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Sample records for correct chromosome poleward

  1. Kinetochore-independent chromosome poleward movement during anaphase of meiosis II in mouse eggs.

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    Manqi Deng

    Full Text Available Kinetochores are considered to be the key structures that physically connect spindle microtubules to the chromosomes and play an important role in chromosome segregation during mitosis. Due to different mechanisms of spindle assembly between centrosome-containing mitotic cells and acentrosomal meiotic oocytes, it is unclear how a meiotic spindle generates the poleward forces to drive two rounds of meiotic chromosome segregation to achieve genome haploidization. We took advantage of the fact that DNA beads are able to induce bipolar spindle formation without kinetochores and studied the behavior of DNA beads in the induced spindle in mouse eggs during meiosis II. Interestingly, DNA beads underwent poleward movements that were similar in timing and speed to the meiotic chromosomes, although all the beads moved together to the same spindle pole. Disruption of dynein function abolished the poleward movements of DNA beads but not of the meiotic chromosomes, suggesting the existence of different dynein-dependent and dynein-independent force generation mechanisms for the chromosome poleward movement, and the latter may be dependent on the presence of kinetochores. Consistent with the observed DNA bead poleward movement, sperm haploid chromatin (which also induced bipolar spindle formation after injection to a metaphase egg without forming detectable kinetochore structures also underwent similar poleward movement at anaphase as DNA beads. The results suggest that in the chromatin-induced meiotic spindles, kinetochore attachments to spindle microtubules are not absolutely required for chromatin poleward movements at anaphase.

  2. Kinetochore dynein generates a poleward pulling force to facilitate congression and full chromosome alignment

    Institute of Scientific and Technical Information of China (English)

    Yan Li; Wei Yu; Yun Liang; Xueliang Zhu

    2007-01-01

    For proper chromosome segregation, all kinetochores must achieve bipolar microtubule (MT) attachment and subsequently align at the spindle equator before anaphase onset. The MT minus end-directed motor dynein/dynactin binds kinetochores in prometaphase and has long been implicated in chromosome congression. Unfortunately, inactivation of dynein usually disturbs spindle organization, thus hampering evaluation of its kinetochore roles. Here we specifically eliminated kinetochore dynein/dynactin by RNAi-mediated depletion of ZW10, a protein essential for kinetochore localization of the motor. Time-lapse microscopy indicated markedly-reduced congression efficiency, though congressing chromosomes displayed similar velocities as in control cells. Moreover, cells frequently failed to achieve full chromosome alignment, despite their normal spindles. Confocal microcopy revealed that the misaligned kinetochores were monoori-ented or unattached and mostly lying outside the spindle, suggesting a difficulty to capture MTs from the opposite pole. Kinetochores on monoastral spindles were dispersed farther away from the pole and exhibited only mild oscillation. Furthermore, inactivating dynein by other means generated similar phenotypes. Therefore, kinetochore dynein produces on monooriented kinetochores a poleward pulling force, which may contribute to efficient bipolar attachment by facilitating their proper microtubule captures to promote congression as well as full chromosome alignment.

  3. Chromosome therapy. Correction of large chromosomal aberrations by inducing ring chromosomes in induced pluripotent stem cells (iPSCs).

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    Kim, Taehyun; Bershteyn, Marina; Wynshaw-Boris, Anthony

    2014-01-01

    The fusion of the short (p) and long (q) arms of a chromosome is referred to as a "ring chromosome." Ring chromosome disorders occur in approximately 1 in 50,000-100,000 patients. Ring chromosomes can result in birth defects, mental disabilities, and growth retardation if additional genes are deleted during the formation of the ring. Due to the severity of these large-scale aberrations affecting multiple contiguous genes, no possible therapeutic strategies for ring chromosome disorders have so far been proposed. Our recent study (Bershteyn et al.) using patient-derived fibroblast lines containing ring chromosomes, found that cellular reprogramming of these fibroblasts into induced pluripotent stem cells (iPSCs) resulted in the cell-autonomous correction of the ring chromosomal aberration via compensatory uniparental disomy (UPD). These observations have important implications for studying the mechanism of chromosomal number control and may lead to the development of effective therapies for other, more common, chromosomal aberrations.

  4. Geometric correction of deformed chromosomes for automatic Karyotyping.

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    Khan, Shadab; DSouza, Alisha; Sanches, João; Ventura, Rodrigo

    2012-01-01

    Automatic Karyotyping is the process of classifying chromosomes from an unordered karyogram into their respective classes to create an ordered karyogram. Automatic karyotyping algorithms typically perform geometrical correction of deformed chromosomes for feature extraction; these features are used by classifier algorithms for classifying the chromosomes. Karyograms of bone marrow cells are known to have poor image quality. An example of such karyograms is the Lisbon-K(1) (LK(1)) dataset that is used in our work. Thus, to correct the geometrical deformation of chromosomes from LK(1), a robust method to obtain the medial axis of the chromosome was necessary. To address this problem, we developed an algorithm that uses the seed points to make a primary prediction. Subsequently, the algorithm computes the distance of boundary from the predicted point, and the gradients at algorithm-specified points on the boundary to compute two auxiliary predictions. Primary prediction is then corrected using auxiliary predictions, and a final prediction is obtained to be included in the seed region. A medial axis is obtained this way, which is further used for geometrical correction of the chromosomes. This algorithm was found capable of correcting geometrical deformations in even highly distorted chromosomes with forked ends.

