillips, James; Raymond, Daniel P.; Pennell, Nathan A.; Almeida, Francisco; Cheah, Jaime H.; Clemons, Paul A.; Shamji, Alykhan; Peacock, Craig D.; Schreiber, Stuart L.; Hammerman, Peter S.; Abazeed, Mohamed E.

    2016-01-01

    Radiotherapy is not currently informed by the genetic composition of an individual patient's tumour. To identify genetic features regulating survival after DNA damage, here we conduct large-scale profiling of cellular survival after exposure to radiation in a diverse collection of 533 genetically annotated human tumour cell lines. We show that sensitivity to radiation is characterized by significant variation across and within lineages. We combine results from our platform with genomic features to identify parameters that predict radiation sensitivity. We identify somatic copy number alterations, gene mutations and the basal expression of individual genes and gene sets that correlate with the radiation survival, revealing new insights into the genetic basis of tumour cellular response to DNA damage. These results demonstrate the diversity of tumour cellular response to ionizing radiation and establish multiple lines of evidence that new genetic features regulating cellular response after DNA damage can be identified. PMID:27109210

  17. Lack of association between mitochondrial DNA G15257A and G15812A variations and multiple sclerosis

    Andalib, Sasan; Talebi, Mahnaz; Sakhinia, Ebrahim;

    2015-01-01

    BACKGROUND: Multiple sclerosis (MS) is a debilitating disease of the central nervous system for which no definitive therapy has yet been developed. The etiology remains uncertain, but there is evidence of genetic susceptibility to the disease, including contributions from mitochondrial DNA (mtDNA......) variations to the pathogenesis of MS. G15257A and G15812A are variations of the mtDNA tRNA(Thr) gene in MS sufferers of different populations. The present study tested the hypothesis of an association of the G15257A and G15812A variations of the mtDNA tRNA(Thr) gene to the susceptibility to MS in an Iranian...... population. MATERIAL AND METHODS: Two hundred subjects included 100 MS patients and 100 unrelated healthy controls. DNA was extracted from blood samples by means of a salting-out method. The mtDNA fragment was amplified by polymerase chain reaction (PCR). Restriction fragment length polymorphism (RFLP...

  18. Variation in blood cell DNA content in fish from Chernobyl-contaminated ponds in Ukraine

    To assess responses of fish to chronic exposure to radionuclides, the authors sampled blood from about 300 crucian carp Carassius carrasius collected from 10 ponds in the Ukraine. The ponds were located 20--30 km from the Chernobyl reactor in areas which received 1--10 Ci 137Cs/km2 as well as other contaminants. Flow cytometric analysis of DNA content of whole blood revealed aneuploid-like patterns in some of the fish, as well as hyperdiploid shoulders. The fish populations consisted of both diploid and triploid individuals. Changes in the coefficient of variation (CV) around the G0/G1 peak have been used in previous studies as an indication of abnormal DNA content; the CV was increased in a number of the fish examined. Some fish had uninterpretable DNA histograms, with a typical diploid or triploid cell population present along with a smaller haploid population. Variations in cellular DNA content similar to those reported here have been associated with exposure to radiation and other genotoxic agents in laboratory studies. While further work is needed, these results suggest that the Chernobyl accident may have long term genetic consequences for wild organisms in the contaminated areas

  19. Genetic variations of East Kalimantan Orangutan based on D-Loop mitochondria DNA

    DIDIK PRASETYO

    2007-10-01

    Full Text Available Analysis of the variation of D-Loop mtDNA of East Kalimantan orangutan was done to provided the genetic information data from endangerd species in order to support their population conservation efforts. The reason using mtDNA in this research is caused by higher level of mutation ( 5 – 10 trimes when compared with nuclear DNA and it enable to transmited via maternal transmission without experience in recombination. From the analysis conducted on 38 samples resulting eight types of haplotype that is A, B, C, D, E, G, H and I haplotype. Level of variation of the haplotype at East Kutai district was more uniform when compared by variation in Kutai district. From the paternal analysis had been got three cluster with the nearer among cluster IADG and cluster EH compared by cluster BC. Dissociation time between haplotype are 250.000-400.000 years ago, and known the population of East Kalimantan orangutan separated from Sumatran orangutan (X97708 since 1.158.300 years ago.

  20. Detection of genetic variation in Hevea brasiliensis using the DNA amplification fingerprinting technique

    Earlier studies on genetic variation and genome analysis of Hevea brasiliensis were based primarily on restriction fragment length polymorphisms (RFLPs). Notwithstanding that the RFLP technique is a powerful tool, the technique is slow, laborious and requires highly polymorphic hybridization probes. The multiplex DAF technique was adopted. Pairs of random 10-mer oligonucleotide primers were tested for their ability to elicit DNA polymorphisms. Preliminary results indicated that the number of amplified products varied with the annealing temperature and the primer pairs. Although it was found that the annealing temperatures had to be varied for different primer pairs in order to achieve satisfactory amplification, all DNA amplification was carried out at a fixed annealing temperature in order to increase the efficiency of screening primer pairs for their ability to reveal comprehensive DNA fingerprints. DNA samples loaded in denaturing buffer and separated through denaturing polyacrylamide gels were found to be more informative than samples loaded in non-denaturing buffer. Staining with silver nitrate was much more sensitive than with ethidium bromide. The DAF marker technique has been developed successfully for Hevea studies. Premilinary investigations with the technique demonstrated that DAF can generate very complex and informative DNA fingerprints and promises to be useful for genetic variability, family relationship and population studies. The technique does not require sophisticated equipment, and is also more robust and reproducible than RAPD. 6 refs

  1. Sequence-length variation of mtDNA HVS-IC-stretch in Chinese ethnic groups

    Feng CHEN; Yong-hui DANG; Chun-xia YAN; Yan-ling LIU; Ya-jun DENG; David J. R. FULTON; Teng CHEN

    2009-01-01

    The purpose of this study was to investigate mitochondrial DNA (mtDNA) hypervariable segment-I (HVS-I) C-stretch variations and explore the significance of these variations in forensic and population genetics studies. The C-stretch sequence variation was studied in 919 unrelated individuals from 8 Chinese ethnic groups using both direct and clone sequencing ap-proaches. Thirty eight C-stretch haplotypes were identified, and some novel and population specific haplotypes were also detected. The C-stretch genetic diversity (GD) values were relatively high, and probability (P) values were low. Additionally, C-stretch length heteroplasmy was observed in approximately 9% of individuals studied. There was a significant correlation (r=-0.961, P<0.01) between the expansion of the cytosine sequence length in the C-stretch of HVS-I and a reduction in the number of up-stream adenines. These results indicate that the C-stretch could be a useful genetic maker in forensic identification of Chinese populations. The results from the Fst and dA genetic distance matrix, neighbor-joining tree, and principal component map also suggest that C-stretch could be used as a reliable genetic marker in population genetics.

  2. Genetic variation in Opisthorchis viverrini (Trematoda: Opisthorchiidae) from northeast Thailand and Laos PDR based on random amplified polymorphic DNA analyses

    Sithithaworn, Paiboon; Nuchjungreed, Chadaporn; Srisawangwong, Tuanchai; Ando, Katsuhiko; Petney, Trevor N.; Chilton, Neil B.; Andrews, Ross H.

    2006-01-01

    Genetic variation in Opisthorchis viverrini adults originating from different locations in northeast Thailand and Laos, People’s Democratic Republic (PDR), was examined using random amplified polymorphic DNA (RAPD) analyses. In an initial analysis, the genomic DNA of one fluke from each of ten localities was amplified using 15 random primers (10-mers); however, genetic variation among O. viverrini specimens was detected reliably for only four primers. A more detailed RAPD analysis using these...

  3. Bridging near and remote Oceania: mtDNA and NRY variation in the Solomon Islands.

    Delfin, Frederick; Myles, Sean; Choi, Ying; Hughes, David; Illek, Robert; van Oven, Mannis; Pakendorf, Brigitte; Kayser, Manfred; Stoneking, Mark

    2012-02-01

    Although genetic studies have contributed greatly to our understanding of the colonization of Near and Remote Oceania, important gaps still exist. One such gap is the Solomon Islands, which extend between Bougainville and Vanuatu, thereby bridging Near and Remote Oceania, and include both Austronesian-speaking and Papuan-speaking groups. Here, we describe patterns of mitochondrial DNA (mtDNA) and nonrecombining Y chromosome (NRY) variation in over 700 individuals from 18 populations in the Solomons, including 11 Austronesian-speaking groups, 3 Papuan-speaking groups, and 4 Polynesian Outliers (descended via back migration from Polynesia). We find evidence for ancient (pre-Lapita) colonization of the Solomons in old NRY paragroups as well as from M2-M353, which probably arose in the Solomons ∼9,200 years ago and is the most frequent NRY haplogroup there. There are no consistent genetic differences between Austronesian-speaking and Papuan-speaking groups, suggesting extensive genetic contact between them. Santa Cruz, which is located in Remote Oceania, shows unusually low frequencies of mtDNA and NRY haplogroups of recent Asian ancestry. This is in apparent contradiction with expectations based on archaeological and linguistic evidence for an early (∼3,200 years ago), direct colonization of Santa Cruz by Lapita people from the Bismarck Archipelago, via a migration that "leapfrogged" over the rest of the Solomons. Polynesian Outliers show dramatic island-specific founder events involving various NRY haplogroups. We also find that NRY, but not mtDNA, genetic distance is correlated with the geographic distance between Solomons groups and that historically attested spheres of cultural interaction are associated with the recent genetic structure of Solomons groups, as revealed by mtDNA HV1 sequence and Y-STR haplotype diversity. Our results fill an important lacuna in human genetic studies of Oceania and aid in understanding the colonization and genetic history of

  4. Regional Variation in mtDNA of the Lesser Prairie-Chicken

    Hagen, Christian A.; Pitman, James C.; Sandercock, Brett K.; Wolfe, Don H.; Robel, Robel J.; Applegate, Roger D.; Oyler-McCance, Sara J.

    2010-01-01

    Cumulative loss of habitat and long-term decline in the populations of the Lesser Prairie-Chicken (Tympanuchus pallidicinctus) have led to concerns for the species' viability throughout its range in the southern Great Plains. For more efficient conservation past and present distributions of genetic variation need to be understood. We examined the distribution of mitochondrial DNA (mtDNA) variation in the Lesser Prairie-Chicken across Kansas, Colorado, Oklahoma, and New Mexico. Throughout the range we found little genetic differentiation except for the population in New Mexico, which was significantly different from most other publications. We did, however, find significant isolation by distance at the rangewide scale (r=0.698). We found no relationship between haplotype phylogeny and geography, and our analyses provide evidence for a post-glacial population expansion within the species that is consistent with the idea that speciation within Tympanuchus is recent. Conservation actions that increase the likelihood of genetically viable populations in the future should be evaluated for implementation.

  5. Fluorescent SSCP of overlapping fragments (FSSCP-OF): a highly sensitive method for the screening of mitochondrial DNA variation

    Salas, A; Rasmussen, Erik Michael; Lareu, M V;

    2001-01-01

    The mtDNA analysis (mtDNA) is increasingly being demanded for forensic purposes due to the fact that many times the use of standard nuclear marker fails to analyze degraded samples (such as bones) and specially for the analysis of hair shafts (a common sample in the crime scene). However, analysis...... of mtDNA sequencing implies a great lab effort when a high number of samples must be analyzed.The present work introduces a novel and reliable method for the screening of mtDNA variation in the first and second hypervariables (HV1 and HV2) regions which we have denominated fluorescent single strand...... d-loop mtDNA variation and for this reason, the probability to detect a polymorphic position by SSCP analysis is clearly increased in comparison to conventional SSCP methods due to the fact that the same polymorphic position is usually placed in a different "relative" position in the two overlapped...

  6. Investigation of the effect of ionizing radiation on gene expression variation by the 'DNA chips': feasibility of a biological dosimeter

    After having described the different biological effects of ionizing radiation and the different approaches to biological dosimetry, and introduced 'DNA chips' or DNA micro-arrays, the author reports the characterization of gene expression variations in the response of cells to a gamma irradiation. Both main aspects of the use DNA chips are investigated: fundamental research and diagnosis. This research thesis thus proposes an analysis of the effect of ionizing radiation using DNA chips, notably by comparing gene expression modifications measured in mouse irradiated lung, heart and kidney. It reports a feasibility study of bio-dosimeter based on expression profiles

  7. Population structure of nuclear and mitochondrial DNA variation among humpback whales in the North Pacific.

    Baker, C S; Medrano-Gonzalez, L; Calambokidis, J; Perry, A; Pichler, F; Rosenbaum, H; Straley, J M; Urban-Ramirez, J; Yamaguchi, M; von Ziegesar, O

    1998-06-01

    The population structure of variation in a nuclear actin intron and the control region of mitochondrial DNA is described for humpback whales from eight regions in the North Pacific Ocean: central California, Baja Peninsula, nearshore Mexico (Bahia Banderas), offshore Mexico (Socorro Island), southeastern Alaska, central Alaska (Prince Williams Sound), Hawaii and Japan (Ogasawara Islands). Primary mtDNA haplotypes and intron alleles were identified using selected restriction fragment length polymorphisms of target sequences amplified by the polymerase chain reaction (PCR-RFLP). There was little evidence of heterogeneity in the frequencies of mtDNA haplotypes or actin intron alleles due to the year or sex composition of the sample. However, frequencies of four mtDNA haplotypes showed marked regional differences in their distributions (phi ST = 0.277; P < 0.001; n = 205 individuals) while the two alleles showed significant, but less marked, regional differences (phi ST = 0.033; P < 0.013; n = 400 chromosomes). An hierarchical analysis of variance in frequencies of haplotypes and alleles supported the grouping of six regions into a central and eastern stock with further partitioning of variance among regions within stocks for haplotypes but not for alleles. Based on available genetic and demographic evidence, the southeastern Alaska and central California feeding grounds were selected for additional analyses of nuclear differentiation using allelic variation at four microsatellite loci. All four loci showed significant differences in allele frequencies (overall FST = 0.043; P < 0.001; average n = 139 chromosomes per locus), indicating at least partial reproductive isolation between the two regions as well as the segregation of mtDNA lineages. Although the two feeding grounds were not panmictic for nuclear or mitochondrial loci, estimates of long-term migration rates suggested that male-mediated gene flow was several-fold greater than female gene flow. These results

  8. HLA DNA sequence variation among human populations: molecular signatures of demographic and selective events.

    Stéphane Buhler

    Full Text Available Molecular differences between HLA alleles vary up to 57 nucleotides within the peptide binding coding region of human Major Histocompatibility Complex (MHC genes, but it is still unclear whether this variation results from a stochastic process or from selective constraints related to functional differences among HLA molecules. Although HLA alleles are generally treated as equidistant molecular units in population genetic studies, DNA sequence diversity among populations is also crucial to interpret the observed HLA polymorphism. In this study, we used a large dataset of 2,062 DNA sequences defined for the different HLA alleles to analyze nucleotide diversity of seven HLA genes in 23,500 individuals of about 200 populations spread worldwide. We first analyzed the HLA molecular structure and diversity of these populations in relation to geographic variation and we further investigated possible departures from selective neutrality through Tajima's tests and mismatch distributions. All results were compared to those obtained by classical approaches applied to HLA allele frequencies.Our study shows that the global patterns of HLA nucleotide diversity among populations are significantly correlated to geography, although in some specific cases the molecular information reveals unexpected genetic relationships. At all loci except HLA-DPB1, populations have accumulated a high proportion of very divergent alleles, suggesting an advantage of heterozygotes expressing molecularly distant HLA molecules (asymmetric overdominant selection model. However, both different intensities of selection and unequal levels of gene conversion may explain the heterogeneous mismatch distributions observed among the loci. Also, distinctive patterns of sequence divergence observed at the HLA-DPB1 locus suggest current neutrality but old selective pressures on this gene. We conclude that HLA DNA sequences advantageously complement HLA allele frequencies as a source of data used

  9. Sources of pre-analytical variations in yield of DNA extracted from blood samples: analysis of 50,000 DNA samples in EPIC.

    Elodie Caboux

    Full Text Available The European Prospective Investigation into Cancer and nutrition (EPIC is a long-term, multi-centric prospective study in Europe investigating the relationships between cancer and nutrition. This study has served as a basis for a number of Genome-Wide Association Studies (GWAS and other types of genetic analyses. Over a period of 5 years, 52,256 EPIC DNA samples have been extracted using an automated DNA extraction platform. Here we have evaluated the pre-analytical factors affecting DNA yield, including anthropometric, epidemiological and technical factors such as center of subject recruitment, age, gender, body-mass index, disease case or control status, tobacco consumption, number of aliquots of buffy coat used for DNA extraction, extraction machine or procedure, DNA quantification method, degree of haemolysis and variations in the timing of sample processing. We show that the largest significant variations in DNA yield were observed with degree of haemolysis and with center of subject recruitment. Age, gender, body-mass index, cancer case or control status and tobacco consumption also significantly impacted DNA yield. Feedback from laboratories which have analyzed DNA with different SNP genotyping technologies demonstrate that the vast majority of samples (approximately 88% performed adequately in different types of assays. To our knowledge this study is the largest to date to evaluate the sources of pre-analytical variations in DNA extracted from peripheral leucocytes. The results provide a strong evidence-based rationale for standardized recommendations on blood collection and processing protocols for large-scale genetic studies.

  10. Genetic Variation Among Vegetative Compatibility Groups of Fusarium oxysporum f. sp. cubense Analyzed by DNA Fingerprinting.

    Bentley, S; Pegg, K G; Moore, N Y; Davis, R D; Buddenhagen, I W

    1998-12-01

    ABSTRACT Genetic variation within a worldwide collection of 208 isolates of Fu-sarium oxysporum f. sp. cubense, representing physiological races 1, 2, 3, and 4 and the 20 reported vegetative compatibility groups (VCGs), was analyzed using modified DNA amplification fingerprinting. Also characterized were 133 isolates that did not belong to any of the reported VCGs of F. oxysporum f. sp. cubense including race 3 isolates from a Heliconia species and isolates from a symptomatic wild banana species growing in the jungle in peninsular Malaysia. The DNA fingerprint patterns were generally VCG specific, irrespective of geographic or host origin. A total of 33 different genotypes were identified within F. oxysporum f. sp. cu-bense; 19 genotypes were distinguished among the isolates that belonged to the 20 reported VCGs, and 14 new genotypes were identified among the isolates that did not belong to any of the existing VCGs. DNA fingerprinting analysis also allowed differentiation of nine clonal lineages within F. oxysporum f. sp. cubense. Five of these lineages each contained numerous closely related VCGs and genotypes, and the remaining four lineages each contained a single genotype. The genetic diversity and geographic distribution of several of these lineages of F. oxysporum f. sp. cubense suggests that they have coevolved with edible bananas and their wild diploid progenitors in Asia. DNA fingerprinting analysis of isolates from the wild pathosystem provides further evidence for the coevolution hypothesis. The genetic isolation and limited geographic distribution of four of the lineages of F. oxysporum f. sp. cubense suggests that the pathogen has also arisen independently, both within and outside of the center of origin of the host. PMID:18944830

  11. Variation in morphotype, karyotype and DNA type of fluconazole resistant Candida albicans from an AIDS patient.

    Takasuka, T; Baily, G G; Birch, M; Anderson, M J; Law, D; Denning, D W

    1998-01-01

    Azole-resistant oropharyngeal and oesophageal candidiasis is a recent phenomenon observed in patients with AIDS usually previously treated with fluconazole. Some variation has been observed in antifungal susceptibility testing among separate colonies of Candida albicans from the same patient. This raises the question of whether there are multiple clones present or simply phenotypic variation in expression of azole resistance. To address this question we took 18 isolates grown from multiple swabs taken before and after experimental azole therapy from a single HIV-positive individual with fluconazole-resistant oral candidiasis and compared morphotype, karyotype, PCR-based DNA typing and azole susceptibility. Ten of the isolates were from a single 2-day period. Amongst these 10 there were seven morphotypes, five karyotypes and four polymerase chain reaction (PCR) types. Three further morphotypes, one karyotype and two PCR types were found amongst the eight isolates obtained during the subsequent 4 months. Limited variation in susceptibility to two azoles--fluconazole and D0870--was also seen. This work emphasizes both the large genotype and phenotypic variability of C. albicans isolates in the mouth of AIDS patients with fluconazole resistance, and the difficulties in interpretation of present typing methods. PMID:9515670

  12. Genetic variation in two conserved local Romanian pig breeds using type 1 DNA markers

    Wales Richard

    2001-07-01

    Full Text Available Abstract Analysis of the genetic variation of an endangered population is an important component for the success of conservation. Animals from two local Romanian pig breeds, the Mangalitsa and Bazna, were analysed for variation at a number of genetic loci using PCR-based DNA tests. Polymorphism was assessed at loci which 1 are known to cause phenotypic variation, 2 are potentially involved in trait differences or 3 are putative candidate genes. The traits considered are disease resistance, growth, coat colour, meat quality and prolificacy. Even though the populations are small and the markers are limited to specific genes, we found significant differences in five of the ten characterised loci. In some cases the observed allele frequencies were interesting in relation to gene function and the phenotype of the breed. These breeds are part of a conservation programme in Romania and marker information may be useful in preserving a representative gene pool in the populations. The use of polymorphisms in type 1 (gene markers may be a useful complement to analysis based on anonymous markers.

  13. Variation in the measurement of DNA damage by comet assay measured by the ECVAG dagger inter-laboratory validation trial

    Forchhammer, Lykke; Johansson, Clara; Loft, Steffen;

    2010-01-01

    The comet assay has become a popular method for the assessment of DNA damage in biomonitoring studies and genetic toxicology. However, few studies have addressed the issue of the noted inter-laboratory variability of DNA damage measured by the comet assay. In this study, 12 laboratories analysed...... by the different laboratories as evidenced by an inter-laboratory coefficient of variation (CV) of 47%. Adjustment of the primary comet assay end points by a calibration curve prepared in each laboratory reduced the CV to 28%, a statistically significant reduction (P <0.05, Levene's test). A large...... fraction of the inter-laboratory variation originated from differences in image analysis, whereas the intra-laboratory variation was considerably smaller than the variation between laboratories. In summary, adjustment of primary comet assay results by reference standards reduces inter-laboratory variation...

  14. The origin of Mosuo people as revealed by mtDNA and Y chromosome variation

    WEN; Bo; SHI; Hong; REN; Ling; XI; Huifeng; LI; Kaiyuan; ZHA

    2004-01-01

    The Mosuo, living in the Lugu Lake area in northwest Yunnan Province, China, is the only matriarchal population in China. The Mosuo was officially identified as Naxi nationality although its relationship with Naxi remains controversial. We studied the genetic relationship between the Mosuo and five other ethnic groups currently residing in northwest Yunnan, i.e. Naxi, Tibetan, Bai, Yi and Pumi, by typing the genetic variations in mtDNA HVS1 and 21 Y chromosome markers (13 SNPs & 8 STR markers). We showed that the maternal lineages of the Mosuo bear the strongest resemblance with those found in Naxi while its paternal lineages are more similar to those that are prevalent in Yunnan Tibetan. The marked difference between paternal and maternal lineages may be attributable to the genetic history, matriarchal structure, and visiting marriage.

  15. Intraspecific Variation in Ribosomal DNA in Populations of the Potato Cyst Nematode Globodera pallida.

    Blok, V C; Malloch, G; Harrower, B; Phillips, M S; Vrain, T C

    1998-06-01

    The relationships among a number of populations of Globodera pallida from Britian, the Netherlands, Germany, Switzerland, and South America were examined using PCR amplification of the ribosomal cistron between the 18S and 28S genes that include the two intergenic spacer regions (ITS1 and ITS2) and the 5.8S gene. Amplifications produced a similar-sized product of 1150 bp from all populations. Digestion of the amplified fragment with a number of restriction enzymes showed differences among the populations. The restriction enzyme RsaI distinguished the most populations. The RFLP patterns revealed by this enzyme were complex and could have arisen from heterogeneity between individuals within populations and from differences between the repeats of an individual. Sequence analysis from six of the populations, together with RFLP analysis of PCR products, shows that there is intraspecific variation in the rDNA of G. pallida. PMID:19274220

  16. Statistical aspects of discerning indel-type structural variation via DNA sequence alignment

    Wilson Richard K

    2009-08-01

    Full Text Available Abstract Background Structural variations in the form of DNA insertions and deletions are an important aspect of human genetics and especially relevant to medical disorders. Investigations have shown that such events can be detected via tell-tale discrepancies in the aligned lengths of paired-end DNA sequencing reads. Quantitative aspects underlying this method remain poorly understood, despite its importance and conceptual simplicity. We report the statistical theory characterizing the length-discrepancy scheme for Gaussian libraries, including coverage-related effects that preceding models are unable to account for. Results Deletion and insertion statistics both depend heavily on physical coverage, but otherwise differ dramatically, refuting a commonly held doctrine of symmetry. Specifically, coverage restrictions render insertions much more difficult to capture. Increased read length has the counterintuitive effect of worsening insertion detection characteristics of short inserts. Variance in library insert length is also a critical factor here and should be minimized to the greatest degree possible. Conversely, no significant improvement would be realized in lowering fosmid variances beyond current levels. Detection power is examined under a straightforward alternative hypothesis and found to be generally acceptable. We also consider the proposition of characterizing variation over the entire spectrum of variant sizes under constant risk of false-positive errors. At 1% risk, many designs will leave a significant gap in the 100 to 200 bp neighborhood, requiring unacceptably high redundancies to compensate. We show that a few modifications largely close this gap and we give a few examples of feasible spectrum-covering designs. Conclusion The theory resolves several outstanding issues and furnishes a general methodology for designing future projects from the standpoint of a spectrum-wide constant risk.

  17. Seasonal variations in levels of DNA adducts and X-spots in human populations living in different parts of Poland.

    Grzybowska, E; Hemminki, K; Choraźy, M

    1993-01-01

    White blood cell DNA adducts were measured in coke oven workers, in residents from the area next to the coke oven in Silesia, Poland (highly industrialized region), and in residents from the rural area of Poland using the 32P-postlabeling technique. This method detected aromatic adducts including adducts formed by polycyclic aromatic hydrocarbons (PAHs). Highest levels of adducts in DNA were seen in the group of coke battery workers (6.9 adducts/10(8) nucleotides). Seasonal variations in leve...

  18. Mitochondrial DNA variation within and between two species of neotropical anopheline mosquitoes (Diptera:Culicidae).

    Conn, J E; Mitchell, S E; Cockburn, A F

    1997-01-01

    We analyzed variation in mitochondrial DNA (mtDNA) of two neotropical mosquitoes, Anopheles rangeli (n = 181) and A. trinkae (n = 45), with very different distribution patterns in Latin America, to assess species boundaries for these putative sister taxa and to examine population genetic structure. Phylogenetic analyses revealed (1) support for the monophyletic origin of each species; (2) diagnostic restriction site differences between the species; (3) geographic partitioning of haplotypes by country in A. rangeli from Bolivia, Ecuador, and Venezuela compared with considerable overlap in haplotypes of A. trinkae from Bolivia and Ecuador; and (4) similar levels of mean haplotype and nucleotide diversity in both species, but lower levels of mean nucleotide divergence in A. trinkae compared with A. rangeli. We hypothesize that higher maternal gene flow and lower divergence in A. trinkae are most likely due either to a distinctive matrilineal history or to a smaller effective population size, which may have been influenced by a smaller, essentially linear geographic range along the eastern flank of the Andes. In the cladistic analysis of A. rangell, the Bolivian haplotypes appear to be more derived than those from Ecuador or Venezuela, yet there is no evidence to support the hypothesis of a recent range expansion from Ecuador into Bolivia. PMID:9099005

  19. Association of mitochondrial DNA variations with lung cancer risk in a Han Chinese population from southwestern China.

    Shizhen Zheng

    Full Text Available Mitochondrial DNA (mtDNA is particularly susceptible to oxidative damage and mutation due to the high rate of reactive oxygen species (ROS production and limited DNA-repair capacity in mitochondrial. Previous studies demonstrated that the increased mtDNA copy number for compensation for damage, which was associated with cigarette smoking, has been found to be associated with lung cancer risk among heavy smokers. Given that the common and "non-pathological" mtDNA variations determine differences in oxidative phosphorylation performance and ROS production, an important determinant of lung cancer risk, we hypothesize that the mtDNA variations may play roles in lung cancer risk. To test this hypothesis, we conducted a case-control study to compare the frequencies of mtDNA haplogroups and an 822 bp mtDNA deletion between 422 lung cancer patients and 504 controls. Multivariate logistic regression analysis revealed that haplogroups D and F were related to individual lung cancer resistance (OR = 0.465, 95%CI = 0.329-0.656, p<0.001; and OR = 0.622, 95%CI = 0.425-0.909, p = 0.014, respectively, while haplogroups G and M7 might be risk factors for lung cancer (OR = 3.924, 95%CI = 1.757-6.689, p<0.001; and OR = 2.037, 95%CI = 1.253-3.312, p = 0.004, respectively. Additionally, multivariate logistic regression analysis revealed that cigarette smoking was a risk factor for the 822 bp mtDNA deletion. Furthermore, the increased frequencies of the mtDNA deletion in male cigarette smoking subjects of combined cases and controls with haplogroup D indicated that the haplogroup D might be susceptible to DNA damage from external ROS caused by heavy cigarette smoking.

  20. Effects of Twelve Germline Missense Variations on DNA Lesion and G-Quadruplex Bypass Activities of Human DNA Polymerase REV1.

    Yeom, Mina; Kim, In-Hyeok; Kim, Jae-Kwon; Kang, KyeongJin; Eoff, Robert L; Guengerich, F Peter; Choi, Jeong-Yun

    2016-03-21

    The Y-family DNA polymerase REV1 is involved in replicative bypass of damaged DNA and G-quadruplex (G4) DNA. In addition to a scaffolding role in the replicative bypass, REV1 acts in a catalytic role as a deoxycytidyl transferase opposite some replication stall sites, e.g., apurinic/apyrimidinic (AP) sites, N(2)-guanyl lesions, and G4 sites. We characterized the biochemical properties of 12 reported germline missense variants of human REV1, including the N373S variant associated with high risk of cervical cancer, using the recombinant REV1 (residues 330-833) proteins and DNA templates containing a G, AP site, N(2)-CH2(2-naphthyl)G (N(2)-NaphG), or G4. In steady-state kinetic analyses, the F427L, R434Q, M656V, D700N, R704Q, and P831L variants displayed 2- to 8-fold decreases in kcat/Km for dCTP insertion opposite all four templates, compared to that of wild-type, while the N373S, M407L, and N497S showed 2- to 3-fold increases with all four and the former three or two templates, respectively. The F427L, R434Q, M656V, and R704Q variants also had 2- to 3-fold lower binding affinities to DNA substrates containing G, an AP site, and/or N(2)-NaphG than wild-type. Distinctively, the N373S variant had a 3-fold higher binding affinity to G4 DNA than the wild-type, as well as a 2-fold higher catalytic activity opposite the first tetrad G, suggesting a facilitating effect of this variation on replication of G4 DNA sequences in certain human papillomavirus genomes. Our results suggest that the catalytic function of REV1 is moderately or slightly altered by at least nine genetic variations, and the G4 DNA processing function of REV1 is slightly enhanced by the N373S variation, which might provide the possibility that certain germline missense REV1 variations affect the individual susceptibility to carcinogenesis by modifying the capability of REV1 for replicative bypass past DNA lesions and G4 motifs derived from chemical and viral carcinogens. PMID:26914252

  1. Effects of a sex-ratio distorting endosymbiont on mtDNA variation in a global insect pest

    Cook James M

    2009-03-01

    Full Text Available Abstract Background Patterns of mtDNA variation within a species reflect long-term population structure, but may also be influenced by maternally inherited endosymbionts, such as Wolbachia. These bacteria often alter host reproductive biology and can drive particular mtDNA haplotypes through populations. We investigated the impacts of Wolbachia infection and geography on mtDNA variation in the diamondback moth, a major global pest whose geographic distribution reflects both natural processes and transport via human agricultural activities. Results The mtDNA phylogeny of 95 individuals sampled from 10 countries on four continents revealed two major clades. One contained only Wolbachia-infected individuals from Malaysia and Kenya, while the other contained only uninfected individuals, from all countries including Malaysia and Kenya. Within the uninfected group was a further clade containing all individuals from Australasia and displaying very limited sequence variation. In contrast, a biparental nuclear gene phylogeny did not have infected and uninfected clades, supporting the notion that maternally-inherited Wolbachia are responsible for the mtDNA pattern. Only about 5% (15/306 of our global sample of individuals was infected with the plutWB1 isolate and even within infected local populations, many insects were uninfected. Comparisons of infected and uninfected isofemale lines revealed that plutWB1 is associated with sex ratio distortion. Uninfected lines have a 1:1 sex ratio, while infected ones show a 2:1 female bias. Conclusion The main correlate of mtDNA variation in P. xylostella is presence or absence of the plutWB1 infection. This is associated with substantial sex ratio distortion and the underlying mechanisms deserve further study. In contrast, geographic origin is a poor predictor of moth mtDNA sequences, reflecting human activity in moving the insects around the globe. The exception is a clade of Australasian individuals, which may

  2. Effects of a sex-ratio distorting endosymbiont on mtDNA variation in a global insect pest

    Delgado, Ana M; Cook, James M

    2009-01-01

    Background Patterns of mtDNA variation within a species reflect long-term population structure, but may also be influenced by maternally inherited endosymbionts, such as Wolbachia. These bacteria often alter host reproductive biology and can drive particular mtDNA haplotypes through populations. We investigated the impacts of Wolbachia infection and geography on mtDNA variation in the diamondback moth, a major global pest whose geographic distribution reflects both natural processes and transport via human agricultural activities. Results The mtDNA phylogeny of 95 individuals sampled from 10 countries on four continents revealed two major clades. One contained only Wolbachia-infected individuals from Malaysia and Kenya, while the other contained only uninfected individuals, from all countries including Malaysia and Kenya. Within the uninfected group was a further clade containing all individuals from Australasia and displaying very limited sequence variation. In contrast, a biparental nuclear gene phylogeny did not have infected and uninfected clades, supporting the notion that maternally-inherited Wolbachia are responsible for the mtDNA pattern. Only about 5% (15/306) of our global sample of individuals was infected with the plutWB1 isolate and even within infected local populations, many insects were uninfected. Comparisons of infected and uninfected isofemale lines revealed that plutWB1 is associated with sex ratio distortion. Uninfected lines have a 1:1 sex ratio, while infected ones show a 2:1 female bias. Conclusion The main correlate of mtDNA variation in P. xylostella is presence or absence of the plutWB1 infection. This is associated with substantial sex ratio distortion and the underlying mechanisms deserve further study. In contrast, geographic origin is a poor predictor of moth mtDNA sequences, reflecting human activity in moving the insects around the globe. The exception is a clade of Australasian individuals, which may reflect a bottleneck during

  3. Comprehensive Analysis of Pan-African Mitochondrial DNA Variation Provides New Insights into Continental Variation and Demography.

    Cerezo, María; Gusmão, Leonor; Černý, Viktor; Uddin, Nabeel; Syndercombe-Court, Denise; Gómez-Carballa, Alberto; Göbel, Tanja; Schneider, Peter M; Salas, Antonio

    2016-03-20

    Africa is the cradle of all human beings, and although it has been the focus of a number of genetic studies, there are many questions that remain unresolved. We have performed one of the largest and most comprehensive meta-analyses of mitochondrial DNA (mtDNA) lineages carried out in the African continent to date. We generated high-throughput mtDNA single nucleotide polymorphism (SNP) data (230 SNPs) from 2024 Africans, where more than 500 of them were additionally genotyped for the control region. These data were analyzed together with over 12,700 control region profiles collected from the literature, representing more than 300 population samples from Africa. Insights into the African homeland of humans are discussed. Phylogeographic patterns for the African continent are shown at a high phylogeographic resolution as well as at the population and regional levels. The deepest branch of the mtDNA tree, haplogroup L0, shows the highest sub-haplogroup diversity in Southeast and East Africa, suggesting this region as the homeland for modern humans. Several demographic estimates point to the coast as a facilitator of human migration in Africa, but the data indicate complex patterns, perhaps mirroring the effect of recent continental-scaled demographic events in re-shaping African mtDNA variability. PMID:27020033

  4. Population structure of African buffalo inferred from mtDNA sequences and microsatellite loci: high variation but low differentiation

    Simonsen, Bo Thisted; Siegismund, H R; Arctander, P

    1998-01-01

    mtDNA and microsatellite data were found to be congruent, disagreeing with the alleged male-biased dispersal. We propose that the observed pattern of the distribution of genetic variation between buffalo populations at the regional level can be caused by fragmentation of a previous panmictic...

  5. Genetic variation and species identification of Thai Boesenbergia (Zingiberaceae) analyzed by chloroplast DNA polymorphism.

    Techaprasan, Jiranan; Ngamriabsakul, Chatchai; Klinbunga, Sirawut; Chusacultanachai, Sudsanguan; Jenjittikul, Thaya

    2006-07-31

    Genetic variation and molecular phylogeny of 22 taxa representing 14 extant species and 3 unidentified taxa of Boesenbergia in Thailand and four outgroup species (Cornukaempferia aurantiflora, Hedychium biflorum, Kaempferia parviflora, and Scaphochlamys rubescens) were examined by sequencing of 3 chloroplast (cp) DNA regions (matK, psbA-trnH and petA-psbJ). Low interspecific genetic divergence (0.25-1.74%) were observed in these investigated taxa. The 50% majority-rule consensus tree constructed from combined chloroplast DNA sequences allocated Boesenbergia in this study into 3 different groups. Using psbA-1F/psbA-3R primers, an insertion of 491 bp was observed in B. petiolata. Restriction analysis of the amplicon (380-410 bp) from the remaining species with Rsa I further differentiated Boesenbergia to 2 groupings; I (B. basispicata, B. longiflora, B. longipes, B. plicata, B.pulcherrima, B. tenuispicata, B. thorelii, B. xiphostachya, Boesenbergia sp.1 and Boesenbergia sp.3; phylogenetic clade A) that possesses a Rsa I restriction site and II (B.curtisii, B. regalis, B. rotunda and Boesenbergia sp.2; phylogenetic clade B and B. siamensis; phylogenetic clade C) that lacks a restriction site of Rsa I. Single nucleotide polymorphism (SNP) and indels found can be unambiguously applied to authenticate specie-origin of all investigated samples and revealed that Boesenbergia sp.1, Boesenbergia sp.2 and B. pulcherrima (Mahidol University, Kanchanaburi), B. cf. pulcherrima1 (Prachuap Khiri Khan) and B. cf. pulcherrima2 (Thong Pha Phum, Kanchanaburi) are B. plicata, B. rotunda and B. pulcherrima, respectively. In addition, molecular data also suggested that Boesenbergia sp.3 should be further differentiated from B. longiflora and regarded as a newly unidentified Boesenbergia species. PMID:16889678

  6. Variation in assessment of oxidatively damaged DNA in mononuclear blood cells by the comet assay with visual scoring

    Forchhammer, Lykke; Bräuner, Elvira Vaclavik; Folkmann, Janne Kjaersgaard;

    2008-01-01

    The comet assay is popular for assessments of genotoxicity, but the comparison of results between studies is challenging because of differences in experimental procedures and reports of DNA damage in different units. We investigated the variation of DNA damage in mononuclear blood cells (MNBCs......) measured by the comet assay with focus on the variation related to alkaline unwinding and electrophoresis time, number of cells scored, as well as the putative benefits of transforming the primary end points to common units by the use of reference standards and calibration curves. Eight experienced...... conclusion, our results indicate that inter-investigator difference in scoring is a strong determinant of DNA damage levels measured by the comet assay....

  7. Assessment and reduction of comet assay variation in relation to DNA damage: studies from the European Comet Assay Validation Group

    Møller, Peter; Möller, Lennart; Godschalk, Roger W L;

    2010-01-01

    The alkaline single cell gel electrophoresis (comet) assay has become a widely used method for the detection of DNA damage and repair in cells and tissues. Still, it has been difficult to compare results from different investigators because of differences in assay conditions and because the data...... are reported in different units. The European Comet Assay Validation Group (ECVAG) was established for the purpose of validation of the comet assay with respect to measures of DNA damage formation and its repair. The results from this inter-laboratory validation trail showed a large variation in...... substantial reliability for the measurement of DNA damage by the comet assay but there is still a need for further validation to reduce both assay and inter-laboratory variation....

  8. Comprehensive Analysis of Pan-African Mitochondrial DNA Variation Provides New Insights into Continental Variation and Demography

    Cerezo, M.; Gusmão, L.; Černý, Viktor; Uddin, N.; Syndercombe-Court, D.; Gómez-Carballa, A.; Göbel, T.; Schneider, P. M.; Salas, A.

    2016-01-01

    Roč. 43, č. 3 (2016), s. 133-143. ISSN 1673-8527 R&D Projects: GA ČR GA13-37998S Institutional support: RVO:67985912 Keywords : mtDNA * haplotype * haplogroup * SNP * MALDI-TOF Subject RIV: AC - Archeology, Anthropology, Ethnology Impact factor: 3.585, year: 2014

  9. Mendelian breeding units versus standard sampling strategies: mitochondrial DNA variation in southwest Sardinia

    Daria Sanna

    2011-01-01

    Full Text Available We report a sampling strategy based on Mendelian Breeding Units (MBUs, representing an interbreeding group of individuals sharing a common gene pool. The identification of MBUs is crucial for case-control experimental design in association studies. The aim of this work was to evaluate the possible existence of bias in terms of genetic variability and haplogroup frequencies in the MBU sample, due to severe sample selection. In order to reach this goal, the MBU sampling strategy was compared to a standard selection of individuals according to their surname and place of birth. We analysed mitochondrial DNA variation (first hypervariable segment and coding region in unrelated healthy subjects from two different areas of Sardinia: the area around the town of Cabras and the western Campidano area. No statistically significant differences were observed when the two sampling methods were compared, indicating that the stringent sample selection needed to establish a MBU does not alter original genetic variability and haplogroup distribution. Therefore, the MBU sampling strategy can be considered a useful tool in association studies of complex traits.

  10. Genetic variation and population differentiation of Michelia formosana (Magnoliaceae) based on cpDNA variation and RAPD fingerprints: relevance to post-Pleistocene recolonization.

    Lu, Sheng-You; Hong, Kuo-Hsiang; Liu, Show-Ling; Cheng, Yu-Pin; Wu, Wen-Luan; Chiang, Tzen-Yuh

    2002-06-01

    We used sequence variation of the atpB- rbcL intergenic spacer of cpDNA and nested clade analysis to assess the phylogeographic pattern of Michelia formosana, a species restricted to Taiwan and the Ryukyus. In total, 31 haplotypes were identified and clustered into four major chlorotypes. Genetic composition of nearly all populations was heterogeneous and paraphyletic phylogenetically. Although the apportionment of cpDNA variation hardly revealed a geographic pattern due to the coancestry of dominant sequences, some chlorotypes were restrictedly distributed. According to the patterns of clade dispersion and displacement, a reconstructed minimum spanning network revealed that historical events of past fragmentation and range expansion, associated with glaciation, may have shaped the phylogeographic patterns of M. formosana. Four possible refugia were identified: the Iriomote and Ishigaki Islands (the southern Ryukyus), Wulai (northern Taiwan), and Nanjen (southern Taiwan), on the basis of the interior positions of their haplotypes in the network and the high level of nucleotide diversity. Given insufficient time for coalescence at the cpDNA locus since the late Pleistocene recolonization, lineage sorting led to low levels of genetic differentiation among populations. In contrast, hierarchical examination of the random amplified polymorphic DNA (RAPD) data scored from six populations across three geographical regions, using an analysis of molecular variance (AMOVA), indicated high genetic differentiation both among populations (Phi(ST) = 0.471) and among regions (Phi(CT) = 0.368). An unweighted pair group method with arithmetic mean (UPGMA) tree of the RAPD fingerprints revealed that populations of two offshore islands of eastern Taiwan ( M. formosana var. kotoensis) were clustered with geographically remote populations of the Ryukyus instead of those in southern Taiwan, suggesting some historical division due to geographic barriers of the central mountain range. In

  11. Linearisation of λDNA molecules by instantaneous variation of the trapping electrode voltage inside a micro-channel

    Because long DNA molecules usually exist in random coil states due to the entropic effect, linearisation is required for devices equipped with nanopores where electrical sequencing is necessary during single-file translocation. We present a novel technique for linearising DNA molecules in a micro-channel. In our device, electrodes are embedded in the bottom surface of the channel. The application of a voltage induces the trapping of λDNA molecules on the positive electrode. An instantaneous voltage drop is used to put the λDNA molecules in a partly released state and the hydrodynamic force of the solution induces linearisation. Phenomena were directly observed using an optical microscopy system equipped with a high-speed camera and the linearisation principle was explored in detail. Furthermore, we estimate the tensile characteristics produced by the flow of the solution through a numerical model of a tethered polymer subject to a Poiseuille flow. The mean tensile force is in the range of 0.1–1 pN. This is sufficiently smaller than the structural transition point of λDNA but counterbalances the entropic elasticity that causes the random coil shape of λDNA molecules in solution. We show the important role of thermal fluctuation in the manipulation of molecules in solution and clarify the tensile conditions required for DNA linearisation using a combination of solution flow and voltage variation in a microchannel. (paper)

  12. Application of a Random Walk Model to Geographic Distributions of Animal Mitochondrial DNA Variation

    Neigel, J. E.; Avise, J C

    1993-01-01

    In rapidly evolving molecules, such as animal mitochondrial DNA, mutations that delineate specific lineages may not be dispersed at sufficient rates to attain an equilibrium between genetic drift and gene flow. Here we predict conditions that lead to nonequilibrium geographic distributions of mtDNA lineages, test the robustness of these predictions and examine mtDNA data sets for consistency with our model. Under a simple isolation by distance model, the variance of an mtDNA lineage's geograp...

  13. Study Of Genetic Variation At The Level Of DNA Between Normal And Steriled Potato Tuber Moth Males (Phthorimaea operculella, Zeller)

    The main objective of current study was to determine the genetic variation at the level of DNA between the normal and sterilized potato tuber moth males. The required mating experiments were carried out to obtain partially sterilize males at 150 Gy and their offspring. Some biological factors of these males were estimated and compared to their unirradiated siblings. To acquire good quality and quantity of DNA for the AFLP technique, several methods were undertaken to isolate DNA of potato tuber moth male from different developmental stages especially from adult stage. However, a method called Modified M5 was used. By Modified M5, which required phenol for the isolation of DNA, in some samples 8 to 12 Mg were obtained from one insect with 95-100% purity. In our study, AFLP technique was used to analyze the DNA samples of irradiated and unirradiated males from required mating. The result analysis showed that there was a clear genetic variability between examined individuals. However, the relationship between unirradiated F1 and F2 males was stronger than that between irradiated males. Thus, our result demonstrates that the AFLP could be efficiently utilized for studying genetic variation between insect species or between individuals of the same line which have biological differences induced by several factors such as irradiation. Moreover, this technique could enhance the effectiveness of sterile insect technique by using the AFLP in the monitoring system of released insects. (author)

  14. Study of genetic variation at the level of DNA between normal and sterilized potato tuber moth males (phthorimaea operculella, zeller)

    The main objective of current study was to determine the genetic variation at the level of DNA between the normal and sterilized potato tuber moth males. The required mating experiments were carried out to obtain partially sterilized males at 150 Gy and their offspring. Some biological factors of these males were estimated and compared to their unirradiated siblings. To acquire good quality and quantity of DNA for the AFLP technique, several methods were undertaken to isolate DNA of potato tuber moth male from different developmental stages especially from adult stage. However, a method called Modified M5 was used. By Modified M5, which required phenol for the isolation of DNA, in some samples 8 to 12 μg were obtained from one insect with 95-100% purity. In our study, AFLP technique was used to analyze the DNA samples of irradiated and unirradiated males from required mating. The result analysis showed that there was a clear genetic variability between examined individuals. However, the relationship between unirradiated F1 and F2 males was stronger than that between irradiated males. Thus, our result demonstrates that the AFLP could be efficiently utilized for studying genetic variation between insect species or between individuals of the same line which have biological differences induced by several factors such as irradiation. Moreover, this technique could enhance the effectiveness of sterile insect technique by using the AFLP in the monitoring system of released insects. (author)

  15. Mitochondrial DNA variation within P-type cytoplasmic male sterility of Plantago lanceolata L

    Groenendijk, C.F.M.; Sandbrink, J.M.; Van Brederode, J.; Van Damme, J.M.M.

    1997-01-01

    MtDNA restriction fragment polymorphisms were found between cytoplasmic male-sterility types P and R of Plantago lanceolata with the homologous probe pPl311 and maize mtDNA fragments derived from the regions of atp1, cox1 and cox2. No mtDNA differences were observed between male-sterile and restored

  16. Sequence-dependent Structural Variation in DNA Undergoing Intrahelical Inspection by the DNA glycosylase MutM

    Sung, Rou-Jia; Zhang, Michael; Qi, Yan; Verdine, Gregory L. (Harvard-Med); (Harvard)

    2012-08-31

    MutM, a bacterial DNA-glycosylase, plays a critical role in maintaining genome integrity by catalyzing glycosidic bond cleavage of 8-oxoguanine (oxoG) lesions to initiate base excision DNA repair. The task faced by MutM of locating rare oxoG residues embedded in an overwhelming excess of undamaged bases is especially challenging given the close structural similarity between oxoG and its normal progenitor, guanine (G). MutM actively interrogates the DNA to detect the presence of an intrahelical, fully base-paired oxoG, whereupon the enzyme promotes extrusion of the target nucleobase from the DNA duplex and insertion into the extrahelical active site. Recent structural studies have begun to provide the first glimpse into the protein-DNA interactions that enable MutM to distinguish an intrahelical oxoG from G; however, these initial studies left open the important question of how MutM can recognize oxoG residues embedded in 16 different neighboring sequence contexts (considering only the 5'- and 3'-neighboring base pairs). In this study we set out to understand the manner and extent to which intrahelical lesion recognition varies as a function of the 5'-neighbor. Here we report a comprehensive, systematic structural analysis of the effect of the 5'-neighboring base pair on recognition of an intrahelical oxoG lesion. These structures reveal that MutM imposes the same extrusion-prone ('extrudogenic') backbone conformation on the oxoG lesion irrespective of its 5'-neighbor while leaving the rest of the DNA relatively free to adjust to the particular demands of individual sequences.

  17. Genetic variation detected by use of the M13 "DNA fingerprint" probe in Malus, Prunus, and Rubus (Rosaceae).

    Nybom, H; Rogstad, S H; Schaal, B A

    1990-02-01

    Recently, "DNA fingerprints" have been reported in a wide array of organisms. We used the M13 repeat probe on several genera and species in the angiosperm family Rosaceae. Four apple cultivars could be differentiated when any one of five restriction enzymes was used to analyze minisatellite DNA. Similarly, four individual trees of Prunus serotina (black cherry) exhibited different "fingerprints" with each of four enyzmes. A total of 14 Rubus (blackberries and raspberries) plants representing four species were investigated with two enzymes. Extensive inter-and intraspecific variation was found. However, some closely growing plants had identical "fingerprints", probably due to their being derived through vegetative propagation. PMID:24226211

  18. Molecular DNA variation among Triturus vittatus vittatus (Urodela from different breeding sites at the southern limit of its distribution

    Oren Pearlson

    2007-11-01

    Full Text Available Molecular DNA variation among Triturus vittatus vittatus (striped newt from different breeding sites at the southern limit of the species distribution (where environmental conditions are most extreme was studied by the random amplification of polymorphic DNA (RAPD method that has been found to be appropriate for other Triturus species. Altitudes of the localities ranged between 15-740 m a.s.l. Of the 20 primers employed, OPA-16 was the only one suitable for T. vittatus, revealing a different band pattern for different populations. Genetic similarity was calculated by band sharing, which demonstrated a high similarity among the Israeli populations.

  19. Population and forensic genetic analyses of mitochondrial DNA control region variation from six major provinces in the Korean population.

    Hong, Seung Beom; Kim, Ki Cheol; Kim, Wook

    2015-07-01

    We generated complete mitochondrial DNA (mtDNA) control region sequences from 704 unrelated individuals residing in six major provinces in Korea. In addition to our earlier survey of the distribution of mtDNA haplogroup variation, a total of 560 different haplotypes characterized by 271 polymorphic sites were identified, of which 473 haplotypes were unique. The gene diversity and random match probability were 0.9989 and 0.0025, respectively. According to the pairwise comparison of the 704 control region sequences, the mean number of pairwise differences between individuals was 13.47±6.06. Based on the result of mtDNA control region sequences, pairwise FST genetic distances revealed genetic homogeneity of the Korean provinces on a peninsular level, except in samples from Jeju Island. This result indicates there may be a need to formulate a local mtDNA database for Jeju Island, to avoid bias in forensic parameter estimates caused by genetic heterogeneity of the population. Thus, the present data may help not only in personal identification but also in determining maternal lineages to provide an expanded and reliable Korean mtDNA database. These data will be available on the EMPOP database via accession number EMP00661. PMID:25900647

  20. MitoLSDB: a comprehensive resource to study genotype to phenotype correlations in human mitochondrial DNA variations.

    Shamnamole K

    Full Text Available Human mitochondrial DNA (mtDNA encodes a set of 37 genes which are essential structural and functional components of the electron transport chain. Variations in these genes have been implicated in a broad spectrum of diseases and are extensively reported in literature and various databases. In this study, we describe MitoLSDB, an integrated platform to catalogue disease association studies on mtDNA (http://mitolsdb.igib.res.in. The main goal of MitoLSDB is to provide a central platform for direct submissions of novel variants that can be curated by the Mitochondrial Research Community. MitoLSDB provides access to standardized and annotated data from literature and databases encompassing information from 5231 individuals, 675 populations and 27 phenotypes. This platform is developed using the Leiden Open (source Variation Database (LOVD software. MitoLSDB houses information on all 37 genes in each population amounting to 132397 variants, 5147 unique variants. For each variant its genomic location as per the Revised Cambridge Reference Sequence, codon and amino acid change for variations in protein-coding regions, frequency, disease/phenotype, population, reference and remarks are also listed. MitoLSDB curators have also reported errors documented in literature which includes 94 phantom mutations, 10 NUMTs, six documentation errors and one artefactual recombination. MitoLSDB is the largest repository of mtDNA variants systematically standardized and presented using the LOVD platform. We believe that this is a good starting resource to curate mtDNA variants and will facilitate direct submissions enhancing data coverage, annotation in context of pathogenesis and quality control by ensuring non-redundancy in reporting novel disease associated variants.

  1. Ribosomal DNA of Aphidius (Hymenoptera: Braconidae) Nees: Structure and intraspecific variations

    An investigation is being carried out on the ribosomal DNA (rDNA) molecular organization of closely related Arphidiinae species belonging to the genus Aphidius Nees, of relevant interest in biological control, with the aim of evaluating the variability within and between species. After construction of a restriction map of the most represented A. ervi rDNA cistrons, the molecular organization of the rDNA repeating units of single individuals and populations was studied in Southern blot analyses. Heterogeneity within the A. ervi rDNA cistrons and between populations of different geographical origin was identified. This approach allowed the conclusion to be reached that differences in the rDNA cistrons can be diagnostic of species and populations, therefore providing a useful tool in biological control programmes. (author). 18 refs, 4 figs

  2. On the edge of Bantu expansions: mtDNA, Y chromosome and lactase persistence genetic variation in southwestern Angola

    Beleza Sandra; Luiselli Donata; Sequeira Fernando; Coelho Margarida; Rocha Jorge

    2009-01-01

    Abstract Background Current information about the expansion of Bantu-speaking peoples is hampered by the scarcity of genetic data from well identified populations from southern Africa. Here, we fill an important gap in the analysis of the western edge of the Bantu migrations by studying for the first time the patterns of Y-chromosome, mtDNA and lactase persistence genetic variation in four representative groups living around the Namib Desert in southwestern Angola (Ovimbundu, Ganguela, Nyanek...

  3. Analysis of domestic dog mitochondrial DNA sequence variation for forensic investigations

    Angleby, Helen

    2005-01-01

    The first method for DNA analysis in forensics was presented in 1985. Since then, the introduction of the polymerase chain reaction (PCR) has rendered possible the analysis of small amounts of DNA and automated sequencing and fragment analysis techniques have facilitated the analyses. In most cases short tandemly repeated regions (STRs) of nuclear DNA are analysed in forensic investigations, but all samples cannot be successfully analysed using this method. For samples containing minute amoun...

  4. The use of high-throughput DNA sequencing in the investigation of antigenic variation: application to Neisseria species.

    John K Davies

    Full Text Available Antigenic variation occurs in a broad range of species. This process resembles gene conversion in that variant DNA is unidirectionally transferred from partial gene copies (or silent loci into an expression locus. Previous studies of antigenic variation have involved the amplification and sequencing of individual genes from hundreds of colonies. Using the pilE gene from Neisseria gonorrhoeae we have demonstrated that it is possible to use PCR amplification, followed by high-throughput DNA sequencing and a novel assembly process, to detect individual antigenic variation events. The ability to detect these events was much greater than has previously been possible. In N. gonorrhoeae most silent loci contain multiple partial gene copies. Here we show that there is a bias towards using the copy at the 3' end of the silent loci (copy 1 as the donor sequence. The pilE gene of N. gonorrhoeae and some strains of Neisseria meningitidis encode class I pilin, but strains of N. meningitidis from clonal complexes 8 and 11 encode a class II pilin. We have confirmed that the class II pili of meningococcal strain FAM18 (clonal complex 11 are non-variable, and this is also true for the class II pili of strain NMB from clonal complex 8. In addition when a gene encoding class I pilin was moved into the meningococcal strain NMB background there was no evidence of antigenic variation. Finally we investigated several members of the opa gene family of N. gonorrhoeae, where it has been suggested that limited variation occurs. Variation was detected in the opaK gene that is located close to pilE, but not at the opaJ gene located elsewhere on the genome. The approach described here promises to dramatically improve studies of the extent and nature of antigenic variation systems in a variety of species.

  5. Sequence variation in three mitochondrial DNA genes among isolates of Ascaridia galli originating from Guangdong, Hunan and Yunnan provinces, China.

    Li, J Y; Liu, G H; Wang, Y; Song, H Q; Lin, R Q; Zou, F C; Liu, W; Xu, M J; Zhu, X Q

    2013-09-01

    The present study examined sequence variation in three mitochondrial DNA (mtDNA) genes, namely cytochrome c oxidase subunit 3 (cox3) and NADH dehydrogenase subunits 1 and 4 (nad1 and nad4), among Ascaridia galli isolates from different geographical localities in China. A portion of cox3 (pcox3), nad1 (pnad1) and nad4 (pnad4) genes were amplified by polymerase chain reaction (PCR) separately from adult A. galli individuals and the amplicons were subjected to sequencing from both directions. The length of the sequences of pcox3, pnad1 and pnad4 were 408 bp, 471 bp and 333 bp, respectively. The intraspecific sequence variations within A. galli were 0-1.7% for pcox3, 0-2.8% for pnad1 and 0-3.4% for pnad4. The A+T contents of the sequences were 67.16-67.65% (pcox3), 67.09-67.94% (pnad1) and 69.91-71.77% (pnad4). The interspecific sequence differences among members of the Ascaridida were significantly higher, being 13.2-30.9%, 12.8-29.0% and 15.1-34.1% for pcox3, pnad1 and pnad4, respectively. Phylogenetic analyses using combined sequences of pcox3, pnad1 and pnad4, with three different computational algorithms (Bayesian analysis, maximum likelihood and maximum parsimony), all revealed distinct groups with high statistical support. These findings demonstrated the existence of intraspecific variation in mitochondrial DNA (mtDNA) sequences among A. galli isolates from different geographical regions in China, and have implications for studying molecular epidemiology and population genetics of A. galli. PMID:23046568

  6. Mitochondrial DNA Sequence and Body Size Variations in Turkish Sardine (Sardina pilchardus) Stocks

    SARMAŞIK, Aliye; ÇOLAKOĞLU, Fatma ARIK; Altun, Tülay

    2008-01-01

    Sardine (Sardina pilchardus) is one of the most important species among Turkish fisheries and is broadly distributed along its coastal waters. In the present study, mitochondrial DNA sequences from the cytochrome b (cytb) gene were examined to assess the genetic diversity of sardines inhabiting Turkish coastal waters. A fragment of sardine cytb DNA from each sample collected from 8 representative regions along the coastal zones was amplified by PCR analysis and subsequently sequenced. The res...

  7. Mitochondrial DNA variation and virologic and immunological HIV outcomes in African Americans

    Aissani, Brahim; Shrestha, Sadeep; Wiener, Howard W.; Tang, Jianming; Kaslow, Richard A.; Wilson, Craig M.

    2016-01-01

    Objective To evaluate the impact of mitochondrial DNA (mtDNA) haplogroups on virologic and immunological outcomes of HIV infection. Design HAART-naive African American adolescent participants to the Reaching for Excellence in Adolescent Care and Health study. Methods The mtDNA haplogroups were inferred from sequenced mtDNA hypervariable regions HV1 and HV2 and their predictive value on HIV outcomes were evaluated in linear mixed models, controlled for human leukocyte antigen (HLA)-B27, HLA-B57 and HLA-B35-Px alleles and other covariates. Results We report data showing that the mtDNA L2 lineage, a group composed of L2a, L2b and L2e mtDNA haplogroups in the studied population, is significantly associated (beta=−0.08; Bonferroni-adjusted P=0.004) with decline of CD4+ T cells (median loss of 8 ± 1 cells per month) in HAART-naive HIV-infected individuals of African American descent (n=133). No significant association (PHIV infection, its phylogenetic divergence from J and U5a, two lineages associated with accelerated HIV progression in European Americans, raises the possibility that interactions with common nucleus-encoded variants drive HIV progression. Disentangling the effects of mitochondrial and nuclear gene variants on the outcomes of HIV infection is an important step to be taken toward a better understanding of HIV/AIDS pathogenesis and pharmacogenomics. PMID:24932613

  8. High variation and very low differentiation in wide ranging plains zebra (Equus quagga): insights from mtDNA and microsatellites

    Lorenzen, Eline D; Arctander, Peter; Siegismund, Hans R

    2008-01-01

    Patterns of genetic differentiation in the plains zebra (Equus quagga) were analysed using mitochondrial DNA control region variation and seven microsatellites. The six morphologically defined subspecies of plains zebra lacked the population genetic structure indicative of distinct evolutionary u...

  9. PRIMARILY RESULTS OF PHYTOPLANKTON DNA AND VARIATION TO ENVIRONMENTAL FACTORS IN DURRES`S BAY COASTAL WATERS (ALBANIA

    Laura Gjyli

    2013-10-01

    Full Text Available After isolation of phytoplankton DNA in coastal waters of Durres Bay, Albania, quantification and analysis of quality were investigated with spectrophotometric analysis. Analysis of UV absorption by the nucleotides provides a simple and accurate estimation of the concentration of nucleic acids in a sample. This method is however limited by the quantity of DNA and the purity of the preparation. Also biotic environment factors as Chlorophyll a and abiotic environment factors as temperature, salinity, pH, dissolved oxygen, turbidity, nitrate, phosphate were investigated to assess DNA quantities in different environment conditions. The Chlorophyll a was studied also to access the level of trophy. The sample stations were: Golem Beach (GB, Channel of Plepa (ChP, Hekurudha Beach (HB, Ex-Fuel Quay in Marine Durres Harbour (EFQ, Water Channel of Durres City (WChDC and Currila Beach (CB. Samples are taken in one meter depth from the water surface. Water samples were collected monthly from April to October 2011. The most abundant stations with phytoplankton DNA are Channel of Plepa and Water Channel of Durres City. This confirms that there are spills of fresh waters, sewage or agricultural water spills, often discharge in coastal waters. Referring Mutliple Regression Analysis and single regression analysis, the association between phytoplankton DNA and environment factors was strong (R2 = 0.75. Basing in single correlation and statistically significance (p-value ≤ 0.05, the enviroment factors that correlated to phytoplankton DNA were pH, salinity and phosphate; explaining thus the variation of total phytoplankton in Durres Bay coastal waters.

  10. Variations in the Processing of DNA Double-Strand Breaks Along 60-MeV Therapeutic Proton Beams

    Chaudhary, Pankaj; Marshall, Thomas I.; Currell, Frederick J.; Kacperek, Andrzej; Schettino, Giuseppe; Prise, Kevin M.

    2016-01-01

    Purpose To investigate the variations in induction and repair of DNA damage along the proton path, after a previous report on the increasing biological effectiveness along clinically modulated 60-MeV proton beams. Methods and Materials Human skin fibroblast (AG01522) cells were irradiated along a monoenergetic and a modulated spread-out Bragg peak (SOBP) proton beam used for treating ocular melanoma at the Douglas Cyclotron, Clatterbridge Centre for Oncology, Wirral, Liverpool, United Kingdom. The DNA damage response was studied using the 53BP1 foci formation assay. The linear energy transfer (LET) dependence was studied by irradiating the cells at depths corresponding to entrance, proximal, middle, and distal positions of SOBP and the entrance and peak position for the pristine beam. Results A significant amount of persistent foci was observed at the distal end of the SOBP, suggesting complex residual DNA double-strand break damage induction corresponding to the highest LET values achievable by modulated proton beams. Unlike the directly irradiated, medium-sharing bystander cells did not show any significant increase in residual foci. Conclusions The DNA damage response along the proton beam path was similar to the response of X rays, confirming the low-LET quality of the proton exposure. However, at the distal end of SOBP our data indicate an increased complexity of DNA lesions and slower repair kinetics. A lack of significant induction of 53BP1 foci in the bystander cells suggests a minor role of cell signaling for DNA damage under these conditions. PMID:26452569

  11. Sources of variation in small rodent trophic niche: new insights from DNA metabarcoding and stable isotope analysis.

    Soininen, Eeva M; Ehrich, Dorothée; Lecomte, Nicolas; Yoccoz, Nigel G; Tarroux, Arnaud; Berteaux, Dominique; Gauthier, Gilles; Gielly, Ludovic; Brochmann, Christian; Gussarova, Galina; Ims, Rolf A

    2014-01-01

    Intraspecific competition for food is expected to increase the trophic niche width of consumers, defined here as their diet diversity, but this process has been little studied in herbivores. Population densities of small rodents fluctuate greatly, providing a good study model to evaluate effects of competition on trophic niche. We studied resource use in five arctic small rodent populations of four species combining DNA metabarcoding of stomach contents and stable isotope analysis (SIA). Our results suggest that for small rodents, the most pronounced effect of competition on trophic niche is due to increased use of secondary habitats and to habitat-specific diets, rather than an expansion of trophic niche in primary habitat. DNA metabarcoding and SIA provided complementary information about the composition and temporal variation of herbivore diets. Combing these two approaches requires caution, as the underlying processes causing observed patterns may differ between methodologies due to different spatiotemporal scales. PMID:24830842

  12. Evaluating the role of mitochondrial DNA variation to the genetic predisposition to radiation-induced toxicity

    Background and purpose: Mitochondrial DNA common variants have been reported to be associated with the development of radiation-induced toxicity. Using a large cohort of patients, we aimed to validate these findings by investigating the potential role of common European mitochondrial DNA SNPs (mtSNPs) to the development of radio-toxicity. Material and methods: Overall acute and late toxicity data were assessed in a cohort of 606 prostate cancer patients by means of Standardized Total Average Toxicity (STAT) score. We carried out association tests between radiation toxicity and a selection of 15 mtSNPs (and the haplogroups defined by them). Results: Statistically significant association between mtSNPs and haplogroups with toxicity could not be validated in our Spanish cohort. Conclusions: The present study suggests that the mtDNA common variants analyzed are not associated with clinically relevant increases in risk of overall radiation-induced toxicity in prostate cancer patients

  13. On the edge of Bantu expansions: mtDNA, Y chromosome and lactase persistence genetic variation in southwestern Angola

    Beleza Sandra

    2009-04-01

    Full Text Available Abstract Background Current information about the expansion of Bantu-speaking peoples is hampered by the scarcity of genetic data from well identified populations from southern Africa. Here, we fill an important gap in the analysis of the western edge of the Bantu migrations by studying for the first time the patterns of Y-chromosome, mtDNA and lactase persistence genetic variation in four representative groups living around the Namib Desert in southwestern Angola (Ovimbundu, Ganguela, Nyaneka-Nkumbi and Kuvale. We assessed the differentiation between these populations and their levels of admixture with Khoe-San groups, and examined their relationship with other sub-Saharan populations. We further combined our dataset with previously published data on Y-chromosome and mtDNA variation to explore a general isolation with migration model and infer the demographic parameters underlying current genetic diversity in Bantu populations. Results Correspondence analysis, lineage sharing patterns and admixture estimates indicate that the gene pool from southwestern Angola is predominantly derived from West-Central Africa. The pastoralist Herero-speaking Kuvale people were additionally characterized by relatively high frequencies of Y-chromosome (12% and mtDNA (22% Khoe-San lineages, as well as by the presence of the -14010C lactase persistence mutation (6%, which likely originated in non-Bantu pastoralists from East Africa. Inferred demographic parameters show that both male and female populations underwent significant size growth after the split between the western and eastern branches of Bantu expansions occurring 4000 years ago. However, males had lower population sizes and migration rates than females throughout the Bantu dispersals. Conclusion Genetic variation in southwestern Angola essentially results from the encounter of an offshoot of West-Central Africa with autochthonous Khoisan-speaking peoples from the south. Interactions between the Bantus

  14. Methodological variations in the isolation of genomic DNA from Streptococcus bacteria

    Mônica Moreira; Juliana Noschang; Ivana Froede Neiva; Yanê Carvalho; llma Hiroko Higuti; Vânia Aparecida Vicente

    2010-01-01

    In this work, genomic DNA of Streptococcus pyogenes, S. mutans and S. sobrinus was isolated using two methods: either using the detergent cetyltrimethylammonium bromide (CTAB) at 65ºC; or by applying ultrasound to a mixture of silica and celite in CTAB. The composite method that used ultrasound was the more efficient, allowing the straightforward extraction of genomic DNA from Gram-positive bacteria with good quality and reproducibility.O gênero Streptococcus encontra-se amplamente distribuíd...

  15. Variations induced to the DNA pattern of the Hump Beetle Gibium Psylloides treated with gamma rays

    This study investigated the effect of gamma rays on the DNA patterns of G. psylloides. The adult males and females were exposed to doses of 30 and 60 Gy. RAPD-PCR patterns showed alterations among the controls and the treated individuals. Exposure to gamma radiation caused very frequently the appearance of some extra bands and the disappearance of others in the RAPD-PCR amplification patterns of the irradiated insects. However, the similarity in DNA patterns between some normal and treated samples was interpreted by supposing that the radiation-induced damage was in regions of the genome other than at the loci under study

  16. Mitochondrial DNA sequence variation and haplogroup distribution in Chinese patients with LHON and m.14484T>C.

    Dandan Yu

    Full Text Available BACKGROUND: Leber hereditary optic neuropathy (LHON, MIM 535000 is one of the most common mitochondrial genetic disorders caused by three primary mtDNA mutations (m.3460G>A, m.11778G>A and m. 14484T>C. The clinical expression of LHON is affected by many additional factors, e.g. mtDNA background, nuclear genes, and environmental factors. Hitherto, there is no comprehensive study of Chinese LHON patients with m.14484T>C. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we analyzed the mtDNA sequence variations and haplogroup distribution pattern of the largest number of Chinese LHON patients with m.14484T>C to date. We first determined the complete mtDNA sequences in eleven LHON probands with m.14484T>C, to discern the potentially pathogenic mutations that co-segregate with m.14484T>C. We then dissected the matrilineal structure of 52 patients with m.14484T>C (including 14 from unrelated families and 38 sporadic cases and compared it with the reported Han Chinese from general populations. Complete mtDNA sequencing showed that the eleven matrilines belonged to nine haplogroups including Y2, C4a, M8a, M10a1a, G1a1, G2a1, G2b2, D5a2a1, and D5c. We did not identify putatively pathogenic mutation that was co-segregated with m.14484T>C in these lineages based on the evolutionary analysis. Compared with the reported Han Chinese from general populations, the LHON patients with m.14484T>C had significantly higher frequency of haplogroups C, G, M10, and Y, but a lower frequency of haplogroup F. Intriguingly, we also observed a lower prevalence of F lineages in LHON subjects with m.11778G>A in our previous study, suggesting that this haplogroup may enact similar role during the onset of LHON in the presence of m.14484T>C or m.11778G>A. CONCLUSIONS/SIGNIFICANCE: Our current study provided a comprehensive profile regarding the mtDNA variation and background of Chinese patients with LHON and m.14484T>C. Matrilineal background might affect the expression of LHON

  17. Discovery and genotyping of existing and induced DNA sequence variation in potato

    Uitdewilligen, J.G.A.M.L.

    2012-01-01

    In this thesis natural and induced DNA sequence diversity in potato (Solanum tuberosum) for use in marker-trait analysis and potato breeding is assessed. The study addresses the challenges of reliable, high-throughput identification and genotyping of sequence variants in existing tetraploid potato c

  18. Validation and Estimation of Additive Genetic Variation Associated with DNA Tests for Quantitative Beef Cattle Traits

    The U.S. National Beef Cattle Evaluation Consortium (NBCEC) has been involved in the validation of commercial DNA tests for quantitative beef quality traits since their first appearance on the U.S. market in the early 2000s. The NBCEC Advisory Council initially requested that the NBCEC set up a syst...

  19. Methodological variations in the isolation of genomic DNA from Streptococcus bacteria

    Mônica Moreira

    2010-08-01

    Full Text Available In this work, genomic DNA of Streptococcus pyogenes, S. mutans and S. sobrinus was isolated using two methods: either using the detergent cetyltrimethylammonium bromide (CTAB at 65ºC; or by applying ultrasound to a mixture of silica and celite in CTAB. The composite method that used ultrasound was the more efficient, allowing the straightforward extraction of genomic DNA from Gram-positive bacteria with good quality and reproducibility.O gênero Streptococcus encontra-se amplamente distribuído na natureza e algumas espécies constituem a microbiota humana da cavidade bucal, como Streptococcus pyogenes, que pode estar associado a importantes doenças humanas, Streptococcus mutans e Streptococcus sobrinus, relacionados à cárie dental. O DNA genômico destas três espécies foi isolado utilizando-se dois métodos, o primeiro utilizando o detergente brometo de cetiltrimetilamônio (CTAB à 65ºC e outro associando ultra-som a uma mistura de sílica e celite em CTAB. O método que possibilitou a extração do DNA genômico das bactérias Gram positivas, com qualidade, boa reprodutibilidade fácil execução foi aquele que utilizou ultra-som associado à sílica e celite em CTAB.

  20. Phylogeography of mitochondrial DNA variation in brown bears and polar bears

    Shields, Gerald F.; Adams, Deborah; Garner, Gerald; Labelle, Martine; Pietsch, Jacy; Ramsay, Malcolm; Schwartz, Charles; Titus, Kimberly; Williamson, Scott

    2000-01-01

    We analyzed 286 nucleotides of the middle portion of the mitochondrial cytochrome b gene of 61 brown bears from three locations in Alaska and 55 polar bears from Arctic Canada and Arctic Siberia to test our earlier observations of paraphyly between polar bears and brown bears as well as to test the extreme uniqueness of mitochondrial DNA types of brown bears on Admiralty, Baranof, and Chichagof (ABC) islands of southeastern Alaska. We also investigated the phylogeography of brown bears of Alaska's Kenai Peninsula in relation to other Alaskan brown bears because the former are being threatened by increased human development. We predicted that: (1) mtDNA paraphyly between brown bears and polar bears would be upheld, (2) the mtDNA uniqueness of brown bears of the ABC islands would be upheld, and (3) brown bears of the Kenai Peninsula would belong to either clade II or clade III of brown bears of our earlier studies of mtDNA. All of our predictions were upheld through the analysis of these additional samples.

  1. Influence of ATM-Mediated DNA Damage Response on Genomic Variation in Human Induced Pluripotent Stem Cells.

    Lu, Junjie; Li, Hu; Baccei, Anna; Sasaki, Takayo; Gilbert, David M; Lerou, Paul H

    2016-05-01

    Genome instability is a potential limitation to the research and therapeutic application of induced pluripotent stem cells (iPSCs). Observed genomic variations reflect the combined activities of DNA damage, cellular DNA damage response (DDR), and selection pressure in culture. To understand the contribution of DDR on the distribution of copy number variations (CNVs) in iPSCs, we mapped CNVs of iPSCs with mutations in the central DDR gene ATM onto genome organization landscapes defined by genome-wide replication timing profiles. We show that following reprogramming the early and late replicating genome is differentially affected by CNVs in ATM-deficient iPSCs relative to wild-type iPSCs. Specifically, the early replicating regions had increased CNV losses during retroviral (RV) reprogramming. This differential CNV distribution was not present after later passage or after episomal reprogramming. Comparison of different reprogramming methods in the setting of defective DDR reveals unique vulnerability of early replicating open chromatin to RV vectors. PMID:26935587

  2. Maternal gestational diabetes is associated with genome-wide DNA methylation variation in placenta and cord blood of exposed offspring.

    Finer, Sarah; Mathews, Chris; Lowe, Rob; Smart, Melissa; Hillman, Sara; Foo, Lin; Sinha, Ajay; Williams, David; Rakyan, Vardhman K; Hitman, Graham A

    2015-06-01

    Exposure of a developing foetus to maternal gestational diabetes (GDM) has been shown to programme future risk of diabetes and obesity. Epigenetic variation in foetal tissue may have a mechanistic role in metabolic disease programming through interaction of the pregnancy environment with gene function. We aimed to identify genome-wide DNA methylation variation in cord blood and placenta from offspring born to mothers with and without GDM. Pregnant women of South Asian origin were studied and foetal tissues sampled at term delivery. The Illumina HumanMethylation450 BeadChip was used to assay genome-wide DNA methylation in placenta and cord blood from 27 GDM exposed and 21 unexposed offspring. We identified 1485 cord blood and 1708 placenta methylation variable positions (MVPs) achieving genome-wide significance (adjusted P-value methylation differences of >5%. MVPs were disproportionately located within first exons. A bioinformatic co-methylation algorithm was used to detect consistent directionality of methylation in 1000 bp window around each MVP was observed at 74% of placenta and 59% of cord blood MVPs. KEGG pathway analysis showed enrichment of pathways involved in endocytosis, MAPK signalling and extracellular triggers to intracellular metabolic processes. Replication studies should integrate genomics and transcriptomics with longitudinal sampling to elucidate stability, determine causality for translation into biomarker and prevention studies. PMID:25634562

  3. Variation of karyotype and nuclear DNA content among four species of Plectranthus L’ Héritier, 1788 (Lamiaceae) from Brazil

    Nani, Thaís Furtado; Mesquita, Amanda Teixeira; Bustamante, Fernanda de Oliveira; Barbosa, Sandro; Barbosa, João Vítor Calvelli; Davide, Lisete Chamma

    2015-01-01

    Abstract Plectranthus is a genus which includes species of ornamental and medicinal potential. It faces taxonomic problems due to aggregating species previously belonging to the genus Coleus, a fact that has contributed to the existence of various synonymies. The species Plectranthus amboinicus, Plectranthus barbatus, Plectranthus grandis and Plectranthus neochilus are included in this context. Some authors consider Plectranthus barbatus and Plectranthus grandis as synonyms. The present work was carried out with the aim of comparing plants of the above-mentioned species, originating from different localities in Brazil, with regards to chromosome number and karyotypic morphology, correlated to the nuclear DNA content. There was no variation in chromosome number among plants of the same species. Plectranthus amboinicus was the only species to exhibit 2n=34, whereas the others had 2n=30. No karyotypic differences were found among the plants of each species, except for Plectranthus barbatus. The plants of the Plectranthus species revealed little coincidence between chromosome pairs. The nuclear DNA content allowed grouping Plectranthus amboinicus and Plectranthus neochilus, with the highest mean values, and Plectranthus grandis and Plectranthus barbatus with the lowest ones. Differences in DNA amount among the plants were identified only for Plectranthus barbatus. These results allow the inference that the populations of Plectranthus amboinicus and Plectranthus neochilus present coincident karyotypes among their plants, and Plectranthus grandis is probably a synonym of Plectranthus barbatus. PMID:26753074

  4. Variation of karyotype and nuclear DNA content among four species of Plectranthus L' Héritier, 1788 (Lamiaceae) from Brazil.

    Nani, Thaís Furtado; Mesquita, Amanda Teixeira; Bustamante, Fernanda de Oliveira; Barbosa, Sandro; Barbosa, João Vítor Calvelli; Davide, Lisete Chamma

    2015-01-01

    Plectranthus is a genus which includes species of ornamental and medicinal potential. It faces taxonomic problems due to aggregating species previously belonging to the genus Coleus, a fact that has contributed to the existence of various synonymies. The species Plectranthus amboinicus, Plectranthus barbatus, Plectranthus grandis and Plectranthus neochilus are included in this context. Some authors consider Plectranthus barbatus and Plectranthus grandis as synonyms. The present work was carried out with the aim of comparing plants of the above-mentioned species, originating from different localities in Brazil, with regards to chromosome number and karyotypic morphology, correlated to the nuclear DNA content. There was no variation in chromosome number among plants of the same species. Plectranthus amboinicus was the only species to exhibit 2n=34, whereas the others had 2n=30. No karyotypic differences were found among the plants of each species, except for Plectranthus barbatus. The plants of the Plectranthus species revealed little coincidence between chromosome pairs. The nuclear DNA content allowed grouping Plectranthus amboinicus and Plectranthus neochilus, with the highest mean values, and Plectranthus grandis and Plectranthus barbatus with the lowest ones. Differences in DNA amount among the plants were identified only for Plectranthus barbatus. These results allow the inference that the populations of Plectranthus amboinicus and Plectranthus neochilus present coincident karyotypes among their plants, and Plectranthus grandis is probably a synonym of Plectranthus barbatus. PMID:26753074

  5. Discovery and genotyping of existing and induced DNA sequence variation in potato

    Uitdewilligen, J.G.A.M.L.

    2012-01-01

    In this thesis natural and induced DNA sequence diversity in potato (Solanum tuberosum) for use in marker-trait analysis and potato breeding is assessed. The study addresses the challenges of reliable, high-throughput identification and genotyping of sequence variants in existing tetraploid potato cultivar panels using traditional Sanger sequencing and next-generation massively parallel sequencing (MPS), and the application of this knowledge in the form of genetic markers. Furthermore, it exp...

  6. Searching for the Optimal Sampling Solution: Variation in Invertebrate Communities, Sample Condition and DNA Quality.

    Martin M Gossner

    Full Text Available There is a great demand for standardising biodiversity assessments in order to allow optimal comparison across research groups. For invertebrates, pitfall or flight-interception traps are commonly used, but sampling solution differs widely between studies, which could influence the communities collected and affect sample processing (morphological or genetic. We assessed arthropod communities with flight-interception traps using three commonly used sampling solutions across two forest types and two vertical strata. We first considered the effect of sampling solution and its interaction with forest type, vertical stratum, and position of sampling jar at the trap on sample condition and community composition. We found that samples collected in copper sulphate were more mouldy and fragmented relative to other solutions which might impair morphological identification, but condition depended on forest type, trap type and the position of the jar. Community composition, based on order-level identification, did not differ across sampling solutions and only varied with forest type and vertical stratum. Species richness and species-level community composition, however, differed greatly among sampling solutions. Renner solution was highly attractant for beetles and repellent for true bugs. Secondly, we tested whether sampling solution affects subsequent molecular analyses and found that DNA barcoding success was species-specific. Samples from copper sulphate produced the fewest successful DNA sequences for genetic identification, and since DNA yield or quality was not particularly reduced in these samples additional interactions between the solution and DNA must also be occurring. Our results show that the choice of sampling solution should be an important consideration in biodiversity studies. Due to the potential bias towards or against certain species by Ethanol-containing sampling solution we suggest ethylene glycol as a suitable sampling solution when

  7. Tracking an invasive honey bee pest: mitochondrial DNA variation in North American small hive beetles

    Jay. D. Evans,; Jeff. S. Pettis,; Michael Hood, W.; Shimanuki, Hachiro

    2003-01-01

    International audience We describe the current and past distributions of North American small hive beetles (Aethina tumida) having two distinct mitochondrial DNA haplotypes. A collection of 539 hive beetles showed irregular distributions of these haplotypes across the southeastern US. Beetles from the first collections made in coastal South Carolina showed haplotype NA1, exclusively. This haplotype is less common in Georgia and was not observed in North Carolina. Later collections from thi...

  8. Systematic Localization of Common Disease-Associated Variation in Regulatory DNA

    Maurano, Matthew T.; Humbert, Richard; Rynes, Eric; Thurman, Robert E; Haugen, Eric; Wang, Hao; Reynolds, Alex P.; Sandstrom, Richard; Qu, Hongzhu; Brody, Jennifer; Shafer, Anthony; Neri, Fidencio; Lee, Kristen; Kutyavin, Tanya; Stehling-Sun, Sandra

    2012-01-01

    Genome-wide association studies (GWAS) have identified many noncoding variants associated with common diseases and traits. We show that these variants are concentrated in regulatory DNA marked by DNase I hypersensitive sites (DHSs). 88% of such DHSs are active during fetal development, and are enriched for gestational exposure-related phenotypes. We identify distant gene targets for hundreds of DHSs that may explain phenotype associations. Disease-associated variants systematically perturb tr...

  9. Chloroplast DNA Variations in Wild Brassicas and Their Implication in Breeding and Population Genetics Studies

    Sarin, Bharti; Martín, Juan Pedro; Kaula, Babeeta Chrungu; Mohanty, Aparajita

    2015-01-01

    Evaluation of chloroplast DNA (cpDNA) diversity in wild relatives of crop brassicas is important for characterization of cytoplasm and also for population genetics/phylogeographic analyses. The former is useful for breeding programs involving wide hybridization and synthesis of alloplasmic lines, while the latter is important for formulating conservation strategies. Therefore, PCR-RFLP (Polymerase Chain Reaction-Restriction Fragment Length Polymorphism) technique was applied to study cpDNA diversity in 14 wild brassicas (including 31 accessions) which revealed a total of 219 polymorphic fragments. The combination of polymorphisms obtained by using only two primer pair-restriction enzyme combinations was sufficient to distinguish all 14 wild brassicas. Moreover, 11 primer pairs-restriction enzyme combinations revealed intraspecific polymorphisms in eight wild brassicas (including endemic and endangered species, B. cretica and B. insularis, resp.). Thus, even within a small number of accessions that were screened, intraspecific polymorphisms were observed, which is important for population genetics analyses in wild brassicas and consequently for conservation studies. PMID:26347851

  10. A pedigree-based study of mitochondrial D-loop DNA sequence variation among Arabian horses.

    Bowling, A T; Del Valle, A; Bowling, M

    2000-02-01

    Through DNA sequence comparisons of a mitochondrial D-loop hypervariable region, we investigated matrilineal diversity for Arabian horses in the United States. Sixty-two horses were tested. From published pedigrees they traced in the maternal line to 34 mares acquired primarily in the mid to late 19th century from nomadic Bedouin tribes. Compared with the reference sequence (GenBank X79547), these samples showed 27 haplotypes with altogether 31 base substitution sites within 397 bp of sequence. Based on examination of pedigrees from a random sampling of 200 horses in current studbooks of the Arabian Horse Registry of America, we estimated that this study defined the expected mtDNA haplotypes for at least 89% of Arabian horses registered in the US. The reliability of the studbook recorded maternal lineages of Arabian pedigrees was demonstrated by haplotype concordance among multiple samplings in 14 lines. Single base differences observed within two maternal lines were interpreted as representing alternative fixations of past heteroplasmy. The study also demonstrated the utility of mtDNA sequence studies to resolve historical maternity questions without access to biological material from the horses whose relationship was in question, provided that representatives of the relevant female lines were available for comparison. The data call into question the traditional assumption that Arabian horses of the same strain necessarily share a common maternal ancestry. PMID:10690354

  11. Analysis of DNA methylation variation in wheat genetic background after alien chromatin introduction based on methylation-sensitive amplification polymorphism

    2008-01-01

    During the process of alien germplasm introduced into wheat genome by chromosome engineering,extensive genetic variations of genome structure and gene expression in recipient could be induced.In this study,we performed GISH(genome in situ hybridization)and AFLP(amplified fragment length polymorphism) on wheat-rye chromosome transIocation lines and their parents to detect the identity in genomic structure of different translocation lines.The results showed that the genome primary structure variations were not obviously detected in different translocation lines except the same 1RS chromosome translocation.Methylation sensitive amplification polymorphism(MSAP)analyses on genomic DNA showed that the ratios of fully-methylated sites were significantly increased in translocation lines(CN12,20.15%;CN17,20.91%;CN18,22.42%),but the ratios of hemimethylated sites were significantly lowered(CN12,21.41%;CN17,23.43%;CN18,22.42%),whereas 16.37%were fully-methylated and 25.44%were hemimethylated in case of their wheat parent.Twenty-nine classes of methylation patterns were identified in a comparative assay of cytosine methylation patterns between wheat-rye translocation lines and their wheat parent,including 13 hypermethylation patterns(33.74%),9 demethylation patterns(22.76%)and 7 uncertain patterns(4.07%).In further sequence analysis,the alterations of methylation pattern affected both repetitive DNA sequences,such as retrotransposons and tandem repetitive sequences,and low-copy DNA.

  12. Contrasting cpDNA Variation in Two Indonesian Endemic Lowland Dipterocarp Species and Implications for their Conservation

    Koichi Kamiya

    2012-01-01

    Full Text Available Shorea javanica (Dipterocarpaceae is an economically important dammar-producing tree, endemic to the tropical lowland forests of Sumatra and Java, Indonesia. However, its total population size is limited and this species is endangered. Shorea selanica is one of the very limited numbers of species in genus Shorea (Dipterocarpaceae that grows in Wallacean. This species can be found only in the central part of the Moluccas, eastern Indonesia. Six populations (77 individuals in total were sampled for S. javanica while three populations (27 individuals in total were sampled for S. selanica. To determine genetic variation and population structure, three non-coding chloroplast DNA regions of trnL-trnF, psbC-trnS, trnS-trnfM and two non-coding chloroplast DNA regions of trnT-trnL, trnL-trnF were sequenced from S. javanica and S. selanica, respectively. There was no variation in the chloroplast DNA regions from S. javanica, except for one unique indel polymorphism. Nucleotide diversity within S. selanica populations ranged from 0 (Seram to 0.00044 (Buru, with a pooled value of 0.00041. S. javanica was determined as having no population structure while high levels of genetic differentiation was found among populations of S. selanica (FST = 0.702. Different pattern of population structure among the two species in this study suggested the need for distinct management and conservation strategies for each species. For S. javanica, connectivity within and among populations, including augmentation of population size across the species range, should be promoted. For S. selanica, an in situ conservation plan that defines core areas completely free from perturbation within each population is necessary.

  13. Intraspecific DNA variation in nuclear genes of the mosquito Aedes aegypti.

    Morlais, I; Severson, D W

    2003-12-01

    Single nucleotide polymorphisms (SNPs) are an abundant source of genetic variation among individual organisms. To assess the usefulness of SNPs for genome analysis in the yellow fever mosquito, Aedes aegypti, we sequenced 25 nuclear genes in each of three strains and analysed nucleotide diversity. The average frequency of nucleotide variation was 12 SNPs per kilobase, indicating that nucleotide variation in Ae. aegypti is similar to that in other organisms, including Drosophila and the malaria vector Anopheles gambiae. Transition polymorphisms outnumbered transversion polymorphisms, at a ratio of about 2:1. We examined codon usage and confirmed that mutational bias favours G and C ending codons. Codon bias was most pronounced in highly expressed genes. Nucleotide diversity estimates indicated that substitution rates are positively correlated in coding and non-coding regions. Nucleotide diversity varied from one gene to another. The unequal distribution of SNPs among Ae. aegypti nuclear genes suggests that single base variations are non-neutral and are subject to selective constraints. Our analysis showed that ubiquitously expressed genes have lower polymorphism rates and are likely under strong purifying selection, whereas tissue specific genes and genes with a putative role in parasite defence exhibit higher levels of polymorphism that may be associated with diversifying selection. PMID:14986924

  14. [Nucleotide variation in the mitochondrial DNA cytochrome oxidase 1 gene in the Siberian sucker (Catostomus catostomus rostratus) from Kolyma River].

    Bachevskaja, L T; Pereverzeva, V V; Ivanova, G D; Agapova, G A

    2014-10-01

    This study presents the data of the first molecular genetic analysis of the Siberian sucker from Kolyma River. Polymorphism of the mtDNA cytochrome oxidase 1 gene was established. Comparative sequence analysis of the gene examined and the GenBank variants characterizing suckers from the rivers of Canada enabled the suggestion that the sucker penetrated to Asia from North America approximately at the end of Early and the beginning of the Middle Pleistocene. It was demonstrated that intrapopulation genetic variation in the Siberian sucker accounted for 11.63% of total variation, while the proportion of the intergroup, component (Fst) constituted 88.37%. It seems likely that a considerable proportion of intergroup variation was caused by the long period of isolation of the Siberian sucker in Kolyma River. The prevalence of one common haplotype, CH-COI 1, in the sample examined indicates that the founder effect played an importaht role in the history of the formation of the Kolyma population. PMID:25720253

  15. Analysis of genetic variation within clonal lineages of grape phylloxera (Daktulosphaira vitifoliae Fitch) using AFLP fingerprinting and DNA sequencing.

    Vorwerk, S; Forneck, A

    2007-07-01

    Two AFLP fingerprinting methods were employed to estimate the potential of AFLP fingerprints for the detection of genetic diversity within single founder lineages of grape phylloxera (Daktulosphaira vitifoliae Fitch). Eight clonal lineages, reared under controlled conditions in a greenhouse and reproducing asexually throughout a minimum of 15 generations, were monitored and mutations were scored as polymorphisms between the founder individual and individuals of succeeding generations. Genetic variation was detected within all lineages, from early generations on. Six to 15 polymorphic loci (from a total of 141 loci) were detected within the lineages, making up 4.3% of the total amount of genetic variation. The presence of contaminating extra-genomic sequences (e.g., viral material, bacteria, or ingested chloroplast DNA) was excluded as a source of intraclonal variation. Sequencing of 37 selected polymorphic bands confirmed their origin in mostly noncoding regions of the grape phylloxera genome. AFLP techniques were revealed to be powerful for the identification of reproducible banding patterns within clonal lineages. PMID:17893744

  16. Pleistocene-Holocene boundary in Southern Arabia from the perspective of human mtDNA variation.

    Al-Abri, Abdulrahim; Podgorná, Eliška; Rose, Jeffrey I; Pereira, Luísa; Mulligan, Connie J; Silva, Nuno M; Bayoumi, Riad; Soares, Pedro; Cerný, Viktor

    2012-10-01

    It is now known that several population movements have taken place at different times throughout southern Arabian prehistory. One of the principal questions under debate is if the Early Holocene peopling of southern Arabia was mainly due to input from the Levant during the Pre-Pottery Neolithic B, to the expansion of an autochthonous population, or some combination of these demographic processes. Since previous genetic studies have not been able to include all parts of southern Arabia, we have helped fill this lacuna by collecting new population datasets from Oman (Dhofar) and Yemen (Al-Mahra and Bab el-Mandab). We identified several new haplotypes belonging to haplogroup R2 and generated its whole genome mtDNA tree with age estimates undertaken by different methods. R2, together with other considerably frequent southern Arabian mtDNA haplogroups (R0a, HV1, summing up more than 20% of the South Arabian gene pool) were used to infer the past effective population size through Bayesian skyline plots. These data indicate that the southern Arabian population underwent a large expansion already some 12 ka. A founder analysis of these haplogroups shows that this expansion is largely attributed to demographic input from the Near East. These results support thus the spread of a population coming from the north, but at a significantly earlier date than presently considered by archaeologists. Our data suggest that some of the mtDNA lineages found in southern Arabia have persisted in the region since the end of the Last Ice Age. PMID:22927010

  17. Organization and variation of mitochondrial DNA control region in pleurodiran turtles

    Ling Wang

    2011-08-01

    Full Text Available Three complete mitochondrial DNA (mtDNA control regions (CRs of Chelodina rugosa (Ogilby, 1890, Chelus fimbriata (Schneider, 1783, and Podocnemis unifilis (Troschel, 1848 were firstly determined using Long-PCR method and the length were 1,016 bp, 1,149 bp, and 985bp, respectively. Together with CRs of Pelomedusa subrufa (Bonnaterre, 1789 and nearly complete CR of Podocnemis expansa (Schweigger, 1812 obtained from GenBank, the structural and evolutionary characteristics of mtDNA CRs in pleurodiran turtle were analyzed in this study. We identified three functional domains (TAS, CD, and CSB domains as well as their conservation sequences (TAS, CSB-F, and CSB-1 according to their homology to those of other turtles. Within the TAS domain, an interrupted poly-C stretch was found in C. rugosa, C. fimbriata, and P. subrufa, which also exists in the published mt DNA CRs of Chrysemys picta (Schneider, 1783, Trachemys scripta (Thunberg in Schoepff, 1792, and Trionyx triunguis (Forskål, 1775. The analysis of the origin for the poly-C sequences in TAS domain from six turtles suggested that the poly-C sequences are more related to "goose hairpin" in birds rather than CSB2 in CSB domain. In the CSB domain, CSB2 and CSB3, which were determined in CRs of Cryptodira, were absent in Pleurodira CRs, indicating the regulative mechanisms of transcription may be varied in both two suborders and the lack of CSB2 and CSB3 could be proposed as one of diagnostic characters between Pleurodira and Cryptodira at molecular level. As for CR of other cryptodiran turtles, variable number of tandem repeats (VNTRs in the 3' end of the CRs was found in the five pleurodiran turtles. Interestingly, the long repeated motifs from each species could form stable stem-loop secondary structures, suggesting that the repeated sequences may play an important role in regulating replication of the mitochondrial genome in Pleurodiran, and the secondary structures of VNTRs may provide some

  18. DNA variation of the mammalian major histocompatibility complex reflects genomic diversity and population history

    The major histocompatibility complex (MHC) is a multigene complex of tightly linked homologous genes that encode cell surface antigens that play a key role in immune regulation and response to foreign antigens. In most species, MHC gene products display extreme antigenic polymorphism, and their variability has been interpreted to reflect an adaptive strategy for accommodating rapidly evolving infectious agents that periodically afflict natural populations. Determination of the extent of MHC variation has been limited to populations in which skin grafting is feasible or for which serological reagents have been developed. The authors present here a quantitative analysis of restriction fragment length polymorphism of MHC class I genes in several mammalian species (cats, rodents, humans) known to have very different levels of genetic diversity based on functional MHC assays and on allozyme surveys. When homologous class I probes were employed, a notable concordance was observed between the extent of MHC restriction fragment variation and functional MHC variation detected by skin grafts or genome-wide diversity estimated by allozyme screens. These results confirm the genetically depauperate character of the African cheetah, Acinonyx jubatus, and the Asiatic lion, Panthera leo persica; further, they support the use of class I MHC molecular reagents in estimating the extent and character of genetic diversity in natural populations

  19. A framework for variation discovery and genotyping using next-generation DNA sequencing data.

    DePristo, Mark A; Banks, Eric; Poplin, Ryan; Garimella, Kiran V; Maguire, Jared R; Hartl, Christopher; Philippakis, Anthony A; del Angel, Guillermo; Rivas, Manuel A; Hanna, Matt; McKenna, Aaron; Fennell, Tim J; Kernytsky, Andrew M; Sivachenko, Andrey Y; Cibulskis, Kristian; Gabriel, Stacey B; Altshuler, David; Daly, Mark J

    2011-05-01

    Recent advances in sequencing technology make it possible to comprehensively catalog genetic variation in population samples, creating a foundation for understanding human disease, ancestry and evolution. The amounts of raw data produced are prodigious, and many computational steps are required to translate this output into high-quality variant calls. We present a unified analytic framework to discover and genotype variation among multiple samples simultaneously that achieves sensitive and specific results across five sequencing technologies and three distinct, canonical experimental designs. Our process includes (i) initial read mapping; (ii) local realignment around indels; (iii) base quality score recalibration; (iv) SNP discovery and genotyping to find all potential variants; and (v) machine learning to separate true segregating variation from machine artifacts common to next-generation sequencing technologies. We here discuss the application of these tools, instantiated in the Genome Analysis Toolkit, to deep whole-genome, whole-exome capture and multi-sample low-pass (∼4×) 1000 Genomes Project datasets. PMID:21478889

  20. Variation induced by DNA rearrangement in a transgenic Bt+CpTI cotton strain

    2001-01-01

    In the development of transgenic Bt + CpTI cotton cultivars, one male and female sterile mutant has been found in a homozygous T4 strain in our laboratory. The mutant plant, as well as its leaves, buds and flowers, is only 1/2-1/3 as large as that of the wild transgenic Bt + CpTI bivalant cotton plants. Cytological observation found that the chromosome number of the mutant is 2n = 52; however, there are 4 - 8 univalents observed in meiosis Ⅰ of pollen mother cells. Laboratory bioassay indicated that the mutant was highly resistant to bollworm as the wild plants. PCR amplification revealed that Bt and CpTI genes in the mutant were still intactly inserted. However, small deletion of flanked area had been observed in the mutant by Southern blotting analysis. So it is proposed that the mutant phenotype might result from either the DNA deletion or T-DNA trans-ferring in plant genome. No such report has been presented that the rearrangement of chromosome structure in a homo-zygous transgenic line occurred. Further analysis is ongoing.

  1. A Bayesian Analysis for Identifying DNA Copy Number Variations Using a Compound Poisson Process

    Yiğiter Ayten

    2010-01-01

    Full Text Available To study chromosomal aberrations that may lead to cancer formation or genetic diseases, the array-based Comparative Genomic Hybridization (aCGH technique is often used for detecting DNA copy number variants (CNVs. Various methods have been developed for gaining CNVs information based on aCGH data. However, most of these methods make use of the log-intensity ratios in aCGH data without taking advantage of other information such as the DNA probe (e.g., biomarker positions/distances contained in the data. Motivated by the specific features of aCGH data, we developed a novel method that takes into account the estimation of a change point or locus of the CNV in aCGH data with its associated biomarker position on the chromosome using a compound Poisson process. We used a Bayesian approach to derive the posterior probability for the estimation of the CNV locus. To detect loci of multiple CNVs in the data, a sliding window process combined with our derived Bayesian posterior probability was proposed. To evaluate the performance of the method in the estimation of the CNV locus, we first performed simulation studies. Finally, we applied our approach to real data from aCGH experiments, demonstrating its applicability.

  2. From DNA to RNA to disease and back: The 'central dogma' of regulatory disease variation

    Stranger Barbara E

    2006-06-01

    Full Text Available Abstract Much of the focus of human disease genetics is directed towards identifying nucleotide variants that contribute to disease phenotypes. This is a complex problem, often involving contributions from multiple loci and their interactions, as well as effects due to environmental factors. Although some diseases with a genetic basis are caused by nucleotide changes that alter an amino acid sequence, in other cases, disease risk is associated with altered gene regulation. This paper focuses on how studies of gene expression variation might complement disease studies and provide crucial links between genotype and phenotype.

  3. Distribution and functional impact of DNA copy number variation in the rat

    Guryev, V.; Saar, K.; Adamovic, T.; Verheul, M.; Van Heesch, S.A.A.C.; Cook, S.; Pravenec, Michal; Aitman, T.; Jacob, H.; Shull, J.D.; Hubner, N.; Cuppen, E.

    2008-01-01

    Roč. 40, č. 5 (2008), s. 538-545. ISSN 1061-4036 R&D Projects: GA MŠk(CZ) 1P05ME791; GA MŠk(CZ) 1M0520 Grant ostatní: HHMI(US) 55005624; -(XE) LSHG-CT-2005-019015 Institutional research plan: CEZ:AV0Z50110509 Source of funding: N - neverejné zdroje ; R - rámcový projekt EK Keywords : copy number variation * rat * recombinant inbred strains Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 30.259, year: 2008

  4. Extensive length variation in the ribosomal DNA intergenic spacer of yellow perch (Perca flavescens).

    Kakou, Bidénam; Angers, Bernard; Glémet, Hélène

    2016-03-01

    The intergenic spacer (IGS) is located between ribosomal RNA (rRNA) gene copies. Within the IGS, regulatory elements for rRNA gene transcription are found, as well as a varying number of other repetitive elements that are at the root of IGS length heterogeneity. This heterogeneity has been shown to have a functional significance through its effect on growth rate. Here, we present the structural organization of yellow perch (Perca flavescens) IGS based on its entire sequence, as well as the IGS length variation within a natural population. Yellow perch IGS structure has four discrete regions containing tandem repeat elements. For three of these regions, no specific length class was detected as allele size was seemingly normally distributed. However, for one repeat region, PCR amplification uncovered the presence of two distinctive IGS variants representing a length difference of 1116 bp. This repeat region was also devoid of any CpG sites despite a high GC content. Balanced selection may be holding the alleles in the population and would account for the high diversity of length variants observed for adjacent regions. Our study is an important precursor for further work aiming to assess the role of IGS length variation in influencing growth rate in fish. PMID:26841134

  5. Molecular DNA variation among Triturus vittatus vittatus (Urodela) from different breeding sites at the southern limit of its distribution

    Oren Pearlson; Gad Degani

    2007-01-01

    Molecular DNA variation among Triturus vittatus vittatus (striped newt) from different breeding sites at the southern limit of the species distribution (where environmental conditions are most extreme) was studied by the random amplification of polymorphic DNA (RAPD) method that has been found to be appropriate for other Triturus species. Altitudes of the localities ranged between 15-740 m a.s.l. Of the 20 primers employed, OPA-16 was the only one suitable for T. vittatus, revealing a differe...

  6. Gene copy number variations in the leukocyte genome of hepatocellular carcinoma patients with integrated hepatitis B virus DNA

    Xu, Guixia; Cheng, Kai; Cao, Guangwen; Wu, Mengchao; Cheng, Shuqun; Liu, Shanrong

    2016-01-01

    Integration of hepatitis B virus (HBV) DNA into the human liver cell genome is believed to promote HBV-related carcinogenesis. This study aimed to quantify the integration of HBV DNA into the leukocyte genome in hepatocellular carcinoma (HCC) patients in order to identify potential biomarkers for HBV-related diseases. Whole-genome comparative genomic hybridization (CGH) chip array analyses were performed to screen gene copy number variations (CNV) in the leukocyte genome, and the results were confirmed by quantitative polymerase chain reaction (qPCR). The commonly detected regions included chromosome arms 19p, 5q, 1q and 15p, where 200 copy number gain events and 270 copy number loss events were noted. In particular, gains were observed in 5q35.3 (OR4F3) and 19p13.3 (OR4F17) in 90% of the samples. Successful homologous recombination of OR4F3 and the HBV P gene was demonstrated, and the amplification at 5q35.3 is potentially associated with the integration of HBV P gene into natural killer cells isolated from peripheral blood mononuclear cells (PBMCs). Receiver operating characteristic (ROC) curve analysis indicated that the combination of OR4F3 and OR4F17 a novel potential biomarker of HBV-related diseases. PMID:26769853

  7. mtDNA variation of aboriginal Siberians reveals distinct genetic affinities with Native Americans

    Torroni, A.; Schurr, T.G.; Cabell, M.F.; Wallace, D.C. (Emory Univ., Atlanta, GA (United States)); Sukernik, R.I.; Starikovskaya, Y.B. (Institute of Cytology and Genetics, Novosibirsk (Russian Federation)); Crawford, M.H.; Comuzzie, A.G. (Univ. of Kansas, Lawrence, KS (United States))

    1993-09-01

    The mtDNA variation of 411 individuals from 10 aboriginal Siberian populations was analyzed in an effort to delineate the relationships between Siberian and Native American populations. All mtDNAs were characterized by PCR amplification and restriction analysis, and a subset of them was characterized by control region sequencing. The resulting data were then compiled with previous mtDNA data from Native Americans and Asians and were used for phylogenetic analysis and sequence divergence estimations. Aboriginal Siberian populations exhibited mtDNAs from three (A, C, and D) of the four haplogroups observed in Native Americans. However, none of the Siberian populations showed mtDNAs from the fourth haplogroup, group B. The presence of group B deletion haplotypes in East Asian and Native American populations but their absence in Siberians raises the possibility that haplogroup B could represent a migratory event distinct from the one(s) which brought group A, C, and D mtDNAs to the Americas. These findings support the hypothesis that the first humans to move from Siberia to the Americas carried with them a limited number of founding mtDNAs and that the initial migration occurred between 17,000-34,000 years before present. 61 refs., 5 figs., 7 tabs.