  5. Correcting improper chromosome-spindle attachments during cell division.

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    Lampson, Michael A; Renduchitala, Kishore; Khodjakov, Alexey; Kapoor, Tarun M

    2004-03-01

    For accurate segregation of chromosomes during cell division, microtubule fibres must attach sister kinetochores to opposite poles of the mitotic spindle (bi-orientation). Aurora kinases are linked to oncogenesis and have been implicated in the regulation of chromosome-microtubule attachments. Although loss of Aurora kinase activity causes an accumulation of mal-orientated chromosomes in dividing cells, it is not known how the active kinase corrects improper chromosome attachments. The use of reversible small-molecule inhibitors allows activation of protein function in living vertebrate cells with temporal control. Here we show that by removal of small-molecule inhibitors, controlled activation of Aurora kinase during mitosis can correct chromosome attachment errors by selective disassembly of kinetochore-microtubule fibres, rather than by alternative mechanisms involving initial release of microtubules from either kinetochores or spindle poles. Observation of chromosomes and microtubule dynamics with real-time high-resolution microscopy showed that mal-orientated, but not bi-orientated, chromosomes move to the spindle pole as both kinetochore-microtubule fibres shorten, followed by alignment at the metaphase plate. Our results provide direct evidence for a mechanism required for the maintenance of genome integrity during cell division.

  6. The chromosomal passenger complex and the spindle assembly checkpoint: kinetochore-microtubule error correction and beyond

    OpenAIRE

    Maia André F; Vader Gerben; Lens Susanne MA

    2008-01-01

    Abstract During mitosis, correct bipolar chromosome attachment to the mitotic spindle is an essential prerequisite for the equal segregation of chromosomes. The spindle assembly checkpoint can prevent chromosome segregation as long as not all chromosome pairs have obtained bipolar attachment to the spindle. The chromosomal passenger complex plays a crucial role during chromosome alignment by correcting faulty chromosome-spindle interactions (e.g. attachments that do not generate tension). In ...

  7. The chromosomal passenger complex and the spindle assembly checkpoint: kinetochore-microtubule error correction and beyond

    Directory of Open Access Journals (Sweden)

    Maia André F

    2008-05-01

    Full Text Available Abstract During mitosis, correct bipolar chromosome attachment to the mitotic spindle is an essential prerequisite for the equal segregation of chromosomes. The spindle assembly checkpoint can prevent chromosome segregation as long as not all chromosome pairs have obtained bipolar attachment to the spindle. The chromosomal passenger complex plays a crucial role during chromosome alignment by correcting faulty chromosome-spindle interactions (e.g. attachments that do not generate tension. In the process of doing so, the chromosomal passenger complex generates unattached chromosomes, a specific situation that is known to promote checkpoint activity. However, several studies have implicated an additional, more direct role for the chromosomal passenger complex in enforcing the mitotic arrest imposed by the spindle assembly checkpoint. In this review, we discuss the different roles played by the chromosomal passenger complex in ensuring proper mitotic checkpoint function. Additionally, we discuss the possibility that besides monitoring the presence of unattached kinetochores, the spindle assembly checkpoint may also be capable of responding to chromosome-microtubule interactions that do not generate tension and we propose experimental set-ups to study this.

  8. The chromosomal passenger complex and the spindle assembly checkpoint: kinetochore-microtubule error correction and beyond.

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    Vader, Gerben; Maia, André F; Lens, Susanne Ma

    2008-05-28

    During mitosis, correct bipolar chromosome attachment to the mitotic spindle is an essential prerequisite for the equal segregation of chromosomes. The spindle assembly checkpoint can prevent chromosome segregation as long as not all chromosome pairs have obtained bipolar attachment to the spindle. The chromosomal passenger complex plays a crucial role during chromosome alignment by correcting faulty chromosome-spindle interactions (e.g. attachments that do not generate tension). In the process of doing so, the chromosomal passenger complex generates unattached chromosomes, a specific situation that is known to promote checkpoint activity. However, several studies have implicated an additional, more direct role for the chromosomal passenger complex in enforcing the mitotic arrest imposed by the spindle assembly checkpoint. In this review, we discuss the different roles played by the chromosomal passenger complex in ensuring proper mitotic checkpoint function. Additionally, we discuss the possibility that besides monitoring the presence of unattached kinetochores, the spindle assembly checkpoint may also be capable of responding to chromosome-microtubule interactions that do not generate tension and we propose experimental set-ups to study this.

  9. Cell-autonomous correction of ring chromosomes in human induced pluripotent stem cells

    Science.gov (United States)

    Bershteyn, Marina; Hayashi, Yohei; Desachy, Guillaume; Hsiao, Edward C.; Sami, Salma; Tsang, Kathryn M.; Weiss, Lauren A.; Kriegstein, Arnold R.; Yamanaka, Shinya; Wynshaw-Boris, Anthony

    2014-03-01

    Ring chromosomes are structural aberrations commonly associated with birth defects, mental disabilities and growth retardation. Rings form after fusion of the long and short arms of a chromosome, and are sometimes associated with large terminal deletions. Owing to the severity of these large aberrations that can affect multiple contiguous genes, no possible therapeutic strategies for ring chromosome disorders have been proposed. During cell division, ring chromosomes can exhibit unstable behaviour leading to continuous production of aneuploid progeny with low viability and high cellular death rate. The overall consequences of this chromosomal instability have been largely unexplored in experimental model systems. Here we generated human induced pluripotent stem cells (iPSCs) from patient fibroblasts containing ring chromosomes with large deletions and found that reprogrammed cells lost the abnormal chromosome and duplicated the wild-type homologue through the compensatory uniparental disomy (UPD) mechanism. The karyotypically normal iPSCs with isodisomy for the corrected chromosome outgrew co-existing aneuploid populations, enabling rapid and efficient isolation of patient-derived iPSCs devoid of the original chromosomal aberration. Our results suggest a fundamentally different function for cellular reprogramming as a means of `chromosome therapy' to reverse combined loss-of-function across many genes in cells with large-scale aberrations involving ring structures. In addition, our work provides an experimentally tractable human cellular system for studying mechanisms of chromosomal number control, which is of critical relevance to human development and disease.

  10. Chromosome aberrations, micronucleus and sperm head abnormalities in mice treated with natamycin, [corrected] a food preservative.

    Science.gov (United States)

    Rasgele, Pinar Goc; Kaymak, Fisun

    2010-03-01

    Natamycin [corrected] is used as preservative in foods. The genotoxic effects of the food preservative natamycin [corrected] were evaluated using chromosome aberrations and micronucleus test in bone marrow cells and sperm head abnormality assays in mice. Blood samples were taken from mice and levels of total testosterone in serum were also determined. Natamycin [corrected] was intraperitoneally (ip) injected at 200, 400 and 800 mg/kg. Natamycin [corrected] did not induce chromosome aberrations but significantly increased the number of micronucleated polychromatic erythrocytes in bone marrow and sperm head abnormalities at all concentrations and treatment periods. It also decreased MI at all concentrations for 6, 12 and 24h treatment periods. Natamycin [corrected] decreased PCE/NCE ratio at all concentrations for 48h in female mice, for 24 and 48h treatment periods in male mice. At the 800 mg/kg concentration, natamycin [corrected] decreased PCE/NCE ratio for 24 and 72h in female mice. A dose dependent increase was observed in the percentage of sperm head abnormalities. The levels of serum testosterone decreased dose-dependently. The obtained results indicate that natamycin [corrected] is not clastogenic, but it is aneugenic in mice bone marrow and it is a potential germ cell mutagen in sperm cells.

  11. Mosaicism for combined tetrasomy of chromosomes 8 and 18 in a dysmorphic child: A result of failed tetraploidy correction?

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    Lybæk Helle

    2009-05-01

    Full Text Available Abstract Background Mosaic whole-chromosome tetrasomy has not previously been described as a cause of fetal malformations. Case presentation In a markedly dysmorphic child with heart malformations and developmental delay, CGH analysis of newborn blood DNA suggested a 50% dose increase of chromosomes 8 and 18, despite a normal standard karyotype investigation. Subsequent FISH analysis revealed leukocytes with four chromosomes 8 and four chromosomes 18. The child's phenotype had resemblance to both mosaic trisomy 8 and mosaic trisomy 18. The double tetrasomy was caused by mitotic malsegregation of all four chromatids of both chromosome pairs. A possible origin of such an error is incomplete correction of a tetraploid state resulting from failed cytokinesis or mitotic slippage during early embryonic development. Conclusion This unique case suggests that embryonic cells may have a mechanism for tetraploidy correction that involves mitotic pairing of homologous chromosomes.

  12. Chromosome

    Science.gov (United States)

    Chromosomes are structures found in the center (nucleus) of cells that carry long pieces of DNA. DNA ... is the building block of the human body. Chromosomes also contain proteins that help DNA exist in ...

  13. Somatic pairing of chromosome 19 in renal oncocytoma is associated with deregulated EGLN2-mediated [corrected] oxygen-sensing response.

    Directory of Open Access Journals (Sweden)

    Julie M Koeman

    Full Text Available Chromosomal abnormalities, such as structural and numerical abnormalities, are a common occurrence in cancer. The close association of homologous chromosomes during interphase, a phenomenon termed somatic chromosome pairing, has been observed in cancerous cells, but the functional consequences of somatic pairing have not been established. Gene expression profiling studies revealed that somatic pairing of chromosome 19 is a recurrent chromosomal abnormality in renal oncocytoma, a neoplasia of the adult kidney. Somatic pairing was associated with significant disruption of gene expression within the paired regions and resulted in the deregulation of the prolyl-hydroxylase EGLN2 [corrected] a key protein that regulates the oxygen-dependent degradation of hypoxia-inducible factor (HIF. Overexpression of EGLN2 [corrected] in renal oncocytoma increased ubiquitin-mediated destruction of HIF and concomitantly suppressed the expression of several HIF-target genes, including the pro-death BNIP3L gene. The transcriptional changes that are associated with somatic pairing of chromosome 19 mimic the transcriptional changes that occur following DNA amplification. Therefore, in addition to numerical and structural chromosomal abnormalities, alterations in chromosomal spatial dynamics should be considered as genomic events that are associated with tumorigenesis. The identification of EGLN2 as a significantly deregulated gene that maps within the paired chromosome region directly implicates defects in the oxygen-sensing network to the biology of renal oncocytoma.

  14. Chromosome congression explained by nanoscale electrostatics.

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    Gagliardi, L John; Shain, Daniel H

    2014-02-24

    Nanoscale electrostatic microtubule disassembly forces between positively charged molecules in kinetochores and negative charges on plus ends of microtubules have been implicated in poleward chromosome motions and may also contribute to antipoleward chromosome movements. We propose that chromosome congression can be understood in terms of antipoleward nanoscale electrostatic microtubule assembly forces between negatively charged microtubule plus ends and like-charged chromosome arms, acting in conjunction with poleward microtubule disassembly forces. Several other aspects of post-attachment prometaphase chromosome motions, as well as metaphase oscillations, are consistently explained within this framework.