  8. Chloroplast DNA variation and phylogeography of Ligularia tongolensis (Asteraceae), a species endemic to the Hengduan Mountains region of China

    Jin-Feng WANG; Yue-Zhi PAN; Xun GONG; Yu-Chung CHIANG; Chiaki KURODA

    2011-01-01

    In this research, we aimed to study the genetic variation and phylogeographic pattern of Ligularia tongolensis, a perennial herb endemic to the Hengduan Mountains region of China. We sequenced two chloroplast DNA (cpDNA) intergenic spacers (trnQ-5'rps 16, trnL-rpl32) in 140 individuals from 14 populations of three groups (Jinshajiang vs. Yalongjiang vs. Wumeng) within this species range. High levels of haplotype diversity (Hd= 0.814)and total genetic diversity (Ht = 0.862) were detected at the species level, based on a total of 12 haplotypes identified.Low levels of intrapopulation diversity (Hs = 0.349), high levels of genetic divergence (Gst = 0.595, Nst = 0.614,Fst = 0.597), and the absence of isolation by distance tests were also found in L. tongolensis. Furthermore, H2 and H5, the dominant haplotypes that located at internal nodes and deviated from extinct ancestral haplotype in the network, were found to be shared between Jinshajiang and Yalongjiang groups. These results indicate that past fragmentation may be the important factor responsible for the present phylogeographical pattern of L. tongolensis.Meanwhile, the locations occupied by each group might have served as independent refugia for L. tongolensis during the Quaternary glaciation. Unimodal mismatch distribution and star-like genealogies indicated this species underwent past demographic expansion events, with expansion ages of 274 ka BP.

  9. Sequence variations of in vitro pUC18 plasmid DNA induced by high energy 7Li ion beams implantation

    High energy heavy ion beams is a new mutagen for crop mutation breeding, but limited data are available on the molecular level induced by this mutagen. The in vitro pUC18 plasmid DNA was implanted by 7Li ion beams by doses of 0, 20, 40, 60, 80 and 100Gy, respectively, with the energy of 42.3Mev. The results showed that the damage effects induced by 7Li ion beams implantation was different from low LET rays, even low doses of 7Li ion beam could induce high damage on hydrogen bonds. Percentage of damages on hydrogen bonds of in vitro DNA induced by 7Li ion beams implantation increased with dosage increase up to 40Gy, then reduced with dosage increase, and higher than those of gamma rays in the same dosage. The relationship of dosage and damage percentage was different from that of gamma rays which was positive-linear correlation. Mutation frequency of 7Li ion beam implantation was 1.6 to 4.3 times to that of spontaneous mutation. The relationship of mutation frequency and dosage was similar with that of damage effects on hydrogen bonds, and showed a peak at 40Gy. The above results were identical with biological effects of wheat implanted by 7Li ion beams. Ten mutants were used for sequence analysis, which indicated that the types of base changes included base transversion, transition and deletion. Among all base changes detected, the frequency of bases transition (60%) was higher than that of bases transversion (30%) and bases deletion (10%). It seemed that thymine was more sensitive to the implantation than any other bases and base changes were mainly T→C and C→T. Bases between T and C were seemed to be easily induced by 7Li ion beams. The high percentage of DNA sequence variations could explain primarily the biological effects caused by 7Li ion beams in the M1 generation of crops. (author)

  10. Variation of DNA Fragmentation Levels During Density Gradient Sperm Selection for Assisted Reproduction Techniques

    Muratori, Monica; Tarozzi, Nicoletta; Cambi, Marta; Boni, Luca; Iorio, Anna Lisa; Passaro, Claudia; Luppino, Benedetta; Nadalini, Marco; Marchiani, Sara; Tamburrino, Lara; Forti, Gianni; Maggi, Mario; Baldi, Elisabetta; Borini, Andrea

    2016-01-01

    Abstract Predicting the outcome of in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) is one main goal of the present research on assisted reproduction. To understand whether density gradient centrifugation (DGC), used to select sperm, can affect sperm DNA integrity and impact pregnancy rate (PR), we prospectively evaluated sperm DNA fragmentation (sDF) by TUNEL/PI, before and after DGC. sDF was studied in a cohort of 90 infertile couples the same day of IVF/ICSI treatment. After DGC, sDF increased in 41 samples (Group A, median sDF value: 29.25% [interquartile range, IQR: 16.01–41.63] in pre- and 60.40% [IQR: 32.92–93.53] in post-DGC) and decreased in 49 (Group B, median sDF value: 18.84% [IQR: 13.70–35.47] in pre- and 8.98% [IQR: 6.24–15.58] in post-DGC). PR was 17.1% and 34.4% in Group A and B, respectively (odds ratio [OR]: 2.58, 95% confidence interval [CI]: 0.95–7.04, P = 0.056). After adjustment for female factor, female and male age and female BMI, the estimated OR increased to 3.12 (95% CI: 1.05–9.27, P = 0.041). According to the subgroup analysis for presence/absence of female factor, heterogeneity in the association between the Group A and B and PR emerged (OR: 4.22, 95% CI: 1.16–15.30 and OR: 1.53, 95% CI: 0.23–10.40, respectively, for couples without, n = 59, and with, n = 31, female factor). This study provides the first evidence that the DGC procedure produces an increase in sDF in about half of the subjects undergoing IVF/ICSI, who then show a much lower probability of pregnancy, raising concerns about the safety of this selection procedure. Evaluation of sDF before and after DGC configures as a possible new prognostic parameter of pregnancy outcome in IVF/ICSI. Alternative sperm selection strategies are recommended for those subjects who undergo the damage after DGC. PMID:27196465

  11. Variation and association to diabetes in 2000 full mtDNA sequences mined from an exome study in a Danish population

    Li, Shengting; Besenbacher, Soren; Li, Yingrui;

    2014-01-01

    In this paper, we mine full mtDNA sequences from an exome capture data set of 2000 Danes, showing that it is possible to get high-quality full-genome sequences of the mitochondrion from this resource. The sample includes 1000 individuals with type 2 diabetes and 1000 controls. We characterise the...... variation found in the mtDNA sequence in Danes and relate the variation to diabetes risk as well as to several blood phenotypes of the controls but find no significant associations. We report 2025 polymorphisms, of which 393 have not been reported previously. These 393 mutations are both very rare and...

  12. Investigating the potential role of genetic and epigenetic variation of DNA methyltransferase genes in hyperplastic polyposis syndrome.

    Musa Drini

    Full Text Available BACKGROUND: Hyperplastic Polyposis Syndrome (HPS is a condition associated with multiple serrated polyps, and an increased risk of colorectal cancer (CRC. At least half of CRCs arising in HPS show a CpG island methylator phenotype (CIMP, potentially linked to aberrant DNA methyltransferase (DNMT activity. CIMP is associated with methylation of tumor suppressor genes including regulators of DNA mismatch repair (such as MLH1, MGMT, and negative regulators of Wnt signaling (such as WIF1. In this study, we investigated the potential for interaction of genetic and epigenetic variation in DNMT genes, in the aetiology of HPS. METHODS: We utilized high resolution melting (HRM analysis to screen 45 cases with HPS for novel sequence variants in DNMT1, DNMT3A, DNMT3B, and DNMT3L. 21 polyps from 13 patients were screened for BRAF and KRAS mutations, with assessment of promoter methylation in the DNMT1, DNMT3A, DNMT3B, DNMT3L MLH1, MGMT, and WIF1 gene promoters. RESULTS: No pathologic germline mutations were observed in any DNA-methyltransferase gene. However, the T allele of rs62106244 (intron 10 of DNMT1 gene was over-represented in cases with HPS (p<0.01 compared with population controls. The DNMT1, DNMT3A and DNMT3B promoters were unmethylated in all instances. Interestingly, the DNMT3L promoter showed low levels of methylation in polyps and normal colonic mucosa relative to matched disease free cells with methylation level negatively correlated to expression level in normal colonic tissue. DNMT3L promoter hypomethylation was more often found in polyps harbouring KRAS mutations (p = 0.0053. BRAF mutations were common (11 out of 21 polyps, whilst KRAS mutations were identified in 4 of 21 polyps. CONCLUSIONS: Genetic or epigenetic alterations in DNMT genes do not appear to be associated with HPS, but further investigation of genetic variation at rs62106244 is justified given the high frequency of the minor allele in this case series.

  13. Genetic relationship of Chinese and Japanese gamecocks revealed by mtDNA sequence variation.

    Liu, Yi-Ping; Zhu, Qing; Yao, Yong-Gang

    2006-02-01

    Cockfighting has a very long history dating back to as early as 2500 years ago in China. Cockfighting was intertwined with human cultural traditions, helped disperse chickens across the world, and influenced the subsequent breed selection. Therefore, tracing the origin of gamecocks could mirror the distribution of the cockfighting culture. In this study, we compared the available mtDNA control region sequences in Chinese and Japanese gamecocks to test the recently proposed hypothesis behind the dual origin of the Japanese cockfighting culture (from China and Southeast Asia independently). We assigned gamecock mtDNAs to different matrilineal components (or phylogenetic clades) that emerged from the phylogenetic tree and network profile, and compared the frequency differences between Chinese and Japanese gamecocks. Among the six clades (A-F) identified, Japanese gamecocks were most frequently found in clades C and D (74%, 32/43), whereas more than half of the Chinese gamecock samples (69%, 35/51) were grouped in clades A and B. Haplotypes in Japanese gamecocks assigned to clades A, B, and E were either shared with those of the Chinese samples or differed from the close Chinese types by no more than a three-mutation distance. This genetic pattern is in accordance with the proposed dual origin of Japanese gamecocks but has left room for single origin of Japanese gamecocks from China. The genetic structure of gamecocks in China and Japan might also be influenced by subsequent breed selection and conservation after the initial gamecock introduction. PMID:16648993

  14. Haplogroup Classification of Korean Cattle Breeds Based on Sequence Variations of mtDNA Control Region.

    Kim, Jae-Hwan; Lee, Seong-Su; Kim, Seung Chang; Choi, Seong-Bok; Kim, Su-Hyun; Lee, Chang Woo; Jung, Kyoung-Sub; Kim, Eun Sung; Choi, Young-Sun; Kim, Sung-Bok; Kim, Woo Hyun; Cho, Chang-Yeon

    2016-05-01

    Many studies have reported the frequency and distribution of haplogroups among various cattle breeds for verification of their origins and genetic diversity. In this study, 318 complete sequences of the mtDNA control region from four Korean cattle breeds were used for haplogroup classification. 71 polymorphic sites and 66 haplotypes were found in these sequences. Consistent with the genetic patterns in previous reports, four haplogroups (T1, T2, T3, and T4) were identified in Korean cattle breeds. In addition, T1a, T3a, and T3b sub-haplogroups were classified. In the phylogenetic tree, each haplogroup formed an independent cluster. The frequencies of T3, T4, T1 (containing T1a), and T2 were 66%, 16%, 10%, and 8%, respectively. Especially, the T1 haplogroup contained only one haplotype and a sample. All four haplogroups were found in Chikso, Jeju black and Hanwoo. However, only the T3 and T4 haplogroups appeared in Heugu, and most Chikso populations showed a partial of four haplogroups. These results will be useful for stable conservation and efficient management of Korean cattle breeds. PMID:26954229

  15. Genetic variation in Labeo fimbriatus (Cypriniformes: Cyprinidae) populations as revealed by partial cytochrome b sequences of mitochondrial DNA.

    Swain, Subrat Kumar; Bej, Dillip; Das, Sofia Priyadarsani; Sahoo, Lakshman; Jayasankar, Pallipuram; Das, Pratap Chandra; Das, Paramananda

    2016-05-01

    Labeo fimbriatus, a medium sized carp is assessed as a commercially important aquaculture species in Indian subcontinent. In the present study, the genetic diversity and population structure of four Indian riverine populations of L. fimbriatus have been evaluated using partial cytochrome b sequences of mitochondrial DNA. Sequencing and analysis of this gene from 108 individuals defined 7 distinct haplotypes. Haplotype diversity (Hd) and nucleotide diversity (π) ranged from 0.067 to 0.405 and 0.00023 to 0.03231, respectively. The Mahanadi population had the highest π level. Analysis of molecular variance (AMOVA) indicated that 47.36% of genetic variation contained within population and 53.76% of genetic variation among groups. Pairwise FST analysis indicated that there was little or no genetic differentiation among populations (-0.0018 to 04572) from different geographical regions except Mahanadi population. The Mahanadi population can be considered as a separate stock from rest three riverine populations. Accordingly, the genetic information generated from this study can be implemented while taking decision in formulating base population for the sustainable selective breeding programs of this species. PMID:25329277

  16. Genetic variations of Lansium domesticum Corr. accessions from Java, Sumatra and Ceram based on Random Amplified Polymorphic DNA fingerprints

    KUSUMADEWI SRI YULITA

    2011-07-01

    Full Text Available Yulita KS (2011 Genetic variations of Lansium domesticum Corr. accessions from Java, Bengkulu and Ceram based on Random Amplified Polymorphic DNA fingerprints. Biodiversitas 12: 125-130. Duku (Lansium domesticum Corr. is one of popular tropical fruits in SE Asia. The spesies has three varieties, known as duku, langsat and kokosan; and duku is the most popular one for being the sweetiest fruit. Indonesia has several local varieties of duku, such as duku Condet, duku Sumber and duku Palembang. This present study aimed to assess genetic diversity of 47 accessions of duku from Java, Sumatra, and Ceram based on RAPD fingerprints. Ten RAPD’s primers were initially screened and five were selected for the analysis. These five primers (OPA 7, 13, 18, OPB 7, and OPN 12 generated 53 scorable bands with an average of 10.6 polymorphic fragment per primer. Percentage of polymorphism ranged from 16.89% (OPA 7 and OPN 12 to 24.54% (OPB 7 with an average of 20.16% polymorphism. OPB 7 at 450 bp was exclusively possessed by accession 20 (Java, OPA 18 at 500 bp was by accession 6 (Java, 550 bp by 3 clones from Bengkulu. While OPN 12 at 300 bp and OPA 13 at 450 bp were shared among the accessions. Clustering analysis was performed based on RAPD profiles using the UPGMA method. The range of genetic similarity value among accessions was 0.02-0.65 suggesting high variation of gene pool existed among accessions.

  17. Sequence variation of Bemisia tabaci Chemosensory Protein 2 in cryptic species B and Q: New DNA markers for whitefly recognition.

    Liu, Guo-Xia; Ma, Hong-Mei; Xie, Hong-Yan; Xuan, Ning; Picimbon, Jean-François

    2016-01-15

    Bemisia tabaci Gennadius biotypes B and Q are two of the most important worldwide agricultural insect pests. Genomic sequences of Type-2 B. tabaci chemosensory protein (BtabCSP2) were cloned and sequenced in B and Q biotypes, revealing key biotype-specific variations in the intron sequence. A Q260 sequence was found specifically in Q-BtabCSP2 and Cucumis melo LN692399, suggesting ancestral horizontal transfer of gene between the insect and the plant through bacteria. A cleaved amplified polymorphic sequences (CAPS) method was then developed to differentiate B and Q based on the sequence variation in exon of BtabCSP2 gene. The performances of CSP2-based CAPS for whitefly recognition were assessed using B. tabaci field collections from Shandong Province (P.R. China). Our SacII based CAPS method led to the same result compared to mitochondrial cytochrome oxidase-based CAPS method in the field collections. We therefore propose an explanation for CSP origin and a new rapid simple molecular method based on genomic DNA and chemosensory gene to differentiate accurately the B and Q whiteflies of the Bemisia complex around the world. PMID:26481237

  18. Mitochondrial DNA variation of indigenous goats in Narok and Isiolo counties of Kenya.

    Kibegwa, F M; Githui, K E; Jung'a, J O; Badamana, M S; Nyamu, M N

    2016-06-01

    Phylogenetic relationships among and genetic variability within 60 goats from two different indigenous breeds in Narok and Isiolo counties in Kenya and 22 published goat samples were analysed using mitochondrial control region sequences. The results showed that there were 54 polymorphic sites in a 481-bp sequence and 29 haplotypes were determined. The mean haplotype diversity and nucleotide diversity were 0.981 ± 0.006 and 0.019 ± 0.001, respectively. The phylogenetic analysis in combination with goat haplogroup reference sequences from GenBank showed that all goat sequences were clustered into two haplogroups (A and G), of which haplogroup A was the commonest in the two populations. A very high percentage (99.90%) of the genetic variation was distributed within the regions, and a smaller percentage (0.10%) distributed among regions as revealed by the analysis of molecular variance (amova). This amova results showed that the divergence between regions was not statistically significant. We concluded that the high levels of intrapopulation diversity in Isiolo and Narok goats and the weak phylogeographic structuring suggested that there existed strong gene flow among goat populations probably caused by extensive transportation of goats in history. PMID:26459231

  19. Nuclear DNA content in Sinningia (Gesneriaceae); intraspecific genome size variation and genome characterization in S. speciosa.

    Zaitlin, David; Pierce, Andrew J

    2010-12-01

    The Gesneriaceae (Lamiales) is a family of flowering plants comprising >3000 species of mainly tropical origin, the most familiar of which is the cultivated African violet (Saintpaulia spp.). Species of Gesneriaceae are poorly represented in the lists of taxa sampled for genome size estimation; measurements are available for three species of Ramonda and one each of Haberlea, Saintpaulia, and Streptocarpus, all species of Old World origin. We report here nuclear genome size estimates for 10 species of Sinningia, a neotropical genus largely restricted to Brazil. Flow cytometry of leaf cell nuclei showed that holoploid genome size in Sinningia is very small (approximately two times the size of the Arabidopsis genome), and is small compared to the other six species of Gesneriaceae with genome size estimates. We also documented intraspecific genome size variation of 21%-26% within a group of wild Sinningia speciosa (Lodd.) Hiern collections. In addition, we analyzed 1210 genome survey sequences from S. speciosa to characterize basic features of the nuclear genome such as guanine-cytosine content, types of repetitive elements, numbers of protein-coding sequences, and sequences unique to S. speciosa. We included several other angiosperm species as genome size standards, one of which was the snapdragon (Antirrhinum majus L.; Veronicaceae, Lamiales). Multiple measurements on three accessions indicated that the genome size of A. majus is ~633 × 10⁶ base pairs, which is approximately 40% of the previously published estimate. PMID:21164539

  20. [Genuineness of Morinda officinalis How germplasm inferred from ITS sequences variation of nuclear ribosomal DNA].

    Ding, Ping; Liu, Jin; Qiu, Jin-Ying; Lai, Xiao-Ping

    2012-04-01

    PCR sequencing ITS genes methods were used to assess the genetic diversity of Morinda officinalis How different populations. The sequence of Morinda officinalis ITS gene was 567 bp in length, and the content of G/C was 64.5%. In this study, 17 haplotypes were obtained, which were at a high level of branching, and the haplotypes of Guangdong population showed to be the expansion origin. The result of the analysis of molecular variance (AMOVA) also showed that the percentage of variation among populations (56.65%) was greater than that within a population (43.35%). The F(ST) value was 0.566 5, and the genetic divergence among populations was significant. Mantel test results also indicated that the level of geneflow was positively correlated with geographic distances (R2 = 0.721 1). The result showed a good correlation between genotype and geographic distribution of Morinda officinalis, and ITS gene sequencing could be useful molecular method for the genuineness and phylogeography of Morinda officinalis. PMID:22799040

  1. DNA variation in the phenotypically-diverse brown alga Saccharina japonica

    Balakirev Evgeniy S

    2012-07-01

    Full Text Available Abstract Background Saccharina japonica (Areschoug Lane, Mayes, Druehl et Saunders is an economically important and highly morphologically variable brown alga inhabiting the northwest Pacific marine waters. On the basis of nuclear (ITS, plastid (rbcLS and mitochondrial (COI DNA sequence data, we have analyzed the genetic composition of typical Saccharina japonica (TYP and its two common morphological varieties, known as the “longipes” (LON and “shallow-water” (SHA forms seeking to clarify their taxonomical status and to evaluate the possibility of cryptic species within S. japonica. Results The data show that the TYP and LON forms are very similar genetically in spite of drastic differences in morphology, life history traits, and ecological preferences. Both, however, are genetically quite different from the SHA form. The two Saccharina lineages are distinguished by 109 fixed single nucleotide differences as well as by seven fixed length polymorphisms (based on a 4,286 bp concatenated dataset that includes three gene regions. The GenBank database reveals a close affinity of the TYP and LON forms to S. japonica and the SHA form to S. cichorioides. The three gene markers used in the present work have different sensitivity for the algal species identification. COI gene was the most discriminant gene marker. However, we have detected instances of interspecific COI recombination reflecting putative historical hybridization events between distantly related algal lineages. The recombinant sequences show highly contrasted level of divergence in the 5’- and 3’- regions of the gene, leading to significantly different tree topologies depending on the gene segment (5’- or 3’- used for tree reconstruction. Consequently, the 5’-COI “barcoding” region (~ 650 bp can be misleading for identification purposes, at least in the case of algal species that might have experienced historical hybridization events. Conclusion Taking into account

  2. Assessment of Genetic Variation Within Indian Mustard(Brassica juncea) Germplasm Using Random Amplified Polymorphic DNA Markers

    Muhammad Ayub Khan; Malik Ashiq Rabbani; Muharnmad Munir; Saifullah Khan Ajmal; Muhammad Azim Malik

    2008-01-01

    Genetic diversity among 45 Indian mustard (Brassica Juncea L.) genotypes comprising 37 germplasm collections, five advance breeding lines and three improved cultivars was investigated at the DNA level using the random amplified polymorphic DNA (RAPD) technique. Fifteen primers used generated a total of 92 RAPD fragments, of which 81 (88%) were polymorphic. Of these, 13 were unique to accession 'Pak85559'. Each primer produced four to nine amplified products with an average of 6.13 bands per primer. Based on pairwise comparisons of RAPD amplification products, Nei and Li's similarity coefficients were calculated to evaluate the relationships among the accessions. Pairwise similarity indices were higher among the oilseed accessions and cultivars showing narrow ranges of 0.77-0.99. An unweighted pair-group method with arithmetic averages cluster analysis based on these genetic similarities placed most of the collections and oilseed cultivars close to each other, showing a low level of polymorphism between the accessions used. However, the clusters formed by oilseed collections and cultivars were comparatively distinct from that of advanced breeding lines. Genetically, all of the accessions were classified into a few major groups and a number of individual accessions. Advanced breeding lines were relatively divergent from the rest of the accessions and formed independent clusters. Clustering of the accessions did not show any pattern of association between the RAPD markers and the collection sites. A low level of genetic variability of oilseed mustard was attributed to the selection for similar traits and horticultural uses. Perhaps close parentage of these accessions further contributed towards their little diversity. The study demonstrated that RAPD is a simple and fast technique to compare the genetic relationship and pattern of variation among the gene pool of this crop.

  3. mtDNA germ line variation mediated ROS generates retrograde signaling and induces pro-cancerous metabolic features

    Singh, Rajnish Kumar; Srivastava, Archita; Kalaiarasan, Ponnusamy; Manvati, Siddharth; Chopra, Rupali; Bamezai, Rameshwar N. K.

    2014-01-01

    mtDNA non-synonymous germ line variation (G10398A; p.A114T) has remained equivocal with least mechanistic understanding in showing an association with cancer. This has necessitated showing in-vitro how an over-expression within mitochondria of either of the variants produces higher intracellular ROS, resulting in differential anchorage dependent and independent growth. Both these features were observed to be relatively higher in ND3:114T variant. An elevated amount of intracellular carbonylated proteins and a reduced activity of a key glycolytic enzyme, Pyruvate kinase M2, along with high glucose uptake and lactate production were other pro-cancerous features observed. The retrograde signaling through surplus ROS was generated by post-ND3 over-expression regulated nuclear gene expression epigenetically, involving selectively the apoptotic-DDR-pathways. The feature of ND3 over-expression, inducing ROS mediated pro-cancerous features in the cells in in vitro, was replicated in a pilot study in a limited number of sporadic breast tumors, suggesting the importance of mitochondrial germ-line variant(s) in enabling the cells to acquire pro-cancerous features. PMID:25300428

  4. Pressure dissociation of integration host factor–DNA complexes reveals flexibility-dependent structural variation at the protein–DNA interface

    Senear, Donald F.; Tretyachenko-Ladokhina, Vira; Opel, Michael L.; Aeling, Kimberly A.; G Wesley Hatfield; Franklin, Laurie M.; Darlington, Reuben C.; Alexander Ross, J. B.

    2007-01-01

    E. coli Integration host factor (IHF) condenses the bacterial nucleoid by wrapping DNA. Previously, we showed that DNA flexibility compensates for structural characteristics of the four consensus recognition elements associated with specific binding (Aeling et al., J. Biol. Chem. 281, 39236–39248, 2006). If elements are missing, high-affinity binding occurs only if DNA deformation energy is low. In contrast, if all elements are present, net binding energy is unaffected by deformation energy. ...

  5. Assessing genetic variation in natural populations of New World screwworm flies: Evidence from microsatellites and mitochondrial DNA

    Full text: The New World screwworm fly (NWS), Cochliomyia hominivorax (Coquerel 1858, Diptera Calliphoridae), is an obligate ectoparasite that causes myiasis in warm-blooded vertebrates throughout the Neotropical region responsible for significant economic losses to livestock rearing. Because of the substantial economic losses caused by this pest, an international effort eradicated the NWS from endemic areas of North and Central America and is preventing invasions into screwworm-free areas. There have been conflicting reports about the existence of non-interbreeding populations and their possible effects on the control programme. The identification of such populations and an understanding of the genetic variability of target populations is necessary in order to maximize the effectiveness of an eradication programme. We have been using different molecular markers to investigate genetic variability and population structure of C. hominivorax throughout its current geographical distribution in South America in order to address these questions. Mitochondrial DNA (mtDNA) is a marker for studying micro-evolutionary processes in animal populations and can be a suitable marker for estimating the genetic variability within populations. One approach for studying population structure of C. hominivorax population from Uruguay was PCR-RFLP of two specific mitochondrial DNA regions (A+T-rich/12S and cox1/cox 2). The aim of this study was to examine the genetic variability among geographically distinct populations of NWS from Brazil and Uruguay, to have a better scenario of the genetic structure of this species distribution. Nine haplotypes were observed among the populations sampled. The mean nucleotide diversity (π= 2.3%) and the haplotype diversity (Hs= 0.6533) indicated high mtDNA variability in this species. The similarity index (96.7%), the average nucleotide divergence (δ= 0.00055) and the AMOVA results showed no evidence of subpopulation differentiation. In this case

  6. Variation in PAH-related DNA adduct levels among non-smokers: the role of multiple genetic polymorphisms and nucleotide excision repair phenotype.

    Etemadi, Arash; Islami, Farhad; Phillips, David H; Godschalk, Roger; Golozar, Asieh; Kamangar, Farin; Malekshah, Akbar Fazel-Tabar; Pourshams, Akram; Elahi, Seerat; Ghojaghi, Farhad; Strickland, Paul T; Taylor, Philip R; Boffetta, Paolo; Abnet, Christian C; Dawsey, Sanford M; Malekzadeh, Reza; van Schooten, Frederik J

    2013-06-15

    Polycyclic aromatic hydrocarbons (PAHs) likely play a role in many cancers even in never-smokers. We tried to find a model to explain the relationship between variation in PAH-related DNA adduct levels among people with similar exposures, multiple genetic polymorphisms in genes related to metabolic and repair pathways, and nucleotide excision repair (NER) capacity. In 111 randomly selected female never-smokers from the Golestan Cohort Study in Iran, we evaluated 21 SNPs in 14 genes related to xenobiotic metabolism and 12 SNPs in eight DNA repair genes. NER capacity was evaluated by a modified comet assay, and aromatic DNA adduct levels were measured in blood by32P-postlabeling. Multivariable regression models were compared by Akaike's information criterion (AIC). Aromatic DNA adduct levels ranged between 1.7 and 18.6 per 10(8) nucleotides (mean: 5.8 ± 3.1). DNA adduct level was significantly lower in homozygotes for NAT2 slow alleles and ERCC5 non-risk-allele genotype, and was higher in the MPO homozygote risk-allele genotype. The sum of risk alleles in these genes significantly correlated with the log-adduct level (r = 0.4, p studies, with large inter-individual variation which could best be explained by a combination of Phase I genes and NER capacity. PMID:23175176

  7. Cylindrotheca closterium Is a Species Complex as Was Evidenced by the Variations of rbcL Gene and SSU rDNA

    LI Haitao; YANG Guanpin; SUN Ying; WU Suihan; ZHANG Xiufang

    2007-01-01

    The genus Cylindrotheca consists of a small group of marine diatoms with a few species described. Eleven isolates of diatoms identified as Cylindrotheca closterium morphologically were obtained from Jiaozhou Bay with their nuclear-encoded small-subunit ribosomal RNA (SSU rDNA) and chloroplast-encoded rbcL gene sequences determined in this study. Interestingly, very high sequence divergences of SSU rDNA and rbcL gene were found among these isolates, and numerous nucleotide variation of rbcL gene caused relatively few variation of deduced amino acid sequence. Phylogenetic analyses based on SSU rDNA and rbcL gene, respectively, grouped the isolates into 6 clades. Phylogenetic tree of SSU rDNA placed all the Cylindrotheca isolates together, separating them into two lineages clearly. LineageⅠ was composed of the eleven C. closterium isolates obtained in this study together with another C. closterium isolate, but some clades were not well supported. LineageⅡ contained two C. closterium isolates and one C. fusiformis isolate. Phylogenetic analysis of rbcL gene also separated the Cylindrotheca isolates into two well-defined lineages. The eleven C. closterium isolates formed a lineage and all clades were supported strongly. Statistical comparisons of SSU rDNA indicated that the average distance within lineage Ⅰ was significantly higher than that of other microalgae species (P < 0.01). These results suggested the existence of cryptic species within C. closterium.

  8. Use of sequence variation in three highly variable regions of the mitochondrial DNA for the discrimination of allogeneic platelets

    Warner, JB; Bruin, EJ; Hannig, H; Hellenkamp, F; Horning, A; Mittmann, K; van der Steege, G; de Leij, LFMH; Garritsen, HSP

    2006-01-01

    BACKGROUND: Human mitochondrial DNA (mtDNA) polymorphisms can be used to detect allogeneic transfused platelets. To increase the number of informative polymorphisms we investigated three hypervariable regions (HVR1, HVR2, and HVR3) within the displacement loop (D-loop) region of the mtDNA. STUDY DES

  9. Evaluation of Interindividual Human Variation in Bioactivation and DNA Adduct Formation of Estragole in Liver Predicted by Physiologically Based Kinetic/Dynamic and Monte Carlo Modeling.

    Punt, Ans; Paini, Alicia; Spenkelink, Albertus; Scholz, Gabriele; Schilter, Benoit; van Bladeren, Peter J; Rietjens, Ivonne M C M

    2016-04-18

    Estragole is a known hepatocarcinogen in rodents at high doses following metabolic conversion to the DNA-reactive metabolite 1'-sulfooxyestragole. The aim of the present study was to model possible levels of DNA adduct formation in (individual) humans upon exposure to estragole. This was done by extending a previously defined PBK model for estragole in humans to include (i) new data on interindividual variation in the kinetics for the major PBK model parameters influencing the formation of 1'-sulfooxyestragole, (ii) an equation describing the relationship between 1'-sulfooxyestragole and DNA adduct formation, (iii) Monte Carlo modeling to simulate interindividual human variation in DNA adduct formation in the population, and (iv) a comparison of the predictions made to human data on DNA adduct formation for the related alkenylbenzene methyleugenol. Adequate model predictions could be made, with the predicted DNA adduct levels at the estimated daily intake of estragole of 0.01 mg/kg bw ranging between 1.6 and 8.8 adducts in 10(8) nucleotides (nts) (50th and 99th percentiles, respectively). This is somewhat lower than values reported in the literature for the related alkenylbenzene methyleugenol in surgical human liver samples. The predicted levels seem to be below DNA adduct levels that are linked with tumor formation by alkenylbenzenes in rodents, which were estimated to amount to 188-500 adducts per 10(8) nts at the BMD10 values of estragole and methyleugenol. Although this does not seem to point to a significant health concern for human dietary exposure, drawing firm conclusions may have to await further validation of the model's predictions. PMID:26952143

  10. High regional genetic diversity and lack of host-specificity in Ostrinia nubilalis (Lepidoptera: Crambidae) as revealed by mtDNA variation.

    Piwczyński, M; Pabijan, M; Grzywacz, A; Glinkowski, W; Bereś, P K; Buszko, J

    2016-08-01

    The European corn borer (Ostrinia nubilalis) infests a wide array of host plants and is considered one of the most serious pests of maize in Europe. Recent studies suggest that individuals feeding on maize in Europe should be referred to O. nubilalis (sensu nov.), while those infesting dicots as Ostrinia scapulalis (sensu nov.). We test if the clear genetic distinctiveness among individuals of O. nubilalis living on maize vs. dicots is tracked by mitochondrial DNA (mtDNA). We used fragments of COI and COII genes of 32 individuals traditionally recognized as O. nubilalis collected on three host plants, maize, mugwort and hop, growing in different parts of Poland. In addition, we reconstructed the mtDNA phylogeny of Ostrinia species based on our data and sequences retrieved from GenBank to assess host and/or biogeographic patterns. We also compared haplotype variation found in Poland (east-central Europe) with other regions (Anatolia, Eastern Europe, Balkans, Far East, North America). Our study showed high mtDNA diversity of O. nubilalis in Poland in comparison with other regions and revealed rare haplotypes likely of Asian origin. We did not find distinct mtDNA haplotypes in larvae feeding on maize vs. dicotyledonous plants. Phylogenetic analyses showed an apparent lack of mtDNA divergence among putatively distinct lineages belonging to the O. nubilalis group as identical haplotypes are shared by Asian and European individuals. We argue that human-mediated dispersal, hybridization and sporadic host jumps are likely responsible for the lack of a geographic pattern in mtDNA variation. PMID:27019346

  11. Mitochondrial DNA variation in a species with two mitochondrial genomes: the case of Mytilus galloprovincialis from the Atlantic, the Mediterranean and the Black Sea.

    Ladoukakis, E D; Saavedra, C; Magoulas, A; Zouros, E

    2002-04-01

    We have examined mitochondrial DNA (mtDNA) variation in samples of the mussel Mytilus galloprovincialis from the Black Sea, the Mediterranean and the Spanish Atlantic coast by scoring for presence or absence of cleavage at 20 restriction sites of a fragment of the COIII gene and at four restriction sites of the 16S RNA gene. This species contains two types of mtDNA genomes, one that is transmitted maternally (the F type) and one that is transmitted paternally (the M type). The M genome evolves at a higher rate than the F genome. Normally, females are homoplasmic for an F type and males are heteroplasmic for an F and an M type. Occasionally molecules from the F lineage invade the paternal transmission route, resulting in males that carry two F-type mtDNA genomes. These features of the mussel mtDNA system give rise to a new set of questions when using mtDNA variation in population studies and phylogeny. We show here that the two mtDNA types provide different information with regard to amounts of variation and genetic distances among populations. The F genome exhibits higher degrees of diversity within populations, while the M genome produces higher degrees of differentiation among populations. There is a strong differentiation between the Atlantic and the Black Sea. The Mediterranean samples have intermediate haplotype frequencies, yet are much closer to the Black Sea than to the Atlantic. We conclude that in this species gene flow among the three Seas is restricted and not enough to erase the combined effect of mutation and random drift. In one sample, that from the Black Sea, the majority of males did not contain an M mtDNA type. This suggests that a molecule of the maternal lineage has recently invaded the paternal route and has increased its frequency in the population to the point that the present pool of paternally transmitted mtDNA molecules is highly heterogeneous and cannot be used to read the population's history. This liability of the paternal route means

  12. Next-Gen phylogeography of rainforest trees: exploring landscape-level cpDNA variation from whole-genome sequencing.

    van der Merwe, M; McPherson, H; Siow, J; Rossetto, M

    2014-01-01

    Standardized phylogeographic studies across codistributed taxa can identify important refugia and biogeographic barriers, and potentially uncover how changes in adaptive constraints through space and time impact on the distribution of genetic diversity. The combination of next-generation sequencing and methodologies that enable uncomplicated analysis of the full chloroplast genome may provide an invaluable resource for such studies. Here, we assess the potential of a shotgun-based method across twelve nonmodel rainforest trees sampled from two evolutionary distinct regions. Whole genomic shotgun sequencing libraries consisting of pooled individuals were used to assemble species-specific chloroplast references (in silicio). For each species, the pooled libraries allowed for the detection of variation within and between data sets (each representing a geographic region). The potential use of nuclear rDNA as an additional marker from the NGS libraries was investigated by mapping reads against available references. We successfully obtained phylogeographically informative sequence data from a range of previously unstudied rainforest trees. Greater levels of diversity were found in northern refugial rainforests than in southern expansion areas. The genetic signatures of varying evolutionary histories were detected, and interesting associative patterns between functional characteristics and genetic diversity were identified. This approach can suit a wide range of landscape-level studies. As the key laboratory-based steps do not require prior species-specific knowledge and can be easily outsourced, the techniques described here are even suitable for researchers without access to wet-laboratory facilities, making evolutionary ecology questions increasingly accessible to the research community. PMID:24119022

  13. Host Plant Mediated Population Variations of Cotton Whitefly Bemisia tabaci Gennadius (Aleyrodidae: Homoptera Characterized with Random DNA Markers

    Yasodha Perumal

    2009-01-01

    Full Text Available Problem statement: Whitefly, Bemisia tabaci is an important sucking pest of field, horticultural and ornamental plants causing feeding injuries besides spreading disease by acting as a vector of Gemini viruses. The polyphagous nature of the pest makes it as a highly complex species. Approach: The influence of host plants utilized by the species on the population differences at molecular level was attempted using Random Amplified Polymorphic DNA (RAPD markers. Results: Ten RAPD primers out of the total seventeen primers screened produced 236 markers. The total number of bands obtained from each primer ranged from 11-35 with an average of 23.60 bands per primer. Of the pair wise combination among thirteen species, Srivilliputhur population showed the highest similarity index (0.826 while the lowest (0.111 was recorded by Namakkal population. The similarity coefficient based on the 236 RAPD markers generated ranged from 0.111-0.826. Three major clusters were formed from UPGMA dendrogram, which was constructed based on Jaccard’s similarity. PCR screening demarcated the whitefly population based on the host species. The first cluster included population collected from okra and cotton, while second cluster comprised of population from eggplant and cauliflower and the third cluster included population from eggplant. It could be deduced that population from cotton and okra had 50% similarity, while 60-70% similarity was observed for population from eggplant and cauliflower. Conclusion: Our investigation offered the lead that within a narrow geographical region there exits variation based on host plants being utilized by the whitefly population.

  14. Assessing Mitochondrial DNA Variation and Copy Number in Lymphocytes of ~2,000 Sardinians Using Tailored Sequencing Analysis Tools.

    Jun Ding

    2015-07-01

    Full Text Available DNA sequencing identifies common and rare genetic variants for association studies, but studies typically focus on variants in nuclear DNA and ignore the mitochondrial genome. In fact, analyzing variants in mitochondrial DNA (mtDNA sequences presents special problems, which we resolve here with a general solution for the analysis of mtDNA in next-generation sequencing studies. The new program package comprises 1 an algorithm designed to identify mtDNA variants (i.e., homoplasmies and heteroplasmies, incorporating sequencing error rates at each base in a likelihood calculation and allowing allele fractions at a variant site to differ across individuals; and 2 an estimation of mtDNA copy number in a cell directly from whole-genome sequencing data. We also apply the methods to DNA sequence from lymphocytes of ~2,000 SardiNIA Project participants. As expected, mothers and offspring share all homoplasmies but a lesser proportion of heteroplasmies. Both homoplasmies and heteroplasmies show 5-fold higher transition/transversion ratios than variants in nuclear DNA. Also, heteroplasmy increases with age, though on average only ~1 heteroplasmy reaches the 4% level between ages 20 and 90. In addition, we find that mtDNA copy number averages ~110 copies/lymphocyte and is ~54% heritable, implying substantial genetic regulation of the level of mtDNA. Copy numbers also decrease modestly but significantly with age, and females on average have significantly more copies than males. The mtDNA copy numbers are significantly associated with waist circumference (p-value = 0.0031 and waist-hip ratio (p-value = 2.4×10-5, but not with body mass index, indicating an association with central fat distribution. To our knowledge, this is the largest population analysis to date of mtDNA dynamics, revealing the age-imposed increase in heteroplasmy, the relatively high heritability of copy number, and the association of copy number with metabolic traits.

  15. In situ labeling of DNA reveals interindividual variation in nuclear DNA breakdown in hair and may be useful to predict success of forensic genotyping of hair

    Szabo, Sandra; Jaeger, Karin; Fischer, Heinz; Tschachler, Erwin; Parson, Walther; Eckhart, Leopold

    2011-01-01

    Hair fibers are formed by keratinocytes of the hair follicle in a process that involves the breakdown of the nucleus including DNA. Accordingly, DNA can be isolated with high yield from the hair bulb which contains living keratinocytes, whereas it is difficult to prepare from the distal portions of hair fibers and from shed hair. Nevertheless, forensic investigations are successful in a fraction of shed hair samples found at crime scenes. Here, we report that interindividual differences in th...

  16. Limited phylogeographic signal in sex-linked and autosomal loci despite geographically, ecologically, and phenotypically concordant structure of mtDNA variation in the Holarctic avian genus Eremophila.

    Sergei V Drovetski

    Full Text Available Phylogeographic studies of Holarctic birds are challenging because they involve vast geographic scale, complex glacial history, extensive phenotypic variation, and heterogeneous taxonomic treatment across countries, all of which require large sample sizes. Knowledge about the quality of phylogeographic information provided by different loci is crucial for study design. We use sequences of one mtDNA gene, one sex-linked intron, and one autosomal intron to elucidate large scale phylogeographic patterns in the Holarctic lark genus Eremophila. The mtDNA ND2 gene identified six geographically, ecologically, and phenotypically concordant clades in the Palearctic that diverged in the Early-Middle Pleistocene and suggested paraphyly of the horned lark (E. alpestris with respect to the Temminck's lark (E. bilopha. In the Nearctic, ND2 identified five subclades which diverged in the Late Pleistocene. They overlapped geographically and were not concordant phenotypically or ecologically. Nuclear alleles provided little information on geographic structuring of genetic variation in horned larks beyond supporting the monophyly of Eremophila and paraphyly of the horned lark. Multilocus species trees based on two nuclear or all three loci provided poor support for haplogroups identified by mtDNA. The node ages calculated using mtDNA were consistent with the available paleontological data, whereas individual nuclear loci and multilocus species trees appeared to underestimate node ages. We argue that mtDNA is capable of discovering independent evolutionary units within avian taxa and can provide a reasonable phylogeographic hypothesis when geographic scale, geologic history, and phenotypic variation in the study system are too complex for proposing reasonable a priori hypotheses required for multilocus methods. Finally, we suggest splitting the currently recognized horned lark into five Palearctic and one Nearctic species.

  17. A Colony Multiplex Quantitative PCR-Based 3S3DBC Method and Variations of It for Screening DNA Libraries

    An, Yang; Toyoda, Atsushi; Zhao, Chen; Fujiyama, Asao; Agata, Kiyokazu

    2015-01-01

    A DNA library is a collection of DNA fragments cloned into vectors and stored individually in host cells, and is a valuable resource for molecular cloning, gene physical mapping, and genome sequencing projects. To take the best advantage of a DNA library, a good screening method is needed. After describing pooling strategies and issues that should be considered in DNA library screening, here we report an efficient colony multiplex quantitative PCR-based 3-step, 3-dimension, and binary-code (3S3DBC) method we used to screen genes from a planarian genomic DNA fosmid library. This method requires only 3 rounds of PCR reactions and only around 6 hours to distinguish one or more desired clones from a large DNA library. According to the particular situations in different research labs, this method can be further modified and simplified to suit their requirements. PMID:25646755

  18. A colony multiplex quantitative PCR-Based 3S3DBC method and variations of it for screening DNA libraries.

    Yang An

    Full Text Available A DNA library is a collection of DNA fragments cloned into vectors and stored individually in host cells, and is a valuable resource for molecular cloning, gene physical mapping, and genome sequencing projects. To take the best advantage of a DNA library, a good screening method is needed. After describing pooling strategies and issues that should be considered in DNA library screening, here we report an efficient colony multiplex quantitative PCR-based 3-step, 3-dimension, and binary-code (3S3DBC method we used to screen genes from a planarian genomic DNA fosmid library. This method requires only 3 rounds of PCR reactions and only around 6 hours to distinguish one or more desired clones from a large DNA library. According to the particular situations in different research labs, this method can be further modified and simplified to suit their requirements.

  19. mtDNA G10398A variation provides risk to type 2 diabetes in population group from the Jammu region of India

    Varun Sharma

    2014-12-01

    Full Text Available Mitochondrion plays an integral role in glucose metabolism and insulin secretion. Mitochondrial electron-transport chain (ETC is involved in adenosine triphosphate (ATP generation and ATP mediated insulin secretion in pancreatic β-cells. β-cell dysfunction is a critical component in the pathogenesis of type 2 diabetes (T2D. The mtDNA G10398A variation (amino acid change: Alanine → Threonine within the NADH dehydrogenase (ND3 subunit of complex I of mtDNA ETC, has emerged as a variation of clinical significance in various disorders including T2D. This variation is supposed to result in altered complex I function, leading to an increased rate of electron leakage and reactive oxygen species (ROS production, which might cause β-cell damage and impaired insulin secretion. The aim of the study was to explore the association of mtDNA G10398A variation with T2D in a total of 439 samples (196 T2D cases and 243 healthy controls belonging to the Jammu region of Jammu and Kashmir (J&K. The candidate gene association analyses showed significant association of mtDNA G10398A variant with T2D and the estimated odds ratio (OR was 2.83 (1.64–4.90 at 95% CI in the studied population group. The extent of genetic heterogeneity in T2D and diversity of the Indian population groups, make such replication studies pertinent to understand the etiology of T2D in these population groups.

  20. Variation in PAH-related DNA adduct levels among non-smokers: the role of multiple genetic polymorphisms and nucleotide excision repair phenotype

    Etemadi, Arash; Islami, Farhad; Phillips, David H.; Godschalk, Roger; Golozar, Asieh; Kamangar, Farin; Malekshah, Akbar Fazel-Tabar; Pourshams, Akram; Elahi, Seerat; Ghojaghi, Farhad; Strickland, Paul T.; Taylor, Philip R.; Boffetta, Paolo; Abnet, Christian C.; Dawsey, Sanford M.

    2012-01-01

    Polycyclic aromatic hydrocarbons (PAHs) likely play a role in many cancers even in never-smokers. We tried to find a model to explain the relationship between variation in PAH-related DNA adduct levels among people with similar exposures, multiple genetic polymorphisms in genes related to metabolic and repair pathways, and nucleotide excision repair (NER) capacity. In 111 randomly selected female never-smokers from the Golestan Cohort Study in Iran, we evaluated 21 SNPs in 14 genes related to...

  1. Differential binding of Lrp to two sets of pap DNA binding sites mediated by Pap I regulates Pap phase variation in Escherichia coli.

    Nou, X; Braaten, B; Kaltenbach, L; Low, D A

    1995-01-01

    Pyelonephritis-associated pili (Pap) expression in Escherichia coli is subject to a phase variation control mechanism that is regulated by the leucine-responsive regulatory protein (Lrp), PapI, and deoxyadenosine methylase (Dam). In previous work, we found that the differential Dam methylation of two target sites in pap regulatory DNA, GATC-I and GATC II, is essential for the transition between active and inactive pap transcriptional states. Here, we identify six Lrp binding sites within the ...

  2. Cytogenetic variation of repetitive DNA elements in Hoplias malabaricus (Characiformes - Erythrinidae from white, black and clear water rivers of the Amazon basin

    Fabíola Araújo dos Santos

    2016-03-01

    Full Text Available Abstract Hoplias malabaricus is a common fish species occurring in white, black and clear water rivers of the Amazon basin. Its large distribution across distinct aquatic environments can pose stressful conditions for dispersal and creates possibilities for the emergence of local adaptive profiles. We investigated the chromosomal localization of repetitive DNA markers (constitutive heterochromatin, rDNA and the transposable element REX-3 in populations from the Amazonas river (white water, the Negro river (black water and the Tapajós river (clear water, in order to address the variation/association of cytogenomic features and environmental conditions. We found a conserved karyotypic macrostructure with a diploid number of 40 chromosomes (20 metacentrics + 20 submetacentrics in all the samples. Heteromorphism in pair 14 was detected as evidence for the initial differentiation of an XX/XY system. Minor differences detected in the amount of repetitive DNA markers are interpreted as possible signatures of local adaptations to distinct aquatic environments.

  3. Cytogenetic variation of repetitive DNA elements in Hoplias malabaricus (Characiformes - Erythrinidae) from white, black and clear water rivers of the Amazon basin.

    Santos, Fabíola Araújo Dos; Marques, Diego Ferreira; Terencio, Maria Leandra; Feldberg, Eliana; Rodrigues, Luís Reginaldo R

    2016-03-01

    Hoplias malabaricus is a common fish species occurring in white, black and clear water rivers of the Amazon basin. Its large distribution across distinct aquatic environments can pose stressful conditions for dispersal and creates possibilities for the emergence of local adaptive profiles. We investigated the chromosomal localization of repetitive DNA markers (constitutive heterochromatin, rDNA and the transposable element REX-3) in populations from the Amazonas river (white water), the Negro river (black water) and the Tapajós river (clear water), in order to address the variation/association of cytogenomic features and environmental conditions. We found a conserved karyotypic macrostructure with a diploid number of 40 chromosomes (20 metacentrics + 20 submetacentrics) in all the samples. Heteromorphism in pair 14 was detected as evidence for the initial differentiation of an XX/XY system. Minor differences detected in the amount of repetitive DNA markers are interpreted as possible signatures of local adaptations to distinct aquatic environments. PMID:27007897

  4. A rapidly photo-activatable light-up fluorescent nucleoside and its application in DNA base variation sensing.

    He, Zhiyong; Chen, Yuqi; Wang, Yafen; Wang, Jiaqi; Mo, Jing; Fu, Boshi; Wang, Zijing; Du, Yuhao; Zhou, Xiang

    2016-06-30

    A new DNA building block (d(Tet)U) bearing a tetrazole and allyloxy group at N-phenyl ring linked through an aminopropynyl linker to the 5-position of 2'-deoxyuridine was synthesized. The modified DNA can be lit up via a photoinduced intramolecular tetrazole-alkene cycloaddition reaction, but quenched when the fully-matched double strand is formed. This conspicuous difference in fluorescence could open a door for DNA single nucleotide polymorphism (SNP) typing. PMID:27315545

  5. Congruence of microsatellite and mitochondrial DNA variation in acrobat ants (Crematogaster subgenus Decacrema, Formicidae: Myrmicinae) inhabiting Macaranga (Euphorbiaceae) myrmecophytes.

    Ueda, Shouhei; Nagano, Yusuke; Kataoka, Yowsuke; Komatsu, Takashi; Itioka, Takao; Shimizu-Kaya, Usun; Inui, Yoko; Itino, Takao

    2015-01-01

    A previously reported mitochondrial DNA (mtDNA) phylogeny of Crematogaster (subgenus Decacrema) ants inhabiting Macaranga myrmecophytes indicated that the partners diversified synchronously and their specific association has been maintained for 20 million years. However, the mtDNA clades did not exactly match morphological species, probably owing to introgressive hybridization among younger species. In this study, we determined the congruence between nuclear simple sequence repeat (SSR, also called microsatellite) genotyping and mtDNA phylogeny to confirm the suitability of the mtDNA phylogeny for inferring the evolutionary history of Decacrema ants. Analyses of ant samples from Lambir Hills National park, northeastern Borneo, showed overall congruence between the SSR and mtDNA groupings, indicating that mtDNA markers are useful for delimiting species, at least at the local level. We also found overall high host-plant specificity of the SSR genotypes of Decacrema ants, consistent with the specificity based on the mtDNA phylogeny. Further, we detected cryptic genetic assemblages exhibiting high specificity toward particular plant species within a single mtDNA clade. This finding, which may be evidence for rapid ecological and genetic differentiation following a host shift, is a new insight into the previously suggested long-term codiversification of Decacrema ants and Macaranga plants. PMID:25692953

  6. Characterization of variation induced by low-energy N+ and cloning of differentially expressed cDNA of a mutant in Arabidopsis thaliana

    2003-01-01

    Using Arabidopsis thaliana as experimental materials, the variations induced by low-energy N+ have been investigated. Germination rate of the treated seeds is lower than that of the control, and it decreases with the intensification of the radiation. The phenotypic variations have been observed in M2 plants irradiated with higher doses, such as chlorisis, semilethality, plant morphology, and changes of blooming habit and fertility. In random amplified polymorphic DNA (RAPD) analysis on M2 seedlings, some differences including band deletions or additions are found in treated plants compared to the control and the differences are associated with the radiation doses. One of the M1 plants from the seeds irradiated with the dose of 80×1015 N+/cm2 is a dwarf variant. Its stable M6 generation, mutant T80II, is used to construct subtractive cDNA library and to clone differentially expressed cDNA. A 721 bp cDNA fragment is partly homologous with GRF7 gene.

  7. Diurnal variations in depth profiles of UV-induced DNA damage and inhibition of bacterioplankton production in tropical coastal waters

    Visser, PM; Poos, JJ; Scheper, BB; Boelen, P; van Duyl, FC

    2002-01-01

    In this study, diurnal changes in bacterial production and DNA damage in bacterio-plankton (measured as cyclobutane pyrimidine dimers, CPDs) incubated in bags at different depths in tropical coastal waters were investigated. The DNA damage and inhibition of the bacterial production was highest at th

  8. Assessment and reduction of comet assay variation in relation to DNA damage: studies from the European Comet Assay Validation Group.

    Moller, Peter; Moller, Lennart; Godschalk, Roger W. L.; Jones, George D. D.

    2010-01-01

    The alkaline single cell gel electrophoresis (comet) assay has become a widely used method for the detection of DNA damage and repair in cells and tissues. Still, it has been difficult to compare results from different investigators because of differences in assay conditions and because the data are reported in different units. The European Comet Assay Validation Group (ECVAG) was established for the purpose of validation of the comet assay with respect to measures of DNA damage formation and...

  9. Investigating the Potential Role of Genetic and Epigenetic Variation of DNA Methyltransferase Genes in Hyperplastic Polyposis Syndrome

    Drini, Musa; Nicholas C. Wong; Hamish S Scott; Craig, Jeffrey M; Dobrovic, Alexander; Chelsee A Hewitt; Dow, Christofer; Young, Joanne P; Jenkins, Mark A; Saffery, Richard; Macrae, Finlay A.