  15. Accurate measurement of poleward microtubule flux in the spindle of Drosophila S2 cells.

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    Munzarova, Alina; Popova, Julia; Razuvaeva, Alena; Shloma, Victor; Gatti, Maurizio; Omelyanchuk, Leonid

    2016-09-01

    The spindle microtubule (MT) flux is the continuous translocation of MTs toward the spindle poles caused by MT polymerization at plus ends coupled to depolymerization at minus ends. Poleward flux is observed in both mitotic and meiotic spindles; it is evolutionarily conserved and contributes to the regulation of spindle length and anaphase chromosome movement. MT photobleaching is a tool frequently used to measure poleward flux. Spindles containing fluorescently tagged tubulin are photobleached to generate a non-fluorescent stripe, which moves toward the spindle poles allowing a measure of the flux. However, this method only permits rapid measurements of the flux, because the fluorescence of the bleached stripe recovers rapidly due to the spindle MT turnover. Here, we describe a modification of the current photobleaching-based method for flux measurement. We photobleached two large areas at the opposite sides of the metaphase plate in spindles of Drosophila S2 cells expressing Cherry-tagged tubulin, leaving unbleached only the area near the chromosomes. We then measured the speed with which the fluorescent MTs move toward the poles. We found that this method allows a measure of the flux over a two- to threefold longer time than the "single stripe" method, providing a reliable evaluation of the flux rate. © 2016 International Federation for Cell Biology.

  16. Progression of colorectal cancer is associated with multiple tumor suppressor gene defects but inhibition of tumorigenicity is accomplished by correction of any single defect via chromosome transfer

    Energy Technology Data Exchange (ETDEWEB)

    Goyette, M.C.; Fasching, C.L.; Stanbridge, E.J. (Univ. of California, Irvine (United States)); Cho, K.; Levy, D.B.; Kinzler, K.W.; Vogelstein, B. (John Hopkins Univ. School of Medicine and Hospital, Baltimore, MD (United States)); Paraskeva, C. (Univ. of Bristol, University Walk, Bristol (United Kingdom))

    1992-03-01

    Colorectal cancer has been associated with the activation of ras oncogenes and with the deletion of multiple chromosomal regions including chromosomes 5q, 17p, and 18q. The candidate tumor suppressor genes from these regions are, respectively, MCC and/or APC, p53, and DCC. In order to further understanding of the molecular and genetic mechanisms involved in tumor progression and, thereby, of normal cell growth, it is important to determine whether defects in one or more of these loci contribute functionally in the progression to malignancy in colorectal cancer and whether correction of any of these defects restores normal growth control in vitro and in vivo. To address this question, the authors have utilized the technique of microcell-mediated chromosome transfer to introduce normal human chromosomes 5, 17, and 18 individually into recipient colorectal cancer cells. Additionally, chromosome 15 was introduced into SW480 cells as an irrelevant control chromosome. While the introduction of chromosome 17 into the tumorigenic colorectal cell line SW480 yielded no viable clones, cell lines were established after the introduction of chromosomes 15, 5, and 18. SW480-chromosome 5 hybrids are strongly suppressed for tumorigenicity, while SW480-chromosome 18 hybrids produce slowly growing tumors in some of the animals injected. Hybrids containing the introduced chromosome 5 express the APC gene present on that chromosome as well as the endogenous mutant transcript. Expression of the putative tumor suppressor gene, DCC, was seen in the clones containing the introduced chromosome 18 but was significantly reduced in several of the tumor reconstitute cell lines. Our findings indicate that while multiple defects in tumor suppressor genes seem to be required for progression to the malignant state in colorectal cancer, correction of only a single defect can have significant effects in vivo and/or in vitro.

  17. Contribution of Oceanic Circulation to the Poleward Heat Flux

    Institute of Scientific and Technical Information of China (English)

    HUANG Ruixin

    2005-01-01

    Oceanic contribution to the poleward heat flux in the climate system includes two components: the sensible heat flux and the latent heat flux. Although the latent heat flux has been classified as atmospheric heat flux exclusively, it is argued that oceanic control over this component of poleward heat flux should play a critically important role. The so-called swamp ocean model practice is analyzed in detail, and the critical role of oceanic circulation in the establishment of the meridional moisture transport is emphasized.

  18. Is Climate Change Shifting the Poleward Limit of Mangroves?

    KAUST Repository

    Hickey, Sharyn M.

    2017-02-01

    Ecological (poleward) regime shifts are a predicted response to climate change and have been well documented in terrestrial and more recently ocean species. Coastal zones are amongst the most susceptible ecosystems to the impacts of climate change, yet studies particularly focused on mangroves are lacking. Recent studies have highlighted the critical ecosystem services mangroves provide, yet there is a lack of data on temporal global population response. This study tests the notion that mangroves are migrating poleward at their biogeographical limits across the globe in line with climate change. A coupled systematic approach utilising literature and land surface and air temperature data was used to determine and validate the global poleward extent of the mangrove population. Our findings indicate that whilst temperature (land and air) have both increased across the analysed time periods, the data we located showed that mangroves were not consistently extending their latitudinal range across the globe. Mangroves, unlike other marine and terrestrial taxa, do not appear to be experiencing a poleward range expansion despite warming occurring at the present distributional limits. Understanding failure for mangroves to realise the global expansion facilitated by climate warming may require a focus on local constraints, including local anthropogenic pressures and impacts, oceanographic, hydrological, and topographical conditions.

  19. Correction

    DEFF Research Database (Denmark)

    Pinkevych, Mykola; Cromer, Deborah; Tolstrup, Martin

    2016-01-01

    [This corrects the article DOI: 10.1371/journal.ppat.1005000.][This corrects the article DOI: 10.1371/journal.ppat.1005740.][This corrects the article DOI: 10.1371/journal.ppat.1005679.].......[This corrects the article DOI: 10.1371/journal.ppat.1005000.][This corrects the article DOI: 10.1371/journal.ppat.1005740.][This corrects the article DOI: 10.1371/journal.ppat.1005679.]....

  20. Poleward tubulin flux in spindles: regulation and function in mitotic cells.

    Science.gov (United States)

    Buster, Daniel W; Zhang, Dong; Sharp, David J

    2007-08-01

    The poleward flux of tubulin subunits through spindle microtubules is a striking and conserved phenomenon whose function and molecular components remain poorly understood. To screen for novel components of the flux machinery, we utilized RNA interference to deplete regulators of microtubule dynamics, individually and in various combinations, from S2 cells and examined the resulting impact on flux rate. This led to the identification of two previously unknown flux inhibitors, KLP59C and KLP67A, and a flux promoter, Mini-spindles. Furthermore, we find that flux rate is regulated by functional antagonism among microtubule stabilizers and destabilizers specifically at plus ends. Finally, by examining mitosis on spindles in which flux has been up- or down-regulated or restored after the codepletion of antagonistic flux regulators, we show that flux is an integral contributor to anaphase A but is not responsible for chromosome congression, interkinetochore tension, or the establishment of normal spindle length during prometaphase/metaphase.

  1. Poleward Expansion of the Hadley Circulation in CMIP5 Simulations

    Institute of Scientific and Technical Information of China (English)

    HU Yongyun; TAO Lijun; LIU Jiping

    2013-01-01

    Observational analyses have demonstrated that the Hadley circulation has expanded poleward in recent decades.Important issues are what caused the widening of the Hadley circulation and whether the observed widening is related to anthropogenic forcing.In the present study,we use currently available simulations of the Coupled Model Intercomparison Project Phase-5 (CMIP5) to analyze changes in the width of the Hadley circulation.It is found that CMIP5 historical simulations with greenhouse gas (GHG) forcing generate a total widening of ~0.15°±0.06° in latitude (10 yr)-1 for the period 1979-2005,and the widening in CMIP5 historical simulations with all forcings is ~0.17° ± 0.06° per decade.Similar to that in CMIP3,the simulated poleward expansion in CMIP5 is much weaker than the observational reanalyses.In CMIP5 projection simulations for the 21st century,magnitudes of widening of the Hadley circulation increase with radiative forcing.For the extreme projected radiative forcing of RCP8.5,the total annual-mean widening of the Hadley circulation is ~ 0.27° ± 0.04° (10 yr)-1 in the 21st century.Although CMIP5 underestimates observed poleward expansion of the Hadley circulation,the results of this study suggest that the observed trends in the width of the Hadley circulation are caused by anthropogenic forcing and that increasing GHGs play an important role in the observed poleward expansion of the Hadley circulation,in addition to other forcings emphasized in previous studies.

  2. Centrosome dynamics as a source of chromosomal instability.

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    Nam, Hyun-Ja; Naylor, Ryan M; van Deursen, Jan M

    2015-02-01

    Accurate segregation of duplicated chromosomes between two daughter cells depends on bipolar spindle formation, a metaphase state in which sister kinetochores are attached to microtubules emanating from opposite spindle poles. To ensure bi-orientation, cells possess surveillance systems that safeguard against microtubule-kinetochore attachment defects, including the spindle assembly checkpoint and the error correction machinery. However, recent developments have identified centrosome dynamics--that is, centrosome disjunction and poleward movement of duplicated centrosomes--as a central target for deregulation of bi-orientation in cancer cells. In this review, we discuss novel insights into the mechanisms that underlie centrosome dynamics and discuss how these mechanisms are perturbed in cancer cells to drive chromosome mis-segregation and advance neoplastic transformation.

  3. Mangrove expansion and salt marsh decline at mangrove poleward limits.

    Science.gov (United States)

    Saintilan, Neil; Wilson, Nicholas C; Rogers, Kerrylee; Rajkaran, Anusha; Krauss, Ken W

    2014-01-01

    Mangroves are species of halophytic intertidal trees and shrubs derived from tropical genera and are likely delimited in latitudinal range by varying sensitivity to cold. There is now sufficient evidence that mangrove species have proliferated at or near their poleward limits on at least five continents over the past half century, at the expense of salt marsh. Avicennia is the most cold-tolerant genus worldwide, and is the subject of most of the observed changes. Avicennia germinans has extended in range along the USA Atlantic coast and expanded into salt marsh as a consequence of lower frost frequency and intensity in the southern USA. The genus has also expanded into salt marsh at its southern limit in Peru, and on the Pacific coast of Mexico. Mangroves of several species have expanded in extent and replaced salt marsh where protected within mangrove reserves in Guangdong Province, China. In south-eastern Australia, the expansion of Avicennia marina into salt marshes is now well documented, and Rhizophora stylosa has extended its range southward, while showing strong population growth within estuaries along its southern limits in northern New South Wales. Avicennia marina has extended its range southwards in South Africa. The changes are consistent with the poleward extension of temperature thresholds coincident with sea-level rise, although the specific mechanism of range extension might be complicated by limitations on dispersal or other factors. The shift from salt marsh to mangrove dominance on subtropical and temperate shorelines has important implications for ecological structure, function, and global change adaptation.