    2011-01-01

    Background Hyperplastic Polyposis Syndrome (HPS) is a condition associated with multiple serrated polyps, and an increased risk of colorectal cancer (CRC). At least half of CRCs arising in HPS show a CpG island methylator phenotype (CIMP), potentially linked to aberrant DNA methyltransferase (DNMT) activity. CIMP is associated with methylation of tumor suppressor genes including regulators of DNA mismatch repair (such as MLH1, MGMT), and negative regulators of Wnt signaling (such as WIF1). In...

  10. New Population and Phylogenetic Features of the Internal Variation within Mitochondrial DNA Macro-Haplogroup R0

    Álvarez Iglesias, Vanesa; Mosquera Miguel, Ana; Cerezo, María; Quintáns, Beatriz; Zarrabeitia Cimiano, María Teresa; Cuscó, Ivon; Lareu, María Victoria; García, Óscar; Pérez Jurado, Luis; Carracedo Álvarez, Ángel; Salas Ellacuriaga, Antonio

    2009-01-01

    BACKGROUND: R0 embraces the most common mitochondrial DNA (mtDNA) lineage in West Eurasia, namely, haplogroup H (approximately 40%). R0 sub-lineages are badly defined in the control region and therefore, the analysis of diagnostic coding region polymorphisms is needed in order to gain resolution in population and medical studies. METHODOLOGY/PRINCIPAL FINDINGS: We sequenced the first hypervariable segment (HVS-I) of 518 individuals from different North Iberian regions. The mtDNAs belongin...

  11. An ECVAG inter-laboratory validation study of the comet assay: inter-laboratory and intra-laboratory variations of DNA strand breaks and FPG-sensitive sites in human mononuclear cells.

    Ersson, Clara; Møller, Peter; Forchhammer, Lykke; Loft, Steffen; Azqueta, Amaya; Godschalk, Roger W L; van Schooten, Frederik-Jan; Jones, George D D; Higgins, Jennifer A; Cooke, Marcus S; Mistry, Vilas; Karbaschi, Mahsa; Phillips, David H; Sozeri, Osman; Routledge, Michael N; Nelson-Smith, Kirsty; Riso, Patrizia; Porrini, Marisa; Matullo, Giuseppe; Allione, Alessandra; Stepnik, Maciej; Ferlińska, Magdalena; Teixeira, João Paulo; Costa, Solange; Corcuera, Laura-Ana; López de Cerain, Adela; Laffon, Blanca; Valdiglesias, Vanessa; Collins, Andrew R; Möller, Lennart

    2013-05-01

    The alkaline comet assay is an established, sensitive method extensively used in biomonitoring studies. This method can be modified to measure a range of different types of DNA damage. However, considerable differences in the protocols used by different research groups affect the inter-laboratory comparisons of results. The aim of this study was to assess the inter-laboratory, intra-laboratory, sample and residual (unexplained) variations in DNA strand breaks and formamidopyrimidine DNA glycosylase (FPG)-sensitive sites measured by the comet assay by using a balanced Latin square design. Fourteen participating laboratories used their own comet assay protocols to measure the level of DNA strand breaks and FPG-sensitive sites in coded samples containing peripheral blood mononuclear cells (PBMC) and the level of DNA strand breaks in coded calibration curve samples (cells exposed to different doses of ionising radiation) on three different days of analysis. Eleven laboratories found dose-response relationships in the coded calibration curve samples on two or three days of analysis, whereas three laboratories had technical problems in their assay. In the coded calibration curve samples, the dose of ionising radiation, inter-laboratory variation, intra-laboratory variation and residual variation contributed to 60.9, 19.4, 0.1 and 19.5%, respectively, of the total variation. In the coded PBMC samples, the inter-laboratory variation explained the largest fraction of the overall variation of DNA strand breaks (79.2%) and the residual variation (19.9%) was much larger than the intra-laboratory (0.3%) and inter-subject (0.5%) variation. The same partitioning of the overall variation of FPG-sensitive sites in the PBMC samples indicated that the inter-laboratory variation was the strongest contributor (56.7%), whereas the residual (42.9%), intra-laboratory (0.2%) and inter-subject (0.3%) variations again contributed less to the overall variation. The results suggest that the

  12. Evaluation of Genetic Variations in Maize Seedlings Exposed to Electric Field Based on Protein and DNA Markers

    Asma A. AL-Huqail

    2015-01-01

    Full Text Available The current study analyzed proteins and nuclear DNA of electric fields (ELF exposed and nonexposed maize seedlings for different exposure periods using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE, isozymes, random amplified polymorphic DNA (RAPD, and comet assay, respectively. SDS-PAGE analysis revealed total of 46 polypeptides bands with different molecular weights ranging from 186.20 to 36.00 KDa. It generated distinctive polymorphism value of 84.62%. Leucine-aminopeptidase, peroxidase, and catalase isozymes showed the highest values of polymorphism (100% based on zymograms number, relative front (Rf, and optical intensity while esterase isozyme generated polymorphism value of 83.33%. Amino acids were analyzed using high-performance liquid chromatography, which revealed the presence of 17 amino acids of variable contents ranging from 22.65% to 28.09%. RAPD revealed that 78 amplified DNA products had highly polymorphism value (95.08% based on band numbers, with variable sizes ranging from 120 to 992 base pairs and band intensity. Comet assay recorded the highest extent of nuclear DNA damage as percentage of tailed DNA (2.38% and tail moment unit (5.36 at ELF exposure of maize nuclei for 5 days. The current study concluded that the longer ELF exposing periods had genotoxic stress on macromolecules of maize cells and biomarkers used should be augmented for reliable estimates of genotoxicity after exposure of economic plants to ELF stressors.

  13. Variations in genomic DNA methylation during the long-term in vitro proliferation of oil palm embryogenic suspension cultures.

    Rival, Alain; Ilbert, Pascal; Labeyrie, Axel; Torres, Esperanza; Doulbeau, Sylvie; Personne, Aline; Dussert, Stéphane; Beulé, Thierry; Durand-Gasselin, Tristan; Tregear, James W; Jaligot, Estelle

    2013-03-01

    KEY MESSAGE : The long-term proliferation of embryogenic cell suspensions of oil palm is associated with changes in both genomic methylation rates and embryogenic capacities. In the aim of exploring the relationship between epigenetic stability and the long-term in vitro proliferation of plant tissues, we have studied changes in genomic DNA methylation levels in embryogenic suspensions of oil palm (Elaeis guineensis Jacq.). Five embryogenic callus lines were obtained from selected hybrid seeds and then proliferated as suspension cultures. Each clonal line obtained from a single genotype was subdivided into three independent subclonal lines. Once established, cultures proliferated for 12 months and genomic DNA was sampled at 4 months intervals for the estimation of global DNA methylation rates through high performance liquid chromatography (HPLC) quantitation of deoxynucleosides. Our results show that in vitro proliferation induces DNA hypermethylation in a time-dependent fashion. Moreover, this trend is statistically significant in several clonal lines and shared between subclonal lines originating from the same genotype. Interestingly, the only clonal line undergoing loss of genomic methylation in the course of proliferation has been found unable to generate somatic embryos. We discuss the possible implications of genome-wide DNA methylation changes in proliferating cells with a view to the maintenance of genomic and epigenomic stability. PMID:23179461

  14. Instability of chromosome number and DNA methylation variation induced by hybridization and amphidiploid formation between Raphanus sativus L. and Brassica alboglabra Bailey

    Wang Yanjie

    2010-09-01

    Full Text Available Abstract Background Distant hybridization can result genome duplication and allopolyploid formation which may play a significant role in the origin and evolution of many plant species. It is unclear how the two or more divergent genomes coordinate in one nucleus with a single parental cytoplasm within allopolyploids. We used cytological and molecular methods to investigate the genetic and epigenetic instabilities associated with the process of distant hybridization and allopolyploid formation, measuring changes in chromosome number and DNA methylation across multiple generations. Results F1 plants from intergeneric hybridization between Raphanus sativus L. (2n = 18, RR and Brassica alboglabra Bailey (2n = 18, CC were obtained by hand crosses and subsequent embryo rescue. Random amplification of polymorphic DNA (RAPD markers were used to identify the F1 hybrid plants. The RAPD data indicated that the hybrids produced specific bands similar to those of parents and new bands that were not present in either parent. Chromosome number variation of somatic cells from allotetraploids in the F4 to F10 generations showed that intensive genetic changes occurred in the early generations of distant hybridization, leading to the formation of mixopolyploids with different chromosome numbers. DNA methylation variation was revealed using MSAP (methylation-sensitive amplification polymorphism, which showed that cytosine methylation patterns changed markedly in the process of hybridization and amphidiploid formation. Differences in cytosine methylation levels demonstrated an epigenetic instability of the allopolyploid of Raphanobrassica between the genetically stable and unstable generations. Conclusions Our results showed that chromosome instability occurred in the early generations of allopolyploidy and then the plants were reverted to largely euploidy in later generations. During this process, DNA methylation changed markedly. These results suggest that

  15. Genetic variation of Kaempferia (Zingiberaceae) in Thailand based on chloroplast DNA (psbA-trnH and petA-psbJ) sequences.

    Techaprasan, J; Klinbunga, S; Ngamriabsakul, C; Jenjittikul, T

    2010-01-01

    Genetic variation and species authentication of 71 Kaempferia accessions (representing 15 recognized, six new, and four unidentified species) found indigenously in Thailand were examined by determining chloroplast psbA-trnH and partial petA-psbJ spacer sequences. Ten closely related species (Boesenbergia rotunda, Gagnepainia godefroyi, G. thoreliana, Globba substrigosa, Smithatris myanmarensis, S. supraneanae, Scaphochlamys biloba, S. minutiflora, S. rubescens, and Stahlianthus sp) were also included. After sequence alignments, 1010 and 865 bp in length were obtained for the respective chloroplast DNA sequences. Intraspecific sequence variation was not observed in Kaempferia candida, K. angustifolia, K. laotica, K. galanga, K. pardi sp nov., K. bambusetorum sp nov., K. albomaculata sp nov., K. minuta sp nov., Kaempferia sp nov. 1, and G. thoreliana, for which more than one specimen was available. In contrast, intraspecific sequence polymorphisms were observed in various populations of K. fallax, K. filifolia, K. elegans, K. pulchra, K. rotunda, K. marginata, K. parviflora, K. larsenii, K. roscoeana, K. siamensis, and G. godefroyi. A strict consensus tree based on combined psbA-trnH and partial petA-psbJ sequences revealed four major groups of Kaempferia species. We suggest that the genus Kaempferia is a polyphyletic group, as K. candida was distantly related and did not group with other Kaempferia species. Polymorphic sites and indels of psbA-trnH and petA-psbJ can be used as DNA barcodes for species diagnosis of most Kaempferia and outgroup species. Nuclear DNA polymorphism should be examined to determine if there has been interspecific hybridization and chloroplast DNA introgression in these taxa. PMID:20927714

  16. Sequence variations in DNA repair gene XPC is associated with lung cancer risk in a Chinese population: a case-control study

    The nucleotide excision repair (NER) protein, xeroderma pigmentosum C (XPC), participates in recognizing DNA lesions and initiating DNA repair in response to DNA damage. Because mutations in XPC cause a high risk of cancer in XP patients, we hypothesized that inherited sequence variations in XPC may alter DNA repair and thus susceptibility to cancer. In this hospital-based case-control study, we investigated five XPC tagging, common single nucleotide polymorphisms (tagging SNPs) in 1,010 patients with newly diagnosed lung cancer and 1,011 matched cancer free controls in a Chinese population. In individual tagging SNP analysis, we found that rs3731055AG+AA variant genotypes were associated with a significantly decreased risk of lung adenocarcinoma [adjusted odds ratio (OR), 0.71; 95% confidence interval (CI), 0.56–0.90] but an increased risk of small cell carcinomas [adjusted OR, 1.79; 95% CI, 1.05–3.07]. Furthermore, we found that haplotype ACCCA was associated with a decreased risk of lung adenocarcinoma [OR, 0.78; 95% CI, 0.62–0.97] but an increased risk of small cell carcinomas [OR, 1.68; 95% CI, 1.04–2.71], which reflected the presence of rs3731055A allele in this haplotype. Further stratified analysis revealed that the protective effect of rs3731055AG+AA on risk of lung adenocarcinoma was more evident among young subjects (age ≤ 60) and never smokers. These results suggest that inherited sequence variations in XPC may modulate risk of lung cancer, especially lung adenocarcinoma, in Chinese populations. However, these findings need to be verified in larger confirmatory studies with more comprehensively selected tagging SNPs

  17. Inter-individual variation in DNA double-strand break repair in human fibroblasts before and after exposure to low doses of ionizing radiation

    DNA double-strand breaks (DSB) are generally considered the most critical lesion induced by ionizing radiation (IR) and may initiate carcinogenesis and other disease. Using an immunofluorescence assay to simultaneously detect nuclear foci of the phosphorylated forms of histone H2AX and ATM kinase at sites of DSBs, we examined the response of 25 apparently normal and 10 DNA repair-deficient (ATM, ATR, NBN, LIG1, LIG4, and FANCG) primary fibroblast strains irradiated with low doses of 137Cs γ-rays. Quiescent G0/G1-phase cultures were exposed to 5, 10, and 25 cGy and allowed to repair for 24 h. The maximum level of IR-induced foci (0.15 foci per cGy, at 10 or 30 min) in the normal strains showed much less inter-individual variation (CV ∼ 0.2) than the level of spontaneous foci, which ranged from 0.2-2.6 foci/cell (CV ∼ 0.6; mean ± SD of 1.00 ± 0.57). Significantly slower focus formation post-irradiation was observed in seven normal strains, similar to most mutant strains examined. There was variation in repair efficiency measured by the fraction of IR-induced foci remaining 24 h post-irradiation, curiously with the strains having slower focus formation showing more efficient repair after 25 cGy. Interestingly, the ranges of spontaneous and residual induced foci levels at 24 h in the normal strains were as least as large as those observed for the repair-defective mutant strains. The inter-individual variation in DSB foci parameters observed in cells exposed to low doses of ionizing radiation in this small survey of apparently normal people suggests that hypomorphic genetic variants in genomic maintenance and/or DNA damage signaling and repair genes may contribute to differential susceptibility to cancer induced by environmental mutagens.

  18. [Genetic structure of the Siberian Sucker (Catostomus catostomus rostratus) according to data on sequence variation of the mtDNA cytochrome B gene].

    Bachevskaia, L T; Pereverzeva, V V; Ivanova, G D; Agapova, G A; Primak, A A

    2014-01-01

    Data regarding the structure and variation of the nucleotide sequence of the cytochrome b gene of mitochondrial DNA of the Siberian Sucker from the Kolyma River were obtained. Analysis of the median network revealed that evolutionary lines diverged from a common ancestor. Penetration of the sucker into Asia from Northern America took place between the Early and Middle Pleistocene. Prolonged reproductive isolation of the Siberian and Northern American suckers led to interspecies divergence with the appearance of amino acid substitutions, which, apparently, fixed due to positive selection. The Siberian Sucker appeared to have three modifications of the Cytb protein. PMID:25735175

  19. Heteroplasmy, length and sequence variation in the mtDNA control regions of three percid fish species (Perca fluviatilis, Acerina cernua, Stizostedion lucioperca).

    Nesbø, C. L.; Arab, M O; Jakobsen, K. S.

    1998-01-01

    The nucleotide sequence of the control region and flanking tRNA genes of perch (Perca fluviatilis) mtDNA was determined. The organization of this region is similar to that of other vertebrates. A tandem array of 10-bp repeats, associated with length variation and heteroplasmy was observed in the 5' end. While the location of the array corresponds to that reported in other species, the length of the repeated unit is shorter than previously observed for tandem repeats in this region. The repeat...

  20. DNA Sequence Analysis of SLC26A5, Encoding Prestin, in a Patient-Control Cohort: Identification of Fourteen Novel DNA Sequence Variations

    Minor, Jacob S.; Tang, Hsiao-Yuan; Pereira, Fred A.; Alford, Raye Lynn

    2009-01-01

    Background Prestin, encoded by the gene SLC26A5, is a transmembrane protein of the cochlear outer hair cell (OHC). Prestin is required for the somatic electromotile activity of OHCs, which is absent in OHCs and causes severe hearing impairment in mice lacking prestin. In humans, the role of sequence variations in SLC26A5 in hearing loss is less clear. Although prestin is expected to be required for functional human OHCs, the clinical significance of reported putative mutant alleles in humans ...

  1. Genetic variation and relationships in Laetiporus sulphureus s. lat., as determined by ITS rDNA sequences and in vitro growth rate.

    Vasaitis, Rimvydas; Menkis, Audrius; Lim, Young Woon; Seok, Soonja; Tomsovsky, Michal; Jankovsky, Libor; Lygis, Vaidotas; Slippers, Bernard; Stenlid, Jan

    2009-03-01

    The aim of this study was to characterise the genetic variation and molecular relationships of the brown rot polypore, Laetiporus sulphureus s. lat., from Europe, South America, Africa, and Asia, using ITS sequences of the nu-rDNA and by comparing the growth rate in vitro. In a NJ analysis of the sequences of 130 individuals of L. sulphureus s. lat., eight distinct clusters emerged, supported by BS values of 70-100%. Within each cluster, the ITS rDNA sequence variation was below 3%. The sequences were also analysed together with Laetiporus sequences available from GenBank. Results demonstrated the possible presence of L. huroniensis in Europe (invalidly named L. montanus) and L. gilbertsonii in South America, and provided more information on the Pan-American and European distribution of one of the clades, currently known in North America as L. sulphureus. L. conifericola formed a separate distinct clade. Moreover, the analysis revealed two unknown Laetiporus taxa in Korea, one in South Africa, and one in Europe. As L. sulphureus is described from Europe (France), and we show that more than one taxon exist here, it is presently not possible to define L. sulphureus s. str. Certain biological differences between some of the clades (in vitro growth rates, chemical composition, and pigmentation) were demonstrated and discussed. PMID:19073254

  2. Genetic variations in DNA repair genes, radiosensitivity to cancer and susceptibility to acute tissue reactions in radiotherapy-treated cancer patients

    Chistiakov, Dimitry A. (Dept. of Pathology, Univ. of Pittsburgh, Pittsburgh (US)); Voronova, Natalia V. (Dept. of Molecular Diagnostics, National Research Center GosNIIgenetika, Moscow (RU)); Chistiakov, Pavel A. (Dept. of Radiology, Cancer Research Center, Moscow (RU))

    2008-06-15

    Ionizing radiation is a well established carcinogen for human cells. At low doses, radiation exposure mainly results in generation of double strand breaks (DSBs). Radiation-related DSBs could be directly linked to the formation of chromosomal rearrangements as has been proven for radiation-induced thyroid tumors. Repair of DSBs presumably involves two main pathways, non-homologous end joining (NHEJ) and homologous recombination (HR). A number of known inherited syndromes, such as ataxia telangiectasia, ataxia-telangiectasia like-disorder, radiosensitive severe combined immunodeficiency, Nijmegen breakage syndrome, and LIG4 deficiency are associated with increased radiosensitivity and/or cancer risk. Many of them are caused by mutations in DNA repair genes. Recent studies also suggest that variations in the DNA repair capacity in the general population may influence cancer susceptibility. In this paper, we summarize the current status of DNA repair proteins as potential targets for radiation-induced cancer risk. We will focus on genetic alterations in genes involved in HR- and NHEJ-mediated repair of DSBs, which could influence predisposition to radiation-related cancer and thereby explain interindividual differences in radiosensitivity or radioresistance in a general population

  3. Mitochondrial DNA confirms low genetic variation of the greater mouse-eared bats, Myotis myotis, in Central Europe

    Bryja, Josef; Uhrin, M.; Kaňuch, P.; Bémová, P.; Martínková, Natália; Zukal, Jan

    2010-01-01

    Roč. 12, č. 1 (2010), s. 73-81. ISSN 1508-1109 R&D Projects: GA ČR GA206/01/1555; GA MŠk LC06073 Grant ostatní: VEGA(SK) 2/0130/08 Institutional research plan: CEZ:AV0Z60930519 Keywords : genetic structure * mtDNA * control region * phylogeography * Myotis myotis Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 1.012, year: 2010

  4. Variations in genomic DNA methylation during the long-term in vitro proliferation of oil palm embryogenic suspension cultures

    Rival, A.; Ilbert, P.; Labeyrie, A.; E. Torres; Doulbeau, Sylvie; Personne, A.; Dussert, Stéphane; Beulé, T.; Durand-Gasselin, T.; Tregear, James; Jaligot, E.

    2013-01-01

    The long-term proliferation of embryogenic cell suspensions of oil palm is associated with changes in both genomic methylation rates and embryogenic capacities. In the aim of exploring the relationship between epigenetic stability and the long-term in vitro proliferation of plant tissues, we have studied changes in genomic DNA methylation levels in embryogenic suspensions of oil palm (Elaeis guineensis Jacq.). Five embryogenic callus lines were obtained from selected hybrid seeds and then pro...

  5. Dynamic DNA cytosine methylation in the Populus trichocarpa genome: tissue-level variation and relationship to gene expression

    Vining Kelly J

    2012-01-01

    Full Text Available Abstract Background DNA cytosine methylation is an epigenetic modification that has been implicated in many biological processes. However, large-scale epigenomic studies have been applied to very few plant species, and variability in methylation among specialized tissues and its relationship to gene expression is poorly understood. Results We surveyed DNA methylation from seven distinct tissue types (vegetative bud, male inflorescence [catkin], female catkin, leaf, root, xylem, phloem in the reference tree species black cottonwood (Populus trichocarpa. Using 5-methyl-cytosine DNA immunoprecipitation followed by Illumina sequencing (MeDIP-seq, we mapped a total of 129,360,151 36- or 32-mer reads to the P. trichocarpa reference genome. We validated MeDIP-seq results by bisulfite sequencing, and compared methylation and gene expression using published microarray data. Qualitative DNA methylation differences among tissues were obvious on a chromosome scale. Methylated genes had lower expression than unmethylated genes, but genes with methylation in transcribed regions ("gene body methylation" had even lower expression than genes with promoter methylation. Promoter methylation was more frequent than gene body methylation in all tissues except male catkins. Male catkins differed in demethylation of particular transposable element categories, in level of gene body methylation, and in expression range of genes with methylated transcribed regions. Tissue-specific gene expression patterns were correlated with both gene body and promoter methylation. Conclusions We found striking differences among tissues in methylation, which were apparent at the chromosomal scale and when genes and transposable elements were examined. In contrast to other studies in plants, gene body methylation had a more repressive effect on transcription than promoter methylation.

  6. European colonization by the spined loach (Cobitis taenia) from Ponto-Caspian refugia based on mitochondrial DNA variation

    Culling, M.; Janko, Karel; Boron, A.; Vasiljev, V. P.; Cote, I. M.; Hewitt, G. M.

    2006-01-01

    Roč. 15, 1 (2006), s. 173-190. ISSN 0962-1083 R&D Projects: GA ČR GP206/05/P586; GA AV ČR IBS5045111 Grant ostatní: RFBR 02-04-48354 Institutional research plan: CEZ:AV0Z50450515 Keywords : colonization * glacial refugia * mitochondrial DNA Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.825, year: 2006

  7. Phylogenetic Analysis of a Privately-owned Korean Native Chicken Population Using mtDNA D-loop Variations

    Hoque, M. R.; Choi, N. R.; Sultana, H.; Kang, B. S.; Heo, K. N.; Hong, S K; Jo, C.; Lee, J.H.

    2013-01-01

    The use of Korean native chicken is increasing, and the discovery of new genetic resources is very important from both economic and genetic conservation points of view. In this study, mtDNA D-loop sequences from 272 privately-owned Korean native chickens from a Hyunin farm were investigated. Seventeen nucleotide substitutions were identified from the sequence analysis and they were classified as 6 haplotypes. Previously investigated haplotypes in five Korean native chicken populations have be...

  8. The historical demography and genetic variation of the endangered Cycas multipinnata (Cycadaceae) in the red river region, examined by chloroplast DNA sequences and microsatellite markers.

    Gong, Yi-Qing; Zhan, Qing-Qing; Nguyen, Khang Sinh; Nguyen, Hiep Tien; Wang, Yue-Hua; Gong, Xun

    2015-01-01

    Cycas multipinnata C.J. Chen & S.Y. Yang is a cycad endemic to the Red River drainage region that occurs under evergreen forest on steep limestone slopes in Southwest China and northern Vietnam. It is listed as endangered due to habitat loss and over-collecting for the ornamental plant trade, and only several populations remain. In this study, we assess the genetic variation, population structure, and phylogeography of C. multipinnata populations to help develop strategies for the conservation of the species. 60 individuals from six populations were used for chloroplast DNA (cpDNA) sequencing and 100 individuals from five populations were genotyped using 17 nuclear microsatellites. High genetic differentiation among populations was detected, suggesting that pollen or seed dispersal was restricted within populations. Two main genetic clusters were observed in both the cpDNA and microsatellite loci, corresponding to Yunnan China and northern Vietnam. These clusters indicated low levels of gene flow between the regions since their divergence in the late Pleistocene, which was inferred from both Bayesian and coalescent analysis. In addition, the result of a Bayesian skyline plot based on cpDNA portrayed a long history of constant population size followed by a decline in the last 50,000 years of C. multipinnata that was perhaps affected by the Quaternary glaciations, a finding that was also supported by the Garza-Williamson index calculated from the microsatellite data. The genetic consequences produced by climatic oscillations and anthropogenic disturbances are considered key pressures on C. multipinnata. To establish a conservation management plan, each population of C. multipinnata should be recognized as a Management Unit (MU). In situ and ex situ actions, such as controlling overexploitation and creating a germplasm bank with high genetic diversity, should be urgently implemented to preserve this species. PMID:25689828

  9. Evaluation of IGFBP-7 DNA methylation changes and serum protein variation in Swedish subjects with and without type 2 diabetes

    Gu, Harvest F.; Gu, Tianwei; Hilding, Agneta; Zhu, Yiming; Kärvestedt, Lars; Östenson, Claes-Göran; Lai, Maode; Kutsukake, Masahiko; Frystyk, Jan; Tamura, Kazuhiro; Brismar, Kerstin

    2013-01-01

    Background Insulin-like growth factor-binding protein 7 (IGFBP-7) is able to interact with insulin-like growth factor 1 (IGF-1) as well as insulin. Previous studies have suggested that serum IGFBP-7 levels may be associated with insulin resistance in type 2 diabetes (T2D). This study aimed to evaluate IGFBP-7 serum protein and IGFBP7 DNA methylation levels in the subjects with and without T2D. Results A total of 340 Swedish subjects including 100 newly diagnosed T2D patients (50 women/50 men)...

  10. Variation patterns of mitochondrial DNA of Abies alba Mill. in suture zones of postglacial migration in Europe

    Duśan Gomory

    2011-04-01

    Full Text Available Thirty silver fir populations originating from the putative suture zones of the postglacial recolonization (Slovenia, Bosnia and Hercegovina, Ukraine were studied using a mitochondrial nad5-4 gene marker. The geographical distribution of mtDNA haplotypes in the Ukrainian Carpathians and their northern foothills indicates a very recent meeting of migration streams arriving from the Romanian Carpathians and Central Europe. In the western part of the Balkan Peninsula, two counterparallel migration streams are the most plausible explanation of the pattern observed. The haplotype typical for the Balkan Peninsula predominates along the Adrian coast, whereas the CentralEuropean haplotype is more represented in the inland.

  11. New population and phylogenetic features of the internal variation within mitochondrial DNA macro-haplogroup R0.

    Vanesa Alvarez-Iglesias

    Full Text Available BACKGROUND: R0 embraces the most common mitochondrial DNA (mtDNA lineage in West Eurasia, namely, haplogroup H (approximately 40%. R0 sub-lineages are badly defined in the control region and therefore, the analysis of diagnostic coding region polymorphisms is needed in order to gain resolution in population and medical studies. METHODOLOGY/PRINCIPAL FINDINGS: We sequenced the first hypervariable segment (HVS-I of 518 individuals from different North Iberian regions. The mtDNAs belonging to R0 (approximately 57% were further genotyped for a set of 71 coding region SNPs characterizing major and minor branches of R0. We found that the North Iberian Peninsula shows moderate levels of population stratification; for instance, haplogroup V reaches the highest frequency in Cantabria (north-central Iberia, but lower in Galicia (northwest Iberia and Catalonia (northeast Iberia. When compared to other European and Middle East populations, haplogroups H1, H3 and H5a show frequency peaks in the Franco-Cantabrian region, declining from West towards the East and South Europe. In addition, we have characterized, by way of complete genome sequencing, a new autochthonous clade of haplogroup H in the Basque country, named H2a5. Its coalescence age, 15.6+/-8 thousand years ago (kya, dates to the period immediately after the Last Glacial Maximum (LGM. CONCLUSIONS/SIGNIFICANCE: In contrast to other H lineages that experienced re-expansion outside the Franco-Cantabrian refuge after the LGM (e.g. H1 and H3, H2a5 most likely remained confined to this area till present days.

  12. Migration and interaction in a contact zone: mtDNA variation among Bantu-speakers in Southern Africa.

    Barbieri, Chiara; Vicente, Mário; Oliveira, Sandra; Bostoen, Koen; Rocha, Jorge; Stoneking, Mark; Pakendorf, Brigitte

    2014-01-01

    Bantu speech communities expanded over large parts of sub-Saharan Africa within the last 4000-5000 years, reaching different parts of southern Africa 1200-2000 years ago. The Bantu languages subdivide in several major branches, with languages belonging to the Eastern and Western Bantu branches spreading over large parts of Central, Eastern, and Southern Africa. There is still debate whether this linguistic divide is correlated with a genetic distinction between Eastern and Western Bantu speakers. During their expansion, Bantu speakers would have come into contact with diverse local populations, such as the Khoisan hunter-gatherers and pastoralists of southern Africa, with whom they may have intermarried. In this study, we analyze complete mtDNA genome sequences from over 900 Bantu-speaking individuals from Angola, Zambia, Namibia, and Botswana to investigate the demographic processes at play during the last stages of the Bantu expansion. Our results show that most of these Bantu-speaking populations are genetically very homogenous, with no genetic division between speakers of Eastern and Western Bantu languages. Most of the mtDNA diversity in our dataset is due to different degrees of admixture with autochthonous populations. Only the pastoralist Himba and Herero stand out due to high frequencies of particular L3f and L3d lineages; the latter are also found in the neighboring Damara, who speak a Khoisan language and were foragers and small-stock herders. In contrast, the close cultural and linguistic relatives of the Herero and Himba, the Kuvale, are genetically similar to other Bantu-speakers. Nevertheless, as demonstrated by resampling tests, the genetic divergence of Herero, Himba, and Kuvale is compatible with a common shared ancestry with high levels of drift, while the similarity of the Herero, Himba, and Damara probably reflects admixture, as also suggested by linguistic analyses. PMID:24901532

  13. Migration and interaction in a contact zone: mtDNA variation among Bantu-speakers in Southern Africa.

    Chiara Barbieri

    Full Text Available Bantu speech communities expanded over large parts of sub-Saharan Africa within the last 4000-5000 years, reaching different parts of southern Africa 1200-2000 years ago. The Bantu languages subdivide in several major branches, with languages belonging to the Eastern and Western Bantu branches spreading over large parts of Central, Eastern, and Southern Africa. There is still debate whether this linguistic divide is correlated with a genetic distinction between Eastern and Western Bantu speakers. During their expansion, Bantu speakers would have come into contact with diverse local populations, such as the Khoisan hunter-gatherers and pastoralists of southern Africa, with whom they may have intermarried. In this study, we analyze complete mtDNA genome sequences from over 900 Bantu-speaking individuals from Angola, Zambia, Namibia, and Botswana to investigate the demographic processes at play during the last stages of the Bantu expansion. Our results show that most of these Bantu-speaking populations are genetically very homogenous, with no genetic division between speakers of Eastern and Western Bantu languages. Most of the mtDNA diversity in our dataset is due to different degrees of admixture with autochthonous populations. Only the pastoralist Himba and Herero stand out due to high frequencies of particular L3f and L3d lineages; the latter are also found in the neighboring Damara, who speak a Khoisan language and were foragers and small-stock herders. In contrast, the close cultural and linguistic relatives of the Herero and Himba, the Kuvale, are genetically similar to other Bantu-speakers. Nevertheless, as demonstrated by resampling tests, the genetic divergence of Herero, Himba, and Kuvale is compatible with a common shared ancestry with high levels of drift, while the similarity of the Herero, Himba, and Damara probably reflects admixture, as also suggested by linguistic analyses.

  14. Phylogeography of Arabidopsis halleri (Brassicaceae) in mountain regions of Central Europe inferred from cpDNA variation and ecological niche modelling.

    Wasowicz, Pawel; Pauwels, Maxime; Pasierbinski, Andrzej; Przedpelska-Wasowicz, Ewa M; Babst-Kostecka, Alicja A; Saumitou-Laprade, Pierre; Rostanski, Adam

    2016-01-01

    The present study aimed to investigate phylogeographical patterns present within A. halleri in Central Europe. 1,281 accessions sampled from 52 populations within the investigated area were used in the study of genetic variation based on chloroplast DNA. Over 500 high-quality species occurrence records were used in ecological niche modelling experiments. We evidenced the presence of a clear phylogeographic structure within A. halleri in Central Europe. Our results showed that two genetically different groups of populations are present in western and eastern part of the Carpathians. The hypothesis of the existence of a glacial refugium in the Western Carpathians adn the Bohemian Forest cannot be rejected from our data. It seems, however, that the evidence collected during the present study is not conclusive. The area of Sudetes was colonised after LGM probably by migrants from the Bohemian Forest. PMID:26835186

  15. Intragenomic sequence variation at the ITS1 - ITS2 region and at the 18S and 28S nuclear ribosomal DNA genes of the New Zealand mud snail, Potamopyrgus antipodarum (Hydrobiidae: mollusca)

    Hoy, Marshal S.; Rodriguez, Rusty J.

    2013-01-01

    Molecular genetic analysis was conducted on two populations of the invasive non-native New Zealand mud snail (Potamopyrgus antipodarum), one from a freshwater ecosystem in Devil's Lake (Oregon, USA) and the other from an ecosystem of higher salinity in the Columbia River estuary (Hammond Harbor, Oregon, USA). To elucidate potential genetic differences between the two populations, three segments of nuclear ribosomal DNA (rDNA), the ITS1-ITS2 regions and the 18S and 28S rDNA genes were cloned and sequenced. Variant sequences within each individual were found in all three rDNA segments. Folding models were utilized for secondary structure analysis and results indicated that there were many sequences which contained structure-altering polymorphisms, which suggests they could be nonfunctional pseudogenes. In addition, analysis of molecular variance (AMOVA) was used for hierarchical analysis of genetic variance to estimate variation within and among populations and within individuals. AMOVA revealed significant variation in the ITS region between the populations and among clones within individuals, while in the 5.8S rDNA significant variation was revealed among individuals within the two populations. High levels of intragenomic variation were found in the ITS regions, which are known to be highly variable in many organisms. More interestingly, intragenomic variation was also found in the 18S and 28S rDNA, which has rarely been observed in animals and is so far unreported in Mollusca. We postulate that in these P. antipodarum populations the effects of concerted evolution are diminished due to the fact that not all of the rDNA genes in their polyploid genome should be essential for sustaining cellular function. This could lead to a lessening of selection pressures, allowing mutations to accumulate in some copies, changing them into variant sequences.                   

  16. Genetic variation of Chinese and Japanese wild Pacific abalone (Haliotis discus hannai) measured by microsatellite DNA markers

    LI Qi; KIJIMA Akihiro

    2006-01-01

    Population differentiation and relationships among three wild populations of the Pacific abalone Haliotis discus hannai collected from coastal seas around China and Japan were estimated using microsatellite DNA analysis. The results obtained with six microsatellite loci showed a high genetic diversity for China and Japan populations. The mean number of alleles per locus ranged from 11.7 to 23.0, and the average of observed and expected heterozygosity ranged from 0.656 to 0.721, and from 0.721 to 0.793, respectively. The observed genotype frequencies at each locus were mostly in agreement with Hardy-Weinberg expectations with five exceptions. Significant differences were detected between Chinese and Japanese H. discus hannai populations [Weir and Cocker-ham's fixation index(Fst) range: 0.020~0.023; Slatkin's fixation index (Rst) range: 0.016~0.044], and no obvious difference was detected between the samples of Japanese H. discus hannai populations (Fst=0.002; Rst = 0.007). The level of differentiation among populations is further evidenced by the nNeighbor-joining tree topology on which the Japanese samples were closely clustered, and the Chinese population formed a separate cluster. These results suggest that care should be taken in future management of different populations.

  17. Phylogeography of Spiraea alpina (Rosaceae) in the Qinghai-Tibetan Plateau inferred from chloroplast DNA sequence variations

    Fa-Qi ZHANG; Qing-Bo GAO; De-Jun ZHANG; Yi-Zhong DUAN; Yin-Hu LI; Peng-Cheng FU; Rui XING; Khan GULZAR; Shi-Long CHEN

    2012-01-01

    The aim of the present study was to investigate the phylogeographic patterns of Spiraea alpina (Rosaceae) and clarify its response to past climatic changes in the climate-sensitive Qinghai-Tibetan Plateau (QTP).We sequenced a chloroplast DNA fragment (trnL-trnF) from 528 individuals representing 43 populations.We identified 10 haplotypes,which were tentatively divided into three groups.These haplotypes or groups were distributed in the different regions of the QTP.Only half the populations were fixed by a single haplotype,whereas the others contained two or more.In the central and eastern regions,adjacent populations at the local scale shared the same haplotype.Our phylogeographic analyses suggest that this alpine shrub survived in multiple refugia during the Last Glacial Maximum and that earlier glaciations may have trigged deep intraspecific divergences.Post-glacial expansions occurred only within populations or across multiple populations within a local range.The findings of the present study together with previous phylogeographic reports suggest that evolutionary histories of plants in the QTP are complex and variable depending on the species investigated.

  18. Mitochondrial DNA sequence variation in Drosophilid species (Diptera: Drosophilidae) along altitudinal gradient from Central Himalayan region of India

    MANISHA SARSWAT; SAURABH DEWAN; RAJENDRA SINGH FARTYAL

    2016-06-01

    Central Himalayan region of India encompasses varied ecological habitats ranging from near tropics to the mid-elevation forests dominated by cool-temperate taxa. In past, we have reported several new records and novel species from Uttarakhand state of India. Here, we assessed genetic variations in three mitochondrial genes, namely, 16S rRNA, cytochrome c oxidase subunit I and cytochrome c oxidase subunit II (COI and COII) in 26 drosophilid species collected along altitudinal transect from 550 to 2700 m above mean sea level. In the present study, overall 543 sequences were generated, 82 for 16S rRNA, 238 forCOI, 223 for COII with 21, 47 and 45 mitochondrial haplotypes for 16S rRNA, COI and COII genes,respectively. Almost all species were represented by 2–3 unique mitochondrial haplotypes, depicting a significant impact of environmental heterogeneity along altitudinal gradient on genetic diversity. Also for the first time, molecular data of some rare species like Drosophila mukteshwarensis , Liodrosophila nitida, Lordiphosa parantillaria , Lordiphosa ayarpathaensis ,Scaptomyza himalayana,Scaptomyza tistai , Zaprionus grandis and Stegana minuta are provided to public domains through this study.

  19. Variation in the genomic locations and sequence conservation of STAR elements among staphylococcal species provides insight into DNA repeat evolution

    Purves Joanne

    2012-09-01

    Full Text Available Abstract Background Staphylococcus aureus Repeat (STAR elements are a type of interspersed intergenic direct repeat. In this study the conservation and variation in these elements was explored by bioinformatic analyses of published staphylococcal genome sequences and through sequencing of specific STAR element loci from a large set of S. aureus isolates. Results Using bioinformatic analyses, we found that the STAR elements were located in different genomic loci within each staphylococcal species. There was no correlation between the number of STAR elements in each genome and the evolutionary relatedness of staphylococcal species, however higher levels of repeats were observed in both S. aureus and S. lugdunensis compared to other staphylococcal species. Unexpectedly, sequencing of the internal spacer sequences of individual repeat elements from multiple isolates showed conservation at the sequence level within deep evolutionary lineages of S. aureus. Whilst individual STAR element loci were demonstrated to expand and contract, the sequences associated with each locus were stable and distinct from one another. Conclusions The high degree of lineage and locus-specific conservation of these intergenic repeat regions suggests that STAR elements are maintained due to selective or molecular forces with some of these elements having an important role in cell physiology. The high prevalence in two of the more virulent staphylococcal species is indicative of a potential role for STAR elements in pathogenesis.

  20. Nuclear and Chloroplast DNA Variation Provides Insights into Population Structure and Multiple Origin of Native Aromatic Rices of Odisha, India.

    Roy, Pritesh Sundar; Rao, Gundimeda Jwala Narasimha; Jena, Sudipta; Samal, Rashmita; Patnaik, Ashok; Patnaik, Sasank Sekhar Chyau; Jambhulkar, Nitiprasad Namdeorao; Sharma, Srigopal; Mohapatra, Trilochan

    2016-01-01

    A large number of short grain aromatic rice suited to the agro-climatic conditions and local preferences are grown in niche areas of different parts of India and their diversity is evolved over centuries as a result of selection by traditional farmers. Systematic characterization of these specialty rices has not been attempted. An effort was made to characterize 126 aromatic short grain rice landraces, collected from 19 different districts in the State of Odisha, from eastern India. High level of variation for grain quality and agronomic traits among these aromatic rices was observed and genotypes having desirable phenotypic traits like erect flag leaf, thick culm, compact and dense panicles, short plant stature, early duration, superior yield and grain quality traits were identified. A total of 24 SSR markers corresponding to the hyper variable regions of rice chromosomes were used to understand the genetic diversity and to establish the genetic relationship among the aromatic short grain rice landraces at nuclear genome level. SSR analysis of 126 genotypes from Odisha and 10 genotypes from other states revealed 110 alleles with an average of 4.583 and the Nei's genetic diversity value (He) was in the range of 0.034-0.880 revealing two sub-populations SP 1 (membership percentage-27.1%) and SP 2 (72.9%). At the organelle genomic level for the C/A repeats in PS1D sequence of chloroplasts, eight different plastid sub types and 33 haplotypes were detected. The japonica (Nipponbare) subtype (6C7A) was detected in 100 genotypes followed by O. rufipogon (KF428978) subtype (6C6A) in 13 genotypes while indica (93-11) sub type (8C8A) was seen in 14 genotypes. The tree constructed based on haplotypes suggests that short grain aromatic landraces might have independent origin of these plastid subtypes. Notably a wide range of diversity was observed among these landraces cultivated in different parts confined to the State of Odisha. PMID:27598392

  1. In search of the genetic footprints of Sumerians: a survey of Y-chromosome and mtDNA variation in the Marsh Arabs of Iraq

    Olivieri Anna

    2011-10-01

    Full Text Available Abstract Background For millennia, the southern part of the Mesopotamia has been a wetland region generated by the Tigris and Euphrates rivers before flowing into the Gulf. This area has been occupied by human communities since ancient times and the present-day inhabitants, the Marsh Arabs, are considered the population with the strongest link to ancient Sumerians. Popular tradition, however, considers the Marsh Arabs as a foreign group, of unknown origin, which arrived in the marshlands when the rearing of water buffalo was introduced to the region. Results To shed some light on the paternal and maternal origin of this population, Y chromosome and mitochondrial DNA (mtDNA variation was surveyed in 143 Marsh Arabs and in a large sample of Iraqi controls. Analyses of the haplogroups and sub-haplogroups observed in the Marsh Arabs revealed a prevalent autochthonous Middle Eastern component for both male and female gene pools, with weak South-West Asian and African contributions, more evident in mtDNA. A higher male than female homogeneity is characteristic of the Marsh Arab gene pool, likely due to a strong male genetic drift determined by socio-cultural factors (patrilocality, polygamy, unequal male and female migration rates. Conclusions Evidence of genetic stratification ascribable to the Sumerian development was provided by the Y-chromosome data where the J1-Page08 branch reveals a local expansion, almost contemporary with the Sumerian City State period that characterized Southern Mesopotamia. On the other hand, a more ancient background shared with Northern Mesopotamia is revealed by the less represented Y-chromosome lineage J1-M267*. Overall our results indicate that the introduction of water buffalo breeding and rice farming, most likely from the Indian sub-continent, only marginally affected the gene pool of autochthonous people of the region. Furthermore, a prevalent Middle Eastern ancestry of the modern population of the marshes of

  2. Genetic variation in DNA-repair pathways and response to radiochemotherapy in esophageal adenocarcinoma: a retrospective cohort study of the Eastern Cooperative Oncology Group

    Wu Xifeng

    2011-05-01

    Full Text Available Abstract Background Recent data in esophageal cancer suggests the variant allele of a single-nucleotide polymorphism (SNP in XRCC1 may be associated with resistance to radiochemotherapy. However, this SNP has not been assessed in a histologically homogeneous clinical trial cohort that has been treated with a uniform approach. In addition, whether germline DNA may serve as a surrogate for tumor genotype at this locus is unknown in this disease. Our objective was to assess this SNP in relation to the pathologic complete response (pCR rate in subjects with esophageal adenocarcinoma who received cisplatin-based preoperative radiochemotherapy in a multicenter clinical trial (Eastern Cooperative Oncology Group 1201. As a secondary aim, we investigated the rate of allelic imbalance between germline and tumor DNA. Methods Eighty-one eligible treatment-naïve subjects with newly diagnosed resectable esophageal adenocarcinoma received radiotherapy (45 Gy concurrent with cisplatin-based chemotherapy, with planned subsequent surgical resection. The primary endpoint was pCR, defined as complete absence of tumor in the surgical specimen after radiochemotherapy. Using germline DNA from 60 subjects, we examined the base-excision repair SNP, XRCC1 Arg399Gln, and 4 other SNPs in nucleotide excision (XPD Lys751Gln and Asp312Asn, ERCC1 3' flank and double-stranded break (XRCC2 5' flank repair pathways, and correlated genotype with pCR rate. Paired tumor tissue was used to estimate the frequency of allelic imbalance at the XRCC1 SNP. Results The variant allele of the XRCC1 SNP (399Gln was detected in 52% of subjects. Only 6% of subjects with the variant allele experienced a pCR, compared to 28% of subjects without the variant allele (odds ratio 5.37 for failing to achieve pCR, p = 0.062. Allelic imbalance at this locus was found in only 10% of informative subjects, suggesting that germline genotype may reflect tumor genotype at this locus. No significant association

  3. Genetic variation in DNA-repair pathways and response to radiochemotherapy in esophageal adenocarcinoma: a retrospective cohort study of the Eastern Cooperative Oncology Group

    Recent data in esophageal cancer suggests the variant allele of a single-nucleotide polymorphism (SNP) in XRCC1 may be associated with resistance to radiochemotherapy. However, this SNP has not been assessed in a histologically homogeneous clinical trial cohort that has been treated with a uniform approach. In addition, whether germline DNA may serve as a surrogate for tumor genotype at this locus is unknown in this disease. Our objective was to assess this SNP in relation to the pathologic complete response (pCR) rate in subjects with esophageal adenocarcinoma who received cisplatin-based preoperative radiochemotherapy in a multicenter clinical trial (Eastern Cooperative Oncology Group 1201). As a secondary aim, we investigated the rate of allelic imbalance between germline and tumor DNA. Eighty-one eligible treatment-naïve subjects with newly diagnosed resectable esophageal adenocarcinoma received radiotherapy (45 Gy) concurrent with cisplatin-based chemotherapy, with planned subsequent surgical resection. The primary endpoint was pCR, defined as complete absence of tumor in the surgical specimen after radiochemotherapy. Using germline DNA from 60 subjects, we examined the base-excision repair SNP, XRCC1 Arg399Gln, and 4 other SNPs in nucleotide excision (XPD Lys751Gln and Asp312Asn, ERCC1 3' flank) and double-stranded break (XRCC2 5' flank) repair pathways, and correlated genotype with pCR rate. Paired tumor tissue was used to estimate the frequency of allelic imbalance at the XRCC1 SNP. The variant allele of the XRCC1 SNP (399Gln) was detected in 52% of subjects. Only 6% of subjects with the variant allele experienced a pCR, compared to 28% of subjects without the variant allele (odds ratio 5.37 for failing to achieve pCR, p = 0.062). Allelic imbalance at this locus was found in only 10% of informative subjects, suggesting that germline genotype may reflect tumor genotype at this locus. No significant association with pCR was noted for other SNPs

  4. Use of novel DNA fingerprinting techniques for the detection and characterization of genetic variation in vegetatively propagated crops. Proceedings of a final research co-ordination meeting

    Vegetative propagated crops, such as banana and platain, sweet potato, yam, sugarcane and cassava, represent important sources of food in the developing countries. Although some of these crops may produce seeds, they must for practical purposes be propagated vegetatively. As normal plant breeding strategies based on genetic hybridization are of limited value or not applicable to such crops, it is necessary to assess the genetic diversity already existing in these crops and to design breeding strategies accordingly. If the existing genetic variation is shown to be too narrow for breeding purposes, one promising possibility for the introduction of genetic variability is the use of mutations induced by radiation or chemical mutagens. This CRP focused on: the detection of genetic diversity induced by mutagenic treatment or in vitro culture; the development of crop-specific markers; and increasing co-operation between molecular biologists in advanced laboratories and plant breeders and molecular biologists in the developing countries. The success of this CRP is evidenced by the introduction and application of new molecular methods by laboratories in developing countries, specially for the analysis of local crop genetic diversity. These exciting preliminary results show the potential for applications in crop improvement but much work remains to be done. Many of the vegetatively propagated species are ''orphan crops'', under-investigated on the international level. The development of new uses of transgenesis for the development of edible vaccines should not be overlooked. The challenge that remains is in the application of these new tools for practical end-user oriented improvements in vegetatively propagated crops. The present publication summarizes the third and final Research Co-ordination Meeting on the Use of Novel DNA Fingerprinting Techniques for the Detection and Characterization of Genetic Variation in Vegetatively Propagated Crops

  5. Radioimmunoassay of chicken growth hormone using growth hormone produced by recombinant DNA technology: validation and observations of plasma hormone variations in genetically fat and lean chickens

    Picaper, G.; Leclercq, B.; Saadoun, A.; Mongin, P.

    1986-01-01

    A radioimmunoassay (RIA) of chicken growth hormone (c-GH) has been developed using growth hormone produced by recombinant DNA technology. The best rabbit antiserum was used at 1/300,000 final dilution. Hormone labelling by iodine-125, achieved by chloramine T, allowed a specific activity of 3.7 MBq/..mu..g. The equilibrium curves show that optimal conditions of incubation were reached at room temperature for 24h. This RIA used a second sheep antibody which precipitated the whole c-GH bound to the first antibody in the presence of polyethylene glycol solution (6%) at room temperature for 30 min. In our conditions, sensitivity was about 30 pg of c-GH per tube. Coefficient of variation was around 10%. No cross reaction was found with avian LH and prolactin. Thyrotrophin-releasing hormone (TRH) injection to young chickens induced 20-fold higher plasma c-GH concentrations. Simultaneous injection of somatostatin and TRH slightly reduced these concentrations. Hypoglycemia induced by insulin led to a drop of the plasma c-GH concentration. Conversely, refeeding or glucose load induced slight increases of the c-GH level. Genetically fat chickens tended to exhibit higher plasma c-GH concentrations than lean chickens.

  6. A radioimmunoassay of chicken growth hormone using growth hormone produced by recombinant DNA technology: validation and observations of plasma hormone variations in genetically fat and lean chickens

    A radioimmunoassay (RIA) of chicken growth hormone (c-GH) has been developed using growth hormone produced by recombinant DNA technology. The best rabbit antiserum was used at 1/300,000 final dilution. Hormone labelling by iodine-125, achieved by chloramine T, allowed a specific activity of 3.7 MBq/μg. The equilibrium curves show that optimal conditions of incubation were reached at room temperature for 24h. This RIA used a second sheep antibody which precipitated the whole c-GH bound to the first antibody in the presence of polyethylene glycol solution (6%) at room temperature for 30 min. In our conditions, sensitivity was about 30 pg of c-GH per tube. Coefficient of variation was around 10%. No cross reaction was found with avian LH and prolactin. Thyrotrophin-releasing hormone (TRH) injection to young chickens induced 20-fold higher plasma c-GH concentrations. Simultaneous injection of somatostatin and TRH slightly reduced these concentrations. Hypoglycemia induced by insulin led to a drop of the plasma c-GH concentration. Conversely, refeeding or glucose load induced slight increases of the c-GH level. Genetically fat chickens tended to exhibit higher plasma c-GH concentrations than lean chickens

  7. Pash 3.0: A versatile software package for read mapping and integrative analysis of genomic and epigenomic variation using massively parallel DNA sequencing

    Chen Zuozhou

    2010-11-01

    Full Text Available Abstract Background Massively parallel sequencing readouts of epigenomic assays are enabling integrative genome-wide analyses of genomic and epigenomic variation. Pash 3.0 performs sequence comparison and read mapping and can be employed as a module within diverse configurable analysis pipelines, including ChIP-Seq and methylome mapping by whole-genome bisulfite sequencing. Results Pash 3.0 generally matches the accuracy and speed of niche programs for fast mapping of short reads, and exceeds their performance on longer reads generated by a new generation of massively parallel sequencing technologies. By exploiting longer read lengths, Pash 3.0 maps reads onto the large fraction of genomic DNA that contains repetitive elements and polymorphic sites, including indel polymorphisms. Conclusions We demonstrate the versatility of Pash 3.0 by analyzing the interaction between CpG methylation, CpG SNPs, and imprinting based on publicly available whole-genome shotgun bisulfite sequencing data. Pash 3.0 makes use of gapped k-mer alignment, a non-seed based comparison method, which is implemented using multi-positional hash tables. This allows Pash 3.0 to run on diverse hardware platforms, including individual computers with standard RAM capacity, multi-core hardware architectures and large clusters.