  4. Movement of chromosomes with severed kinetochore microtubules.

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    Forer, Arthur; Johansen, Kristen M; Johansen, Jørgen

    2015-05-01

    Experiments dating from 1966 and thereafter showed that anaphase chromosomes continued to move poleward after their kinetochore microtubules were severed by ultraviolet microbeam irradiation. These observations were initially met with scepticism as they contradicted the prevailing view that kinetochore fibre microtubules pulled chromosomes to the pole. However, recent experiments using visible light laser microbeam irradiations have corroborated these earlier experiments as anaphase chromosomes again were shown to move poleward after their kinetochore microtubules were severed. Thus, multiple independent studies using different techniques have shown that chromosomes can indeed move poleward without direct microtubule connections to the pole, with only a kinetochore 'stub' of microtubules. An issue not yet settled is: what propels the disconnected chromosome? There are two not necessarily mutually exclusive proposals in the literature: (1) chromosome movement is propelled by the kinetochore stub interacting with non-kinetochore microtubules and (2) chromosome movement is propelled by a spindle matrix acting on the stub. In this review, we summarise the data indicating that chromosomes can move with severed kinetochore microtubules and we discuss proposed mechanisms for chromosome movement with severed kinetochore microtubules.

  5. Correction of chromosomal instability and sensitivity to diverse mutagens by a cloned cDNA of the XRCC3 DNA repair gene

    Energy Technology Data Exchange (ETDEWEB)

    Tebbs, R.S.; Tucker, J.D.; Hwang, M. [Lawrence Livermore National Lab., CA (United States)] [and others

    1995-07-03

    The mutagen-sensitive CHO line irs1SF was previously isolated on the basis of hypersensitivity to ionizing radiation and was found to be chromosomally unstable as well as cross-sensitive to diverse kinds of DNA-damaging agents. The analysis of somatic cell hybrids formed between irs1SF and human lymphocytes implicated a human gene (defined as XRCC3; x-ray repair cross-complementing), which partially restored mitomycin C resistance to the mutant. A functional cDNA that confers mitomycin C resistance was transferred to irs1SF cells by transforming them with an expression cDNA library and obtaining primary and secondary transformants. Functional cDNA clones were recovered from a cosmid library prepared from a secondary transformant. Transformants also showed partial correction of sensitivity to displatin and {gamma}-rays, efficient correction of chromosomal instability, and substantially improved plating efficiency and growth rate. The XRCC3 cDNA insert is {approx} 2.5 kb and detects an {approx} 3.0-kb mRNA on Northern blots. The cDNA was mapped by fluorescence in situ hybridization to human chromosome 14q32.3, which was consistent with the chromosome concordance data of two independent hybrid clone panels. 30 refs., 5 figs., 2 tabs.

  6. Co-variability of poleward propagating atmospheric energy with tropical and higher-latitude climate oscillations

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Wan-Ru [Iowa State University, Department of Geological and Atmospheric Sciences, Ames, IA (United States); City University of Hong Kong, Guy Carpenter Asia-Pacific Climate Impact Centre, School of Energy and Environment, Kowloon, Hong Kong (China); Chen, Tsing-Chang [Iowa State University, Department of Geological and Atmospheric Sciences, Ames, IA (United States); Wang, Shih-Yu [Utah State University, Utah Climate Center and Department of Plants, Soils and Climate, Logan, UT (United States)

    2012-10-15

    One may infer from the poleward propagation of angular momentum that energy change in tropical regions may be manifested in polar regions through a poleward propagation. This idea does not seem to be extensively addressed in the literature. It has been found that the poleward propagation of total atmospheric energy appears to connect the tropics and the polar regions on the interannual timescale. The present study explores how this poleward propagation may be linked to prominent climate oscillations such as ENSO, PNA, NAO, AO, AAO, and PSA. Analysis suggests that the poleward propagation of energy is likely a result of the atmospheric circulation change modulated by the climate patterns of ENSO, PNA, NAO, AO from tropical to Arctic regions and by the climate patterns of ENSO, PSA, AAO from tropical to Antarctic regions. The existence of the poleward energy propagation may shed light on studies exploring the linkage between topical climate and polar climate. (orig.)

  7. Source of a Prominent Poleward Surge During Solar Cycle 24

    CERN Document Server

    Yeates, A R; van Driel-Gesztelyi, L

    2015-01-01

    As an observational case study, we consider the origin of a prominent poleward surge of leading polarity, visible in the magnetic butterfly diagram during Solar Cycle 24. A new technique is developed for assimilating individual regions of strong magnetic flux into a surface flux transport model. By isolating the contribution of each of these regions, the model shows the surge to originate primarily in a single high-latitude activity group consisting of a bipolar active region present in Carrington Rotations 2104-05 (November 2010-January 2011) and a multipolar active region in Rotations 2107-08 (February-April 2011). This group had a strong axial dipole moment opposed to Joy's law. On the other hand, the modelling suggests that the transient influence of this group on the butterfly diagram will not be matched by a large long-term contribution to the polar field, because of its location at high latitude. This is in accordance with previous flux transport models.

  8. Mangrove expansion and saltmarsh decline at mangrove poleward limits

    Science.gov (United States)

    Saintilan, Neil; Wilson, Nicholas C.; Rogers, Kerrylee; Rajkaran, Anusha; Krauss, Ken W.