  8. Gene expression profiling of Spodoptera frugiperda hemocytes and fat body using cDNA microarray reveals polydnavirus-associated variations in lepidopteran host genes transcript levels

    Feyereisen R

    2006-06-01

    Full Text Available Abstract Background Genomic approaches provide unique opportunities to study interactions of insects with their pathogens. We developed a cDNA microarray to analyze the gene transcription profile of the lepidopteran pest Spodoptera frugiperda in response to injection of the polydnavirus HdIV associated with the ichneumonid wasp Hyposoter didymator. Polydnaviruses are associated with parasitic ichneumonoid wasps and are required for their development within the lepidopteran host, in which they act as potent immunosuppressive pathogens. In this study, we analyzed transcriptional variations in the two main effectors of the insect immune response, the hemocytes and the fat body, after injection of filter-purified HdIV. Results Results show that 24 hours post-injection, about 4% of the 1750 arrayed host genes display changes in their transcript levels with a large proportion (76% showing a decrease. As a comparison, in S. frugiperda fat body, after injection of the pathogenic JcDNV densovirus, 8 genes display significant changes in their transcript level. They differ from the 7 affected by HdIV and, as opposed to HdIV injection, are all up-regulated. Interestingly, several of the genes that are modulated by HdIV injection have been shown to be involved in lepidopteran innate immunity. Levels of transcripts related to calreticulin, prophenoloxidase-activating enzyme, immulectin-2 and a novel lepidopteran scavenger receptor are decreased in hemocytes of HdIV-injected caterpillars. This was confirmed by quantitative RT-PCR analysis but not observed after injection of heat-inactivated HdIV. Conversely, an increased level of transcripts was found for a galactose-binding lectin and, surprisingly, for the prophenoloxidase subunits. The results obtained suggest that HdIV injection affects transcript levels of genes encoding different components of the host immune response (non-self recognition, humoral and cellular responses. Conclusion This analysis of the

  9. Cryptic variation in an ecological indicator organism: mitochondrial and nuclear DNA sequence data confirm distinct lineages of Baetis harrisoni Barnard (Ephemeroptera: Baetidae in southern Africa

    Pereira-da-Conceicoa Lyndall L

    2012-02-01

    Full Text Available Abstract Background Baetis harrisoni Barnard is a mayfly frequently encountered in river studies across Africa, but the external morphological features used for identifying nymphs have been observed to vary subtly between different geographic locations. It has been associated with a wide range of ecological conditions, including pH extremes of pH 2.9–10.0 in polluted waters. We present a molecular study of the genetic variation within B. harrisoni across 21 rivers in its distribution range in southern Africa. Results Four gene regions were examined, two mitochondrial (cytochrome c oxidase subunit I [COI] and small subunit ribosomal 16S rDNA [16S] and two nuclear (elongation factor 1 alpha [EF1α] and phosphoenolpyruvate carboxykinase [PEPCK]. Bayesian and parsimony approaches to phylogeny reconstruction resulted in five well-supported major lineages, which were confirmed using a general mixed Yule-coalescent (GMYC model. Results from the EF1α gene were significantly incongruent with both mitochondrial and nuclear (PEPCK results, possibly due to incomplete lineage sorting of the EF1α gene. Mean between-clade distance estimated using the COI and PEPCK data was found to be an order of magnitude greater than the within-clade distance and comparable to that previously reported for other recognised Baetis species. Analysis of the Isolation by Distance (IBD between all samples showed a small but significant effect of IBD. Within each lineage the contribution of IBD was minimal. Tentative dating analyses using an uncorrelated log-normal relaxed clock and two published estimates of COI mutation rates suggest that diversification within the group occurred throughout the Pliocene and mid-Miocene (~2.4–11.5 mya. Conclusions The distinct lineages of B. harrisoni correspond to categorical environmental variation, with two lineages comprising samples from streams that flow through acidic Table Mountain Sandstone and three lineages with samples from

  10. Grapes, galls, and geography: the distribution of nuclear and mitochondrial DNA variation across host-plant species and regions in a specialist herbivore.

    Downie, D A; Fisher, J R; Granett, J

    2001-07-01

    Studies of patterns of molecular variation in natural populations can provide important insights into a number of evolutionary problems. Among these, the question of whether geographic factors are more important than ecological factors in promoting population differentiation and ultimately speciation has been an important and contentious area in evolutionary biology. Systems involving herbivorous insects have played a leading role in this discussion. This study examined the distribution of molecular variation in a highly specialized gall-forming insect, grape phylloxera (Daktulosphaira vitifoliae Fitch), that is found on both sympatric and allopatric host-plant species of the genus Vitis. In addition, the relationship of insects in the introduced range in the United States to ancestral populations in the native range was examined. Evidence for differentiation along host-plant lines from both nuclear (RAPD) and mitochondrial (COI) DNA was confounded with the effect of geography. Differentiation was found where hosts were allopatric or parapatric, but no evidence was found for such differentiation on two hosts, V. vulpina and V. aestivalis, that are broadly sympatric. The question of population differentiation onto these sympatric hosts can be considered to be resolved--it has not occurred in spite of a long history of association. Evidence was equivocal, but suggestive of a period of divergence in allopatry prior to reestablishment of contact, for insects associated with another host plant species, V. cinerea, found in both sympatric and parapatric populations. A low level of diversity and placement of samples collected from the grape species V. riparia at the tip of a phylogenetic tree supports the hypothesis that this host has been recently colonized from populations from the Mississippi Valley. A polyphyletic origin for biotype B grape phylloxera was supported: Although most samples collected from vineyards in the introduced range in California had similar

  11. Seasonal variation of DNA damage and repair in patients with non-melanoma skin cancer and referents with and without psoriasis

    Møller, P; Knudsen, Lisbeth E.; Frentz, G;

    1998-01-01

    Quadruples of skin cancer patients with and without psoriasis and referents with and without psoriasis (4 x 20 study persons) were identified and examined for DNA damage by single cell gel electrophoresis (comet-assay) and DNA-repair by UV-induced unscheduled DNA synthesis (UDS) in mononuclear...... solar radiation. When the comet tail moment data were stratified by sampling period, an interaction between psoriasis and skin cancer was detected, with patients with psoriasis and skin cancer exhibiting more DNA damage. Patients with psoriasis and skin cancer also had lower UDS compared to healthy...

  12. VARIATION IN MITOCHONDRIAL-DNA LEVELS IN MUSCLE FROM NORMAL CONTROLS - IS DEPLETION OF MTDNA IN PATIENTS WITH MITOCHONDRIAL MYOPATHY A DISTINCT CLINICAL SYNDROME

    POULTON, J; SEWRY, C; POTTER, CG; BOUGERON, T; CHRETIEN, D; WIJBURG, FA; MORTEN, KJ; BROWN, G

    1995-01-01

    Recent studies have identified a group of patients with cytochrome oxidase (COX) deficiency presenting in infancy associated with a deficiency of mtDNA in muscle or other affected tissue (Moraes et al 1991). We used a navel approach to compare the level of mitochondrial (mtDNA) compared to nuclear D

  13. Evaluation of Interindividual Human Variation in Bioactivation and DNA Adduct Formation of Estragole in Liver Predicted by Physiologically Based Kinetic/Dynamic and Monte Carlo Modeling

    Punt, Ans; Paini, Alicia; Spenkelink, Bert; Scholz, Gabriele; Schilter, Benoit; Bladeren, Van Peter J.; Rietjens, Ivonne M.C.M.

    2016-01-01

    Estragole is a known hepatocarcinogen in rodents at high doses following metabolic conversion to the DNA-reactive metabolite 1′-sulfooxyestragole. The aim of the present study was to model possible levels of DNA adduct formation in (individual) humans upon exposure to estragole. This was done by

  14. Genuineness of Morinda officinalis How germplasm inferred from ITS sequences variation of nuclear ribosomal DNA%基于核糖体rDNA ITS序列变异探讨巴戟天道地性

    丁平; 刘瑾; 邱金英; 赖小平

    2012-01-01

    本文应用PCR测序技术,对不同产地巴戟天(Morinda officinalis How)的rDNA ITS区片段进行检测,ITS全序列为567 bp,G/C含量为64.5%.本研究共获得17个单倍型,各单倍型呈高水平的树状演化,来自广东群体的单倍型显示是扩张的源头.分子变异等级分析(AMOVA)的计算结果显示,群体间变异占变异的比例(56.65%)大于群体内变异(43.35%),FST值为0.566 5,各群体间出现遗传分化.Mantel检验结果也显示基因流水平与地理距离呈正相关关系(R2=0.721 1),表明巴戟天群体间的亲缘关系与地理分布有较好的相关性.本研究为探讨巴戟天道地药材形成的分子机制以及谱系地理学的研究奠定基础.%PCR sequencing ITS genes methods were used to assess the genetic diversity of Morinda officinalis How different populations. The sequence of Morinda officinalis ITS gene was 567 bp in length, and the content of G/C was 64.5%. In this study, 17 haplotypes were obtained, which were at a high level of branching, and the haplotypes of Guangdong population showed to be the expansion origin. The result of the analysis of molecular variance (AMOVA) also showed that the percentage of variation among populations (56.65%) was greater than that within a population (43.35%). The FST value was 0.566 5, and the genetic divergence among populations was significant. Mantel test results also indicated that the level of geneflow was positively correlated with geographic distances (R2= 0.721 1). The result showed a good correlation between genotype and geographic distribution of Morinda officinalis, and ITS gene sequencing could be useful molecular method for the genuineness and phylogeography of Morinda officinalis.

  15. Variation through the cell cycle in the dose-response of DNA neutral filter elution in X-irradiated synchronous CHO-cells

    Dose-response curves for DNA neutral (pH 9.6) filter elution were obtained with synchronized CHO cells exposed to X-rays at various phases of cell cycle. The dose response was similar in synchronized and plateau-phase G1 cells, as well as in cells arrested at the G1/S border using aphidicolin; it flattened as cells progressed into S phase and reached a minimum in the middle of this phase. An increase in DNA elution dose response, to values only slightly lower than those obtained with G1 cells, was observed as cells entered G2 phase. Significant alterations in the sedimentation properties of the DNA during S phase were also observed in Ehrlich ascites tumor cells using the neutral sucrose gradient centrifugation technique. A significant proportion of the DNA from S cells irradiated with 10 Gy sedimented at speeds (350S-700S) well above the maximum sedimentation speed expected for free sedimenting DNA molecules (ssub(max) = 350S), indicating the formation of a DNA complex. DNA from G1, G1/S, or G2 + M cells sedimented as expected for free sedimenting molecules. (author)

  16. High frequency of the IVS2-2A>G DNA sequence variation in SLC26A5, encoding the cochlear motor protein prestin, precludes its involvement in hereditary hearing loss

    Pereira Fred A

    2005-08-01

    Full Text Available Abstract Background Cochlear outer hair cells change their length in response to variations in membrane potential. This capability, called electromotility, is believed to enable the sensitivity and frequency selectivity of the mammalian cochlea. Prestin is a transmembrane protein required for electromotility. Homozygous prestin knockout mice are profoundly hearing impaired. In humans, a single nucleotide change in SLC26A5, encoding prestin, has been reported in association with hearing loss. This DNA sequence variation, IVS2-2A>G, occurs in the exon 3 splice acceptor site and is expected to abolish splicing of exon 3. Methods To further explore the relationship between hearing loss and the IVS2-2A>G transition, and assess allele frequency, genomic DNA from hearing impaired and control subjects was analyzed by DNA sequencing. SLC26A5 genomic DNA sequences from human, chimp, rat, mouse, zebrafish and fruit fly were aligned and compared for evolutionary conservation of the exon 3 splice acceptor site. Alternative splice acceptor sites within intron 2 of human SLC26A5 were sought using a splice site prediction program from the Berkeley Drosophila Genome Project. Results The IVS2-2A>G variant was found in a heterozygous state in 4 of 74 hearing impaired subjects of Hispanic, Caucasian or uncertain ethnicity and 4 of 150 Hispanic or Caucasian controls (p = 0.45. The IVS2-2A>G variant was not found in 106 subjects of Asian or African American descent. No homozygous subjects were identified (n = 330. Sequence alignment of SLC26A5 orthologs demonstrated that the A nucleotide at position IVS2-2 is invariant among several eukaryotic species. Sequence analysis also revealed five potential alternative splice acceptor sites in intron 2 of human SLC26A5. Conclusion These data suggest that the IVS2-2A>G variant may not occur more frequently in hearing impaired subjects than in controls. The identification of five potential alternative splice acceptor sites in

  17. A physiologically based in silico model for trans-2-hexenal detoxicifcation and DNA adduct formation in human including interindividual variation indicates efficient detoxification and a negligible genotoxicity risk

    Kiwamoto, R.; Spenkelink, A.; Rietjens, I.M.C.M.; Punt, A.

    2013-01-01

    A number of a,ß-unsaturated aldehydes are present in food both as natural constituents and as flavouring agents. Their reaction with DNA due to their electrophilic a,ß-unsaturated aldehyde moiety may result in genotoxicity as observed in some in vitro models, thereby raising a safety concern. A ques

  18. DNA Polymerase-Catalyzed DNA Network Growth

    Keller, Sascha; Wang, Jie; Chandra, Madhaviah; Berger, Rüdiger; Marx, Andreas

    2008-01-01

    The distinct base pairing property of DNA is an advantageous phenomenon that has been exploited in the usage of DNA as scaffold for directed self-organization to form nanometer-sized objects in a desirable fashion. Herein we report the construction of three-dimensional DNA-based networks that can be generated and amplified by the DNA polymerase chain reaction (PCR). The approach is flexible allowing tuning of the meshes of the network by variation of the size of the template. Additionally, fu...

  19. Identification of variations of gene expression of visceral adipose and renal tissue in type 2 diabetic rats using cDNA representational difference analysis

    杨架林; 李果; 张芳林; 刘优萍; 张迪; 周文中; 许光武; 杨义生; 罗敏

    2003-01-01

    Objectives To identify differences in gene expression in renal and visceral adipose tissue in type 2 diabetic rats using cDNA representational difference analysis (RDA) and to explore the molecular pathogenesis of type 2 diabetes and its chronic vascular complications.Methods A rat model of type 2 diabetes was generated by administration of a high fat and calorie diet combined with a low dose of streptozocin (STZ) injected into the tail vein. The difference bands were generated by cDNA representational difference analysis (cDNA RDA). The final difference products were ligated into the pUC-18 vector and sequenced. A bioformatics analysis was performed on the obtained expressed sequence tags (ESTs), and then the expression levels of known and novel genes were verified by semi-quantitative reverse transcription-PCR (RT-PCR). At the same time, full-length cDNA of a novel gene was cloned in silico.Results The type 2 diabetic rats in this experiment experienced hyperglycemia, lipidemia, lower insulin sensitivity and normal body weight. We obtained 9 novel ESTs and 2 novel genes from renal tissue of rats and 6 novel ESTs and 1 known gene, the rat lipoprotein lipase (LPL) gene from their visceral adipose tissue. The 2 novel genes (RS91 and RS2) from the renal tissue were both very similar to serine (or cysteine) proteinase inhibitor, clade F and eukaryotic translation initiation factor 3 and subunit 5 (EIF-3 epsilon). The expression of both novel genes and the LPL gene were upregulated in renal and visceral adipose tissue of type 2 diabetic and fat-enriched rats. Full-length cDNA of the novel gene RS91 was cloned in silico.Conclusions① The rat model of type 2 diabetes generated in this study was ideal because the disease in the animals closely mimicked type 2 diabetic patients ② cDNA RDA is a flexible, inexpensive, more accurate, sensitive and highly effective technique for identifying differences in gene expression ③ Six novel ESTs and 1 known gene were obtained

  20. Ancient DNA

    Willerslev, Eske; Cooper, Alan

    2004-01-01

    ancient DNA, palaeontology, palaeoecology, archaeology, population genetics, DNA damage and repair......ancient DNA, palaeontology, palaeoecology, archaeology, population genetics, DNA damage and repair...

  1. Identification of a New Variable Sequence in the P1 Cytadhesin Gene of Mycoplasma pneumoniae: Evidence for the Generation of Antigenic Variation by DNA Recombination between Repetitive Sequences

    Kenri, Tsuyoshi; Taniguchi, Rie; Sasaki, Yuko; Okazaki, Norio; Narita, Mitsuo; Izumikawa, Kinichi; Umetsu, Masao; Sasaki, Tsuguo

    1999-01-01

    A Mycoplasma pneumoniae cytadhesin P1 gene with novel nucleotide sequence variation has been identified. Four clinical strains of M. pneumoniae were found to carry this type of P1 gene. This new P1 gene is similar to the known group II P1 genes but possesses novel sequence variation of approximately 300 bp in the RepMP2/3 region. The position of the new variable region is distant from the previously reported variable regions known to differ between group I and II P1 genes. Two sequences close...

  2. Population structure and gene flow of the Atlantic walrus ( Odobenus rosmarus rosmarus ) in the eastern Atlantic Arctic based on mitochondrial DNA and microsatellite variation

    Andersen, L.W.; Born, E.W.; Gjertz, I.; Wiig, O.; Holm, L.E.; Bendixen, C.

    1998-01-01

    individual sampled in E Greenland exhibited a Pacific haplotype, which proved a connection between the Pacific walrus and walruses in eastern Greenland. The Franz Joseph Land, Svalbard and E Greenland samples shared the most common haplotype, indicating very little differentiation at the mtDNA level. Gene......The population structure of the Atlantic walrus, Odobenus rosmarus rosmarus, was studied using 11 polymorphic microsatellites and restriction fragment length polymorphism detected in the NADH-dehydrogenase ND1, ND2 and ND3/4 segments in mtDNA. A total of 105 walrus samples were analysed from...... northwest (NW) Greenland, east (E) Greenland, Svalbard and Franz Joseph Land. Two of the 10 haplotypes detected in the four samples were diagnostic for the NW Greenland sample, which implied that the group of walruses in this area is evolutionary distinct from walruses in the other three areas. One...

  3. 人类线粒体DNA变异的检测方法和思路%Methods and Thoughts on Detecting Nucleotide Variations in Human Mitochondrial DNA

    姚永刚; 孔庆鹏; 张亚平

    2001-01-01

    基于线粒体DNA(mtDNA)的研究对于人群源流迁移、线粒体相关疾病病因的探讨和法医鉴定等具有重要意义,就检测人线粒体突变的一些常用方法,如RFLP、SSO和控制区测序等作一小结和归纳,并重点介绍目前mtDNA突变的筛选方法和思路。另外,还总结了近年来对人mtDNA方面的研究结果,对世界人群中主要单倍型类群(haplogroup)特征变异位点和相应的酶切检测引物作了归纳。

  4. Gene expression profiling of Spodoptera frugiperda hemocytes and fat body using cDNA microarray reveals polydnavirus-associated variations in lepidopteran host genes transcript levels

    Barat-Houari, M; Hilliou, F.; Jousset, F-X; Sofer, L; Deleury, E.; Rocher, J.; Ravallec, M.; Galibert, L; Delobel, P; Feyereisen, R.; Fournier, P.; Volkoff, A-N.

    2006-01-01

    Background Genomic approaches provide unique opportunities to study interactions of insects with their pathogens. We developed a cDNA microarray to analyze the gene transcription profile of the lepidopteran pest Spodoptera frugiperda in response to injection of the polydnavirus HdIV associated with the ichneumonid wasp Hyposoter didymator. Polydnaviruses are associated with parasitic ichneumonoid wasps and are required for their development within the lepidopteran host, in which they act as p...

  5. Host-Associated Population Variations of Bemisia tabaci (Genn.) (Hemiptera:Sternorrhyncha: Aleyrodidae) Characterized with Random DNA Markers

    Helmi, A.

    2011-01-01

    Whitefly, Bemisia tabaci (Genn.) is an important sucking plant sap pest of field, horticultural and ornamental plants causing feeding injuries besides spreading plant diseases by acting as a vector of Gemini-viruses. The polyphagous nature of the pest makes it as a highly complex species. The influence of six host plants belonging to three different plant families utilized by the species on the population differences at molecular level was attempted using Random Amplified Polymorphic DNA (RAP...

  6. Using next-generation sequencing for high resolution multiplex analysis of copy number variation from nanogram quantities of DNA from formalin-fixed paraffin-embedded specimens

    Wood, HM; Belvedere,O; Conway, C; Daly, C; Chalkley, R; Bickerdike, M; McKinley, C; Egan, P; Ross, L; Hayward, B; Morgan, J.; Davidson, L; MacLennan, K; Ong, TK; Papagiannopoulos, K.

    2010-01-01

    The use of next-generation sequencing technologies to produce genomic copy number data has recently been described. Most approaches, however, reply on optimal starting DNA, and are therefore unsuitable for the analysis of formalin-fixed paraffin-embedded (FFPE) samples, which largely precludes the analysis of many tumour series. We have sought to challenge the limits of this technique with regards to quality and quantity of starting material and the depth of sequencing required. We confirm th...

  7. Analysis and validation of genome-specific DNA variations in 5' flanking conserved sequences of wheat low-molecular-weight glutenin subunit genes

    LONG; Hai; WEI; Yuming

    2006-01-01

    The thirty-three 5' flanking conserved sequences of the known low-molecular-weight subunit (LMW-GS) genes have been divided into eight clusters, which was in agreement with the classification based on the deduced N-terminal protein sequences. The DNA polymorphism between the eight clusters was obtained by sequence alignment, and a total of 34 polymorphic positions were observed in the approximately 200 bp regions, among which 18 polymorphic positions were candidate SNPs. Seven cluster-specific primer sets were designed for seven out of eight clusters containing cluster-specific bases, with which the genomic DNA of the ditelosomic lines of group 1 chromosomes of a wheat variety 'Chinese Spring' was employed to carry out chromosome assignment. The subsequent cloning and DNA sequencing of PCR fragments validated the sequences specificity of the 5' flanking conserved sequences between LMW-GS gene groups in different genomes. These results suggested that the coding and 5' flanking regions of LMW-GS genes are likely to have evolved in a concerted fashion. The seven primer sets developed in this study could be used to isolate the complete ORFs of seven groups of LMW-GS genes, respectively, and therefore possess great value for further research in the contributions of a single LMW-GS gene to wheat quality in the complex genetic background and the efficient selections of quality-related components in breeding programs.

  8. Identification of DNA sequence variation in Campylobacter jejuni strains associated with the Guillain-Barré syndrome by high-throughput AFLP analysis

    Endtz Hubert P

    2006-04-01

    Full Text Available Abstract Background Campylobacter jejuni is the predominant cause of antecedent infection in post-infectious neuropathies such as the Guillain-Barré (GBS and Miller Fisher syndromes (MFS. GBS and MFS are probably induced by molecular mimicry between human gangliosides and bacterial lipo-oligosaccharides (LOS. This study describes a new C. jejuni-specific high-throughput AFLP (htAFLP approach for detection and identification of DNA polymorphism, in general, and of putative GBS/MFS-markers, in particular. Results We compared 6 different isolates of the "genome strain" NCTC 11168 obtained from different laboratories. HtAFLP analysis generated approximately 3000 markers per stain, 19 of which were polymorphic. The DNA polymorphisms could not be confirmed by PCR-RFLP analysis, suggesting a baseline level of 0.6% AFLP artefacts. Comparison of NCTC 11168 with 4 GBS-associated strains revealed 23 potentially GBS-specific markers, 17 of which were identified by DNA sequencing. A collection of 27 GBS/MFS-associated and 17 enteritis control strains was analyzed with PCR-RFLP tests based on 11 of these markers. We identified 3 markers, located in the LOS biosynthesis genes cj1136, cj1138 and cj1139c, that were significantly associated with GBS (P = 0.024, P = 0.047 and P Conclusion This study shows that bacterial GBS markers are limited in number and located in the LOS biosynthesis genes, which corroborates the current consensus that LOS mimicry may be the prime etiologic determinant of GBS. Furthermore, our results demonstrate that htAFLP, with its high reproducibility and resolution, is an effective technique for the detection and subsequent identification of putative bacterial disease markers.

  9. Repetitive DNA and Plant Domestication: Variation in Copy Number and Proximity to Genes of LTR-Retrotransposons among Wild and Cultivated Sunflower (Helianthus annuus) Genotypes

    Mascagni, Flavia; Barghini, Elena; Giordani, Tommaso; Rieseberg, Loren H.; Cavallini, Andrea; Natali, Lucia

    2015-01-01

    The sunflower (Helianthus annuus) genome contains a very large proportion of transposable elements, especially long terminal repeat retrotransposons. However, knowledge on the retrotransposon-related variability within this species is still limited. We used next-generation sequencing (NGS) technologies to perform a quantitative and qualitative survey of intraspecific variation of the retrotransposon fraction of the genome across 15 genotypes—7 wild accessions and 8 cultivars—of H. annuus. By ...

  10. Mitochondrial DNA Variation Reveals a Sharp Genetic Break within the Distribution of the Blue Land Crab Cardisoma guanhumi in the Western Central Atlantic

    Maria Rosimere Xavier Amaral

    2015-08-01

    Full Text Available The blue land crab Cardisoma guanhumi is widely distributed throughout tropical and subtropical estuarine regions in the Western Central Atlantic (WCA. Patterns of population genetic structure and historical demographics of the species were assessed by mtDNA control region sequence analysis to examine the connectivity among five populations (n = 97 within the region for future conservation strategies and decision-making of fishery management. A total of 234 polymorphic nucleotides were revealed within the sequence region, which have defined 93 distinct haplotypes. No dominant mtDNA haplotypes were found but instead a distribution of a few low-frequency recurrent haplotypes with a large number of singletons. A NJ-tree and a median-joining haplotype network revealed two distinct clusters, corresponding to individuals from estuaries located along the Caribbean Sea and Brazilian waters, respectively. AMOVA and FST statistics supported the hypothesis that two main geographic regions exists. Phylogeographical discontinuity was further demonstrated by the Bayesian assignment analysis and a significant pattern of isolation-by-distance. Additionally, tests of neutral evolution and analysis of mismatch distribution indicate a complex demographic history in the WCA, which corresponds to bottleneck and subsequent population growth. Overall, a sharp genetic break between Caribbean and Brazilian populations raised concerns over the conservation status of the blue land crab.

  11. [On the Population Genetic Portrait of Kaluga, Acipenser dauricus Georgi, 1775 Analysis of Sequence Variation in the Mitochondrial DNA Control Region].

    Shedko, S V; Miroshnichenko, I L; Nemkova, G A; Shedko, M B

    2015-09-01

    The variability of the mtDNA D-loop was examined in kaluga endemic to the Amur River, which is classified as critically endangered by the IUCN Red List of Threatened species. Sequencing of the D-loop fragment (819 bp) in 122 kaluga specimens collected in Lower Amur revealed 27 unique genotypes. The sample was characterized by a relatively low level of haplotypic (0.927) and nucleotide (0.0044) diversity. No considerable deviations from the neutral mutation model of DNA polymorphism were observed. Overall, the mismatch distribution patterns and the results of testing of simple demographic models (sudden demographic expansion and exponential population growth) pointed to a past increase in the number of kaluga sturgeons. According to the Bayesian skyline, the kaluga population doubled over the last two to three thousand years. The number of mature females in the modern kaluga population and the assessment of their long-term effective population size (Nef) are roughly at the same level (about three thousand individuals), which confirms the validity of assigning kaluga to the category of species on the brink of extinction. PMID:26606799

  12. Clonal variation of DNA repair in a human glioma cell line This study was supported by the Cancer Research Campaign and the Bob Champion Cancer Trust

    Clonal heterogeneity in response to ionizing radiation was found for a human glioma cell line, IN859. The authors have investigated the most sensitive clone, the most resistant clone and the parent line for differences in DNA repair fidelity using the method of plasmid reconstitution. Significant differences in repair fidelity were found between the two clones, and between the sensitive clone and the parent line. The resistant clone and the parent lines showed the greater repair fidelity. A comparison of two different restriction enzymes, which cleave the plasmid with blunt or cohesive-ended double-strand breaks, did not reveal differences in repair fidelity. Equal numbers of plasmids were integrated in each cell line, but the sensitive clone showed a higher frequency of misrepair of cleaved plasmid. Misrepair was characterized by partial or complete loss of sequence at the site of plasmid cleavage. It is concluded that the radiosensitive clone exhibits increased misrepair. (author). 15 refs.; 5 figs.; 2 tabs

  13. Variation of DNA Fragmentation Levels During Density Gradient Sperm Selection for Assisted Reproduction Techniques: A Possible New Male Predictive Parameter of Pregnancy?

    Muratori, Monica; Tarozzi, Nicoletta; Cambi, Marta; Boni, Luca; Iorio, Anna Lisa; Passaro, Claudia; Luppino, Benedetta; Nadalini, Marco; Marchiani, Sara; Tamburrino, Lara; Forti, Gianni; Maggi, Mario; Baldi, Elisabetta; Borini, Andrea

    2016-05-01

    Predicting the outcome of in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) is one main goal of the present research on assisted reproduction. To understand whether density gradient centrifugation (DGC), used to select sperm, can affect sperm DNA integrity and impact pregnancy rate (PR), we prospectively evaluated sperm DNA fragmentation (sDF) by TUNEL/PI, before and after DGC. sDF was studied in a cohort of 90 infertile couples the same day of IVF/ICSI treatment. After DGC, sDF increased in 41 samples (Group A, median sDF value: 29.25% [interquartile range, IQR: 16.01-41.63] in pre- and 60.40% [IQR: 32.92-93.53] in post-DGC) and decreased in 49 (Group B, median sDF value: 18.84% [IQR: 13.70-35.47] in pre- and 8.98% [IQR: 6.24-15.58] in post-DGC). PR was 17.1% and 34.4% in Group A and B, respectively (odds ratio [OR]: 2.58, 95% confidence interval [CI]: 0.95-7.04, P = 0.056). After adjustment for female factor, female and male age and female BMI, the estimated OR increased to 3.12 (95% CI: 1.05-9.27, P = 0.041). According to the subgroup analysis for presence/absence of female factor, heterogeneity in the association between the Group A and B and PR emerged (OR: 4.22, 95% CI: 1.16-15.30 and OR: 1.53, 95% CI: 0.23-10.40, respectively, for couples without, n = 59, and with, n = 31, female factor).This study provides the first evidence that the DGC procedure produces an increase in sDF in about half of the subjects undergoing IVF/ICSI, who then show a much lower probability of pregnancy, raising concerns about the safety of this selection procedure. Evaluation of sDF before and after DGC configures as a possible new prognostic parameter of pregnancy outcome in IVF/ICSI. Alternative sperm selection strategies are recommended for those subjects who undergo the damage after DGC. PMID:27196465

  14. Diversity within the genus Elymus (Poaceae: Triticeae) as investigated by the analysis of the nr5S rDNA variation in species with St and H haplomes.

    Baum, B R; Edwards, T; Johnson, D A

    2015-02-01

    The genus Elymus ("Ryegrass") is a repository for a range of species with a variety of haplome contents; hence the pejorative name "dustbin" genus. We have analyzed 1,059 sequences from 128 accessions representing 24 species to investigate the relationships among the StH haplomes-containing species described by Yen and Yang (Genus Elymus Beijing 5:58-362, 2013). Sequences were assigned to "unit classes" of orthologous sequences and subjected to a suite of analyses including BLAST (Basic Local Alignment Search Tool) searches, phylogenetic analysis and population genetic analysis to estimate species diversity. Our results support the genome analyses in Yen and Yang (Genus Elymus Beijing 5:58-362, 2013), i.e., genomic constitution StStHH including variants restricted to Elymus. Population genetic analysis of the 5S nrDNA sequence data revealed that the within-species variance component is roughly ±89 %; thus, we were unable to identify molecular markers capable to separate the 24 species analyzed. Separate phylogenetic analyses of the two unit classes and of all the data exhibit a trend only of the species to cluster on the phylograms. Finally, the analysis provides evidence for the multiple origins of American and Eurasian species. PMID:25248636

  15. Phylogeography of an alpine plant (Bupleurum smithii, Apiaceae) endemic to the Qinghai-Tibetan Plateau and adjacent regions inferred from chloroplast DNA sequence variation

    Cai ZHAO; Xiang-Guang MA; Qian-Long LIANG; Chang-Bao WANG; Xing-Jin HE

    2013-01-01

    To obtain a better understanding of how Quaternary climatic oscillations influenced range distributions and intraspecific split of alpine plants on the Qinghai-Tibetan Plateau (QTP) and in adjacent regions,we investigated the extant phylogeographical structure of Bupleurum smithii in this area based on 22 populations and 103 individuals spanning the entire distribution region of this species using chloroplast DNA sequences.Two major haplotype lineages were identified,and at least two corresponding glacial refugia maintaining in the northeastern and eastern edge of the QTP during the Last Glacial Maximum were revealed.Secondary contact between populations and efficient gene flow were also found between two major haplotype lineages.In addition,based on the geographic distribution of haplotypes,we found that populations on the platform derived from individuals that recolonized this area from refugia situated at the northeastem and eastern edges of the QTP,and that B.smithii recolonized from southern to northern China during inter-and post-glacial periods.

  16. Indole acetic acid production by fluorescent Pseudomonas spp. from the rhizosphere of Plectranthus amboinicus (Lour.) Spreng. and their variation in extragenic repetitive DNA sequences.

    Sethia, Bedhya; Mustafa, Mariam; Manohar, Sneha; Patil, Savita V; Jayamohan, Nellickal Subramanian; Kumudini, Belur Satyan

    2015-06-01

    Fluorescent Pseudomonas (FP) is a heterogenous group of growth promoting rhizobacteria that regulate plant growth by releasing secondary metabolic compounds viz., indole acetic acid (IAA), siderophores, ammonia and hydrogen cyanide. In the present study, IAA producing FPs from the rhizosphere of Plectranthus amboinicus were characterized morphologically, biochemically and at the molecular level. Molecular identification of the isolates were carried out using Pseudomonas specific primers. The effect of varying time (24, 48, 72 and 96 h), Trp concentrations (100, 200, 300, 400 and 500 μg x ml(-1)), temperature (10, 26, 37 and 50 ± 2 degrees C) and pH (6, 7 and 8) on IAA production by 10 best isolates were studied. Results showed higher IAA production at 72 h incubation, at 300 μg x ml(-1) Trp concentration, temperature 26 ± 2 degrees C and pH 7. TLC with acidified ethyl acetate extract showed that the IAA produced has a similar Rf value to that of the standard IAA. Results of TLC were confirmed by HPLC analysis. Genetic diversity of the isolates was also studied using 40 RAPD and 4 Rep primers. Genetic diversity parameters such as dominance, Shannon index and Simpson index were calculated. Out of 40 RAPD primers tested, 9 (2 OP-D series and 7 OP-E series) were shortlisted for further analysis. Studies using RAPD, ERIC, BOX, REP and GTG5 primers revealed that isolates exhibit significant diversity in repetitive DNA sequences irrespective of the rhizosphere. PMID:26155673

  17. Influence of allelic Variations of hypoxia-related and DNA repair genes on patient outcome and toxicity in head and neck cancer treated with radiotherapy plus cetuximab.

    Muñoz, Carmen; Caballero, Miguel; Hakim, Sofia; Verger, Eugenia; Grau, Juan Jose

    2016-08-01

    Although cetuximab plus radiotherapy is a standard treatment for patients with inoperable head and neck squamous cell carcinoma (HNSCC), its efficacy varies greatly among individuals. To identify predictive markers of efficacy, we examined the effects of single nucleotide polymorphisms (SNPs) in hypoxia-related and DNA repair genes on the clinical outcome and occurrence of skin toxicity. We analyzed 61 consecutive patients with HNSCC for the presence of specific SNPs (HIF-1α, HIF-2α, HIF-1β, VHL, FIH-1, XRCC1, and XRCC5). The results were then correlated with time to progression (TTP), overall survival (OS), and toxicity (epithelitis, mucositis, and folliculitis). The median TTP and OS were better in patients with severe vs mild mucositis (17 vs 7 months, p = 0.03; and 26 vs 12 months, p = 0.016, respectively) and folliculitis (10 vs 7 months, p = 0.01, and 26 vs 10 months, p < 0.001, respectively). Patients with the HIF-1α CT/TT genotype had better OS than those with the wild-type HIF-1α CC genotype (28 vs 13 months, p = 0.035). Patients with the XRCC5 GG/AA genotype had longer TTP than patients with the XRCC5 AG genotype (11 vs 7 months, p = 0.035). Severe skin toxicity and SNPs of HIF-1α and XRCC5 were associated with different outcomes among patients treated with radiotherapy plus cetuximab. PMID:26245169

  18. Mitochondrial DNA suggests a single maternal origin for the widespread triploid parthenogenetic pest species, Paratanytarsus grimmii, but microsatellite variation shows local endemism

    Melissa Carew; Bryant Gagliardi; Ary A.Hoffmann

    2013-01-01

    Parthenogenesis is common among invasive pest species,with many parthenogenetic species also showing polyploidy.Parthenogenetic polyploid species often have multiple hybrid origins and the potential to rapidly spread over vast geographical areas.In this study,we examine patterns of mitochondrial and microsatellite variation in a widespread triploid parthenogenetic chironomid pest species,Paratanytarsus grimmii.Based on samples from five countries,including Australia,England,Germany,Japan,and Canada,we found extremely low mitochondrial diversity (< 0.14%),with most individuals sharing a common and widespread haplotype.In contrast,microsatellite diversity revealed 41 clonal variants,which were regionally endemic.These findings suggest a single invasive maternal lineage of P.grimmii is likely to have recently spread over a broad geographical range.High levels of genotypic endemism suggest P.grimmii populations have remained relatively isolated after an initial spread,with little ongoing migration.This,in part,can be attributed to rapid genetic differentiation via mutations of common clonal genotypes after P.grimmii spread,but multiple polyploidization and subsequent founder events are also likely to be contributing factors.

  19. Repetitive DNA and Plant Domestication: Variation in Copy Number and Proximity to Genes of LTR-Retrotransposons among Wild and Cultivated Sunflower (Helianthus annuus) Genotypes.

    Mascagni, Flavia; Barghini, Elena; Giordani, Tommaso; Rieseberg, Loren H; Cavallini, Andrea; Natali, Lucia

    2015-12-01

    The sunflower (Helianthus annuus) genome contains a very large proportion of transposable elements, especially long terminal repeat retrotransposons. However, knowledge on the retrotransposon-related variability within this species is still limited. We used next-generation sequencing (NGS) technologies to perform a quantitative and qualitative survey of intraspecific variation of the retrotransposon fraction of the genome across 15 genotypes--7 wild accessions and 8 cultivars--of H. annuus. By mapping the Illumina reads of the 15 genotypes onto a library of sunflower long terminal repeat retrotransposons, we observed considerable variability in redundancy among genotypes, at both superfamily and family levels. In another analysis, we mapped Illumina paired reads to two sets of sequences, that is, long terminal repeat retrotransposons and protein-encoding sequences, and evaluated the extent of retrotransposon proximity to genes in the sunflower genome by counting the number of paired reads in which one read mapped to a retrotransposon and the other to a gene. Large variability among genotypes was also ascertained for retrotransposon proximity to genes. Both long terminal repeat retrotransposon redundancy and proximity to genes varied among retrotransposon families and also between cultivated and wild genotypes. Such differences are discussed in relation to the possible role of long terminal repeat retrotransposons in the domestication of sunflower. PMID:26608057

  20. Parkinson's disease and mitochondrial gene variations

    Andalib, Sasan; Vafaee, Manouchehr Seyedi; Gjedde, Albert

    2014-01-01

    Parkinson's disease (PD) is a common disorder of the central nervous system in the elderly. The pathogenesis of PD is a complex process, with genetics as an important contributing factor. This factor may stem from mitochondrial gene variations and mutations as well as from nuclear gene variations...... and mutations. More recently, a particular role of mitochondrial dysfunction has been suggested, arising from mitochondrial DNA variations or acquired mutations in PD pathogenesis. The present review summarizes and weighs the evidence in support of mitochondrial DNA (mtDNA) variations as important...

  1. DNA Book

    Kawai, Jun; Hayashizaki, Yoshihide

    2003-01-01

    We propose herein a new method of DNA distribution, whereby DNA clones or PCR products are printed directly onto the pages of books and delivered to users along with relevant scientific information. DNA sheets, comprising water-soluble paper onto which DNA is spotted, can be bound into books. Readers can easily extract the DNA fragments from DNA sheets and amplify them using PCR. We show that DNA sheets can withstand various conditions that may be experienced during bookbinding and deli...

  2. Cleaving DNA with DNA

    Carmi, Nir; Balkhi, Shameelah R.; Breaker, Ronald R.

    1998-03-01

    A DNA structure is described that can cleave single-stranded DNA oligonucleotides in the presence of ionic copper. This ``deoxyribozyme'' can self-cleave or can operate as a bimolecular complex that simultaneously makes use of duplex and triplex interactions to bind and cleave separate DNA substrates. Bimolecular deoxyribozyme-mediated strand scission proceeds with a kobs of 0.2 min-1, whereas the corresponding uncatalyzed reaction could not be detected. The duplex and triplex recognition domains can be altered, making possible the targeted cleavage of single-stranded DNAs with different nucleotide sequences. Several small synthetic DNAs were made to function as simple ``restriction enzymes'' for the site-specific cleavage of single-stranded DNA.

  3. DNA Probes Show Genetic Variation in Cyanobacterial Symbionts of the Azolla Fern and a Closer Relationship to Free-Living Nostoc Strains than to Free-Living Anabaena Strains

    Plazinski, Jacek; Zheng, Qi; Taylor, Rona; Croft, Lynn; Rolfe, Barry G.; Gunning, Brian E. S.

    1990-01-01

    Twenty-two isolates of Anabaena azollae derived from seven Azolla species from various geographic and ecological sources were characterized by DNA-DNA hybridization. Cloned DNA fragments derived from the genomic sequences of three different A. azollae isolates were used to detect restriction fragment length polymorphism among all symbiotic anabaenas. DNA clones were radiolabeled and hybridized against southern blot transfers of genomic DNAs of different isolates of A. azollae digested with re...

  4. Ser1369Ala Variant in Sulfonylurea Receptor Gene ABCC8 Is Associated With Antidiabetic Efficacy of Gliclazide in Chinese Type 2 Diabetic Patients

    Feng, Yan; Mao, Guangyun; Ren, Xiaowei; Xing, Houxun; Tang, Genfu; Li, Qiang; Li, Xueqi; SUN, LIRONG; Yang, Jinqui; Ma, Weiqing; Wang, Xiaobin; Xu, Xiping

    2008-01-01

    OBJECTIVE—The purpose of this study was to investigate whether genetic variants could influence the antidiabetic efficacy of gliclazide in type 2 diabetic patients. RESEARCH DESIGN AND METHODS—A total of 1,268 type 2 diabetic patients whose diabetes was diagnosed within the past 5 years and who had no recent hypoglycemic treatment were enrolled from 23 hospitals in China. All of the patients were treated with gliclazide for 8 weeks. Fasting and oral glucose tolerance test 2-h plasma glucose, ...

  5. Common DNA sequence variation and psychiatric disease

    Ripke, S

    2014-01-01

    In a genome-wide association study (GWAS), a large number of SNPs are genotyped in a large number of cases (with disease) and controls (without disease) using commercially available high-throughput genotyping platforms. In a GWAS, the genotype data collected in cases and unaffected, population-matched controls are compared. Other than identifying individuals with the disease, there is no requirement for prior biological knowledge of the trait under investigation. This analysis approach has di...

  6. DNA supercoiling inhibits DNA knotting.

    Burnier Y.; Dorier J.; Stasiak A.

    2008-01-01

    Despite the fact that in living cells DNA molecules are long and highly crowded, they are rarely knotted. DNA knotting interferes with the normal functioning of the DNA and, therefore, molecular mechanisms evolved that maintain the knotting and catenation level below that which would be achieved if the DNA segments could pass randomly through each other. Biochemical experiments with torsionally relaxed DNA demonstrated earlier that type II DNA topoisomerases that permit inter- and intramolecu...

  7. DNA vaccines

    Coban, Cevayir; Kobiyama, Kouji; Jounai, Nao; Tozuka, Miyuki; Ishii, Ken J.

    2013-01-01

    Since the introduction of DNA vaccines two decades ago, this attractive strategy has been hampered by its low immunogenicity in humans. Studies conducted to improve the immunogenicity of DNA vaccines have shown that understanding the mechanism of action of DNA vaccines might be the key to successfully improving their immunogenicity. Our current understanding is that DNA vaccines induce innate and adaptive immune responses in two ways: (1) encoded protein (or polypeptide) antigen(s) by the DNA...

  8. Mitochondrial DNA Evolution in Mice

    Ferris, Stephen D.; Sage, Richard D.; Prager, Ellen M.; Ritte, Uzi; Wilson, Allan C.

    1983-01-01

    This study extends knowledge of mitochondrial DNA (mtDNA) diversity in mice to include 208 animals belonging to eight species in the subgenus Mus. Highly purified mtDNA from each has been subjected to high-resolution restriction mapping with respect to the known sequence of one mouse mtDNA. Variation attributed to base substitutions was encountered at about 200 of the 300 cleavage sites examined, and a length mutation was located in or near the displacement loop. The variability of different ...

  9. Variational MCMC

    De Freitas, Nando; Hojen-Sorensen, Pedro; Jordan, Michael I.; Russell, Stuart

    2013-01-01

    We propose a new class of learning algorithms that combines variational approximation and Markov chain Monte Carlo (MCMC) simulation. Naive algorithms that use the variational approximation as proposal distribution can perform poorly because this approximation tends to underestimate the true variance and other features of the data. We solve this problem by introducing more sophisticated MCMC algorithms. One of these algorithms is a mixture of two MCMC kernels: a random walk Metropolis kernel ...

  10. FROG - Fingerprinting Genomic Variation Ontology.

    E Abinaya

    Full Text Available Genetic variations play a crucial role in differential phenotypic outcomes. Given the complexity in establishing this correlation and the enormous data available today, it is imperative to design machine-readable, efficient methods to store, label, search and analyze this data. A semantic approach, FROG: "FingeRprinting Ontology of Genomic variations" is implemented to label variation data, based on its location, function and interactions. FROG has six levels to describe the variation annotation, namely, chromosome, DNA, RNA, protein, variations and interactions. Each level is a conceptual aggregation of logically connected attributes each of which comprises of various properties for the variant. For example, in chromosome level, one of the attributes is location of variation and which has two properties, allosomes or autosomes. Another attribute is variation kind which has four properties, namely, indel, deletion, insertion, substitution. Likewise, there are 48 attributes and 278 properties to capture the variation annotation across six levels. Each property is then assigned a bit score which in turn leads to generation of a binary fingerprint based on the combination of these properties (mostly taken from existing variation ontologies. FROG is a novel and unique method designed for the purpose of labeling the entire variation data generated till date for efficient storage, search and analysis. A web-based platform is designed as a test case for users to navigate sample datasets and generate fingerprints. The platform is available at http://ab-openlab.csir.res.in/frog.

  11. DNA Methylation

    Alokail, Majed S.; Alenad, Amal M

    2015-01-01

    The DNA of E. coli contains 19,120 6-methyladenines and 12,045 5-methylcytosines in addition to the four regular bases and these are formed by the postreplicative action of three DNA methyltransferases. The majority of the methylated bases are formed by the Dam and Dcm methyltransferases encoded by the dam (DNA adenine methyltransferase) and dcm (DNA cytosine methyltransferase) genes. Although not essential, Dam methylation is important for strand discrimination during repair of replication e...

  12. DNA looping.

    Matthews, K S

    1992-01-01

    DNA-looping mechanisms are part of networks that regulate all aspects of DNA metabolism, including transcription, replication, and recombination. DNA looping is involved in regulation of transcriptional initiation in prokaryotic operons, including ara, gal, lac, and deo, and in phage systems. Similarly, in eukaryotic organisms, the effects of enhancers appear to be mediated at least in part by loop formation, and examples of DNA looping by hormone receptor proteins and developmental regulator...

  13. DNA structure

    Bowater, R

    2003-01-01

    Deoxyribonucleic acid (DNA) is a polymer of nucleotides. In the cell, DNA usually adopts a double-stranded helical form, with complementary base-pairing holding the two strands together. The most stable conformation is called B-form DNA, although other structures can occur under specific conditions.

  14. Variational analysis

    Rockafellar, R Tyrrell

    1998-01-01

    From its origins in the minimization of integral functionals, the notion of 'variations' has evolved greatly in connection with applications in optimization, equilibrium, and control. It refers not only to constrained movement away from a point, but also to modes of perturbation and approximation that are best describable by 'set convergence', variational convergence of functions and the like. This book develops a unified framework and, in finite dimension, provides a detailed exposition of variational geometry and subdifferential calculus in their current forms beyond classical and convex analysis. Also covered are set-convergence, set-valued mappings, epi-convergence, duality, maximal monotone mappings, second-order subderivatives, measurable selections and normal integrands. The changes in this 3rd printing mainly concern various typographical corrections, and reference omissions that came to light in the previous printings. Many of these reached the authors' notice through their own re-reading, that of th...

  15. Variational principles

    Moiseiwitsch, B L

    2004-01-01

    This graduate-level text's primary objective is to demonstrate the expression of the equations of the various branches of mathematical physics in the succinct and elegant form of variational principles (and thereby illuminate their interrelationship). Its related intentions are to show how variational principles may be employed to determine the discrete eigenvalues for stationary state problems and to illustrate how to find the values of quantities (such as the phase shifts) that arise in the theory of scattering. Chapter-by-chapter treatment consists of analytical dynamics; optics, wave mecha

  16. Heritable epigenetic variation among maize inbreds.

    Steve R Eichten

    2011-11-01

    Full Text Available Epigenetic variation describes heritable differences that are not attributable to changes in DNA sequence. There is the potential for pure epigenetic variation that occurs in the absence of any genetic change or for more complex situations that involve both genetic and epigenetic differences. Methylation of cytosine residues provides one mechanism for the inheritance of epigenetic information. A genome-wide profiling of DNA methylation in two different genotypes of Zea mays (ssp. mays, an organism with a complex genome of interspersed genes and repetitive elements, allowed the identification and characterization of examples of natural epigenetic variation. The distribution of DNA methylation was profiled using immunoprecipitation of methylated DNA followed by hybridization to a high-density tiling microarray. The comparison of the DNA methylation levels in the two genotypes, B73 and Mo17, allowed for the identification of approximately 700 differentially methylated regions (DMRs. Several of these DMRs occur in genomic regions that are apparently identical by descent in B73 and Mo17 suggesting that they may be examples of pure epigenetic variation. The methylation levels of the DMRs were further studied in a panel of near-isogenic lines to evaluate the stable inheritance of the methylation levels and to assess the contribution of cis- and trans- acting information to natural epigenetic variation. The majority of DMRs that occur in genomic regions without genetic variation are controlled by cis-acting differences and exhibit relatively stable inheritance. This study provides evidence for naturally occurring epigenetic variation in maize, including examples of pure epigenetic variation that is not conditioned by genetic differences. The epigenetic differences are variable within maize populations and exhibit relatively stable trans-generational inheritance. The detected examples of epigenetic variation, including some without tightly linked genetic

  17. Human DNA ligase III recognizes DNA ends by dynamic switching between two DNA-bound states.

    Cotner-Gohara, Elizabeth; Kim, In-Kwon; Hammel, Michal; Tainer, John A; Tomkinson, Alan E; Ellenberger, Tom

    2010-07-27

    Human DNA ligase III has essential functions in nuclear and mitochondrial DNA replication and repair and contains a PARP-like zinc finger (ZnF) that increases the extent of DNA nick joining and intermolecular DNA ligation, yet the bases for ligase III specificity and structural variation among human ligases are not understood. Here combined crystal structure and small-angle X-ray scattering results reveal dynamic switching between two nick-binding components of ligase III: the ZnF-DNA binding domain (DBD) forms a crescent-shaped surface used for DNA end recognition which switches to a ring formed by the nucleotidyl transferase (NTase) and OB-fold (OBD) domains for catalysis. Structural and mutational analyses indicate that high flexibility and distinct DNA binding domain features in ligase III assist both nick sensing and the transition from nick sensing by the ZnF to nick joining by the catalytic core. The collective results support a "jackknife model" in which the ZnF loads ligase III onto nicked DNA and conformational changes deliver DNA into the active site. This work has implications for the biological specificity of DNA ligases and functions of PARP-like zinc fingers. PMID:20518483

  18. DNA Immunization

    Wang, Shixia; Lu, Shan

    2013-01-01

    DNA immunization was discovered in early 1990s and its use has been expanded from vaccine studies to a broader range of biomedical research, such as the generation of high quality polyclonal and monoclonal antibodies as research reagents. In this unit, three common DNA immunization methods are described: needle injection, electroporation and gene gun. In addition, several common considerations related to DNA immunization are discussed.

  19. DNA deoxyribophosphodiesterase.

    Franklin, W A; Lindahl, T

    1988-01-01

    A previously unrecognized enzyme acting on damaged termini in DNA is present in Escherichia coli. The enzyme catalyses the hydrolytic release of 2-deoxyribose-5-phosphate from single-strand interruptions in DNA with a base-free residue on the 5' side. The partly purified protein appears to be free from endonuclease activity for apurinic/apyrimidinic sites, exonuclease activity and DNA 5'-phosphatase activity. The enzyme has a mol. wt of approximately 50,000-55,000 and has been termed DNA deox...

  20. Programmable Quantitative DNA Nanothermometers.

    Gareau, David; Desrosiers, Arnaud; Vallée-Bélisle, Alexis

    2016-07-13

    Developing molecules, switches, probes or nanomaterials that are able to respond to specific temperature changes should prove of utility for several applications in nanotechnology. Here, we describe bioinspired strategies to design DNA thermoswitches with programmable linear response ranges that can provide either a precise ultrasensitive response over a desired, small temperature interval (±0.05 °C) or an extended linear response over a wide temperature range (e.g., from 25 to 90 °C). Using structural modifications or inexpensive DNA stabilizers, we show that we can tune the transition midpoints of DNA thermometers from 30 to 85 °C. Using multimeric switch architectures, we are able to create ultrasensitive thermometers that display large quantitative fluorescence gains within small temperature variation (e.g., > 700% over 10 °C). Using a combination of thermoswitches of different stabilities or a mix of stabilizers of various strengths, we can create extended thermometers that respond linearly up to 50 °C in temperature range. Here, we demonstrate the reversibility, robustness, and efficiency of these programmable DNA thermometers by monitoring temperature change inside individual wells during polymerase chain reactions. We discuss the potential applications of these programmable DNA thermoswitches in various nanotechnology fields including cell imaging, nanofluidics, nanomedecine, nanoelectronics, nanomaterial, and synthetic biology. PMID:27058370

  1. Cleaving DNA with DNA

    Carmi, Nir; Balkhi, Shameelah R.; Breaker, Ronald R.

    1998-01-01

    A DNA structure is described that can cleave single-stranded DNA oligonucleotides in the presence of ionic copper. This “deoxyribozyme” can self-cleave or can operate as a bimolecular complex that simultaneously makes use of duplex and triplex interactions to bind and cleave separate DNA substrates. Bimolecular deoxyribozyme-mediated strand scission proceeds with a kobs of 0.2 min−1, whereas the corresponding uncatalyzed reaction could not be detected. The duplex and triplex recognition domai...

  2. DNA glue

    Filichev, Vyacheslav V; Astakhova, Irina V.; Malakhov, Andrei D.;

    2008-01-01

    Significant alterations in thermal stability of parallel DNA triplexes and antiparallel duplexes were observed upon changing the attachment of ethynylpyrenes from para to ortho in the structure of phenylmethylglycerol inserted as a bulge into DNA (TINA). Insertions of two ortho-TINAs as a pseudo...