    2014-01-01

    Mangroves are species of halophytic intertidal trees and shrubs derived from tropical genera and are likely delimited in latitudinal range by varying sensitivity to cold. There is now sufficient evidence that mangrove species have proliferated at or near their poleward limits on at least five continents over the past half century, at the expense of salt marsh. Avicennia is the most cold-tolerant genus worldwide, and is the subject of most of the observed changes. Avicennia germinans has extended in range along the US Atlantic coast and expanded into salt marsh as a consequence of lower frost frequency and intensity in the southern USA. The genus has also expanded into salt marsh at its southern limit in Peru, and on the Pacific coast of Mexico. Mangroves of several species have expanded in extent and replaced salt marsh where protected within mangrove reserves in Guangdong Province. In south-eastern Australia, the expansion of Avicennia marina into salt marshes is now well documented, and Rhizophora stylosa has extended its range southward, while showing strong population growth within estuaries along its southern limits in northern New South Wales. Avicennia marina has extended its range southwards in South Africa. The changes are consistent with the pole-ward extension of temperature thresholds co-incident with sea-level rise, although the specific mechanism of range extension might be complicated by limitations on dispersal or other factors. The shift from salt marsh to mangrove dominance on subtropical and temperate shorelines has important implications for ecological structure, function, and global change adaptation.

  9. Correction

    CERN Document Server

    2002-01-01

    Tile Calorimeter modules stored at CERN. The larger modules belong to the Barrel, whereas the smaller ones are for the two Extended Barrels. (The article was about the completion of the 64 modules for one of the latter.) The photo on the first page of the Bulletin n°26/2002, from 24 July 2002, illustrating the article «The ATLAS Tile Calorimeter gets into shape» was published with a wrong caption. We would like to apologise for this mistake and so publish it again with the correct caption.

  10. A Regulatory Switch Alters Chromosome Motions at the Metaphase-to-Anaphase Transition

    Directory of Open Access Journals (Sweden)

    Kuan-Chung Su

    2016-11-01

    Full Text Available To achieve chromosome segregation during mitosis, sister chromatids must undergo a dramatic change in their behavior to switch from balanced oscillations at the metaphase plate to directed poleward motion during anaphase. However, the factors that alter chromosome behavior at the metaphase-to-anaphase transition remain incompletely understood. Here, we perform time-lapse imaging to analyze anaphase chromosome dynamics in human cells. Using multiple directed biochemical, genetic, and physical perturbations, our results demonstrate that differences in the global phosphorylation states between metaphase and anaphase are the major determinant of chromosome motion dynamics. Indeed, causing a mitotic phosphorylation state to persist into anaphase produces dramatic metaphase-like oscillations. These induced oscillations depend on both kinetochore-derived and polar ejection forces that oppose poleward motion. Thus, our analysis of anaphase chromosome motion reveals that dephosphorylation of multiple mitotic substrates is required to suppress metaphase chromosome oscillatory motions and achieve directed poleward motion for successful chromosome segregation.

  11. Individualized correction for maternal weight in calculating the risk of chromosomal abnormalities with first-trimester screening data.

    Science.gov (United States)

    Merz, E; Thode, C; Eiben, B; Faber, R; Hackelöer, B J; Huesgen, G; Pruggmaier, M; Wellek, S

    2011-02-01

    In the algorithm developed by the Fetal Medicine Foundation (FMF) Germany designed to evaluate the findings of routine first-trimester screening, the false-positive rate (FPR) was determined for the entire study group without stratification by maternal weight. Based on the data received from the continuous audit we were able to identify an increase in the FPR for the weight-related subgroups of patients, particularly for patients with extremely high body weights. The aim of this study was to demonstrate that the variability of the FPR can be reduced through adjusting the concentrations of free β-HCG and PAPP-A measured in the maternal serum by means of a nonlinear regression function modeling the dependence of these values on maternal weight. The database used to establish a version of the algorithm enabling control of the FPR over the whole range of maternal weight consisted of n = 123 546 pregnancies resulting in the birth of a child without chromosomal anomalies. The group with positive outcomes covered n = 500 cases of trisomy 21 and n = 159 trisomies 13 or 18. The dependency of the serum parameters free β-HCG and PAPP-A on maternal weight was analyzed in the sample of negative outcomes by means of nonlinear regression. The fitted regression curve was of exponential form with negative slope. Using this model, all individual measurements were corrected through multiplication with a factor obtained as the ratio of the concentration level predicted by the model to belong to the average maternal body weight of 68.2 kg, over the ordinate of that point on the regression curve which belongs to the weight actually measured. Subsequently, the totality of all values of free β-HCG and PAPP-A corrected for deviation from average weight were used as input data for carrying out the construction of diagnostic discrimination rules described in our recent paper for a database to which no corrections for over- or under-weight had been applied. This entailed in particular the

  12. Correction

    CERN Multimedia

    2002-01-01

    The photo on the second page of the Bulletin n°48/2002, from 25 November 2002, illustrating the article «Spanish Visit to CERN» was published with a wrong caption. We would like to apologise for this mistake and so publish it again with the correct caption.   The Spanish delegation, accompanied by Spanish scientists at CERN, also visited the LHC superconducting magnet test hall (photo). From left to right: Felix Rodriguez Mateos of CERN LHC Division, Josep Piqué i Camps, Spanish Minister of Science and Technology, César Dopazo, Director-General of CIEMAT (Spanish Research Centre for Energy, Environment and Technology), Juan Antonio Rubio, ETT Division Leader at CERN, Manuel Aguilar-Benitez, Spanish Delegate to Council, Manuel Delfino, IT Division Leader at CERN, and Gonzalo León, Secretary-General of Scientific Policy to the Minister.