  3. Human mitochondrial DNA (mtDNA) types in Malaysia

    Each human cell contains hundreds of mitochondria and thousands of double-stranded circular mtDNA. The delineation of human mtDNA variation and genetics over the past decade has provided unique and often startling insights into human evolution, degenerative diseases, and aging. Each mtDNA of 16,569 base pairs, encodes 13 polypeptides essential to the enzymes of the mitochondrial energy generating pathway, plus the necessary tRNAs and rRNAs. The highly polymorphic noncoding D-(displacement) loop region, also called the control region, is approximately 1.2 kb long. It contains two well-characterized hypervariable (HV-) regions, HV1 and HV2. MtDNA identification is usually based on these sequence differences. According to the TWTGDAM (Technical Working Group for DNA Analysis Methods), the minimum requirement for a mtDNA database for HV1 is from positions 16024 to 16365 and for HV2, from positions 00073 to 00340. The targeted Malaysian population subgroups for this study were mainly the Malays, Chinese, Indians, and indigenous Ibans, Bidayuhs, Kadazan-Dusuns, and Bajaus. Research methodologies undertaken included DNA extraction of samples from unrelated individuals, amplification of the specific regions via the polymerase chain reaction (PCR), and preparation of template DNA for sequencing by using an automated DNA sequencer. Sufficient nucleotide sequence data were generated from the mtDNA analysis. When the sequences were analyzed, sequence variations were found to be caused by nucleotide substitutions, insertions, and deletions. Of the three causes of the sequence variations, nucleotide substitutions (86.1%) accounted for the vast majority of polymorphism. It is noted that transitions (83.5%) were predominant when compared to the significantly lower frequencies of transversions (2.6%). Insertions (0.9%) and deletions (13.0%) were rather rare and found only in HV2. The data generated will also form the basis of a Malaysian DNA sequence database of mtDNA D

  4. DNA probes

    The creation of DNA probes for detection of specific nucleotide segments differs from ligand detection in that it is a chemical rather than an immunological reaction. Complementary DNA or RNA is used in place of the antibody and is labelled with 32P. So far, DNA probes have been successfully employed in the diagnosis of inherited disorders, infectious diseases, and for identification of human oncogenes. The latest approach to the diagnosis of communicable and parasitic infections is based on the use of deoxyribonucleic acid (DNA) probes. The genetic information of all cells is encoded by DNA and DNA probe approach to identification of pathogens is unique because the focus of the method is the nucleic acid content of the organism rather than the products that the nucleic acid encodes. Since every properly classified species has some unique nucleotide sequences that distinguish it from every other species, each organism's genetic composition is in essence a finger print that can be used for its identification. In addition to this specificity, DNA probes offer other advantages in that pathogens may be identified directly in clinical specimens

  5. [DNA computing].

    Błasiak, Janusz; Krasiński, Tadeusz; Popławski, Tomasz; Sakowski, Sebastian

    2011-01-01

    Biocomputers can be an alternative for traditional "silicon-based" computers, which continuous development may be limited due to further miniaturization (imposed by the Heisenberg Uncertainty Principle) and increasing the amount of information between the central processing unit and the main memory (von Neuman bottleneck). The idea of DNA computing came true for the first time in 1994, when Adleman solved the Hamiltonian Path Problem using short DNA oligomers and DNA ligase. In the early 2000s a series of biocomputer models was presented with a seminal work of Shapiro and his colleguas who presented molecular 2 state finite automaton, in which the restriction enzyme, FokI, constituted hardware and short DNA oligomers were software as well as input/output signals. DNA molecules provided also energy for this machine. DNA computing can be exploited in many applications, from study on the gene expression pattern to diagnosis and therapy of cancer. The idea of DNA computing is still in progress in research both in vitro and in vivo and at least promising results of these research allow to have a hope for a breakthrough in the computer science. PMID:21735816

  6. DNA methylation

    Williams, Kristine; Christensen, Jesper; Helin, Kristian

    2012-01-01

    DNA methylation is involved in key cellular processes, including X-chromosome inactivation, imprinting and transcriptional silencing of specific genes and repetitive elements. DNA methylation patterns are frequently perturbed in human diseases such as imprinting disorders and cancer. The recent...... discovery that the three members of the TET protein family can convert 5-methylcytosine (5mC) into 5-hydroxymethylcytosine (5hmC) has provided a potential mechanism leading to DNA demethylation. Moreover, the demonstration that TET2 is frequently mutated in haematopoietic tumours suggests that the TET...... proteins are important regulators of cellular identity. Here, we review the current knowledge regarding the function of the TET proteins, and discuss various mechanisms by which they contribute to transcriptional control. We propose that the TET proteins have an important role in regulating DNA methylation...

  7. DNA data

    National Oceanic and Atmospheric Administration, Department of Commerce — Raw DNA chromatogram data produced by the ABI 373, 377, 3130 and 3730 automated sequencing machines in ABI format. These are from fish (primarily Sebastes spp.,...

  8. Ancient DNA

    Willerslev, Eske; Cooper, Alan

    2004-01-01

    In the past two decades, ancient DNA research has progressed from the retrieval of small fragments of mitochondrial DNA from a few late Holocene specimens, to large-scale studies of ancient populations, phenotypically important nuclear loci, and even whole mitochondrial genome sequences of extinct species. However, the field is still regularly marred by erroneous reports, which underestimate the extent of contamination within laboratories and samples themselves. An improved understanding of t...

  9. DNA Photolyasen

    Maul, Melanie

    2009-01-01

    Neben der fehlerfreien Weitergabe der genetischen Information während der Zellteilung durch einen intakten Replikationsapparat, ist auch die Aufrechterhaltung der genetischen Integrität der DNA durch Reparaturenzyme entscheidend für das Überleben der Zellen, sowie für einen gesunden Organismus. Um die genomische Integrität zu wahren, entwickelten sich im Laufe der Evolution verschiedene Mechanismen, u.a. die Exzisionreparatur von geschädigter DNA oder die direkte chemische R...

  10. DNA damage

    Kumari, Sunita; Rastogi, Rajesh P.; Singh, Kanchan L.; Singh, Shailendra P; Sinha, Rajeshwar P.

    2008-01-01

    Even under the best of circumstances, DNA is constantly subjected to chemical modifications. Several types of DNA damage such as SSB (single strand break), DSB (double strand break), CPDs (cyclobutane pyrimidine dimers), 6-4PPs (6-4 photoproducts) and their Dewar valence isomers have been identified that result from alkylating agents, hydrolytic deamination, free radicals and reactive oxygen species formed by various photochemical processes including UV radiation. There are a n...

  11. DNA expressions - A formal notation for DNA

    Vliet, Rudy van

    2015-01-01

    We describe a formal notation for DNA molecules that may contain nicks and gaps. The resulting DNA expressions denote formal DNA molecules. Different DNA expressions may denote the same molecule. Such DNA expressions are called equivalent. We examine which DNA expressions are minimal, which

  12. Fleet DNA (Presentation)

    Walkokwicz, K.; Duran, A.

    2014-06-01

    The Fleet DNA project objectives include capturing and quantifying drive cycle and technology variation for the multitude of medium- and heavy-duty vocations; providing a common data storage warehouse for medium- and heavy-duty vehicle fleet data across DOE activities and laboratories; and integrating existing DOE tools, models, and analyses to provide data-driven decision making capabilities. Fleet DNA advantages include: for Government - providing in-use data for standard drive cycle development, R&D, tech targets, and rule making; for OEMs - real-world usage datasets provide concrete examples of customer use profiles; for fleets - vocational datasets help illustrate how to maximize return on technology investments; for Funding Agencies - ways are revealed to optimize the impact of financial incentive offers; and for researchers -a data source is provided for modeling and simulation.

  13. What Is Mitochondrial DNA?

    ... DNA What is mitochondrial DNA? What is mitochondrial DNA? Although most DNA is packaged in chromosomes within ... proteins. For more information about mitochondria and mitochondrial DNA: Molecular Expressions, a web site from the Florida ...

  14. DNA and RNA sensor

    LIU; Tao; LIN; Lin; ZHAO; Hong; JIANG; Long

    2005-01-01

    This review summarizes recent advances in DNA sensor. Major areas of DNA sensor covered in this review include immobilization methods of DNA, general techniques of DNA detection and application of nanoparticles in DNA sensor.

  15. DNA-repair gene variants are associated with glioblastoma survival

    Wibom, Carl; Sjöström, Sara; Henriksson, Roger;

    2012-01-01

    Abstract Patient outcome from glioma may be influenced by germline variation. Considering the importance of DNA repair in cancer biology as well as in response to treatment, we studied the relationship between 1458 SNPs, which captured the majority of the common genetic variation in 136 DNA repair...

  16. Genetic variation between susceptible and non-susceptible snails to Schistosoma infection using random amplified polymorphic DNA analysis (RAPDs Variação genética entre moluscos susceptíveis e não susceptíveis à infecção pelo Schistosoma através da análise do DNA polimórfico amplificado aleatóriamente (RAPDs

    Abdel-Hamid Zaki ABDEL-HAMID

    1999-09-01

    Full Text Available Susceptibility of snails to infection by certain trematodes and their suitability as hosts for continued development has been a bewildering problem in host-parasite relationships. The present work emphasizes our interest in snail genetics to determine what genes or gene products are specifically responsible for susceptibility of snails to infection. High molecular weight DNA was extracted from both susceptible and non-susceptible snails within the same species Biomphalaria tenagophila. RAPD was undertaken to distinguish between the two types of snails. Random primers (10 mers were used to amplify the extracted DNA by the polymerase chain reaction (PCR followed by polyacrylamide gel electrophoresis (PAGE and silver staining. The results suggest that RAPD represents an efficient means of genome comparison, since many molecular markers were detected as genetic variations between susceptible and non-susceptible snails.A susceptibilidade de moluscos à infecção por certos trematódeos e a sua capacidade como hospedeiro para o contínuo desenvolvimento é o problema mais deslumbrante nas relações parasita hospedeiro. O presente trabalho, focaliza nosso interesse na genética dos moluscos para determinar quais genes ou produtos gênicos são especificamente responsáveis pela susceptibilidade do molusco à infecção. DNA de alto peso molecular, foi extraído de ambos moluscos susceptíveis e não susceptíveis da espécie Biomphalaria tenagophila. Iniciadores aleatórios com 10 pares de bases foram usados na amplificação aleatória (RAPD de ambos os DNAs e análise por eletroforese em gel de poliacrilamida e coloração com prata. Os resultados mostram que a amplificação aleatória do DNA representa um eficiente caminho para a comparação dos genomas desde que marcadores moleculares foram detectados como variantes genéticos entre os moluscos susceptíveis e não susceptíveis.

  17. Analysis of chromatin integrity and DNA damage of buffalo spermatozoa.

    Mahmoud, K Gh M; El-Sokary, A A E; Abdel-Ghaffar, A E; Abou El-Roos, M E A; Ahmed, Y F

    2015-01-01

    This study was conducted to determine chromatin integrity and DNA damage by DNA electrophoresis and comet assays of buffalo fresh and frozen semen. Semen samples were collected from four buffalo bulls and evaluated after freezing for semen motility, viability, sperm abnormalities, chromatin integrity and DNA damage. A significant variation was found in semen parameters after thawing. Highly significant differences (Partificial insemination. PMID:27175169

  18. DNA nanotechnology

    Nadrian C Seeman

    2003-01-01

    We are all aware that the DNA found in cells is a double helix consisting of two antiparallel strands held together by specific hydrogen-bonded base pairs; adenine (A always pairs with thymine (T, and guanine (G always pairs with cytosine (C. The specificity of this base pairing and the ability to ensure that it occurs in this fashion (and not some other1 is key to the use of DNA in materials applications. The double helical arrangement of the two molecules leads to a linear helix axis, linear not in the geometrical sense of being a straight line, but in the topological sense of being unbranched. Genetic engineers discovered in the 1970s how to splice together pieces of DNA to add new genes to DNA molecules2, and synthetic chemists worked out convenient syntheses for short pieces of DNA (up to ∼100–150 units in the 1980s3. Regardless of the impact of these technologies on biological systems, hooking together linear molecules leads only to longer linear molecules, with circles, knots, and catenanes perhaps resulting from time to time.

  19. DNA nanotechnology

    Seeman, Nadrian C.

    2003-01-01

    Since Watson and Crick’s determination of its structure nearly 50 years ago, DNA has come to fill our lives in many areas, from genetic counseling to forensics, from genomics to gene therapy. These, and other ways in which DNA affects human activities, are related to its function as genetic material, not just our genetic material, but the genetic material of all living organisms. Here, we will ignore DNA’s biological role; rather, we will discuss how the properties that make it so successful ...

  20. Modeling inhomogeneous DNA replication kinetics.

    Michel G Gauthier

    Full Text Available In eukaryotic organisms, DNA replication is initiated at a series of chromosomal locations called origins, where replication forks are assembled proceeding bidirectionally to replicate the genome. The distribution and firing rate of these origins, in conjunction with the velocity at which forks progress, dictate the program of the replication process. Previous attempts at modeling DNA replication in eukaryotes have focused on cases where the firing rate and the velocity of replication forks are homogeneous, or uniform, across the genome. However, it is now known that there are large variations in origin activity along the genome and variations in fork velocities can also take place. Here, we generalize previous approaches to modeling replication, to allow for arbitrary spatial variation of initiation rates and fork velocities. We derive rate equations for left- and right-moving forks and for replication probability over time that can be solved numerically to obtain the mean-field replication program. This method accurately reproduces the results of DNA replication simulation. We also successfully adapted our approach to the inverse problem of fitting measurements of DNA replication performed on single DNA molecules. Since such measurements are performed on specified portion of the genome, the examined DNA molecules may be replicated by forks that originate either within the studied molecule or outside of it. This problem was solved by using an effective flux of incoming replication forks at the model boundaries to represent the origin activity outside the studied region. Using this approach, we show that reliable inferences can be made about the replication of specific portions of the genome even if the amount of data that can be obtained from single-molecule experiments is generally limited.

  1. Synthetic DNA

    O’ Driscoll, Aisling; Sleator, Roy D.

    2013-01-01

    With world wide data predicted to exceed 40 trillion gigabytes by 2020, big data storage is a very real and escalating problem. Herein, we discuss the utility of synthetic DNA as a robust and eco-friendly archival data storage solution of the future.

  2. DNA Investigations.

    Mayo, Ellen S.; Bertino, Anthony J.

    1991-01-01

    Presents a simulation activity that allow students to work through the exercise of DNA profiling and to grapple with some analytical and ethical questions involving a couple arranging with a surrogate mother to have a baby. Can be used to teach the principles of restriction enzyme digestion, gel electrophoresis, and probe hybridization. (MDH)

  3. Genetic Variation of Host Populations of Liriomyza sativae Blanchard

    WANG Li-ping; DU Yu-zhou; HE Ya-ting; ZHENG Fu-shan; LU Zi-qiang

    2008-01-01

    In this study, partial sequences of the mitochondrial cytochrome oxidase subunit Ⅰ (mtDNA-COI) gene and the ribosomal internal transcribed spacer 1 (rDNA-ITS1) gene, isolated from five artificial populations of Liriomyza sativae (Diptera:Agromyzidae), were sequenced and compared, to analyze their genetic variation. Analysis of the mtDNA-CO1 gene showed that a low genetic variation was detected among the five populations and only five variable sites were found in the nucleotide sequences. Most of the observed variations that occurred within the populations were because of nucleotide transitions, whereas, the interpopulation variation was because of the differences in haplotype frequencies occurring among the host populations. Analysis of the rDNA-ITS1 gene revealed a small diversity in the five host populations. The trend of genetic differentiation in the host populations was consistent with the preference of L. sativae to the plant hosts.

  4. Individual epigenetic variation: When, why, and so what?

    Epigenetics provides a potential explanation for how environmental factors modify the risk for common diseases among individuals. Interindividual variation in DNA methylation and epigenetic regulation has been reported at specific genomic regions including transposable elements, genomically imprinte...

  5. African Mitochondrial DNA Subhaplogroups and Peripheral Neuropathy during Antiretroviral Therapy

    Canter, Jeffrey A.; Robbins, Gregory K.; Selph, Doug; Clifford, David B.; Kallianpur, Asha R.; Shafer, Robert; Levy, Shawn; Murdock, Deborah G.; Ritchie, Marylyn D.; Haas, David W.; Hulgan, Todd

    2010-01-01

    Susceptibility to peripheral neuropathy during antiretroviral therapy with nucleoside reverse transcriptase inhibitors (NRTIs) was previously associated with a European mitochondrial DNA (mtDNA) haplogroup among non-Hispanic white persons. To determine if NRTI-associated peripheral neuropathy was related to mtDNA variation in non-Hispanic black persons, we sequenced mtDNA of participants from AIDS Clinical Trials Group study 384. Of 156 non-Hispanic blacks with genomic data, 51 (33%) develope...

  6. Analysis diagnosis and clinical study of simple mitochondria DNA variations in type 2 diabetes mellitus%单纯线粒体DNA变异的2型糖尿病的检验诊断和临床研究

    郦卫星; 吕建新

    2007-01-01

    目的 分析线粒体DNA(mitochondria DNA,mtDNA)变异与2型糖尿病(T2DM)及其并发症的关系,探讨mtDNA检测对于T2DM的诊断价值.方法 采用PCR产物直接测序法对浙江籍汉族人群中无血缘关系的315例T2DM患者及158名正常对照个体的mtDNA片段(nt3153~nt3551)进行分析,同时对每例患者作常规生化检测.结果 T2DM患者组和健康对照组与标准序列比对存在着大量的基因变异位点,具有中国汉族人的多态性.把患者检测到的变异位点结合临床资料分析发现T3183A、A3243G、T3290C、T3338C、T3398C、G3421A、C3435T等基因变异与糖尿病家族史或并发症有密切联系.比较有家族史和无家族史的有基因变异的T2DM患者,有家族史组发病年龄较无家族史组明显提前[(47.7±11.1)岁与(55.1±13.8)岁,t=2.489,P<0.05],有家族史组的体重指数(BMI)显著低于无家族史组[(20.59±5.16)kg/m2与(23.82±2.32)kg/m2,t=3.234,P<0.01],差异有统计学意义;而两组的甘油三酯(TG)[(1.32±0.60)mmol/L与(1.33±0.68)mmol/L,t=0.071,P>0.05]、总胆固醇(TC)[(4.07±1.23)mmol/L与(4.13±0.72)mmol/L,t=0.277,P>0.05]、空腹血糖(FBG)[(9.27±2.52)mmol/L与(9.49±3.36)mmol/L,t=0.308,P>0.05]等差异无统计学意义.结论 中国汉族人mtDNA存在多态性,T2DM患者mtDNA中存在着大量的变异位点,尽管mtDNA变异位点与糖尿病特征、家族史或并发症有一定关系,但目前尚不能作为诊断T2DM的独立指标.

  7. DNA-modified Electrodes Fabricated using Copper-Free Click Chemistry for Enhanced Protein Detection

    Furst, Ariel L.; Hill, Michael G.; Barton, Jacqueline K.

    2013-01-01

    A method of DNA monolayer formation has been developed using copper-free click chemistry that yields enhanced surface homogeneity and enables variation in the amount of DNA assembled; extremely low-density DNA monolayers, with as little as 5% of the monolayer being DNA, have been formed. These DNA-modified electrodes (DMEs) were characterized visually, with AFM, and electrochemically, and were found to facilitate DNA-mediated reduction of a distally bound redox probe. These low-density monola...

  8. DNA Repair by Reversal of DNA Damage

    Yi, Chengqi; He, Chuan

    2013-01-01

    Endogenous and exogenous factors constantly challenge cellular DNA, generating cytotoxic and/or mutagenic DNA adducts. As a result, organisms have evolved different mechanisms to defend against the deleterious effects of DNA damage. Among these diverse repair pathways, direct DNA-repair systems provide cells with simple yet efficient solutions to reverse covalent DNA adducts. In this review, we focus on recent advances in the field of direct DNA repair, namely, photolyase-, alkyltransferase-,...

  9. DNA Methylation

    İzmirli, Müzeyyen; Tufan, Turan; Alptekin, Davut

    2012-01-01

    Methylation is a chemical reaction in biological systems for normal genome regulation and development. It is a well known type of epigenetic mechanism. Methylation which regulates gene expression via epigenetic events like gene activation, repression, and chromatin remodelling, consists of two methylation systems. One of these systems is DNA methylation whereas the other is protein (histone) methylation. These systems are associated with some fundamental abnormalities and diseases. This revi...

  10. DNA Nanorobotics

    Hamdi M; Ferreira A

    2006-01-01

    This paper presents a molecular mechanics study for new nanorobotic structures using molecular dynamics (MD) simulations coupled to virtual reality (VR) techniques. The operator can design and characterize through molecular dynamics simulation the behavior of bionanorobotic components and structures through 3-D visualization. The main novelty of the proposed simulations is based on the mechanical characterization of passive/active robotic devices based on double stranded DNA molecules. Their ...

  11. DNA Methylation

    Muzeyyen Izmirli; Turan Tufan; Davut Alptekin

    2012-01-01

    Methylation is a chemical reaction in biological systems for normal genome regulation and development. It is a well known type of epigenetic mechanism. Methylation which regulates gene expression via epigenetic events like gene activation, repression, and chromatin remodelling, consists of two methylation systems. One of these systems is DNA methylation whereas the other is protein (histone) methylation. These systems are associated with some fundamental abnormalities and diseases. This revie...

  12. Mitochondrial DNA haplotype predicts deafness risk

    Hutchin, T.; Cortopassi, G. [Univ. of Southern California, Los Angeles, CA (United States)

    1995-12-18

    Since mitochondrial DNA (mtDNA) does not recombine in humans, once deleterious variation arises within a particular mtDNA clone it remains linked to that clonal type. An A to G mutation at mtDNA position 1555 confers matrilineal deafness among Asians and others. Two major mtDNA types (I and II) have been defined in Asians by D-loop sequencing. We have determined the D-loop sequence of 8 unrelated deaf Asians bearing the 1555G mutation, and find that 7 are of type II, whereas only one is of type I. Thus the frequency of the 1555G mutation is higher in type II mtDNA than type I (P = 0.035, binomial test), and persons with type II mtDNA are more likely to become deaf. Type II mtDNAs are rare in the Caucasian population, which may explain the rarity of this form of deafness in the United States. Negative Darwinian selection is expected to rapidly eliminate mtDNAs bearing severely deleterious mutations; but mildly deleterious mutations whose phenotype is expressed after reproduction should persist on the mtDNA background in which they arose. Thus determination of mtDNA clonal type has the potential to predict human risk for diseases that are the result of mildly deleterious mtDNA mutations which confer a post-reproductive phenotype. 4 refs., 1 fig.

  13. Study on Somaclonal Variation of Spring Wheat

    JIANG Shu-mei; HU Shang-lian; LI Wen-xiong

    2004-01-01

    Somaclonal variation of calli and regenerated plants of spring wheat ware detected by using technique RAPD in the study. Calli at different culture stages and regenerated plants derived from young spikes and immature embryos were used as materials. Molecular variation could be reflected from electrophoresis patternof RAPD fragments at different culture stage in calli, and in regenerated plants derived from different explants, even no phenotype variations were found. Somaclonal variation in calli and in regenerated plants appeared regularly: A higher frequency of variation in hybrids F2 was detected than that of the cultivar that is stable genetically. High variation frequency of RAPD fragments appeared in calli when cultured 75 days. The identical variations of RAPD fragments were observed in calli and in the regenerated plants induced from different genotype or explants. The variation frequency detected is higher in regenerated plants than that of in calli. RAPD could be applied easily and simply to determine variation in level of DNA at each stage cultured in vitro.

  14. Protocol for extraction of genomic DNA from swine solid tissues

    Fernando Henrique Biase

    2002-01-01

    Full Text Available Molecular diagnostics are performed by using DNA from different body tissues. However, it is necessary to obtain genomic DNA of good quality. Due to the impossibility of collecting blood from slaughtered animals, DNA extraction from solid tissues is necessary. The objective of this study was to describe a protocol of DNA extraction from swine skin, adipose, brain, liver, kidney and muscle tissues. We obtained high molecular weight DNA of good quality, shown by agarose gel and amplification of two DNA fragments, 605bp and 891pb, by PCR. Spectrophotometric analysis of DNA concentration showed variation among the DNA from different tissues, with the liver and adipose tissues presenting the greatest and the smallest concentration, respectively. The described protocol has proven to be advantageous due to its simplicity, quickness, affordable reagents and absence of phenol, resulting in a high molecular weight DNA of good quality from several tissues.

  15. Forensic DNA methylation profiling from evidence material for investigative leads.

    Lee, Hwan Young; Lee, Soong Deok; Shin, Kyoung-Jin

    2016-07-01

    DNA methylation is emerging as an attractive marker providing investigative leads to solve crimes in forensic genetics. The identification of body fluids that utilizes tissue-specific DNA methylation can contribute to solving crimes by predicting activity related to the evidence material. The age estimation based on DNA methylation is expected to reduce the number of potential suspects, when the DNA profile from the evidence does not match with any known person, including those stored in the forensic database. Moreover, the variation in DNA implicates environmental exposure, such as cigarette smoking and alcohol consumption, thereby suggesting the possibility to be used as a marker for predicting the lifestyle of potential suspect. In this review, we describe recent advances in our understanding of DNA methylation variations and the utility of DNA methylation as a forensic marker for advanced investigative leads from evidence materials. [BMB Reports 2016; 49(7): 359-369]. PMID:27099236

  16. Studies of DNA-carbon nanotube interactions

    Hughes, Mary Elizabeth

    2008-10-01

    Recently a new biomaterial consisting of a DNA-wrapped single-walled carbon nanotube, and known as a DNA/SWNT, has been discovered. The possible applications of this hybrid are varied and range from genomic sequencing to nanoscale electronics to molecular delivery. The realization of these potential applications requires more knowledge about the microscopic properties of this material. In this thesis, I present studies of: the orientation of nucleobases on the nanotube sidewall; the sequence and length dependence of the DNA-nanotube interaction; and solution conditions to manipulate the DNA/SWNT hybrid. The measurement of the UV optical absorbance of DNA/SWNT and the nucleotide absorbance from DNA/SWNT provide the first experimental confirmation that DNA binds to nanotubes through pi-stacking. Because the hypochromic absorbance typical of pi-stacked structures are expected to occur primarily for DNA dipole transitions that lie along the axis of the optically anisotropic SWNTs, the absorbance changes following binding of DNA to the nanotubes reveals the preferred orientation assumed by each of the four bound nucleotides with respect to the nanotube's long axis. The first observations of pronounced sequence- and length-dependent variations in the binding between ssDNA and SWNTs in aqueous solution are presented. These observations rely on the discovery that there exists a range of DNA lengths able to hybridize with SWNTs that can nevertheless be dissociated at temperatures below the boiling point of water. Quantitative results comparing the isochronal dissociation temperatures and binding energies of DNA/SWNT composed of differing DNA sequences and lengths are given. These results indicate variability and complexity in the binding mechanism responsible for the stability of the hybrid system that transcends simple models based on the sum of independent base-nanotube interactions. Binding energies between a DNA base and nanotube (0.05 to 0.09 eV per base) are similar

  17. DNA repair

    In this chapter a series of DNA repair pathways are discussed which are available to the cell to cope with the problem of DNA damaged by chemical or physical agents. In the case of microorganisms our knowledge about the precise mechanism of each DNA repair pathway and the regulation of it has been improved considerably when mutants deficient in these repair mechanisms became available. In the case of mammalian cells in culture, until recently there were very little repair deficient mutants available, because in almost all mammalian cells in culture at least the diploid number of chromosomes is present. Therefore the frequency of repair deficient mutants in such populations is very low. Nevertheless because replica plating techniques are improving some mutants from Chinese hamsters ovary cells and L5178Y mouse lymphoma cells are now available. In the case of human cells, cultures obtained from patients with certain genetic diseases are available. A number of cells appear to be sensitive to some chemical or physical mutagens. These include cells from patients suffering from xeroderma pigmentosum, Ataxia telangiectasia, Fanconi's anemia, Cockayne's syndrome. However, only in the case of xeroderma pigmentosum cells, has the sensitivity to ultraviolet light been clearly correlated with a deficiency in excision repair of pyrimidine dimers. Furthermore the work with strains obtained from biopsies from man is difficult because these cells generally have low cloning efficiencies and also have a limited lifespan in vitro. It is therefore very important that more repair deficient mutants will become available from established cell lines from human or animal origin

  18. Child Development and Structural Variation in the Human Genome

    Zhang, Ying; Haraksingh, Rajini; Grubert, Fabian; Abyzov, Alexej; Gerstein, Mark; Weissman, Sherman; Urban, Alexander E.

    2013-01-01

    Structural variation of the human genome sequence is the insertion, deletion, or rearrangement of stretches of DNA sequence sized from around 1,000 to millions of base pairs. Over the past few years, structural variation has been shown to be far more common in human genomes than previously thought. Very little is currently known about the effects…

  19. Wrinkled DNA.

    Arnott, S.; Chandrasekaran, R.; Puigjaner, L C; Walker, J K; Hall, I H; Birdsall, D L; Ratliff, R L

    1983-01-01

    The B form of poly d(GC):poly d(GC) in orthorhombic microcrystallites in oriented fibers has a secondary structure in which a dinucleotide is the repeated motif rather than a mononucleotide as in standard, smooth B DNA. One set of nucleotides (probably GpC) has the same conformations as the smooth form but the alternate (CpG) nucleotides have a different conformation at C3'-O3'. This leads to a distinctive change in the orientation of the phosphate groups. Similar perturbations can be detecte...

  20. Active DNA Demethylation Mediated by DNA Glycosylases

    Zhu, Jian-Kang

    2009-01-01

    Active DNA demethylation is involved in many vital developmental and physiological processes of plants and animals. Recent genetic and biochemical studies in Arabidopsis have demonstrated that a subfamily of DNA glycosylases function to promote DNA demethylation through a base excision-repair pathway. These specialized bifunctional DNA glycosylases remove the 5-methylcytosine base and then cleave the DNA backbone at the abasic site, resulting in a gap that is then filled with an unmethylated ...

  1. Optimal Placement of Origins for DNA Replication

    Karschau, Jens; Blow, J. Julian; de Moura, Alessandro P. S.

    2012-01-01

    DNA replication is an essential process in biology and its timing must be robust so that cells can divide properly. Random fluctuations in the formation of replication starting points, called origins, and the subsequent activation of proteins lead to variations in the replication time. We analyse these stochastic properties of DNA and derive the positions of origins corresponding to the minimum replication time. We show that under some conditions the minimization of replication time leads to ...

  2. Salt-Dependent DNA-DNA Spacings in Intact Bacteriophage lambda Reflect Relative Importance of DNA Self-Repulsion and Bending Energies

    X Qiu; D Rau; V Parsegian; L Fang; C Knobler; W Gelbart

    2011-12-31

    Using solution synchrotron x-ray scattering, we measure the variation of DNA-DNA d spacings in bacteriophage {lambda} with mono-, di-, and polyvalent salt concentrations, for wild-type [48.5 x 10{sup 3} base pairs (bp)] and short-genome-mutant (37.8 kbp) strains. From the decrease in d spacings with increasing salt, we deduce the relative contributions of DNA self-repulsion and bending to the energetics of packaged phage genomes. We quantify the DNA-DNA interaction energies within the intact phage by combining the measured d spacings in the capsid with measurements of osmotic pressure in DNA assemblies under the same salt conditions in bulk solution. In the commonly used Tris-Mg buffer, the DNA-DNA interaction energies inside the phage capsids are shown to be about 1 kT/bp, an order of magnitude larger than the bending energies.

  3. φ29 DNA polymerase

    Blanco, Luis; Bernad, Antonio; Salas, Margarita

    1996-01-01

    An improved method for determining the nucleotide base sequence of a DNA molecule employs a φ-29 type DNA polymerase modified to have reduced or no exonuclease activity. The method includes annealing the DNA molecule with a primer molecule able to hybridize to the DNA molecule; incubating the annealed mixture in a vessel containing four different deoxynucleoside triphosphates, a DNA polymerase, and one or more DNA synthesis terminating agents which terminate DNA synthesis at a specific nucleo...

  4. Calculus of variations

    Elsgolc, L E; Stark, M

    1961-01-01

    Calculus of Variations aims to provide an understanding of the basic notions and standard methods of the calculus of variations, including the direct methods of solution of the variational problems. The wide variety of applications of variational methods to different fields of mechanics and technology has made it essential for engineers to learn the fundamentals of the calculus of variations. The book begins with a discussion of the method of variation in problems with fixed boundaries. Subsequent chapters cover variational problems with movable boundaries and some other problems; sufficiency

  5. Recombination, extrachromosomal dna and genome stability

    Eukaryotic chromosomes are faithfully transmitted from one generation to another. However, eukaryotic genomes are much more dynamic than this view permits. Repetitive sequences are among the most rapidly evolving genome constituents and copy number variations are extremely abundant even within species. Rapid evolution of repetitive DNA is particularly apparent during domestication of many crops and is, for example, well documented in cereals such as maize or barley. Importantly, deletions or insertions of such sequences may contribute to variation in protein-coding gene expression. This can occur by altering gene copy number and expression, by disrupting regulatory sequences or by altering regulatory RNA production. One mechanism that may significantly contribute to copy number variation and rapid evolution of crop genomes involves the formation of extrachromosomal circular DNA molecules (eccs). I will present evidence for eccDNA derived from centromeres, 5S rDNA and telomeres in Arabidopsis. I will further discuss the role of homologous recombination, telomere metabolism and chromatin modification in eccDNA biogenesis. Finally, I will discuss the impact of eccDNA metabolism on the stability and evolution of plant genomes. (author)

  6. Carcinogen-induced damage to DNA

    Human cells respond to carcinogen-induced damage in their DNA in at least two ways. The first response, excision repair, proceeds by at least three variations, depending on the nature of the damage. Nucleotide excision results in relatively large repair patches but few free DNA breaks, since the endonuclease step is limiting. Apurinic repair is characterized by the appearance of numerous breaks in the DNA and by short repair patches. The pathways behave as though they function independently. Lymphoic cells derived from a xeroderma pigmentosum complementation group C patient are deficient in their ability to perform nucleotide excision and also to excise 6 methoxyguanine adducts, but they are apurinic repair competent. Organisms may bypass damage in their DNA. Lymphoblastoid cells, including those derived from xeroderma pigmentosum treated with 3H-anti-BPDE, can replicate their DNA at low doses of carcinogen. Unexcised 3H is found in the light or parental strand of the resulting hybrid DNA when replication occurs in medium with BrdUrd. This observation indicates a bypass reaction occurring by a mechanism involving branch migration at DNA growing points. Branch migration in DNA preparations have been observed, but the evidence is that most occurs in BrdUrd-containing DNA during cell lysis. The measurement of the bifilarly substituted DNA resulting from branch migration is a convenient method of estimating the proportion of new synthesis remaining in the vicinity of the DNA growing point. Treatment with carcinogens or caffeine results in accumulation of DNA growing points accompanied by the synthesis of shortened pieces of daughter DNA

  7. DNA ligase I, the replicative DNA ligase

    Howes, Timothy R.L.; Tomkinson, Alan E.

    2012-01-01

    Multiple DNA ligation events are required to join the Okazaki fragments generated during lagging strand DNA synthesis. In eukaryotes, this is primarily carried out by members of the DNA ligase I family. The C-terminal catalytic region of these enzymes is composed of three domains: a DNA binding domain, an adenylation domain and an OB-fold domain. In the absence of DNA, these domains adopt an extended structure but transition into a compact ring structure when they engage a DNA nick, with each...

  8. Keeping mtDNA in shape between generations.

    James B Stewart

    2014-10-01

    Full Text Available Since the unexpected discovery that mitochondria contain their own distinct DNA molecules, studies of the mitochondrial DNA (mtDNA have yielded many surprises. In animals, transmission of the mtDNA genome is explicitly non-Mendelian, with a very high number of genome copies being inherited from the mother after a drastic bottleneck. Recent work has begun to uncover the molecular details of this unusual mode of transmission. Many surprising variations in animal mitochondrial biology are known; however, a series of recent studies have identified a core of evolutionarily conserved mechanisms relating to mtDNA inheritance, e.g., mtDNA bottlenecks during germ cell development, selection against specific mtDNA mutation types during maternal transmission, and targeted destruction of sperm mitochondria. In this review, we outline recent literature on the transmission of mtDNA in animals and highlight the implications for human health and ageing.

  9. Comparative Analysis of Eubacterial DNA Polymerase Ⅲ Alpha Subunits

    Xiao-Qian Zhao; Jian-Fei Hu; Jun Yu

    2006-01-01

    DNA polymerase Ⅲ is one of the five eubacterial DNA polymerases that is responsible for the replication of DNA duplex. Among the ten subunits of the DNA polymerase Ⅲ core enzyme, the alpha subunit catalyzes the reaction for polymerizing both DNA strands. In this study, we extracted genomic sequences of the alpha subunit from 159 sequenced eubacterial genomes, and carried out sequencebased phylogenetic and structural analyses. We found that all eubacterial genomes have one or more alpha subunits, which form either homodimers or heterodimers.Phylogenetic and domain structural analyses as well as copy number variations of the alpha subunit in each bacterium indicate the classification of alpha subunit into four basic groups: polC, dnaE1, dnaE2, and dnaE3. This classification is of essence in genome composition analysis. We also consolidated the naming convention to avoid further confusion in gene annotations.

  10. Mitochondrial DNA sequences in single hairs from a southern African population.

    Vigilant, L.; Pennington, R; Harpending, H; Kocher, T.D.; Wilson, A C

    1989-01-01

    Hypervariable parts of mitochondrial DNA (mtDNA) were amplified enzymatically and sequenced directly by using genomic DNA from single plucked human hairs. This method has been applied to study mtDNA sequence variation among 15 members of the !Kung population. A genealogical tree relating these aboriginal, Khoisan-speaking southern Africans to 68 other humans and to one chimpanzee has the deepest branches occurring amongst the !Kung, a result consistent with an African origin of human mtDNA. F...

  11. Mitochondrial DNA Haplogroups and the Risk of Sporadic Parkinson's Disease in Han Chinese

    Ya-Fang Chen,; Wan-Jin Chen; Xiao-Zhen Lin; Qi-Jie Zhang; Jiang-Ping Cai; Chia-Wei Liou; Ning Wang

    2015-01-01

    Background: Mitochondrial dysfunction is linked to the pathogenesis of Parkinson′s disease (PD). However, the precise role of mitochondrial DNA (mtDNA) variations is obscure. On the other hand, mtDNA haplogroups have been inconsistently reported to modify the risk of PD among different population. Here, we try to explore the relationship between mtDNA haplogroups and sporadic PD in a Han Chinese population. Methods: Nine single-nucleotide polymorphisms, which define the major Asian mtDNA ...

  12. DNA modifications: Another stable base in DNA

    Brazauskas, Pijus; Kriaucionis, Skirmantas

    2014-12-01

    Oxidation of 5-methylcytosine has been proposed to mediate active and passive DNA demethylation. Tracking the history of DNA modifications has now provided the first solid evidence that 5-hydroxymethylcytosine is a stable epigenetic modification.

  13. Synthesis of DNA

    Mariella, Jr., Raymond P.

    2008-11-18

    A method of synthesizing a desired double-stranded DNA of a predetermined length and of a predetermined sequence. Preselected sequence segments that will complete the desired double-stranded DNA are determined. Preselected segment sequences of DNA that will be used to complete the desired double-stranded DNA are provided. The preselected segment sequences of DNA are assembled to produce the desired double-stranded DNA.

  14. Sperm DNA oxidative damage and DNA adducts.

    Jeng, Hueiwang Anna; Pan, Chih-Hong; Chao, Mu-Rong; Lin, Wen-Yi

    2015-12-01

    The objective of this study was to investigate DNA damage and adducts in sperm from coke oven workers who have been exposed to polycyclic aromatic hydrocarbons. A longitudinal study was conducted with repeated measurements during spermatogenesis. Coke-oven workers (n=112) from a coke-oven plant served the PAH-exposed group, while administrators and security personnel (n=67) served the control. Routine semen parameters (concentration, motility, vitality, and morphology) were analyzed simultaneously; the assessment of sperm DNA integrity endpoints included DNA fragmentation, bulky DNA adducts, and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxo-dGuo). The degree of sperm DNA fragmentation was measured using the terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assay and sperm chromatin structure assay (SCSA). The PAH-exposed group had a significant increase in bulky DNA adducts and 8-oxo-dGuo compared to the control subjects (Ps=0.002 and 0.045, respectively). Coke oven workers' percentages of DNA fragmentation and denaturation from the PAH-exposed group were not significantly different from those of the control subjects (Ps=0.232 and 0.245, respectively). Routine semen parameters and DNA integrity endpoints were not correlated. Concentrations of 8-oxo-dGuo were positively correlated with percentages of DNA fragmentation measured by both TUNEL and SCSA (Ps=0.045 and 0.034, respectively). However, the concentrations of 8-oxo-dGuo and percentages of DNA fragmentation did not correlate with concentrations of bulky DNA adducts. In summary, coke oven workers with chronic exposure to PAHs experienced decreased sperm DNA integrity. Oxidative stress could contribute to the degree of DNA fragmentation. Bulky DNA adducts may be independent of the formation of DNA fragmentation and oxidative adducts in sperm. Monitoring sperm DNA integrity is recommended as a part of the process of assessing the impact of occupational and environmental toxins on sperm

  15. DNA glycosylases: in DNA repair and beyond

    Jacobs, Angelika L.; Schär, Primo

    2011-01-01

    The base excision repair machinery protects DNA in cells from the damaging effects of oxidation, alkylation, and deamination; it is specialized to fix single-base damage in the form of small chemical modifications. Base modifications can be mutagenic and/or cytotoxic, depending on how they interfere with the template function of the DNA during replication and transcription. DNA glycosylases play a key role in the elimination of such DNA lesions; they recognize and excise damaged bases, thereb...

  16. DNA vaccines and bacterial DNA in immunity

    Bandholtz, Lisa Charlotta

    2002-01-01

    This thesis describes DNA-based vaccination and the importance of bacterial DNA in different immunological perspectives. Intranasal (i.n.) DNA vaccination utilizing a plasmid encoding the chlamydial heat shock protein 60 (p-hsp-60) generated lower bacterial burden and reduced pathology in the lungs of mice after subsequent infection with C. pneumoniae. This DNA vaccine- induced protection was dependent on T cells and induction of IFN-gamma. Co-administration of a plasmid...

  17. Wolbachia and DNA Barcoding Insects: Patterns, Potential, and Problems

    M. Alex Smith; Claudia Bertrand; Kate Crosby; Eveleigh, Eldon S.; Jose Fernandez-Triana; Fisher, Brian L.; Jason Gibbs; Mehrdad Hajibabaei; Winnie Hallwachs; Katharine Hind; Jan Hrcek; Da-Wei Huang; Milan Janda; Janzen, Daniel H.; Yanwei Li

    2012-01-01

    Wolbachia is a genus of bacterial endosymbionts that impacts the breeding systems of their hosts. Wolbachia can confuse the patterns of mitochondrial variation, including DNA barcodes, because it influences the pathways through which mitochondria are inherited. We examined the extent to which these endosymbionts are detected in routine DNA barcoding, assessed their impact upon the insect sequence divergence and identification accuracy, and considered the variation present in Wolbachia COI. Us...

  18. MitoVariome: a variome database of human mitochondrial DNA

    Lee, Yong Seok; Kim, Woo-Yeon; Ji, Mihyun; Kim, Ji Han; Bhak, Jong

    2009-01-01

    Background Mitochondrial sequence variation provides critical information for studying human evolution and variation. Mitochondrial DNA provides information on the origin of humans, and plays a substantial role in forensics, degenerative diseases, cancers, and aging process. Typically, human mitochondrial DNA has various features such as HVSI, HVSII, single-nucleotide polymorphism (SNP), restriction enzyme sites, and short tandem repeat (STR). Results We present a variome database (MitoVariom...

  19. Human beta-defensin gene copy number variation and consequences in disease and evolution

    Pala, Raquel Rodrigues

    2012-01-01

    Research on human genetic variation has shown that the human genome is not a fixed, invariant framework, but that there can be extensive structural variation. This variation includes copy number variation (CNV), which can lead to changes in DNA dosage contributing significantly to variation between individual human genomes and heritable traits. Human beta-defensins are small, secreted antimicrobial peptides encoded by DEFB genes located in a cluster of at least seven genes on 8p23.1. These...

  20. Mitochondrial DNA variants in obesity.

    Nadja Knoll

    Full Text Available Heritability estimates for body mass index (BMI variation are high. For mothers and their offspring higher BMI correlations have been described than for fathers. Variation(s in the exclusively maternally inherited mitochondrial DNA (mtDNA might contribute to this parental effect. Thirty-two to 40 mtDNA single nucleotide polymorphisms (SNPs were available from genome-wide association study SNP arrays (Affymetrix 6.0. For discovery, we analyzed association in a case-control (CC sample of 1,158 extremely obese children and adolescents and 435 lean adult controls. For independent confirmation, 7,014 population-based adults were analyzed as CC sample of n = 1,697 obese cases (BMI ≥ 30 kg/m2 and n = 2,373 normal weight and lean controls (BMI<25 kg/m2. SNPs were analyzed as single SNPs and haplogroups determined by HaploGrep. Fisher's two-sided exact test was used for association testing. Moreover, the D-loop was re-sequenced (Sanger in 192 extremely obese children and adolescents and 192 lean adult controls. Association testing of detected variants was performed using Fisher's two-sided exact test. For discovery, nominal association with obesity was found for the frequent allele G of m.8994G/A (rs28358887, p = 0.002 located in ATP6. Haplogroup W was nominally overrepresented in the controls (p = 0.039. These findings could not be confirmed independently. For two of the 252 identified D-loop variants nominal association was detected (m.16292C/T, p = 0.007, m.16189T/C, p = 0.048. Only eight controls carried the m.16292T allele, five of whom belonged to haplogroup W that was initially enriched among these controls. m.16189T/C might create an uninterrupted poly-C tract located near a regulatory element involved in replication of mtDNA. Though follow-up of some D-loop variants still is conceivable, our hypothesis of a contribution of variation in the exclusively maternally inherited mtDNA to the observed larger correlations for BMI between mothers and

  1. Osmylated DNA, a novel concept for sequencing DNA using nanopores

    Saenger sequencing has led the advances in molecular biology, while faster and cheaper next generation technologies are urgently needed. A newer approach exploits nanopores, natural or solid-state, set in an electrical field, and obtains base sequence information from current variations due to the passage of a ssDNA molecule through the pore. A hurdle in this approach is the fact that the four bases are chemically comparable to each other which leads to small differences in current obstruction. ‘Base calling’ becomes even more challenging because most nanopores sense a short sequence and not individual bases. Perhaps sequencing DNA via nanopores would be more manageable, if only the bases were two, and chemically very different from each other; a sequence of 1s and 0s comes to mind. Osmylated DNA comes close to such a sequence of 1s and 0s. Osmylation is the addition of osmium tetroxide bipyridine across the C5–C6 double bond of the pyrimidines. Osmylation adds almost 400% mass to the reactive base, creates a sterically and electronically notably different molecule, labeled 1, compared to the unreactive purines, labeled 0. If osmylated DNA were successfully sequenced, the result would be a sequence of osmylated pyrimidines (1), and purines (0), and not of the actual nucleobases. To solve this problem we studied the osmylation reaction with short oligos and with M13mp18, a long ssDNA, developed a UV–vis assay to measure extent of osmylation, and designed two protocols. Protocol A uses mild conditions and yields osmylated thymidines (1), while leaving the other three bases (0) practically intact. Protocol B uses harsher conditions and effectively osmylates both pyrimidines, but not the purines. Applying these two protocols also to the complementary of the target polynucleotide yields a total of four osmylated strands that collectively could define the actual base sequence of the target DNA. (paper)

  2. DNA encoding a DNA repair protein

    Petrini, John H.; Morgan, William Francis; Maser, Richard Scott; Carney, James Patrick

    2006-08-15

    An isolated and purified DNA molecule encoding a DNA repair protein, p95, is provided, as is isolated and purified p95. Also provided are methods of detecting p95 and DNA encoding p95. The invention further provides p95 knock-out mice.

  3. SNP and gene networks construction and analysis from classification of copy number variations data

    Liu, Yang; Lee, Yiu Fai; Ng, Michael K.

    2011-01-01

    Background Detection of genomic DNA copy number variations (CNVs) can provide a complete and more comprehensive view of human disease. It is interesting to identify and represent relevant CNVs from a genome-wide data due to high data volume and the complexity of interactions. Results In this paper, we incorporate the DNA copy number variation data derived from SNP arrays into a computational shrunken model and formalize the detection of copy number variations as a case-control classification ...

  4. DNA Sequence Determinants Controlling Affinity, Stability and Shape of DNA Complexes Bound by the Nucleoid Protein Fis.

    Hancock, Stephen P; Stella, Stefano; Cascio, Duilio; Johnson, Reid C

    2016-01-01

    The abundant Fis nucleoid protein selectively binds poorly related DNA sequences with high affinities to regulate diverse DNA reactions. Fis binds DNA primarily through DNA backbone contacts and selects target sites by reading conformational properties of DNA sequences, most prominently intrinsic minor groove widths. High-affinity binding requires Fis-stabilized DNA conformational changes that vary depending on DNA sequence. In order to better understand the molecular basis for high affinity site recognition, we analyzed the effects of DNA sequence within and flanking the core Fis binding site on binding affinity and DNA structure. X-ray crystal structures of Fis-DNA complexes containing variable sequences in the noncontacted center of the binding site or variations within the major groove interfaces show that the DNA can adapt to the Fis dimer surface asymmetrically. We show that the presence and position of pyrimidine-purine base steps within the major groove interfaces affect both local DNA bending and minor groove compression to modulate affinities and lifetimes of Fis-DNA complexes. Sequences flanking the core binding site also modulate complex affinities, lifetimes, and the degree of local and global Fis-induced DNA bending. In particular, a G immediately upstream of the 15 bp core sequence inhibits binding and bending, and A-tracts within the flanking base pairs increase both complex lifetimes and global DNA curvatures. Taken together, our observations support a revised DNA motif specifying high-affinity Fis binding and highlight the range of conformations that Fis-bound DNA can adopt. The affinities and DNA conformations of individual Fis-DNA complexes are likely to be tailored to their context-specific biological functions. PMID:26959646

  5. Studying Variation in Tunes

    Janssen, B.; van Kranenburg, P.

    2014-01-01

    Variation in music can be caused by different phenomena: conscious, creative manipulation of musical ideas; but also unconscious variation during music recall. It is the latter phenomenon that we wish to study: variation which occurs in oral transmission, in which a melody is taught without the help

  6. Identifying Genetic Variation for Alcohol Dependence

    Agrawal, Arpana; Bierut, Laura J.

    2012-01-01

    Researchers are using various strategies to identify the genes that may be associated with alcoholism. The initial efforts primarily relied on candidate gene and linkage studies; more recently, however, modern advances in genotyping have resulted in widespread use of genome-wide association studies for alcohol dependence. The key findings of the earlier studies were that variations (i.e., polymorphisms) in the DNA sequences of the genes encoding alcohol dehydrogenase 1B (i.e., the ADH1B gene)...

  7. Method for improved extraction of DNA from Nocardia asteroides.

    Loeffelholz, M. J.; Scholl, D R

    1989-01-01

    In a variation of standard DNA extraction methods, Nocardia asteroides was repeatedly exposed to sodium dodecyl sulfate at 60 degrees C for 30 min; each extraction was followed by centrifugation, removal of the nucleic acid-rich supernatant, and suspension of the cell pellet in fresh sodium dodecyl sulfate. The pooled supernatants contained a substantially higher amount of DNA than the first supernatant alone. The possible implications of this procedure on the development of DNA probes are di...

  8. The Power to Detect Disease Associations with Mitochondrial DNA Haplogroups

    Samuels, David C.; Carothers, Andrew D.; Horton, Robin; Chinnery, Patrick F

    2006-01-01

    Genetic variation of mitochondrial DNA (mtDNA) has been linked to a number of multifactorial diseases, but there is currently no tool available to predict the optimal size for these investigations. We used a simulation-based (Monte Carlo) permutation test to generate power curves for European mtDNA haplogroup studies, to derive a universal equation to enable power calculations for prospective studies across the globe, and to show that very large cohorts are required to reliably detect an asso...

  9. Species-specific patterns of DNA bending and sequence.

    VanWye, J D; Bronson, E C; Anderson, J N

    1991-01-01

    Nucleotide sequences in the GenEMBL database were analyzed using strategies designed to reveal species-specific patterns of DNA bending and DNA sequence. The results uncovered striking species-dependent patterns of bending with more variations among individual organisms than between prokaryotes and eukaryotes. The frequency of bent sites in sequences from different bacteria was related to genomic A + T content and this relationship was confirmed by electrophoretic analysis of genomic DNA. How...

  10. Functionalizing Designer DNA Crystals

    Chandrasekaran, Arun Richard

    nucleotides is usually pH dependent (pH TFOs were examined: TFO-1 was unmodified while TFOs 2-4 contained additional stabilizing analogues capable of extending triplex formation to pH 7. In addition, each of the TFOs contained a Cy5 dye at the 5'-end of the oligonucleotide to aid in characterization of TFO binding - crystals were obtained with all four variations of TFOs. Formation of DNA triplex in the motif was characterized by an electrophoretic mobility shift assay (EMSA), UV melting studies and FRET. Crystals containing TFO-1 (unmodified) and TFO-2 (with 2'-amino ethoxy modification) were isolated and flash-frozen in liquid nitrogen for X-ray data collection at beam line NSLS-X25. X-ray data was also collected for crystals of the 3-turn triangle without any TFO bound to it. Difference maps were done between the crystals with TFO against the one without to identify any additional electron density corresponding to the third strand in the triplex binding region. The data from the crystal containing TFO-2 was used to further analyze if the additional density can match the expected position of the TFO on the triangle motif. Since the additional density did not correspond to the entire binding region, 2Fo-Fc, 3Fo-2Fc and 4Fo-3Fc maps were done to check for missing pieces of the electron density. From the resulting 2Fo-Fc map, the asymmetric unit from the 3-turn triangle (31-bp duplex model based on previous structure 3UBI) was inserted into the density as a reference. However, the electron density corresponding to the TFO was still not continuous throughout the 13-nt triplex binding region and allowed only a partial fit of the TFO. The third nucleotide in positions 1, 3, 4, 6, 7 were fit into the density in the major groove of the underlying duplex with proper triplex configuration. The third chapter describes the triplex approach to position a functional group (the UV cross-linking agent psoralen) within a pre-formed DNA motif. Triplex formation and psoralen cross-linking of

  11. DNA fork displacement rates in human cells

    DNA fork displacement rates were measured in 20 human cell lines by a bromodeoxyuridine-313 nm photolysis technique. Cell lines included representatives of normal diploid, Fanconi's anemia, ataxia telangiectasia, xeroderma pigmentosum, trisomy-21 and several transformed lines. The average value for all the cell lines was 0.53 +- 0.08 μm/min. The average value for individual cell lines, however, displayed a 30% variation. Less than 10% of variation in the fork displacement rate appears to be due to the experimental technique; the remainder is probably due to true variation among the cell types and to culture conditions. (Auth.)

  12. A positron annihilation study of hydrated DNA

    Warman, J. M.; Eldrup, Morten Mostgaard

    1986-01-01

    Positron annihilation measurements are reported for hydrated DNA as a function of water content and as a function of temperature (20 to -180.degree. C) for samples containing 10 and 50% wt of water. The ortho-positronium mean lifetime and its intensity show distinct variations with the degree of ...

  13. An integrated epigenetic and genetic analysis of DNA methyltransferase genes (DNMTs) in tumor resistant and susceptible chicken lines

    Both epigenetic alterations and genetic variations play essential roles in tumorigenesis. The epigenetic modification of DNA methylation is catalyzed and maintained by the DNA methyltransferases (DNMT3a, DNMT3b and DNMT1). DNA mutations and DNA methylation profiles of DNMTs themselves and their rela...

  14. Ethanol Induced Shortening of DNA in Nanochannels

    Gemmen, Greg; Reisner, Walter; Tegenfeldt, Jonas; Linke, Heiner

    2010-03-01

    The confinement of DNA in nanochannels has greatly facilitated the study of DNA polymer physics and holds promise as a powerful tool for genomic sequencing. Ethanol precipitation of DNA is a common tool in molecular biology, typically in >70% [EtOH]. Even at lower ethanol concentrations, however, DNA transforms from B-form to A-form, a shorter yet slightly less twisted conformation. Accordingly, we isolated individual YOYO-1 labeled λ-DNA molecules in 100nmx100nm channels in 0, 20, 40 and 60% [EtOH]. We observed a dramatic shortening in the mean measured lengths with increasing [EtOH] and a broadening of the distribution of measured lengths at the intermediate concentrations. These observed lengths are less than those expected from fully A-form λ-DNA, suggesting that poor solvency effects are involved. Also, substantial spatial variations in intensity in a small number of molecules at the higher [EtOH] suggest the presence of higher order DNA conformations, in accord with the observation that the effective persistence length of DNA has been greatly reduced.

  15. DNA gyrase can cleave short DNA fragments in the presence of quinolone drugs.

    Cove, M E; Tingey, A P; Maxwell, A

    1997-01-01

    We have analysed the DNA cleavage reaction of DNA gyrase using oligonucleotides annealed to a single-stranded M13 derivative containing a preferred gyrase cleavage site. We find that gyrase can cleave duplexes down to approximately 20 bp in size in the presence of the quinolone drugs ciprofloxacin and oxolinic acid. Ciprofloxacin shows a variation in its site specificity with an apparent preference for G bases adjacent to the cleavage sites, whereas oxolinic acid stimulates cleavage predomina...

  16. Human placental DNA methyltransferase: DNA substrate and DNA binding specificity.

    Wang, R.Y.; Huang, L. H.; Ehrlich, M

    1984-01-01

    We have partially purified a DNA methyltransferase from human placenta using a novel substrate for a highly sensitive assay of methylation of hemimethylated DNA. This substrate was prepared by extensive nick translation of bacteriophage XP12 DNA, which normally has virtually all of its cytosine residues replaced by 5-methylcytosine (m5C). Micrococcus luteus DNA was just as good a substrate if it was first similarly nick translated with m5dCTP instead of dCTP in the polymerization mixture. At ...

  17. A role for the weak DnaA binding sites in bacterial replication origins

    Charbon, Godefroid; Løbner-Olesen, Anders

    2011-01-01

    DnaA initiates the chromosomal DNA replication in nearly all bacteria, and replication origins are characterized by binding sites for the DnaA protein (DnaA-boxes) along with an ‘AT-rich’ region. However, great variation in number, spatial organization and specificity of DnaA-boxes is observed...... between species. In the study by Taylor et al. (2011), new and unexpectedly weak DnaA-boxes were identified within the Caulobacter crescentus origin of replication (Cori). The position of weak and stronger DnaA-boxes follows a pattern seen in Escherichia coli oriC. This raises the possibility that...

  18. Nuclear DNA content variation within the genus Taraxacum (Asteraceae)

    Záveský, L.; Jarolímová, Vlasta; Štěpánek, Jan

    2005-01-01

    Roč. 40, - (2005), s. 91-104. ISSN 1211-9520 R&D Projects: GA ČR(CZ) GD206/03/H137; GA ČR(CZ) GA206/05/0970 Institutional research plan: CEZ:AV0Z60050516 Keywords : Taraxacum * C-value * genome size Subject RIV: EF - Botanics Impact factor: 1.033, year: 2005

  19. Mitochondrial DNA HV1 and HV2 variation in Danes

    Mikkelsen, Martin; Sørensen, Erik; Rasmussen, Erik Michael;

    2010-01-01

    least twice. The samples were sequenced using flanking sequencing primes and both terminator and primer chemistry. Sequence evaluation was performed by two independent scientists. The haplogroup distribution of the samples resembles that found in other European population. All the sequences have been...

  20. Melanesian mtDNA complexity.

    Jonathan S Friedlaender

    Full Text Available Melanesian populations are known for their diversity, but it has been hard to grasp the pattern of the variation or its underlying dynamic. Using 1,223 mitochondrial DNA (mtDNA sequences from hypervariable regions 1 and 2 (HVR1 and HVR2 from 32 populations, we found the among-group variation is structured by island, island size, and also by language affiliation. The more isolated inland Papuan-speaking groups on the largest islands have the greatest distinctions, while shore dwelling populations are considerably less diverse (at the same time, within-group haplotype diversity is less in the most isolated groups. Persistent differences between shore and inland groups in effective population sizes and marital migration rates probably cause these differences. We also add 16 whole sequences to the Melanesian mtDNA phylogenies. We identify the likely origins of a number of the haplogroups and ancient branches in specific islands, point to some ancient mtDNA connections between Near Oceania and Australia, and show additional Holocene connections between Island Southeast Asia/Taiwan and Island Melanesia with branches of haplogroup E. Coalescence estimates based on synonymous transitions in the coding region suggest an initial settlement and expansion in the region at approximately 30-50,000 years before present (YBP, and a second important expansion from Island Southeast Asia/Taiwan during the interval approximately 3,500-8,000 YBP. However, there are some important variance components in molecular dating that have been overlooked, and the specific nature of ancestral (maternal Austronesian influence in this region remains unresolved.

  1. DNA extraction by zinc.

    Kejnovský, E; Kypr, J

    1997-01-01

    A fast, very simple and efficient method of DNA extraction is described which takes advantage of DNA sedimentation induced by millimolar concentrations of ZnCl2. The zinc-induced sedimentation is furthermore strongly promoted by submillimolar phosphate anion concentrations. Within 90% of DNA irrespective of whether a plasmid DNA or short oligonucleotides are the extracted material. The method works with plasmid DNA and oligonucleotide concentrations as low as 100 ng/ml and 10 microg/ml, respe...

  2. Wedging out DNA damage

    Schärer, Orlando D.; Campbell, Arthur J

    2009-01-01

    The DNA-repair machinery is faced with the significant challenge of differentiating DNA lesions from unmodified DNA. Two recent publications, one in this issue of Nature Structural & Molecular Biology, uncover a new way of recognizing minimally distorting DNA lesions: insertion of a 3- or 4-amino-acid wedge into DNA to extrude the lesion into a shallow binding pocket that can accommodate various damaged bases.

  3. Repetitive DNA in eukaryotic genomes.

    Biscotti, Maria Assunta; Olmo, Ettore; Heslop-Harrison, J S Pat

    2015-09-01

    Repetitive DNA--sequence motifs repeated hundreds or thousands of times in the genome--makes up the major proportion of all the nuclear DNA in most eukaryotic genomes. However, the significance of repetitive DNA in the genome is not completely understood, and it has been considered to have both structural and functional roles, or perhaps even no essential role. High-throughput DNA sequencing reveals huge numbers of repetitive sequences. Most bioinformatic studies focus on low-copy DNA including genes, and hence, the analyses collapse repeats in assemblies presenting only one or a few copies, often masking out and ignoring them in both DNA and RNA read data. Chromosomal studies are proving vital to examine the distribution and evolution of sequences because of the challenges of analysis of sequence data. Many questions are open about the origin, evolutionary mode and functions that repetitive sequences might have in the genome. Some, the satellite DNAs, are present in long arrays of similar motifs at a small number of sites, while others, particularly the transposable elements (DNA transposons and retrotranposons), are dispersed over regions of the genome; in both cases, sequence motifs may be located at relatively specific chromosome domains such as centromeres or subtelomeric regions. Here, we overview a range of works involving detailed characterization of the nature of all types of repetitive sequences, in particular their organization, abundance, chromosome localization, variation in sequence within and between chromosomes, and, importantly, the investigation of their transcription or expression activity. Comparison of the nature and locations of sequences between more, and less, related species is providing extensive information about their evolution and amplification. Some repetitive sequences are extremely well conserved between species, while others are among the most variable, defining differences between even closely relative species. These data suggest

  4. New environmental metabarcodes for analysing soil DNA

    Epp, Laura S.; Boessenkool, Sanne; Bellemain, Eva P.;

    2012-01-01

    taxonomic resolution, minimal bias in amplification of the target organism group and short sequence length. Using bioinformatic tools, we developed metabarcodes for several groups of organisms: fungi, bryophytes, enchytraeids, beetles and birds. The ability of these metabarcodes to amplify the target groups...... was systematically evaluated by (i) in silico PCRs using all standard sequences in the EMBL public database as templates, (ii) in vitro PCRs of DNA extracts from surface soil samples from a site in Varanger, northern Norway and (iii) in vitro PCRs of DNA extracts from permanently frozen sediment...... groups were detected in the environmental DNA, but we found large variation in the level of detection among the groups and between modern and ancient samples. Success rates for the Pleistocene samples were highest for fungal DNA, whereas bryophyte, beetle and bird sequences could also be retrieved, but...

  5. Variation of fundamental constants

    Flambaum, V V

    2006-01-01

    We present a review of recent works devoted to the variation of the fine structure constant alpha, strong interaction and fundamental masses. There are some hints for the variation in quasar absorption spectra, Big Bang nucleosynthesis, and Oklo natural nuclear reactor data. A very promising method to search for the variation of the fundamental constants consists in comparison of different atomic clocks. Huge enhancement of the variation effects happens in transition between accidentally degenerate atomic and molecular energy levels. A new idea is to build a ``nuclear'' clock based on the ultraviolet transition between very low excited state and ground state in Thorium nucleus. This may allow to improve sensitivity to the variation up to 10 orders of magnitude! Huge enhancement of the variation effects is also possible in cold atomic and molecular collisions near Feschbach resonance.

  6. Recognition of DNA Termini by the C-Terminal Region of the Ku80 and the DNA-Dependent Protein Kinase Catalytic Subunit

    Woods, Derek S.; Catherine R Sears; Turchi, John J.

    2015-01-01

    DNA double strand breaks (DSBs) can be generated by endogenous cellular processes or exogenous agents in mammalian cells. These breaks are highly variable with respect to DNA sequence and structure and all are recognized in some context by the DNA-dependent protein kinase (DNA-PK). DNA-PK is a critical component necessary for the recognition and repair of DSBs via non-homologous end joining (NHEJ). Previously studies have shown that DNA-PK responds differentially to variations in DSB structur...

  7. Asynchronous Variational Integrators

    Lew, A.; Marsden, J. E.; Ortiz, M.; West, M

    2003-01-01

    We describe a new class of asynchronous variational integrators (AVI) for nonlinear elastodynamics. The AVIs are distinguished by the following attributes: (i) The algorithms permit the selection of independent time steps in each element, and the local time steps need not bear an integral relation to each other; (ii) the algorithms derive from a spacetime form of a discrete version of Hamilton’s variational principle. As a consequence of this variational structure, the algorith...

  8. 3DNA: A Tool for DNA Sculpting

    Gupta, Shikhar Kumar; Joshi, Foram; Limbachiya, Dixita; Gupta, Manish K.

    2014-01-01

    DNA self-assembly is a robust and programmable approach for building structures at nanoscale. Researchers around the world have proposed and implemented different techniques to build two dimensional and three dimensional nano structures. One such technique involves the implementation of DNA Bricks proposed by Ke et al., 2012 to create complex three-dimensional (3D) structures. Modeling these DNA nano structures can prove to be a cumbersome and tedious task. Exploiting the programmability of b...

  9. Calculus of variations

    Gelfand, I M

    2000-01-01

    Based on a series of lectures given by I. M. Gelfand at Moscow State University, this book actually goes considerably beyond the material presented in the lectures. The aim is to give a treatment of the elements of the calculus of variations in a form both easily understandable and sufficiently modern. Considerable attention is devoted to physical applications of variational methods, e.g., canonical equations, variational principles of mechanics, and conservation laws.The reader who merely wishes to become familiar with the most basic concepts and methods of the calculus of variations need on

  10. DNA polymerase δ and DNA repair: DNA repair synthesis in human fibroblasts requires DNA polymerase δ

    When UV-irradiated cultured diploid human fibroblasts were permeabilized with Brij-58 then separated from soluble material by centrifugation, conservative DNA repair synthesis could be restored by a soluble factor obtained from the supernate of similarly treated HeLa cells. Monoclonal antibody to KB cell DNA polymerase α, while binding to HeLa DNA polymerase α, did not bind to the HeLa DNA polymerase δ. Moreover, at micromolar concentrations N2-(p-n-butylphenyl)-2'-deoxyguanosine 5'-triphosphate (BuPdGT) and 2(p-n-butylanilino)-2'-deoxyadenosine 5'-triphosphate (BuAdATP) were potent inhibitors of DNA polymerase α, but did not inhibit the DNA polymerase δ. Neither purified DNA polymerase α nor β could promote repair DNA synthesis in the permeabilized cells. Furthermore, if monoclonal antibodies to DNA polymerase α BuPdGTP, or BuAdATP was added to the reconstituted system, there was no significant inhibition

  11. DNA fragmentation in apoptosis

    2000-01-01

    Cleavage of chromosomal DNA into oligonucleosomal size fragments is an integral part of apoptosis. Elegant biochemical work identified the DNA fragmentation factor (DFF) as a major apoptotic endonuclease for DNA fragmentation in vitro. Genetic studies in mice support the importance of DFF in DNA fragmentation and possibly in apoptosis in vivo. Recent work also suggests the existence of additional endonucleases for DNA degradation. Understanding the roles of individual endonucleases in apoptosis, and how they might coordinate to degrade DNA in different tissues during normal development and homeostasis, as well as in various diseased states, will be a major research focus in the near future.

  12. Functionalizing Designer DNA Crystals

    Chandrasekaran, Arun Richard

    nucleotides is usually pH dependent (pH < 6) four different TFOs were examined: TFO-1 was unmodified while TFOs 2-4 contained additional stabilizing analogues capable of extending triplex formation to pH 7. In addition, each of the TFOs contained a Cy5 dye at the 5'-end of the oligonucleotide to aid in characterization of TFO binding - crystals were obtained with all four variations of TFOs. Formation of DNA triplex in the motif was characterized by an electrophoretic mobility shift assay (EMSA), UV melting studies and FRET. Crystals containing TFO-1 (unmodified) and TFO-2 (with 2'-amino ethoxy modification) were isolated and flash-frozen in liquid nitrogen for X-ray data collection at beam line NSLS-X25. X-ray data was also collected for crystals of the 3-turn triangle without any TFO bound to it. Difference maps were done between the crystals with TFO against the one without to identify any additional electron density corresponding to the third strand in the triplex binding region. The data from the crystal containing TFO-2 was used to further analyze if the additional density can match the expected position of the TFO on the triangle motif. Since the additional density did not correspond to the entire binding region, 2Fo-Fc, 3Fo-2Fc and 4Fo-3Fc maps were done to check for missing pieces of the electron density. From the resulting 2Fo-Fc map, the asymmetric unit from the 3-turn triangle (31-bp duplex model based on previous structure 3UBI) was inserted into the density as a reference. However, the electron density corresponding to the TFO was still not continuous throughout the 13-nt triplex binding region and allowed only a partial fit of the TFO. The third nucleotide in positions 1, 3, 4, 6, 7 were fit into the density in the major groove of the underlying duplex with proper triplex configuration. The third chapter describes the triplex approach to position a functional group (the UV cross-linking agent psoralen) within a pre-formed DNA motif. Triplex formation and

  13. The Variational Fair Autoencoder

    C. Louizos; K. Swersky; Y. Li; M. Welling; R. Zemel

    2016-01-01

    We investigate the problem of learning representations that are invariant to certain nuisance or sensitive factors of variation in the data while retaining as much of the remaining information as possible. Our model is based on a variational autoencoding architecture with priors that encourage indep

  14. Mitochondrial DNA mutations in single human blood cells.

    Yao, Yong-Gang; Kajigaya, Sachiko; Young, Neal S

    2015-09-01

    Determination mitochondrial DNA (mtDNA) sequences from extremely small amounts of DNA extracted from tissue of limited amounts and/or degraded samples is frequently employed in medical, forensic, and anthropologic studies. Polymerase chain reaction (PCR) amplification followed by DNA cloning is a routine method, especially to examine heteroplasmy of mtDNA mutations. In this review, we compare the mtDNA mutation patterns detected by three different sequencing strategies. Cloning and sequencing methods that are based on PCR amplification of DNA extracted from either single cells or pooled cells yield a high frequency of mutations, partly due to the artifacts introduced by PCR and/or the DNA cloning process. Direct sequencing of PCR product which has been amplified from DNA in individual cells is able to detect the low levels of mtDNA mutations present within a cell. We further summarize the findings in our recent studies that utilized this single cell method to assay mtDNA mutation patterns in different human blood cells. Our data show that many somatic mutations observed in the end-stage differentiated cells are found in hematopoietic stem cells (HSCs) and progenitors within the CD34(+) cell compartment. Accumulation of mtDNA variations in the individual CD34+ cells is affected by both aging and family genetic background. Granulocytes harbor higher numbers of mutations compared with the other cells, such as CD34(+) cells and lymphocytes. Serial assessment of mtDNA mutations in a population of single CD34(+) cells obtained from the same donor over time suggests stability of some somatic mutations. CD34(+) cell clones from a donor marked by specific mtDNA somatic mutations can be found in the recipient after transplantation. The significance of these findings is discussed in terms of the lineage tracing of HSCs, aging effect on accumulation of mtDNA mutations and the usage of mtDNA sequence in forensic identification. PMID:26149767

  15. Massively Parallel Sequencing Approaches for Characterization of Structural Variation

    Koboldt, Daniel C.; Larson, David E.; Chen, Ken; Ding, Li; Wilson, Richard K.

    2012-01-01

    The emergence of next-generation sequencing (NGS) technologies offers an incredible opportunity to comprehensively study DNA sequence variation in human genomes. Commercially available platforms from Roche (454), Illumina (Genome Analyzer and Hiseq 2000), and Applied Biosystems (SOLiD) have the capability to completely sequence individual genomes to high levels of coverage. NGS data is particularly advantageous for the study of structural variation (SV) because it offers the sensitivity to de...

  16. Triplet repeat length bias and variation in the human transcriptome

    Molla, Michael; Delcher, Arthur; Sunyaev, Shamil; Cantor, Charles; Kasif, Simon

    2009-01-01

    Length variation in short tandem repeats (STRs) is an important family of DNA polymorphisms with numerous applications in genetics, medicine, forensics, and evolutionary analysis. Several major diseases have been associated with length variation of trinucleotide (triplet) repeats including Huntington's disease, hereditary ataxias and spinobulbar muscular atrophy. Using the reference human genome, we have catalogued all triplet repeats in genic regions. This data revealed a bias in noncoding D...

  17. Bonobos Fall within the Genomic Variation of Chimpanzees

    Fischer, A; Prüfer, K.; Good, J.; Halbwax, M.; Wiebe, V; André, C; Atencia, R.; Mugisha, L; Ptak, S.; Pääbo, S

    2011-01-01

    To gain insight into the patterns of genetic variation and evolutionary relationships within and between bonobos and chimpanzees, we sequenced 150,000 base pairs of nuclear DNA divided among 15 autosomal regions as well as the complete mitochondrial genomes from 20 bonobos and 58 chimpanzees. Except for western chimpanzees, we found poor genetic separation of chimpanzees based on sample locality. In contrast, bonobos consistently cluster together but fall as a group within the variation of ch...

  18. Low copy number of mitochondrial DNA (mtDNA) predicts worse prognosis in early-stage laryngeal cancer patients

    Dang, Siwen; Qu, Yiping; Wei, Jing; Shao, Yuan; Yang, Qi; Ji, Meiju; Shi, Bingyin; Hou, Peng

    2014-01-01

    Objectives Alterations in mitochondrial DNA (mtDNA) copy number have been widely reported in various human cancers, and been considered to be an important hallmark of cancers. However, little is known about the value of copy number variations of mtDNA in the prognostic evaluation of laryngeal cancer. Design and methods Using real-time quantitative PCR method, we investigated mtDNA copy number in a cohort of laryngeal cancers (n =204) and normal laryngeal tissues (n =40), and explored the asso...

  19. DNA damage and autophagy

    Both exogenous and endogenous agents are a threat to DNA integrity. Exogenous environmental agents such as ultraviolet (UV) and ionizing radiation, genotoxic chemicals and endogenous byproducts of metabolism including reactive oxygen species can cause alterations in DNA structure (DNA damage). Unrepaired DNA damage has been linked to a variety of human disorders including cancer and neurodegenerative disease. Thus, efficient mechanisms to detect DNA lesions, signal their presence and promote their repair have been evolved in cells. If DNA is effectively repaired, DNA damage response is inactivated and normal cell functioning resumes. In contrast, when DNA lesions cannot be removed, chronic DNA damage triggers specific cell responses such as cell death and senescence. Recently, DNA damage has been shown to induce autophagy, a cellular catabolic process that maintains a balance between synthesis, degradation, and recycling of cellular components. But the exact mechanisms by which DNA damage triggers autophagy are unclear. More importantly, the role of autophagy in the DNA damage response and cellular fate is unknown. In this review we analyze evidence that supports a role for autophagy as an integral part of the DNA damage response.

  20. DNA Open states and DNA hydratation

    It is a very well-known fact that an protonic exchange exists among natural DNA filaments and synthetic polynucleotides with the solvent (1--2). The existence of DNA open states, that is to say states for which the interior of the DNA molecule is exposed to the external environment, it has been demonstrated by means of proton-deuterium exchange (3). This work has carried out experiments measuring the dispersion of the traverse relaxation rate (4), as a pulsation rate function in a Carr-Purcell-Meiboom-Gill (CPMG) pulses sequence rate, to determine changes in the moist layer of the DNA molecule. The experiments were carried out under different experimental conditions in order to vary the probability that open states occurs, such as temperature or the exposure to electromagnetic fields. Some theoretical models were supposed to adjust the experimental results including those related to DNA non linear dynamic

  1. VariOtator, a Software Tool for Variation Annotation with the Variation Ontology.

    Schaafsma, Gerard C P; Vihinen, Mauno

    2016-04-01

    The Variation Ontology (VariO) is used for describing and annotating types, effects, consequences, and mechanisms of variations. To facilitate easy and consistent annotations, the online application VariOtator was developed. For variation type annotations, VariOtator is fully automated, accepting variant descriptions in Human Genome Variation Society (HGVS) format, and generating VariO terms, either with or without full lineage, that is, all parent terms. When a coding DNA variant description with a reference sequence is provided, VariOtator checks the description first with Mutalyzer and then generates the predicted RNA and protein descriptions with their respective VariO annotations. For the other sublevels, function, structure, and property, annotations cannot be automated, and VariOtator generates annotation based on provided details. For VariO terms relating to structure and property, one can use attribute terms as modifiers and evidence code terms for annotating experimental evidence. There is an online batch version, and stand-alone batch versions to be used with a Leiden Open Variation Database (LOVD) download file. A SOAP Web service allows client programs to access VariOtator programmatically. Thus, systematic variation effect and type annotations can be efficiently generated to allow easy use and integration of variations and their consequences. PMID:26773573

  2. Gene Expression Analysis Using Agilent DNA Microarrays

    Stangegaard, Michael

    2009-01-01

    Hybridization of labeled cDNA to microarrays is an intuitively simple and a vastly underestimated process. If it is not performed, optimized, and standardized with the same attention to detail as e.g., RNA amplification, information may be overlooked or even lost. Careful balancing of the amount of...... labeled cDNA added to each slide reduces dye-bias and slide to slide variation. Efficient mixing of the hybridization solution throughout the hybridization reaction increases signals several fold. The amount of near perfect target-probe hybrids may be reduced by efficient stringency washes of the...

  3. HPV DNA test

    The HPV DNA test is used to check for high-risk HPV infection in women. HPV infection around the genitals is ... warts spread when you have sex. The HPV-DNA test is generally not recommended for detecting low- ...

  4. Modeling DNA Replication.

    Bennett, Joan

    1998-01-01

    Recommends the use of a model of DNA made out of Velcro to help students visualize the steps of DNA replication. Includes a materials list, construction directions, and details of the demonstration using the model parts. (DDR)

  5. Mitochondrial DNA Haplogroup Analysis Reveals no Association between the Common Genetic Lineages and Prostate Cancer in the Korean Population

    Kim, Wook; Yoo, Tag-Keun; Shin, Dong-Jik; Rho, Hyun-Wook; Jin, Han-Jun; Kim, Eun-Tak; Bae, Yoon-Sun

    2008-01-01

    Mitochondrial DNA (mtDNA) variation has recently been suggested to have an association with various cancers, including prostate cancer risk, in human populations. Since mtDNA is haploid and lacks recombination, specific mutations in the mtDNA genome associated with human diseases arise and remain in particular genetic backgrounds referred to as haplogroups. To assess the possible contribution of mtDNA haplogroup-specific mutations to the occurrence of prostate cancer, we have therefore perfor...

  6. Survival and mitochondrial function in septic patients according to mitochondrial DNA haplogroup

    Lorente, Leonardo; Iceta, Ruth; Martín, María M.; López-Gallardo, Esther; Solé-Violán, Jordi; Blanquer, José; Labarta, Lorenzo; Díaz, César; Jiménez, Alejandro; Montoya, Julio; Ruiz-Pesini, Eduardo

    2012-01-01

    Introduction We recently found that platelet cytochrome c oxidase (COX) activities and quantities in 6-month-survival septic patients are significantly higher than those of patients who died before 6 months. Other studies suggested that the mitochondrial DNA (mtDNA) genotype could play a major role in sepsis survival. Given that COX catalytic subunits are encoded by mtDNA, the objective of the present study was to explore whether mtDNA population genetic variation could affect COX activity an...

  7. Hysteresis in pressure-driven DNA denaturation.

    Enrique Hernández-Lemus

    Full Text Available In the past, a great deal of attention has been drawn to thermal driven denaturation processes. In recent years, however, the discovery of stress-induced denaturation, observed at the one-molecule level, has revealed new insights into the complex phenomena involved in the thermo-mechanics of DNA function. Understanding the effect of local pressure variations in DNA stability is thus an appealing topic. Such processes as cellular stress, dehydration, and changes in the ionic strength of the medium could explain local pressure changes that will affect the molecular mechanics of DNA and hence its stability. In this work, a theory that accounts for hysteresis in pressure-driven DNA denaturation is proposed. We here combine an irreversible thermodynamic approach with an equation of state based on the Poisson-Boltzmann cell model. The latter one provides a good description of the osmotic pressure over a wide range of DNA concentrations. The resulting theoretical framework predicts, in general, the process of denaturation and, in particular, hysteresis curves for a DNA sequence in terms of system parameters such as salt concentration, density of DNA molecules and temperature in addition to structural and configurational states of DNA. Furthermore, this formalism can be naturally extended to more complex situations, for example, in cases where the host medium is made up of asymmetric salts or in the description of the (helical-like charge distribution along the DNA molecule. Moreover, since this study incorporates the effect of pressure through a thermodynamic analysis, much of what is known from temperature-driven experiments will shed light on the pressure-induced melting issue.

  8. Recombinant DNA in Medicine

    Cederbaum, Stephen D.; Fareed, George C.; Lovett, Michael A.; Shapiro, Larry J.

    1984-01-01

    Studies in bacteria and bacterial viruses have led to methods to manipulate and recombine DNA in unique and reproducible ways and to amplify these recombined molecules millions of times. Once properly identified, the recombinant DNA molecules can be used in various ways useful in medicine and human biology. There are many applications for recombinant DNA technology. Cloned complementary DNA has been used to produce various human proteins in microorganisms. Insulin and growth hormone have been...

  9. Is DNA a language?

    Tsonis, A A; Elsner, J B; Tsonis, P A

    1997-01-01

    DNA sequences usually involve local construction rules that affect different scales. As such their "dictionary" may not follow Zipf's law (a power law) which is followed in every natural language. Indeed, analysis of many DNA sequences suggests that no linguistics connections to DNA exist and that even though it has structure DNA is not a language. Computer simulations and a biological approach to this problem further support these results. PMID:9039397

  10. DNA Damage Response

    Giglia-Mari, Giuseppina; Zotter, Angelika; Vermeulen, Wim

    2011-01-01

    Structural changes to DNA severely affect its functions, such as replication and transcription, and play a major role in age-related diseases and cancer. A complicated and entangled network of DNA damage response (DDR) mechanisms, including multiple DNA repair pathways, damage tolerance processes, and cell-cycle checkpoints safeguard genomic integrity. Like transcription and replication, DDR is a chromatin-associated process that is generally tightly controlled in time and space. As DNA damag...

  11. DNA-Mediated Electrochemistry

    Gorodetsky, Alon A.; Buzzeo, Marisa C.; Barton, Jacqueline K.

    2008-01-01

    The base pair stack of DNA has been demonstrated as a medium for long-range charge transport chemistry both in solution and at DNA-modified surfaces. This chemistry is exquisitely sensitive to structural perturbations in the base pair stack as occur with lesions, single base mismatches, and protein binding. We have exploited this sensitivity for the development of reliable electrochemical assays based on DNA charge transport at self-assembled DNA monolayers. Here, we discuss the characteristi...

  12. Reduced mitochondrial DNA copy number in Chinese patients with osteosarcoma.

    Yu, Man; Wan, Yanfang; Zou, Qinghua

    2013-03-01

    A plethora of somatic mutations and germline variations in mitochondrial DNA (mtDNA) have been increasingly reported in numerous cancer entities including osteosarcoma. However, it remains largely unclear whether mtDNA copy number changes occur during the multistep process of osteosarcoma carcinogenesis. For this purpose, we determined quantitative mtDNA levels in 31 primary osteosarcoma specimens and 5 normal bone tissue samples using a real-time polymerase chain reaction assay. Our data showed that the average mtDNA amount was significantly reduced in osteosarcoma tissues compared with normal bone controls. The copy number of mtDNA was statistically associated with tumor metastasis. There was an approximately 2-fold decrease of mtDNA quantity in tumors with metastasis than that in low-grade tumors without metastasis. Furthermore, change in mtDNA content was linked with somatic mutations in the D-loop regulatory region. Tumors carrying somatic D-loop mutations, at the polycytidine stretch between nucleotide positions 303 and 309 or close to the replication origin sites of the heavy strand, had significantly lowered mtDNA levels in comparison with those without mutations. Taken together, these results provide evidence for the first time that reduced mtDNA content may be critically implicated in the development and/or progression of osteosarcoma. Somatic D-loop mutation is likely one key factor among others leading to altered mtDNA amount in osteosarcoma. PMID:23177796

  13. Ensembl variation resources

    Marin-Garcia Pablo

    2010-05-01

    Full Text Available Abstract Background The maturing field of genomics is rapidly increasing the number of sequenced genomes and producing more information from those previously sequenced. Much of this additional information is variation data derived from sampling multiple individuals of a given species with the goal of discovering new variants and characterising the population frequencies of the variants that are already known. These data have immense value for many studies, including those designed to understand evolution and connect genotype to phenotype. Maximising the utility of the data requires that it be stored in an accessible manner that facilitates the integration of variation data with other genome resources such as gene annotation and comparative genomics. Description The Ensembl project provides comprehensive and integrated variation resources for a wide variety of chordate genomes. This paper provides a detailed description of the sources of data and the methods for creating the Ensembl variation databases. It also explores the utility of the information by explaining the range of query options available, from using interactive web displays, to online data mining tools and connecting directly to the data servers programmatically. It gives a good overview of the variation resources and future plans for expanding the variation data within Ensembl. Conclusions Variation data is an important key to understanding the functional and phenotypic differences between individuals. The development of new sequencing and genotyping technologies is greatly increasing the amount of variation data known for almost all genomes. The Ensembl variation resources are integrated into the Ensembl genome browser and provide a comprehensive way to access this data in the context of a widely used genome bioinformatics system. All Ensembl data is freely available at http://www.ensembl.org and from the public MySQL database server at ensembldb.ensembl.org.

  14. Variability of chloroplast DNA and nuclear ribosomal DNA in cassava (Manihot esculenta Crantz) and its wild relatives.

    Fregene, M A; Vargas, J; Ikea, J; Angel, F; Tohme, J; Asiedu, R A; Akoroda, M O; Roca, W M

    1994-11-01

    Chloroplast DNA (cp) and nuclear ribosomal DNA (rDNA) variation was investigated in 45 accessions of cultivated and wild Manihot species. Ten independent mutations, 8 point mutations and 2 length mutations were identified, using eight restriction enzymes and 12 heterologous cpDNA probes from mungbean. Restriction fragment length polymorphism analysis defined nine distinct chloroplast types, three of which were found among the cultivated accessions and six among the wild species. Cladistic analysis of the cpDNA data using parsimony yielded a hypothetical phylogeny of lineages among the cpDNAs of cassava and its wild relatives that is congruent with morphological evolutionary differentiation in the genus. The results of our survey of cpDNA, together with rDNA restriction site change at the intergenic spacer region and rDNA repeat unit length variation (using rDNA cloned fragments from taro as probe), suggest that cassava might have arisen from the domestication of wild tuberous accessions of some Manihot species, followed by intensive selection. M. esculenta subspp flabellifolia is probably a wild progenitor. Introgressive hybridization with wild forms and pressures to adapt to the widely varying climates and topography in which cassava is found might have enhanced the crop's present day variability. PMID:24178017

  15. Replicating animal mitochondrial DNA

    Emily A. McKinney

    2013-01-01

    Full Text Available The field of mitochondrial DNA (mtDNA replication has been experiencing incredible progress in recent years, and yet little is certain about the mechanism(s used by animal cells to replicate this plasmid-like genome. The long-standing strand-displacement model of mammalian mtDNA replication (for which single-stranded DNA intermediates are a hallmark has been intensively challenged by a new set of data, which suggests that replication proceeds via coupled leading-and lagging-strand synthesis (resembling bacterial genome replication and/or via long stretches of RNA intermediates laid on the mtDNA lagging-strand (the so called RITOLS. The set of proteins required for mtDNA replication is small and includes the catalytic and accessory subunits of DNA polymerase y, the mtDNA helicase Twinkle, the mitochondrial single-stranded DNA-binding protein, and the mitochondrial RNA polymerase (which most likely functions as the mtDNA primase. Mutations in the genes coding for the first three proteins are associated with human diseases and premature aging, justifying the research interest in the genetic, biochemical and structural properties of the mtDNA replication machinery. Here we summarize these properties and discuss the current models of mtDNA replication in animal cells.

  16. DNA damage response

    G. Giglia-Mari (Giuseppina); A. Zotter (Angelika); W. Vermeulen (Wim)

    2011-01-01

    textabstractStructural changes to DNA severely affect its functions, such as replication and transcription, and play a major role in age-related diseases and cancer. A complicated and entangled network ofDNA damage response (DDR) mechanisms, including multiple DNA repair pathways, damage tolerance p

  17. Theory of conjectural variations

    Jean-Marie, Alain

    2004-01-01

    We have witnessed in recent years a revival of Conjectural Variations in Game Theory. This reincarnation of an old idea, using a dynamic point of view, aims at combining the adequacy with facts to the requirements of a firmly grounded theory. This book presents, for the first time, a comprehensive account of conjectural variations equilibria in their static inceptions, featuring new comparative results of equilibria with regard to efficiency. It then describes several advances in Dynamic Game Theory, allowing to understand Conjectural Variations Equilibria as dynamic equilibria. The question o

  18. Comparisons of direct extraction methods of microbial DNA from different paddy soils

    Islam, Md. Rashedul; Sultana, Tahera; Melvin Joe, M.; Cho, Jang-Cheon; Sa, Tongmin

    2012-01-01

    Molecular analyses for the study of soil microbial communities often depend on the direct extraction of DNA from soils. The present work compares the effectiveness of three different methods of extracting microbial DNA from seven different paddy soils. Comparison among different DNA extraction methods against different paddy soil samples revealed a marked variation in DNA yields from 3.18–20.17 μg DNA/g of dry soil. However, irrespective of the soil samples and extraction methods the DNA frag...

  19. Electrophile and oxidant damage of mitochondrial DNA leading to rapid evolution of homoplasmic mutations

    Mambo, Elizabeth; Gao, Xiangqun; Cohen, Yoram; Guo, Zhongmin; Talalay, Paul; Sidransky, David

    2003-01-01

    mtDNA mutations occur in a wide variety of degenerative diseases and cancer. mtDNA seems to be more susceptible to DNA damage and consequently sustains higher rates of mutation than does nuclear DNA (nDNA). Many of the somatic mtDNA mutations in human cancers are located in the displacement loop (D-loop) and in particular in a polycytidine stretch (C-tract) termed D310. The D310 region exhibits polymorphic length variation among individuals and has been described as a “hot spot” for somatic m...

  20. A mechanism of gene amplification driven by small DNA fragments.

    Kuntal Mukherjee

    Full Text Available DNA amplification is a molecular process that increases the copy number of a chromosomal tract and often causes elevated expression of the amplified gene(s. Although gene amplification is frequently observed in cancer and other degenerative disorders, the molecular mechanisms involved in the process of DNA copy number increase remain largely unknown. We hypothesized that small DNA fragments could be the trigger of DNA amplification events. Following our findings that small fragments of DNA in the form of DNA oligonucleotides can be highly recombinogenic, we have developed a system in the yeast Saccharomyces cerevisiae to capture events of chromosomal DNA amplification initiated by small DNA fragments. Here we demonstrate that small DNAs can amplify a chromosomal region, generating either tandem duplications or acentric extrachromosomal DNA circles. Small fragment-driven DNA amplification (SFDA occurs with a frequency that increases with the length of homology between the small DNAs and the target chromosomal regions. SFDA events are triggered even by small single-stranded molecules with as little as 20-nt homology with the genomic target. A double-strand break (DSB external to the chromosomal amplicon region stimulates the amplification event up to a factor of 20 and favors formation of extrachromosomal circles. SFDA is dependent on Rad52 and Rad59, partially dependent on Rad1, Rad10, and Pol32, and independent of Rad51, suggesting a single-strand annealing mechanism. Our results reveal a novel molecular model for gene amplification, in which small DNA fragments drive DNA amplification and define the boundaries of the amplicon region. As DNA fragments are frequently found both inside cells and in the extracellular environment, such as the serum of patients with cancer or other degenerative disorders, we propose that SFDA may be a common mechanism for DNA amplification in cancer cells, as well as a more general cause of DNA copy number variation

  1. A mechanism of gene amplification driven by small DNA fragments.

    Mukherjee, Kuntal; Storici, Francesca

    2012-01-01

    DNA amplification is a molecular process that increases the copy number of a chromosomal tract and often causes elevated expression of the amplified gene(s). Although gene amplification is frequently observed in cancer and other degenerative disorders, the molecular mechanisms involved in the process of DNA copy number increase remain largely unknown. We hypothesized that small DNA fragments could be the trigger of DNA amplification events. Following our findings that small fragments of DNA in the form of DNA oligonucleotides can be highly recombinogenic, we have developed a system in the yeast Saccharomyces cerevisiae to capture events of chromosomal DNA amplification initiated by small DNA fragments. Here we demonstrate that small DNAs can amplify a chromosomal region, generating either tandem duplications or acentric extrachromosomal DNA circles. Small fragment-driven DNA amplification (SFDA) occurs with a frequency that increases with the length of homology between the small DNAs and the target chromosomal regions. SFDA events are triggered even by small single-stranded molecules with as little as 20-nt homology with the genomic target. A double-strand break (DSB) external to the chromosomal amplicon region stimulates the amplification event up to a factor of 20 and favors formation of extrachromosomal circles. SFDA is dependent on Rad52 and Rad59, partially dependent on Rad1, Rad10, and Pol32, and independent of Rad51, suggesting a single-strand annealing mechanism. Our results reveal a novel molecular model for gene amplification, in which small DNA fragments drive DNA amplification and define the boundaries of the amplicon region. As DNA fragments are frequently found both inside cells and in the extracellular environment, such as the serum of patients with cancer or other degenerative disorders, we propose that SFDA may be a common mechanism for DNA amplification in cancer cells, as well as a more general cause of DNA copy number variation in nature. PMID

  2. Risk assessment of DNA-reactive carcinogens in food

    Risk assessment of DNA-reactive carcinogens in food requires knowledge of the extent of DNA damage in the target organ which results from the competition between DNA adduct formation and repair. Estimates of DNA adduct levels can be made by direct measurement or indirectly as a consequence of their presence, for example, by tumor formation in animal models or exposed populations epidemiologically. Food-borne DNA-reactive carcinogens are present from a variety of sources. They are generally not intrinsically DNA-reactive but require bioactivation to DNA-reactive metabolites a process which may be modulated by the compound itself or the presence of other xenobiotics. A single DNA reactant may form several distinct DNA adducts each undergoing different rates of repair. Some DNA reactants may be photochemically activated or produce reactive oxygen species and thus indirect oxidative DNA damage. The levels of DNA adducts arising from exposures influenced by variations in the doses, the frequency with which an individual is exposed, and rates of DNA repair for specific adducts. Each adduct has a characteristic efficiency with which it induces mutations. Based on experience with the well-studied DNA-reactive food carcinogen aflatoxin B1 (AFB1), a limit of 20 ppb or ∼30 μg/day has been set and is considered a tolerable daily intake (TDI). Since AFB1 is considered a potent carcinogen, doses of 32P-postlabeling or the use of surrogates such as hemoglobin adducts, together with approaches to evaluate the results. A discussion of approaches to estimating possible threshold effects for DNA-reactive carcinogens is made

  3. Estimates of DNA strand breakage in bottlenose dolphin (Tursiops truncatus) leukocytes measured with the Comet and DNA diffusion assays.

    Díaz, Adriana; Carro, Sandra; Santiago, Livia; Estévez, Juan; Guevara, Celia; Blanco, Miriam; Sánchez, Laima; Sánchez, Liena; López, Nirka; Cruz, Danilo; López, Ronar; Cuetara, Elizabeth B; Fuentes, Jorge Luis

    2009-04-01

    The analysis of DNA damage by mean of Comet or single cell gel electrophoresis (SCGE) assay has been commonly used to assess genotoxic impact in aquatic animals being able to detect exposure to low concentrations of contaminants in a wide range of species. The aims of this work were 1) to evaluate the usefulness of the Comet to detect DNA strand breakage in dolphin leukocytes, 2) to use the DNA diffusion assay to determine the amount of DNA strand breakage associated with apoptosis or necrosis, and 3) to determine the proportion of DNA strand breakage that was unrelated to apoptosis and necrosis. Significant intra-individual variation was observed in all of the estimates of DNA damage. DNA strand breakage was overestimated because a considerable amount (~29%) of the DNA damage was derived from apoptosis and necrosis. The remaining DNA damage in dolphin leukocytes was caused by factors unrelated to apoptosis and necrosis. These results indicate that the DNA diffusion assay is a complementary tool that can be used together with the Comet assay to assess DNA damage in bottlenose dolphins. PMID:21637693

  4. Estimates of DNA strand breakage in bottlenose dolphin (Tursiops truncatus leukocytes measured with the Comet and DNA diffusion assays

    Adriana Díaz

    2009-01-01

    Full Text Available The analysis of DNA damage by mean of Comet or single cell gel electrophoresis (SCGE assay has been commonly used to assess genotoxic impact in aquatic animals being able to detect exposure to low concentrations of contaminants in a wide range of species. The aims of this work were 1 to evaluate the usefulness of the Comet to detect DNA strand breakage in dolphin leukocytes, 2 to use the DNA diffusion assay to determine the amount of DNA strand breakage associated with apoptosis or necrosis, and 3 to determine the proportion of DNA strand breakage that was unrelated to apoptosis and necrosis. Significant intra-individual variation was observed in all of the estimates of DNA damage. DNA strand breakage was overestimated because a considerable amount (~29% of the DNA damage was derived from apoptosis and necrosis. The remaining DNA damage in dolphin leukocytes was caused by factors unrelated to apoptosis and necrosis. These results indicate that the DNA diffusion assay is a complementary tool that can be used together with the Comet assay to assess DNA damage in bottlenose dolphins.

  5. Introgression of mitochondrial DNA among Myodes voles: consequences for energetics?

    Boratyński Zbyszek

    2011-12-01

    Full Text Available Abstract Background Introgression of mitochondrial DNA (mtDNA is among the most frequently described cases of reticulate evolution. The tendency of mtDNA to cross interspecific barriers is somewhat counter-intuitive considering the key function of enzymes that it encodes in the oxidative-phosphorylation process, which could give rise to hybrid dysfunction. How mtDNA reticulation affects the evolution of metabolic functions is, however, uncertain. Here we investigated how morpho-physiological traits vary in natural populations of a common rodent (the bank vole, Myodes glareolus and whether this variation could be associated with mtDNA introgression. First, we confirmed that M. glareolus harbour mtDNA introgressed from M. rutilus by analyzing mtDNA (cytochrome b, 954 bp and nuclear DNA (four markers; 2333 bp in total sequence variation and reconstructing loci phylogenies among six natural populations in Finland. We then studied geographic variation in body size and basal metabolic rate (BMR among the populations of M. glareolus and tested its relationship with mtDNA type. Results Myodes glareolus and its arctic neighbour, M. rutilus, are reciprocally monophyletic at the analyzed nuclear DNA loci. In contrast, the two northernmost populations of M. glareolus have a fixed mitotype that is shared with M. rutilus, likely due to introgressive hybridization. The analyses of phenotypic traits revealed that the body mass and whole-body, but not mass corrected, BMR are significantly reduced in M. glareolus females from northern Finland that also have the introgressed mitotype. Restricting the analysis to the single population where the mitotypes coexist, the association of mtDNA type with whole-body BMR remained but those with mass corrected BMR and body mass did not. Mitochondrial sequence variation in the introgressed haplotypes is compatible with demographic growth of the populations, but may also be a result of positive selection. Conclusion Our

  6. DNA interaction with cis- and trans- isomers of photosensitive surfactant

    Unksov, I. N.; Kasyanenko, N. A.

    2014-12-01

    Interaction between DNA and photosensitive cationic surfactant in a solution is studied. Studies were conducted to examine the impact of the surfactant in its cis- conformation on the size of DNA molecule and also to investigate the phase behavior of the system depending on DNA and surfactant concentration. We conclude that trans- isomer of surfactant requires its smaller concentration to reach the DNA compaction compared with cis- isomer received by UV radiation of solutions. Studies of DNA-surfactant systems were performed by means of spectrophotometry and viscometry. Variation of surfactant concentration enables us to determine the precipitation zone on phase diagram. From the viscosity study it can be indicated that precipitation zone is narrower for UV-radiated surfactant and it shifts to higher surfactant concentration. Also we examine the reversibility of DNA compaction in systems with the surfactant in its trans- form.

  7. DNA interaction with cis- and trans- isomers of photosensitive surfactant

    Interaction between DNA and photosensitive cationic surfactant in a solution is studied. Studies were conducted to examine the impact of the surfactant in its cis- conformation on the size of DNA molecule and also to investigate the phase behavior of the system depending on DNA and surfactant concentration. We conclude that trans- isomer of surfactant requires its smaller concentration to reach the DNA compaction compared with cis- isomer received by UV radiation of solutions. Studies of DNA-surfactant systems were performed by means of spectrophotometry and viscometry. Variation of surfactant concentration enables us to determine the precipitation zone on phase diagram. From the viscosity study it can be indicated that precipitation zone is narrower for UV-radiated surfactant and it shifts to higher surfactant concentration. Also we examine the reversibility of DNA compaction in systems with the surfactant in its trans- form

  8. Conformation dependent electronic transport in a DNA double-helix

    We present a tight-binding study of conformation dependent electronic transport properties of DNA double-helix including its helical symmetry. We have studied the changes in the localization properties of DNA as we alter the number of stacked bases within every pitch of the double-helix keeping fixed the total number of nitrogen bases within the DNA molecule. We take three DNA sequences, two of them are periodic and one is random and observe that in all the cases localization length increases as we increase the radius of DNA double-helix i.e., number of nucleobases within a pitch. We have also investigated the effect of backbone energetic on the I-V response of the system and found that in presence of helical symmetry, depending on the interplay of conformal variation and disorder, DNA can be found in either metallic, semiconducting and insulating phases, as observed experimentally

  9. Conformation dependent electronic transport in a DNA double-helix

    Kundu, Sourav, E-mail: sourav.kundu@saha.ac.in; Karmakar, S. N., E-mail: sachindranath.karmakar@saha.ac.in [Condensed Matter Physics Division, Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata 700 064 (India)

    2015-10-15

    We present a tight-binding study of conformation dependent electronic transport properties of DNA double-helix including its helical symmetry. We have studied the changes in the localization properties of DNA as we alter the number of stacked bases within every pitch of the double-helix keeping fixed the total number of nitrogen bases within the DNA molecule. We take three DNA sequences, two of them are periodic and one is random and observe that in all the cases localization length increases as we increase the radius of DNA double-helix i.e., number of nucleobases within a pitch. We have also investigated the effect of backbone energetic on the I-V response of the system and found that in presence of helical symmetry, depending on the interplay of conformal variation and disorder, DNA can be found in either metallic, semiconducting and insulating phases, as observed experimentally.

  10. DNA-Metallodrugs Interactions Signaled by Electrochemical Biosensors: An Overview

    Mauro Ravera

    2007-01-01

    Full Text Available The interaction of drugs with DNA is an important aspect in pharmacology. In recent years, many important technological advances have been made to develop new techniques to monitor biorecognition and biointeraction on solid devices. The interaction between DNA and drugs can cause chemical and conformational modifications and, thus, variation of the electrochemical properties of nucleobases. The propensity of a given compound to interact with DNA is measured as a function of the decrease of guanine oxidation signal on a DNA electrochemical biosensor. Covalent binding at N7 of guanine, electrostatic interactions, and intercalation are the events that this kind of biosensor can detect. In this context, the interaction between a panel of antitumoral Pt-, Ru-, and Ti-based metallodrugs with DNA immobilized on screen-printed electrodes has been studied. The DNA biosensors are used for semiquantitative evaluation of the analogous interaction occurring in the biological environment.

  11. DNA loops and semicatenated DNA junctions

    Strauss François; Gaillard Claire

    2000-01-01

    Abstract Background Alternative DNA conformations are of particular interest as potential signals to mark important sites on the genome. The structural variability of CA microsatellites is particularly pronounced; these are repetitive poly(CA) · poly(TG) DNA sequences spread in all eukaryotic genomes as tracts of up to 60 base pairs long. Many in vitro studies have shown that the structure of poly(CA) · poly(TG) can vary markedly from the classical right handed DNA double helix and adopt dive...

  12. Mitochondrial Dna Replacement Versus Nuclear Dna Persistence

    Serva, Maurizio

    2006-01-01

    In this paper we consider two populations whose generations are not overlapping and whose size is large. The number of males and females in both populations is constant. Any generation is replaced by a new one and any individual has two parents for what concerns nuclear DNA and a single one (the mother) for what concerns mtDNA. Moreover, at any generation some individuals migrate from the first population to the second. In a finite random time $T$, the mtDNA of the second population is comple...

  13. Quantum variational calculus

    Malinowska, Agnieszka B

    2014-01-01

    This Brief puts together two subjects, quantum and variational calculi by considering variational problems involving Hahn quantum operators. The main advantage of its results is that they are able to deal with nondifferentiable (even discontinuous) functions, which are important in applications. Possible applications in economics are discussed. Economists model time as continuous or discrete. Although individual economic decisions are generally made at discrete time intervals, they may well be less than perfectly synchronized in ways discrete models postulate. On the other hand, the usual assumption that economic activity takes place continuously, is nothing else than a convenient abstraction that in many applications is far from reality. The Hahn quantum calculus helps to bridge the gap between the two families of models: continuous and discrete. Quantum Variational Calculus is self-contained and unified in presentation. It provides an opportunity for an introduction to the quantum calculus of variations fo...

  14. Variational Inequalities with Applications

    Sofonea, Mircea

    2009-01-01

    Motivated by stimulating problems in contact mechanics, emphasizing antiplane frictional contact with linearly elastic and viscoelastic materials, this book focuses on the essentials with respect to the qualitative aspects of several classes of variational inequalities (VIs)

  15. Variational principles in physics

    Basdevant, Jean-Louis

    2007-01-01

    Optimization under constraints is an essential part of everyday life. Indeed, we routinely solve problems by striking a balance between contradictory interests, individual desires and material contingencies. This notion of equilibrium was dear to thinkers of the enlightenment, as illustrated by Montesquieu’s famous formulation: "In all magistracies, the greatness of the power must be compensated by the brevity of the duration." Astonishingly, natural laws are guided by a similar principle. Variational principles have proven to be surprisingly fertile. For example, Fermat used variational methods to demonstrate that light follows the fastest route from one point to another, an idea which came to be known as Fermat’s principle, a cornerstone of geometrical optics. Variational Principles in Physics explains variational principles and charts their use throughout modern physics. The heart of the book is devoted to the analytical mechanics of Lagrange and Hamilton, the basic tools of any physicist. Prof. Basdev...

  16. Mitochondrial DNA hypomethylation in chrome plating workers.

    Yang, Linqing; Xia, Bo; Yang, Xueqin; Ding, Hong; Wu, Desheng; Zhang, Huimin; Jiang, Gaofeng; Liu, Jianjun; Zhuang, Zhixiong

    2016-01-22

    A matched case-control study was conducted to examine the relationship between chromium (Cr) exposure and variation in mitochondrial (mt) DNA methylation. We enrolled 29 pairs of subjects in this study; Cr exposure was confirmed in the cases by detecting blood Cr and other metal ion concentrations. DNA damage caused by Cr exposure was determined in terms of binucleated micronucleus frequency (BNMN) and mtDNA copy number. Finally, a Sequenom MassARRAY platform was applied to inspect the DNA methylation levels of mitochondrially encoded tRNA phenylalanine (MT-TF), mitochondrially encoded 12S RNA (MT-RNR1), and long interspersed nucleotide element-1 (LINE-1) genes. The blood Cr ion concentration and micronucleus frequency of the Cr-exposed group were higher than those of the control group, whereas the mtDNA copy number remained unchanged. The methylation levels of MT-TF and MT-RNR1 but not LINE-1 were significantly lower in Cr-exposed workers. Pearson correlation analysis showed that workers with higher blood Cr ion concentrations exhibited lower MT-TF and MT-RNR1 gene methylation, and multiple linear regression analysis indicated that CpG sites 1 and 2 in MT-TF and CpG site 6 in MT-RNR1 were affected. These results suggested that methylation level of mtDNA has the possibility of acting as an alternative effect biomarker for Cr exposure. PMID:26656300

  17. Generalized quasi variational inequalities

    Noor, M.A. [King Saud Univ., Riyadh (Saudi Arabia)

    1996-12-31

    In this paper, we establish the equivalence between the generalized quasi variational inequalities and the generalized implicit Wiener-Hopf equations using essentially the projection technique. This equivalence is used to suggest and analyze a number of new iterative algorithms for solving generalized quasi variational inequalities and the related complementarity problems. The convergence criteria is also considered. The results proved in this paper represent a significant improvement and refinement of the previously known results.

  18. Variational time integrators

    Lew, A.; Marsden, J. E.; Ortiz, M.; West, M

    2004-01-01

    The purpose of this paper is to review and further develop the subject of variational integration algorithms as it applies to mechanical systems of engineering interest. In particular, the conservation properties of both synchronous and asynchronous variational integrators (AVIs) are discussed in detail. We present selected numerical examples which demonstrate the excellent accuracy, conservation and convergence characteristics of AVIs. In these tests, AVIs are found to result in substantial ...

  19. Fast phylogenetic DNA barcoding

    Terkelsen, Kasper Munch; Boomsma, Wouter Krogh; Willerslev, Eske;

    2008-01-01

    We present a heuristic approach to the DNA assignment problem based on phylogenetic inferences using constrained neighbour joining and non-parametric bootstrapping. We show that this method performs as well as the more computationally intensive full Bayesian approach in an analysis of 500 insect...... DNA sequences obtained from GenBank. We also analyse a previously published dataset of environmental DNA sequences from soil from New Zealand and Siberia, and use these data to illustrate the fact that statistical approaches to the DNA assignment problem allow for more appropriate criteria...... for determining the taxonomic level at which a particular DNA sequence can be assigned....

  20. Electronic Transport in DNA

    Klotsa, Daphne; Römer, Rudolf A.; Turner, Matthew S.

    2005-01-01

    We study the electronic properties of DNA by way of a tight-binding model applied to four particular DNA sequences. The charge transfer properties are presented in terms of localisation lengths, crudely speaking the length over which electrons travel. Various types of disorder, including random potentials, are employed to account for different real environments. We have performed calculations on poly(dG)-poly(dC), telomeric-DNA, random-ATGC DNA and lambda-DNA. We find that random and lambda-D...

  1. DNA氧化性损伤标志物8-羟基脱氧鸟苷在阿尔茨海默病和血管性痴呆患者血浆中的变化%Variation of plasma oxidative DNA damage marker 8-hydroxy-2'-deoxyguanosine in patients with Alzheimer's disease versus vascular dementia

    朱红敏; 章军建; 杨英

    2013-01-01

    目的 观察阿尔茨海默病(AD)与血管性痴呆(VaD)患者血浆中DNA氧化损伤标志物8羟基脱氧鸟苷(8-OHdG)水平的变化,探讨DNA氧化损伤在AD和VaD发病中的作用. 方法 用酶联免疫吸附试验的方法测定35例AD患者和28例VaD患者以及与之年龄相匹配的23例健康者血浆中8-OHdG的水平,用简易智力量表(MMSE)评测AD和VaD患者的认知功能. 结果 AD组、VaD组、健康对照组患者血浆中8-OHdG浓度分别为(601.8±266.0)ng/L、(1748.0±665.6)ng/L和(352.0±94.5)ng/L,各组间血浆8OHdG水平差异有统计学意义(P<0.001).VaD组患者血浆中8-OHdG水平与对照组比较差异有统计学意义(P<0.05);而AD组患者血浆中8-OHdG水平与对照组比较差异无统计学意义(P>0.05);并且VaD组与AD组比较,8-OHdG水平变化的差异也有统计学意义(P<0.05).各组血浆8-OHdG水平与年龄均呈正相关,分别为:AD组(r=0.661,P<0.01)、VaD组(r=0.702,P<0.01)、正常对照组(r=0.719,P<0.01).而各组血浆8-OHdG水平与教育水平无明显相关性(均P>0.05).在AD组和VaD组患者中根据其危险因素(性别、吸烟、高血压、糖尿病、高血脂)进行分组,比较各组间血浆8-OHdG水平的差异,结果发现各组间比较差异均无统计学意义(均P>0.05).校正了性别、年龄、教育水平、吸烟、高血压、高血脂、糖尿病因素的影响后,采用多分类Logistic回归分析结果显示:血浆中高水平8-OHdG在VaD组中比AD组和正常对照组的可能性均高.VaD组血浆8-OHdG水平与MMSE分数呈显著负相关性(r=-0.592,P<0.01);AD组血浆8-OHdG水平与MMSE分数无相关性(r=-0.122,P>0.05). 结论 VaD患者存在明显的DNA氧化损伤,其血浆DNA氧化损伤程度显著高于AD患者与健康者;VaD患者的血浆DNA氧化损伤标志物8-OHdG与其认知功能损害程度密切相关.%Objective To observe the variation of plasma 8-hydroxy-2'-deoxyguanosine (8-OHdG),a biomarker of oxidative DNA

  2. Chromatic variations suppress suprathreshold brightness variations.

    Kingdom, Frederick A A; Bell, Jason; Gheorghiu, Elena; Malkoc, Gokhan

    2010-01-01

    Most objects in natural scenes are suprathreshold in both color (chromatic) and luminance contrast. How salient is each dimension? We have developed a novel method employing a stimulus similar to that used by B. C. Regan and J. D. Mollon (1997) who studied the relative saliencies of the two chromatic cardinal directions. Our stimuli consist of left- and right-oblique modulations of color and/or luminance defined within a lattice of circles. In the "separated" condition, the two modulations were presented separately as forced-choice pairs, and the task was to indicate which was more salient. In the "combined" condition, the two orthogonal-in-orientation modulations were added, and the task was to indicate the more salient orientation. The ratio of color to luminance contrast at the PSE was calculated for both conditions. Across color directions, 48% more luminance contrast relative to color contrast was required to achieve a PSE in the "combined" compared to the "separated" condition. A second experiment showed that the PSE difference was due to the luminance being masked by the color, rather than due to superior color grouping. We conclude that suprathreshold brightness variations are masked by suprathreshold color variations. PMID:20884478

  3. Variation in Metaphor Variation in Metaphor

    Zóltan Kövecses

    2010-05-01

    Full Text Available

    Cognitive linguists have so far paid a great deal of attention to the emarkable universality of many conceptual metaphors. However, their theories fail to account for the equally impressive diversity of metaphorical conceptualization both across and within cultures. The present paper is an attempt to lay down the foundations of a theory of metaphor that is capable of simultaneously accounting for both universality and variation in metaphor.

     

    Cognitive linguists have so far paid a great deal of attention to the emarkable universality of many conceptual metaphors. However, their theories fail to account for the equally impressive diversity of metaphorical conceptualization both across and within cultures. The present paper is an attempt to lay down the foundations of a theory of metaphor that is capable of simultaneously accounting for both universality and variation in metaphor.

  4. DNA in Nanoscale Electronics

    Slinker, Jason

    2012-10-01

    DNA, the quintessential molecule of life, possesses a number of attractive properties for use in nanoscale circuits. Charge transport (CT) through DNA itself is of both fundamental and practical interest. Fundamentally, DNA has a unique configuration of π-stacked bases in a well ordered, double helical structure. Given its unparalleled importance to life processes and its arrangement of conjugated subunits, DNA has been a compelling target of conductivity studies. In addition, further understanding of DNA CT will elucidate the biological implications of this process and advance its use in sensing technologies. We have investigated the fundamentals of DNA CT by measuring the electrochemistry of DNA monolayers under biologically-relevant conditions. We have uncovered both fundamental kinetic parameters to distinguish between competing models of operation as well as the practical implications of DNA CT for sensing. Furthermore, we are leveraging our studies of DNA conductivity for the manufacture of nanoscale circuits. We are investigating the electrical properties and self-assembly of DNA nanowires containing artificial base pair surrogates, which can be prepared through low cost and high throughput automated DNA synthesis. This unique and economically viable approach will establish a new paradigm for the scalable manufacture of nanoscale semiconductor devices.

  5. DNA: Structure and function

    Sinden, Richard R.; E. Pearson, Christopher; N. Potaman, Vladimir;

    1998-01-01

    This chapter discusses the structure and function of DNA. DNA occupies a critical role in cells, because it is the source of all intrinsic genetic information. Chemically, DNA is a very stable molecule, a characteristic important for a macromolecule that may have to persist in an intact form for a...... long period of time before its information is accessed by the cell. Although DNA plays a critical role as an informational storage molecule, it is by no means as unexciting as a computer tape or disk drive. The structure of the DNA described by Watson and Crick in 1953 is a right handed helix of two...... individual antiparallel DNA strands. Hydrogen bonds provide specificity that allows pairing between the complementary bases (A.T and G.C) in opposite strands. Base stacking occurs near the center of the DNA helix and provides a great deal of stability to the helix (in addition to hydrogen bonding). The sugar...

  6. DNA from keratinous tissue

    Olsen, Maia E.; Bengtsson, Camilla Friis; Bertelsen, Mads Frost;

    2012-01-01

    Although good quality DNA can be recovered from the base of the calamus of freshly sampled feathers, as from other fully keratinized tissues such as nail or hair shaft, the quality and quantity of DNA in the majority of feather structures is much poorer. Little research has been performed...... to characterize the quality of this DNA is, and thus what a researcher might be able to achieve when using feathers as a source of DNA. In this review, we expand on our companion article detailing the quality of DNA in nail and hair, by synthesizing published, and new preliminary genetic data obtained from...... feathers. As with nail and hair, we demonstrate that although DNA can, in general, be recovered from all parts of the feather, the quality of such DNA varies. As such, although one can expect a priori that genetic analyses are possible on the feather, for PCR based analyses, it is extremely difficult...

  7. Biophysics of DNA

    Vologodskii, Alexander

    2015-01-01

    Surveying the last sixty years of research, this book describes the physical properties of DNA in the context of its biological functioning. It is designed to enable both students and researchers of molecular biology, biochemistry and physics to better understand the biophysics of DNA, addressing key questions and facilitating further research. The chapters integrate theoretical and experimental approaches, emphasising throughout the importance of a quantitative knowledge of physical properties in building and analysing models of DNA functioning. For example, the book shows how the relationship between DNA mechanical properties and the sequence specificity of DNA-protein binding can be analyzed quantitatively by using our current knowledge of the physical and structural properties of DNA. Theoretical models and experimental methods in the field are critically considered to enable the reader to engage effectively with the current scientific literature on the physical properties of DNA.

  8. DNA Hairpins: Fuel for Autonomous DNA Devices

    Green, Simon J.; Lubrich, Daniel; Turberfield, Andrew J.

    2006-01-01

    We present a study of the hybridization of complementary DNA hairpin loops, with particular reference to their use as fuel for autonomous DNA devices. The rate of spontaneous hybridization between complementary hairpins can be reduced by increasing the neck length or decreasing the loop length. Hairpins with larger loops rapidly form long-lived kissed complexes. Hairpin loops may be opened by strand displacement using an opening strand that contains the same sequence as half of the neck and a...

  9. Novel DNA probes for sensitive DNA detection

    Richardson, James Alistair

    2010-01-01

    The ability to detect and interrogate DNA sequences allows further understanding and diagnosis of genetic disease. The ability to perform such analysis of genetic material requires highly selective and reliable technologies. Furthermore techniques which can use simple and cheap equipment allow the use of such technologies for point of care analysis. Described in this thesis are two novel DNA probe systems designed for mutation discrimination and sequence recognition of PCR pro...

  10. Fidelity of DNA polymerases in DNA amplification.

    Keohavong, P; Thilly, W G

    1989-01-01

    Denaturing gradient gel electrophoresis (DGGE) was used to separate and isolate the products of DNA amplification by polymerase chain reaction (PCR). The strategy permitted direct enumeration and identification of point mutations created by T4, modified T7, Klenow fragment of polymerase I, and Thermus aquaticus (Taq) DNA polymerases. Incorrectly synthesized sequences were separated from the wild type by DGGE as mutant/wild-type heteroduplexes and the heteroduplex fraction was used to calculat...

  11. DNA degradation and Apoptosis : DNA degradation

    Torriglia, Alicia; Padron, Laura

    2005-01-01

    Apoptosis, is a form of programmed cell death essential for the development and maintenance of multicellular organisms. DNA degradation is one of the hallmarks of apoptosis. The central component of the apoptotic machinery is a proteolytic system involving caspases and non-caspases proteases. CAD, a caspase-activated DNase, is the endonuclease responsible for DNA degradation during caspase-dependent apoptosis. The relationship between non-caspase proteases and endonucleases is less clear and ...

  12. Transposable Elements: No More 'Junk DNA'

    Kim, Yun-Ji; Lee, Jungnam; Han, Kyudong

    2012-01-01

    Since the advent of whole-genome sequencing, transposable elements (TEs), just thought to be 'junk' DNA, have been noticed because of their numerous copies in various eukaryotic genomes. Many studies about TEs have been conducted to discover their functions in their host genomes. Based on the results of those studies, it has been generally accepted that they have a function to cause genomic and genetic variations. However, their infinite functions are not fully elucidated. Through various mec...

  13. A positron annihilation study of hydrated DNA

    Warman, J. M.; Eldrup, Morten Mostgaard

    1986-01-01

    Positron annihilation measurements are reported for hydrated DNA as a function of water content and as a function of temperature (20 to -180.degree. C) for samples containing 10 and 50% wt of water. The ortho-positronium mean lifetime and its intensity show distinct variations with the degree of...... content until, for approximately 50% water, its properties resemble more those of a highly viscous fluid....

  14. Development of novel electrical characterization methods and measurements of G4-DNA and DNA Derivatives

    Livshits, Gideon I

    2015-01-01

    This dissertation presents an investigation into the electrical properties of two types of G4-DNA and several DNA-based molecules, targeting them as candidates for molecular wires and devices. Atomic force microscopy (AFM) and electrostatic force microscopy (EFM) comparison of co-deposited tetra- and intra-molecular G4-DNA reveals variations in morphology and different sensitivity to the applied electric field, suggesting that the folding orientation of the strands affects the molecular structure, i.e. either the tetrad unit or the tetrad-tetrad stacking or both, and therefore the charge mobility. Tetra-molecular G4-DNA is found to be twice as polarizable as intra-molecular G4-DNA, suggesting it has greater charge mobility. These promising results motivated direct electrical transport measurements on tetra-molecular G4-DNA using a special conductive AFM setup, profiling the conductance along the molecule. Reproducible currents of tens to over 100 pA were measured in many tetra-molecular G4-DNA molecules over ...

  15. Genetic variation and the de novo assembly of human genomes.

    Chaisson, Mark J P; Wilson, Richard K; Eichler, Evan E

    2015-11-01

    The discovery of genetic variation and the assembly of genome sequences are both inextricably linked to advances in DNA-sequencing technology. Short-read massively parallel sequencing has revolutionized our ability to discover genetic variation but is insufficient to generate high-quality genome assemblies or resolve most structural variation. Full resolution of variation is only guaranteed by complete de novo assembly of a genome. Here, we review approaches to genome assembly, the nature of gaps or missing sequences, and biases in the assembly process. We describe the challenges of generating a complete de novo genome assembly using current technologies and the impact that being able to perfectly sequence the genome would have on understanding human disease and evolution. Finally, we summarize recent technological advances that improve both contiguity and accuracy and emphasize the importance of complete de novo assembly as opposed to read mapping as the primary means to understanding the full range of human genetic variation. PMID:26442640

  16. Forensic DNA analysis.

    McDonald, Jessica; Lehman, Donald C

    2012-01-01

    Before the routine use of DNA profiling, blood typing was an important forensic tool. However, blood typing was not very discriminating. For example, roughly 30% of the United States population has type A-positive blood. Therefore, if A-positive blood were found at a crime scene, it could have come from 30% of the population. DNA profiling has a much better ability for discrimination. Forensic laboratories no longer routinely determine blood type. If blood is found at a crime scene, DNA profiling is performed. From Jeffrey's discovery of DNA fingerprinting to the development of PCR of STRs to the formation of DNA databases, our knowledge of DNA and DNA profiling have expanded greatly. Also, the applications for which we use DNA profiling have increased. DNA profiling is not just used for criminal case work, but it has expanded to encompass paternity testing, disaster victim identification, monitoring bone marrow transplants, detecting fetal cells in a mother's blood, tracing human history, and a multitude of other areas. The future of DNA profiling looks expansive with the development of newer instrumentation and techniques. PMID:22693781

  17. Nucleosomes shape DNA polymorphism and divergence.

    Sasha A Langley

    2014-07-01

    Full Text Available An estimated 80% of genomic DNA in eukaryotes is packaged as nucleosomes, which, together with the remaining interstitial linker regions, generate higher order chromatin structures [1]. Nucleosome sequences isolated from diverse organisms exhibit ∼10 bp periodic variations in AA, TT and GC dinucleotide frequencies. These sequence elements generate intrinsically curved DNA and help establish the histone-DNA interface. We investigated an important unanswered question concerning the interplay between chromatin organization and genome evolution: do the DNA sequence preferences inherent to the highly conserved histone core exert detectable natural selection on genomic divergence and polymorphism? To address this hypothesis, we isolated nucleosomal DNA sequences from Drosophila melanogaster embryos and examined the underlying genomic variation within and between species. We found that divergence along the D. melanogaster lineage is periodic across nucleosome regions with base changes following preferred nucleotides, providing new evidence for systematic evolutionary forces in the generation and maintenance of nucleosome-associated dinucleotide periodicities. Further, Single Nucleotide Polymorphism (SNP frequency spectra show striking periodicities across nucleosomal regions, paralleling divergence patterns. Preferred alleles occur at higher frequencies in natural populations, consistent with a central role for natural selection. These patterns are stronger for nucleosomes in introns than in intergenic regions, suggesting selection is stronger in transcribed regions where nucleosomes undergo more displacement, remodeling and functional modification. In addition, we observe a large-scale (∼180 bp periodic enrichment of AA/TT dinucleotides associated with nucleosome occupancy, while GC dinucleotide frequency peaks in linker regions. Divergence and polymorphism data also support a role for natural selection in the generation and maintenance of these

  18. Distinct evolutionary histories of the DNA-A and DNA-B components of bipartite begomoviruses

    Nawaz-ul-Rehman Muhammad

    2010-04-01

    Full Text Available Abstract Background Viruses of the genus Begomovirus (family Geminiviridae have genomes consisting of either one or two genomic components. The component of bipartite begomoviruses known as DNA-A is homologous to the genomes of all geminiviruses and encodes proteins required for replication, control of gene expression, overcoming host defenses, encapsidation and insect transmission. The second component, referred to as DNA-B, encodes two proteins with functions in intra- and intercellular movement in host plants. The origin of the DNA-B component remains unclear. The study described here was initiated to investigate the relationship between the DNA-A and DNA-B components of bipartite begomoviruses with a view to unraveling their evolutionary histories and providing information on the possible origin of the DNA-B component. Results Comparative phylogenetic and exhaustive pairwise sequence comparison of all DNA-A and DNA-B components of begomoviruses demonstrates that the two molecules have very distinct molecular evolutionary histories and likely are under very different evolutionary pressures. The analysis highlights that component exchange has played a far greater role in diversification of begomoviruses than previously suspected, although there are distinct differences in the apparent ability of different groups of viruses to utilize this "sexual" mechanism of genetic exchange. Additionally we explore the hypothesis that DNA-B originated as a satellite that was captured by the monopartite progenitor of all extant bipartite begomoviruses and subsequently evolved to become the integral (essential genome component that we recognize today. The situation with present-day satellites associated with begomoviruses provides some clues to the processes and selection pressures that may have led to the "domestication" of a wild progenitor of the DNA-B component. Conclusions The analysis has highlighted the greater genetic variation of DNA-B components, in

  19. Mediterranean sea level variations.

    Vigo, I.; Sánchez Reales, J. M.; García, D.; Chao, B. F.

    2009-04-01

    In this work we report an updated study of the sea level variations for the Mediterranean sea for the period from October 1992 to January 2008. The study addresses two mayor issues: (i)The analysis of the spatial and temporal variability of sea surface height (SSH) from radar altimetry measurements (from TOPEX/Poseidon (T/P) + Jason-1, etc.). We use EOF analysis to explain most of its interannual variation, and how the different basins interact. (ii) The analysis of dynamics and balance of water mass transport for the whole period. We estimate the steric SSH by combining the steric SSH estimated from temperature and salt profiles simulated by the ECCO model with time-variable gravity (TVG) data (from GRACE) for the Mediterranean Sea. The estimated steric SSH together with the SSH obtained from altimetry allow for a more realistic estimation of the water mass variations in the Mediterranean for the whole period.

  20. Variation and Synthetic Speech

    Miller, C; Massey, N; Miller, Corey; Karaali, Orhan; Massey, Noel

    1997-01-01

    We describe the approach to linguistic variation taken by the Motorola speech synthesizer. A pan-dialectal pronunciation dictionary is described, which serves as the training data for a neural network based letter-to-sound converter. Subsequent to dictionary retrieval or letter-to-sound generation, pronunciations are submitted a neural network based postlexical module. The postlexical module has been trained on aligned dictionary pronunciations and hand-labeled narrow phonetic transcriptions. This architecture permits the learning of individual postlexical variation, and can be retrained for each speaker whose voice is being modeled for synthesis. Learning variation in this way can result in greater naturalness for the synthetic speech that is produced by the system.

  1. Essential Variational Poisson Cohomology

    De Sole, Alberto; Kac, Victor G.

    2012-08-01

    In our recent paper "The variational Poisson cohomology" (2011) we computed the dimension of the variational Poisson cohomology {{{H}^bullet_K({V})}} for any quasiconstant coefficient ℓ × ℓ matrix differential operator K of order N with invertible leading coefficient, provided that {{{V}}} is a normal algebra of differential functions over a linearly closed differential field. In the present paper we show that, for K skewadjoint, the {{{Z}}} -graded Lie superalgebra {{{H}^bullet_K({V})}} is isomorphic to the finite dimensional Lie superalgebra {{widetilde{H}(Nell,S)}} . We also prove that the subalgebra of "essential" variational Poisson cohomology, consisting of classes vanishing on the Casimirs of K, is zero. This vanishing result has applications to the theory of bi-Hamiltonian structures and their deformations. At the end of the paper we consider also the translation invariant case.

  2. Identification of somaclonal variation in rice using RAPD markers

    Somaclonal variation in 13 R2 families and the FR-13A parent was investigated at the DNA level using the random, amplified polymorphic DNA (RAPD) method via polymerase chain reaction. Thirty-four random primers were employed to amplify the DNA segments. Six 10-mer primers revealed a total of 67 scorable bands, all of which were polymorphic across the 70 individual plants (five plants and 65 R2 lines). On the basis of the simple matching coefficient of the RAPD banding patterns, all the somaclonal R2 families showed significant dissimilarity with the FR-13A parent. This study demonstrated that molecular makers such as RAPD are useful in revealing changes in DNA sequence not readily seen in morphological or physiological screening. 1 fig

  3. Genomic and gene variation in Mycoplasma hominis strains

    Christiansen, Gunna; Andersen, H; Birkelund, Svend;

    1987-01-01

    DNAs from 14 strains of Mycoplasma hominis isolated from various habitats, including strain PG21, were analyzed for genomic heterogeneity. DNA-DNA filter hybridization values were from 51 to 91%. Restriction endonuclease digestion patterns, analyzed by agarose gel electrophoresis, revealed no...... identity or cluster formation between strains. Variation within M. hominis rRNA genes was analyzed by Southern hybridization of EcoRI-cleaved DNA hybridized with a cloned fragment of the rRNA gene from the mycoplasma strain PG50. Five of the M. hominis strains showed identical hybridization patterns. These...... hybridization patterns were compared with those of 12 other mycoplasma species, which showed a much more complex band pattern. Cloned nonribosomal RNA gene fragments of M. hominis PG21 DNA were analyzed, and the fragments were used to demonstrate heterogeneity among the strains. A monoclonal antibody against...

  4. DNA profiles from fingermarks.

    Templeton, Jennifer E L; Linacre, Adrian

    2014-11-01

    Criminal investigations would be considerably improved if DNA profiles could be routinely generated from single fingermarks. Here we report a direct DNA profiling method that was able to generate interpretable profiles from 71% of 170 fingermarks. The data are based on fingermarks from all 5 digits of 34 individuals. DNA was obtained from the fingermarks using a swab moistened with Triton-X, and the fibers were added directly to one of two commercial DNA profiling kits. All profiles were obtained without increasing the number of amplification cycles; therefore, our method is ideally suited for adoption by the forensic science community. We indicate the use of the technique in a criminal case in which a DNA profile was generated from a fingermark on tape that was wrapped around a drug seizure. Our direct DNA profiling approach is rapid and able to generate profiles from touched items when current forensic practices have little chance of success. PMID:25391915

  5. DNA media storage

    Christy M.Bogard; Eric C.Rouchka; Benjamin Arazi

    2008-01-01

    In 1994. University of Southern California computer scientist,Dr.Leonard Adleman solved the Hamiltonian path problem using DNA as a computational mechanism.He proved the principle that DNA computing could be used to solve computationally complex problems.Because of the limitations in discovery time,resource requirements,and sequence mismatches,DNA computing has not yet become a commonly accepted practice.However,advancements are continually being discovered that are evolving the field of DNA computing.Practical applications of DNA are not restricted to computation alone.This research presents a novel approach in which DNA could be used as a means of storing files.Through the use of multiple sequence alignment combined with intelligent heuristics,the most probabilistic file contents can be determined with minimal errors.

  6. Electrocatalysis in DNA Sensors.

    Furst, Ariel; Hill, Michael G; Barton, Jacqueline K

    2014-12-14

    Electrocatalysis is often thought of solely in the inorganic realm, most often applied to energy conversion in fuel cells. However, the ever-growing field of bioelectrocatalysis has made great strides in advancing technology for both biofuel cells as well as biological detection platforms. Within the context of bioelectrocatalytic detection systems, DNA-based platforms are especially prevalent. One subset of these platforms, the one we have developed, takes advantage of the inherent charge transport properties of DNA. Electrocatalysis coupled with DNA-mediated charge transport has enabled specific and sensitive detection of lesions, mismatches and DNA-binding proteins. Even greater signal amplification from these platforms is now being achieved through the incorporation of a secondary electrode to the platform both for patterning DNA arrays and for detection. Here, we describe the evolution of this new DNA sensor technology. PMID:25435647

  7. Summary Statistics of Neutral Mutations in Longitudinal DNA Samples

    Liu, Xiaoming; Fu, Yun-Xin

    2008-01-01

    Longitudinal samples of DNA sequences are the DNA sequences sampled from the same population at different time points. For fast evolving organisms, e.g. RNA virus, these kind of samples have increasingly been used to study the evolutionary process in action. Longitudinal samples provide some interesting new summary statistics of genetic variation, such as the frequency of mutation of size i in one sample and size j in another, the average number of mutations accumulated since the common ances...

  8. Asynchronous Variational Contact Mechanics

    Vouga, Etienne; Tamstorf, Rasmus; Grinspun, Eitan

    2010-01-01

    An asynchronous, variational method for simulating elastica in complex contact and impact scenarios is developed. Asynchronous Variational Integrators (AVIs) are extended to handle contact forces by associating different time steps to forces instead of to spatial elements. By discretizing a barrier potential by an infinite sum of nested quadratic potentials, these extended AVIs are used to resolve contact while obeying momentum- and energy-conservation laws. A series of two- and three-dimensional examples illustrate the robustness and good energy behavior of the method.

  9. Innovations. DNA detectives.

    May, M

    1999-01-01

    To understand the many potential causes and resulting consequences of DNA damage, scientists first need methods to detect it. Canadian scientists X. Chris Le and Michael Weinfeld, with help from U.S. molecular biologist Steven Leadon, developed a selective, sensitive technique for measuring DNA damage. The scientists combined a thymine glycol antibody with thymine glycol to selectively tag a specific type of DNA damage. They then added a second antibody with fluorescing properties, and used l...

  10. Genetic variation of Scomberomorus niphonius in the coastal waters of China based on mtDNA COI sequences%基于线粒体CO I序列的中国沿海蓝点马鲛遗传多样性

    曹艳; 章群; 宫亚运; 吕金磊; 杨喜书

    2015-01-01

    (Hd =0.442 ±0.145,π=0.001 7 ±0.000 6 ).Apart from five haplotypes shared by various populations,the remaining ones were unique to each population.Two shallow clades could be found in the Kimura 2-parameter based neighbor-joining tree,and 17 haplotypes from various locations in parsimony network were intertwined together,suggesting the absence of obvious geographical structure.Analysis of molecular variance of three different hierarchical levels detected no significant differentiation in all combinations of sampling sites and the resultant main sources of variation were within population variation (101.52% -106.56%).Pairwise fixation indexes Fst value among six populations ranged from -0.138 to 0.040 (P>0.05),and gene flow ranged from -81.145 to 146.559,indicating frequent gene flow among six sites,and no significant genetic differentiation was found in the coastal areas of China.Wide distribution, long-distance migrations,schooling behavior and strong dispersal potential of pelagic larvae of S.niphonius may account for the lack of genetic structure.Molecular variance (76.36% variation between clades), pairwise Fst(0.76,P=0)and gene flow (0.158)analyses revealed significant differentiation between two clades.Thus the lack of geographic structure in coastal waters of China may reflect a relatively recent range expansion in late Pleistocene era,a mixture of two clades and the insufficient time to approach migration-drift equilibrium.In CladeA,the significant negative values of neutral test (Tajima’s D=-1 .032,P>0.05;Fu’s Fs=-1.961,P=0.05),the Ramos-Onsins &Rozas’s R2 value was 0.098 (P=0.05),and the unimodal mismatch distribution all suggested a recent population expansion in this clade about 39,600-1 18, 700 years ago,and the similar result also revealed in CladeB (Tajima’s D=-2.134,P=0.003;Fu’s Fs=-5.840,P=0.0),about 22,700-68,100 years ago,due to the effects of glacial and interglacial cycle and the changed living space caused by fluctuation of sea level

  11. The Bacillus subtilis DnaD and DnaB Proteins Exhibit Different DNA Remodelling Activities

    Zhang, Wenke; Carneiro, Maria J. V. M.; Turner, Ian J.; ALLEN, Stephanie; Roberts, Clive J.; Soultanas, Panos

    2005-01-01

    Primosomal protein cascades load the replicative helicase onto DNA. In Bacillus subtilis a putative primosomal cascade involving the DnaD-DnaB-DnaI proteins has been suggested to participate in both the DnaA and PriA-dependent loading of the replicative helicase DnaC onto the DNA. Recently we discovered that DnaD has a global remodelling DNA activity suggesting a more widespread role in bacterial nucleoid architecture. Here, we show that DnaB forms a “square-like” tetramer with a hole in the ...

  12. DNA Microarray Technique

    Thakare SP

    2012-11-01

    Full Text Available DNA Microarray is the emerging technique in Biotechnology. The many varieties of DNA microarray or DNA chip devices and systems are described along with their methods for fabrication and their use. It also includes screening and diagnostic applications. The DNA microarray hybridization applications include the important areas of gene expression analysis and genotyping for point mutations, single nucleotide polymorphisms (SNPs, and short tandem repeats (STRs. In addition to the many molecular biological and genomic research uses, this review covers applications of microarray devices and systems for pharmacogenomic research and drug discovery, infectious and genetic disease and cancer diagnostics, and forensic and genetic identification purposes.

  13. DNA ELECTROPHORESIS AT SURFACES

    RAFAILOVICH, MIRIAM; SOKOLOV, JONATHAN; GERSAPPE, DILIP

    2003-09-01

    During this year we performed two major projects: I. We developed a detailed theoretical model which complements our experiments on surface DNA electrophoresis. We found that it was possible to enhance the separation of DNA chains by imposing a chemical nanoscale pattern on the surface. This approach utilized the surface interaction effect of the DNA chains with the substrate and is a refinement to our previous method in which DNA chains were separated on homogeneous flat surfaces. By introducing the nano-patterns on the surface, the conformational changes of DNA chains of different lengths can be amplified, which results in the different friction strengths with the substrate surface. Our results also show that, when compared to the DNA electrophoresis performed on homogeneous flat surfaces, nanopatterned surfaces offer a larger window in choosing different surface interactions to achieve separation. II. In collaboration with a large international manufacturer of skin care products we also embarked on a project involving photo toxicity of titanium dioxide nanoparticles, which are a key ingredient in sunscreen and cosmetic lotions. The results clearly implicated the nanoparticles in catalyzing damage to chromosomal DNA. We then used this knowledge to develop a polymer/anti-oxidant coating which prevented the photocatalytic reaction on DNA while still retaining the UV absorptive properties of the nanoparticles. The standard gel electrophoresis was not sufficient in determining the extent of the DNA damage. The conclusions of this study were based predominantly on analysis obtained with the surface electrophoresis method.

  14. Natural 14C variations

    This thesis deals with the natural variations in the atmospheric 14C activity, their geophysical origin and their impact on radiocarbon dating. Studies confirm the idea that one is dealing with a mechanism of a certain regularity. The correlation between a 14C variation during the Little Ice Age and the absence of sunspots on the solar surface suggest the sun to be responsible for some kind of modulation of the galactic cosmic ray spectrum. The background of a changing natural 14C level is relevant when studying the antropogenic perturbation of the atmospheric 14C concentration by the addition of CO2 from fossil fuel combustion. The results presented point to a Suess effect over the past 150 years of about 20 per thousand, but also show a local dilution effect. If this local effect is present over large continental parts of the Northern Hemisphere this will put limits to the use of tree ring 14C measurements for testing carbon reservoir models. Finally the influence of 14C variations upon the interpretations of 14C dates for archaeological and geological purposes has been investigated. It is shown that care must be taken especially in the interpretation of highly accurate 14C data of material only covering a few years of growth. One geological example illustrates that 14C variations can easily be interpretated as alternating fast and slow rises of the sea level. (Auth.)

  15. Variational transition state theory

    Truhlar, D.G. [Univ. of Minnesota, Minneapolis (United States)

    1993-12-01

    This research program involves the development of variational transition state theory (VTST) and semiclassical tunneling methods for the calculation of gas-phase reaction rates and selected applications. The applications are selected for their fundamental interest and/or their relevance to combustion.

  16. Seasonal Variation in Epidemiology

    Marrero, Osvaldo

    2013-01-01

    Seasonality analyses are important in medical research. If the incidence of a disease shows a seasonal pattern, then an environmental factor must be considered in its etiology. We discuss a method for the simultaneous analysis of seasonal variation in multiple groups. The nuts and bolts are explained using simple trigonometry, an elementary…

  17. Bounded variation and around

    Appell, Jürgen; Merentes Díaz, Nelson José

    2013-01-01

    This monographis a self-contained exposition of the definition and properties of functionsof bounded variation and their various generalizations; the analytical properties of nonlinear composition operators in spaces of such functions; applications to Fourier analysis, nonlinear integral equations, and boundary value problems. The book is written for non-specialists. Every chapter closes with a list of exercises and open problems.

  18. Variation and Linguistic Theory.

    Bailey, Charles-James N.

    This volume presents principles and models for describing language variation, and introduces a time-based, dynamic framework for linguistic description. The book first summarizes some of the problems of grammatical description encountered from Saussure through the present and then outlines possibilities for new descriptions of language which take…

  19. Long Span DNA Paired-End-Tag (DNA-PET) Sequencing Strategy for the Interrogation of Genomic Structural Mutations and Fusion-Point-Guided Reconstruction of Amplicons

    Yao, Fei; Ariyaratne, Pramila N.; Hillmer, Axel M.; Lee, Wah Heng; Li, Guoliang; Teo, Audrey S. M.; Woo, Xing Yi; Zhang, Zhenshui; Chen, Jieqi P.; Poh, Wan Ting; Zawack, Kelson F. B.; Chan, Chee Seng; Leong, See Ting; Neo, Say Chuan; Choi, Poh Sum D.

    2012-01-01

    Structural variations (SVs) contribute significantly to the variability of the human genome and extensive genomic rearrangements are a hallmark of cancer. While genomic DNA paired-end-tag (DNA-PET) sequencing is an attractive approach to identify genomic SVs, the current application of PET sequencing with short insert size DNA can be insufficient for the comprehensive mapping of SVs in low complexity and repeat-rich genomic regions. We employed a recently developed procedure to generate PET s...

  20. The variation of D-loop in mitochondrial genome and the mutation induced by irradiation

    As the non-code region of mitochondrial genome, the displacement-loop region (D-loop) controls the replication and transcription of mtDNA, but it is easy to be altered. The variation, including mutation and polymorphism, plays an important role in disease. Finally, the status quo of radiation induced D-loop variation and its perspective were outlined. (authors)

  1. Duck hepatitis B virus covalently closed circular DNA appears to survive hepatocyte mitosis in the growing liver

    Reaiche-Miller, Georget Y.; Thorpe, Michael; Low, Huey Chi; Qiao, Qiao; Scougall, Catherine A. [School of Molecular and Biomedical Science, University of Adelaide, Adelaide, SA 5005 (Australia); Mason, William S.; Litwin, Samuel [Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, PA 19111 (United States); Jilbert, Allison R., E-mail: allison.jilbert@adelaide.edu.au [School of Molecular and Biomedical Science, University of Adelaide, Adelaide, SA 5005 (Australia)

    2013-11-15

    Nucleos(t)ide analogues that inhibit hepatitis B virus (HBV) DNA replication are typically used as monotherapy for chronically infected patients. Treatment with a nucleos(t)ide analogue eliminates most HBV DNA replication intermediates and produces a gradual decline in levels of covalently closed circular DNA (cccDNA), the template for viral RNA synthesis. It remains uncertain if levels of cccDNA decline primarily through hepatocyte death, or if loss also occurs during hepatocyte mitosis. To determine if cccDNA survives mitosis, growing ducklings infected with duck hepatitis B virus (DHBV) were treated with the nucleoside analogue, Entecavir. Viremia was suppressed at least 10{sup 5}-fold, during a period when average liver mass increased 23-fold. Analysis of the data suggested that if cccDNA synthesis was completely inhibited, at least 49% of cccDNA survived hepatocyte mitosis. However, there was a large duck-to-duck variation in cccDNA levels, suggesting that low level cccDNA synthesis may contribute to this apparent survival through mitosis. - Highlights: • The hepatitis B virus nuclear template is covalently closed circular DNA (cccDNA). • cccDNA was studied during liver growth in duck hepatitis B virus infected ducks. • Virus DNA replication and new cccDNA synthesis were inhibited with Entecavir. • At least 49% of cccDNA appeared to survive hepatocyte mitosis. • Low level virus DNA synthesis may contribute to survival of cccDNA through mitosis.

  2. Duck hepatitis B virus covalently closed circular DNA appears to survive hepatocyte mitosis in the growing liver

    Nucleos(t)ide analogues that inhibit hepatitis B virus (HBV) DNA replication are typically used as monotherapy for chronically infected patients. Treatment with a nucleos(t)ide analogue eliminates most HBV DNA replication intermediates and produces a gradual decline in levels of covalently closed circular DNA (cccDNA), the template for viral RNA synthesis. It remains uncertain if levels of cccDNA decline primarily through hepatocyte death, or if loss also occurs during hepatocyte mitosis. To determine if cccDNA survives mitosis, growing ducklings infected with duck hepatitis B virus (DHBV) were treated with the nucleoside analogue, Entecavir. Viremia was suppressed at least 105-fold, during a period when average liver mass increased 23-fold. Analysis of the data suggested that if cccDNA synthesis was completely inhibited, at least 49% of cccDNA survived hepatocyte mitosis. However, there was a large duck-to-duck variation in cccDNA levels, suggesting that low level cccDNA synthesis may contribute to this apparent survival through mitosis. - Highlights: • The hepatitis B virus nuclear template is covalently closed circular DNA (cccDNA). • cccDNA was studied during liver growth in duck hepatitis B virus infected ducks. • Virus DNA replication and new cccDNA synthesis were inhibited with Entecavir. • At least 49% of cccDNA appeared to survive hepatocyte mitosis. • Low level virus DNA synthesis may contribute to survival of cccDNA through mitosis

  3. Diurnal variations of Titan

    Cui, J.; Galand, M.; Yelle, R. V.; Vuitton, V.; Wahlund, J.-E.; Lavvas, P. P.; Mueller-Wodarg, I. C. F.; Kasprzak, W. T.; Waite, J. H.

    2009-04-01

    We present our analysis of the diurnal variations of Titan's ionosphere (between 1,000 and 1,400 km) based on a sample of Ion Neutral Mass Spectrometer (INMS) measurements in the Open Source Ion (OSI) mode obtained from 8 close encounters of the Cassini spacecraft with Titan. Though there is an overall ion depletion well beyond the terminator, the ion content on Titan's nightside is still appreciable, with a density plateau of ~700 cm-3 below ~1,300 km. Such a plateau is associated with the combination of distinct diurnal variations of light and heavy ions. Light ions (e.g. CH5+, HCNH+, C2H5+) show strong diurnal variation, with clear bite-outs in their nightside distributions. In contrast, heavy ions (e.g. c-C3H3+, C2H3CNH+, C6H7+) present modest diurnal variation, with significant densities observed on the nightside. We propose that the distinctions between light and heavy ions are associated with their different chemical loss pathways, with the former primarily through "fast" ion-neutral chemistry and the latter through "slow" electron dissociative recombination. The INMS data suggest day-to-night transport as an important source of ions on Titan's nightside, to be distinguished from the conventional scenario of auroral ionization by magnetospheric particles as the only ionizing source on the nightside. This is supported by the strong correlation between the observed night-to-day ion density ratios and the associated ion lifetimes. We construct a time-dependent ion chemistry model to investigate the effects of day-to-night transport on the ionospheric structures of Titan. The predicted diurnal variation has similar general characteristics to those observed, with some apparent discrepancies which could be reconciled by imposing fast horizontal thermal winds in Titan's upper atmosphere.

  4. Microbial food safety: Potential of DNA extraction methods for use in diagnostic metagenomics.

    Josefsen, Mathilde H; Andersen, Sandra C; Christensen, Julia; Hoorfar, Jeffrey

    2015-07-01

    The efficiency of ten widely applied DNA extraction protocols was evaluated for suitability for diagnostic metagenomics. The protocols were selected based on a thorough literature study. Chicken fecal samples inoculated with about 1×10(3) and 1×10(6) CFU/g Campylobacter jejuni were used as a model. The evaluation was performed based on total DNA yield measured by fluorometry, and quality and quantity of C. jejuni DNA measured by real-time PCR. There was up to a 25-fold variance between the lowest (NucliSens miniMAG, BIOMÉRIEUX) and highest (PowerLyzer PowerSoil DNA Isolation Kit, MO BIO Laboratories) yielding protocols. The PowerLyzer PowerSoil DNA Isolation Kit performed significantly better than all other protocols tested. Selected protocols were modified, i.e., extended heating and homogenization, resulting in increased yields of total DNA. For QIAamp Fast DNA Stool Mini Kit (Qiagen) a 7-fold increase in total DNA was observed following the protocol for human DNA analysis and including a 5 min heating step at 70°C. For the PowerLyzer PowerSoil and the PowerFecal DNA Isolation Kit (MO BIO Laboratories) the total DNA fold increase was 1.6 to 1.8 when including an extra 10 min of bead-vortexing. There was no correlation between the yield of total DNA and the amount of PCR-amplifiable DNA from C. jejuni. The protocols resulting in the highest yield of total DNA did not show correspondingly increased levels of C. jejuni DNA as determined by PCR. In conclusion, substantial variation in the efficiency of the protocols to extract DNA was observed. The highest DNA yield was obtained with the PowerLyzer PowerSoil DNA Isolation Kit, whereas the FastDNA SPIN Kit for Feces (MP Biomedicals) resulted in the highest amount of PCR-amplifiable C. jejuni DNA. PMID:25937085

  5. Physiological and pathological variability of DNA repair in human

    DNA repair plays a crucial role in protection of human genetic material against genotoxic agents including carcinogens, ensuring genome stability. Variability of DNA repair was observed on many levels. These are several mechanisms of damage removal and a number of enzymes taking part in the specific steps of DNA repair. Hence, variations in efficiency of DNA repair among healthy individuals can be explained in term of genetic polymorphism. There are also some exogenous and endogenous factors affecting the DNA repair machinery in human organism. The first group includes diet and genotoxic exposure whereas the second comprises age (negative linear correlation) and health status. Within the group of health status factor neo-plasticity and diseases with hereditary DNA repair deficit are discussed extensively. The well documented heterogeneity of DNA repair inside the genome concerns differences between classes of DNA (e.g. nuclear v. mitochondrial or repetitive v. single copy) and preferential repair of activity transcribed genes. The main message of the article is that DNA repair should be recognized as fairly individual and, moreover, as being modulated by many factors. (author). 25 refs, 2 figs

  6. cDNA: 53887 [

    Full Text Available M. musculus + Mm.196480 Mus musculus adult male testis cDNA, RIKEN full-length enriched library, ... uct:DNA Segment, Chr 15 Massachusetts Institute of Technology ... 260, full insert sequence gnl|UG|Mm#S10837764 AK07 ...

  7. cDNA: 53885 [

    Full Text Available M. musculus + Mm.196480 Mus musculus adult male testis cDNA, RIKEN full-length enriched library, ... uct:DNA Segment, Chr 15 Massachusetts Institute of Technology ... 260, full insert sequence gnl|UG|Mm#S10837547 AK07 ...

  8. Recombinant DNA for Teachers.

    Duvall, James G., III

    1992-01-01

    A science teacher describes his experience at a workshop to learn to teach the Cold Spring Harbor DNA Science Laboratory Protocols. These protocols lead students through processes for taking E. coli cells and transforming them into a new antibiotic resistant strain. The workshop featured discussions of the role of DNA recombinant technology in…

  9. Characterization of muntjac DNA

    Sister chromatid exchange (SCE) in muntjac chromosomes is generally proportional to the chromosomal DNA content, but the SCE frequency is reduced in the heterochromatic neck region of the X chromosome. The physical properties of muntjac DNA and the kinetics of repair of UV damage in muntjac heterochromatin and euchromatin were examined and compared with the distribution of sister chromatid exchange

  10. Routine DNA testing

    Routine DNA testing. It’s done once you’ve Marker-Assisted Breeding Pipelined promising Qantitative Trait Loci within your own breeding program and thereby established the performance-predictive power of each DNA test for your germplasm under your conditions. By then you are ready to screen your par...

  11. DNA-cell conjugates

    Hsiao, Shih-Chia; Francis, Matthew B.; Bertozzi, Carolyn; Mathies, Richard; Chandra, Ravi; Douglas, Erik; Twite, Amy; Toriello, Nicholas; Onoe, Hiroaki

    2016-05-03

    The present invention provides conjugates of DNA and cells by linking the DNA to a native functional group on the cell surface. The cells can be without cell walls or can have cell walls. The modified cells can be linked to a substrate surface and used in assay or bioreactors.

  12. Extended DNA Tile Actuators

    Kristiansen, Martin; Kryger, Mille; Zhang, Zhao;

    2012-01-01

    A dynamic linear DNA tile actuator is expanded to three new structures of higher complexity. The original DNA actuator was constructed from a central roller strand which hybridizes with two piston strands by forming two half-crossover junctions. A linear expansion of the actuator is obtained...

  13. Characterization of muntjac DNA

    Davis, R.C.

    1981-05-27

    Sister chromatid exchange (SCE) in muntjac chromosomes is generally proportional to the chromosomal DNA content, but the SCE frequency is reduced in the heterochromatic neck region of the X chromosome. The physical properties of muntjac DNA and the kinetics of repair of UV damage in muntjac heterochromatin and euchromatin were examined and compared with the distribution of sister chromatid exchange.

  14. Workshop on DNA repair.

    A.R. Lehmann (Alan); J.H.J. Hoeijmakers (Jan); A.A. van Zeeland (Albert); C.M.P. Backendorf (Claude); B.A. Bridges; A. Collins; R.P.D. Fuchs; G.P. Margison; R. Montesano; E. Moustacchi; A.T. Natarajan; M. Radman; A. Sarasin; E. Seeberg; C.A. Smith; M. Stefanini (Miria); L.H. Thompson; G.P. van der Schans; C.A. Weber (Christine); M.Z. Zdzienika

    1992-01-01

    textabstractA workshop on DNA repair with emphasis on eukaryotic systems was held, under the auspices of the EC Concerted Action on DNA Repair and Cancer, at Noordwijkerhout (The Netherlands) 14-19 April 1991. The local organization of the meeting was done under the auspices of the Medical Genetic C

  15. Protein–DNA Interactions

    Kovacic, L.; Boelens, R.

    2012-01-01

    The recognition of specific DNA sequences by proteins and the coupling to signaling events are fundamental occurrences that lie at the root of many cellular processes. Many examples of tight control by protein–DNA interactions can be found in such dynamic processes as transcription, replication and

  16. Premeltons in DNA.

    Sobell, Henry M

    2016-03-01

    Premeltons are examples of emergent-structures (i.e., structural-solitons) that arise spontaneously in DNA due to the presence of nonlinear-excitations in its structure. They are of two kinds: B-B (or A-A) premeltons form at specific DNA-regions to nucleate site-specific DNA melting. These are stationary and, being globally-nontopological, undergo breather-motions that allow drugs and dyes to intercalate into DNA. B-A (or A-B) premeltons, on the other hand, are mobile, and being globally-topological, act as phase-boundaries transforming B- into A-DNA during the structural phase-transition. They are not expected to undergo breather motions. A key feature of both types of premeltons is the presence of an intermediate structural-form in their central regions (proposed as being a transition-state intermediate in DNA-melting and in the B- to A-transition), which differs from either A- or B-DNA. Called beta-DNA, this is both metastable and hyperflexible-and contains an alternating sugar-puckering pattern along the polymer backbone combined with the partial unstacking (in its lower energy-forms) of every-other base-pair. Beta-DNA is connected to either B- or to A-DNA on either side by boundaries possessing a gradation of nonlinear structural-change, these being called the kink and the antikink regions. The presence of premeltons in DNA leads to a unifying theory to understand much of DNA physical chemistry and molecular biology. In particular, premeltons are predicted to define the 5' and 3' ends of genes in naked-DNA and DNA in active-chromatin, this having important implications for understanding physical aspects of the initiation, elongation and termination of RNA-synthesis during transcription. For these and other reasons, the model will be of broader interest to the general-audience working in these areas. The model explains a wide variety of data, and carries with it a number of experimental predictions-all readily testable-as will be described in this review. PMID

  17. Whose DNA is this?

    Taroni, Franco; Biedermann, Alex; Vuille, Joëlle;

    2013-01-01

    This communication seeks to draw the attention of researchers and practitioners dealing with forensic DNA profiling analyses to the following question: is a scientist's report, offering support to a hypothesis according to which a particular individual is the source of DNA detected during...... evoked during the international conference "The hidden side of DNA profiles. Artifacts, errors and uncertain evidence" held in Rome (April 27th to 28th, 2012). Indeed, despite the fact that this conference brought together some of the world's leading forensic DNA specialists, it appeared clearly...... talk considerably different languages. It thus is fundamental to address this issue of communication about results of forensic DNA analyses, and open a dialogue with practicing non-scientists at large who need to make meaningful use of scientific results to approach and help solve judicial cases...

  18. DNA repair protocols

    Bjergbæk, Lotte

    In its 3rd edition, this Methods in Molecular Biology(TM) book covers the eukaryotic response to genomic insult including advanced protocols and standard techniques in the field of DNA repair. Offers expert guidance for DNA repair, recombination, and replication. Current knowledge of the mechanisms...... that regulate DNA repair has grown significantly over the past years with technology advances such as RNA interference, advanced proteomics and microscopy as well as high throughput screens. The third edition of DNA Repair Protocols covers various aspects of the eukaryotic response to genomic insult including...... recent advanced protocols as well as standard techniques used in the field of DNA repair. Both mammalian and non-mammalian model organisms are covered in the book, and many of the techniques can be applied with only minor modifications to other systems than the one described. Written in the highly...

  19. Archaeal DNA replication.

    Kelman, Lori M; Kelman, Zvi

    2014-01-01

    DNA replication is essential for all life forms. Although the process is fundamentally conserved in the three domains of life, bioinformatic, biochemical, structural, and genetic studies have demonstrated that the process and the proteins involved in archaeal DNA replication are more similar to those in eukaryal DNA replication than in bacterial DNA replication, but have some archaeal-specific features. The archaeal replication system, however, is not monolithic, and there are some differences in the replication process between different species. In this review, the current knowledge of the mechanisms governing DNA replication in Archaea is summarized. The general features of the replication process as well as some of the differences are discussed. PMID:25421597

  20. DNA-repair measurements by use of the modified comet assay

    Godschalk, Roger W L; Ersson, Clara; Riso, Patrizia;

    2013-01-01

    The measurement of DNA-repair activity by extracts from cells or tissues by means of the single-cell gel electrophoresis (comet) assay has a high potential to become widely used in biomonitoring studies. We assessed the inter-laboratory variation in reported values of DNA-repair activity on...... line as having the highest level of DNA-repair activity. The two laboratories that reported discordant results (with another cell line having the highest level of DNA-repair activity) were those that reported to have little experience with the modified comet assay to assess DNA repair. The laboratories...