  13. Correction

    Directory of Open Access Journals (Sweden)

    2012-01-01

    Full Text Available Regarding Gorelik, G., & Shackelford, T.K. (2011. Human sexual conflict from molecules to culture. Evolutionary Psychology, 9, 564–587: The authors wish to correct an omission in citation to the existing literature. In the final paragraph on p. 570, we neglected to cite Burch and Gallup (2006 [Burch, R. L., & Gallup, G. G., Jr. (2006. The psychobiology of human semen. In S. M. Platek & T. K. Shackelford (Eds., Female infidelity and paternal uncertainty (pp. 141–172. New York: Cambridge University Press.]. Burch and Gallup (2006 reviewed the relevant literature on FSH and LH discussed in this paragraph, and should have been cited accordingly. In addition, Burch and Gallup (2006 should have been cited as the originators of the hypothesis regarding the role of FSH and LH in the semen of rapists. The authors apologize for this oversight.

  14. Correction

    Directory of Open Access Journals (Sweden)

    2014-01-01

    Full Text Available Regarding Tagler, M. J., and Jeffers, H. M. (2013. Sex differences in attitudes toward partner infidelity. Evolutionary Psychology, 11, 821–832: The authors wish to correct values in the originally published manuscript. Specifically, incorrect 95% confidence intervals around the Cohen's d values were reported on page 826 of the manuscript where we reported the within-sex simple effects for the significant Participant Sex × Infidelity Type interaction (first paragraph, and for attitudes toward partner infidelity (second paragraph. Corrected values are presented in bold below. The authors would like to thank Dr. Bernard Beins at Ithaca College for bringing these errors to our attention. Men rated sexual infidelity significantly more distressing (M = 4.69, SD = 0.74 than they rated emotional infidelity (M = 4.32, SD = 0.92, F(1, 322 = 23.96, p < .001, d = 0.44, 95% CI [0.23, 0.65], but there was little difference between women's ratings of sexual (M = 4.80, SD = 0.48 and emotional infidelity (M = 4.76, SD = 0.57, F(1, 322 = 0.48, p = .29, d = 0.08, 95% CI [−0.10, 0.26]. As expected, men rated sexual infidelity (M = 1.44, SD = 0.70 more negatively than they rated emotional infidelity (M = 2.66, SD = 1.37, F(1, 322 = 120.00, p < .001, d = 1.12, 95% CI [0.85, 1.39]. Although women also rated sexual infidelity (M = 1.40, SD = 0.62 more negatively than they rated emotional infidelity (M = 2.09, SD = 1.10, this difference was not as large and thus in the evolutionary theory supportive direction, F(1, 322 = 72.03, p < .001, d = 0.77, 95% CI [0.60, 0.94].

  15. Correction.

    Science.gov (United States)

    2015-10-01

    In the article by Quintavalle et al (Quintavalle C, Anselmi CV, De Micco F, Roscigno G, Visconti G, Golia B, Focaccio A, Ricciardelli B, Perna E, Papa L, Donnarumma E, Condorelli G, Briguori C. Neutrophil gelatinase–associated lipocalin and contrast-induced acute kidney injury. Circ Cardiovasc Interv. 2015;8:e002673. DOI: 10.1161/CIRCINTERVENTIONS.115.002673.), which published online September 2, 2015, and appears in the September 2015 issue of the journal, a correction was needed. On page 1, the institutional affiliation for Elvira Donnarumma, PhD, “SDN Foundation,” has been changed to read, “IRCCS SDN, Naples, Italy.” The institutional affiliation for Laura Papa, PhD, “Institute for Endocrinology and Experimental Oncology, National Research Council, Naples, Italy,” has been changed to read, “Institute of Genetics and Biomedical Research, Milan Unit, Milan, Italy” and “Humanitas Research Hospital, Rozzano, Italy.” The authors regret this error.

  16. Simultaneous storm time equatorward and poleward large-scale TIDs on a global scale

    Science.gov (United States)

    Habarulema, John Bosco; Katamzi, Zama Thobeka; Yizengaw, Endawoke; Yamazaki, Yosuke; Seemala, Gopi

    2016-07-01

    We report on the first simultaneous observations of poleward and equatorward traveling ionospheric disturbances (TIDs) during the same geomagnetic storm period on a global scale. While poleward propagating TIDs originate from the geomagnetic equator region, equatorward propagating TIDs are launched from the auroral regions. On a global scale, we use total electron content observations from the Global Navigation Satellite Systems to show that these TIDs existed over South American, African, and Asian sectors. The American and African sectors exhibited predominantly strong poleward TIDs, while the Asian sector recorded mostly equatorward TIDs which crossed the geomagnetic equator to either hemisphere on 9 March 2012. However, both poleward and equatorward TIDs are simultaneously present in all three sectors. Using a combination of ground-based magnetometer observations and available low-latitude radar (JULIA) data, we have established and confirmed that poleward TIDs of geomagnetic equator origin are due to ionospheric electrodynamics, specifically changes in E × B vertical drift after the storm onset.

  17. Saturation of poleward atmospheric heat transport in warm climates and the low-gradient paradox.

    Science.gov (United States)

    Caballero, R.; Langen, P.

    2004-12-01

    The equable climates of the deep past featured higher atmospheric greenhouse gas concentrations, greater global-mean surface temperatures and much weaker equator-to-pole temperature contrasts than today. Climate models readily reproduce the higher mean temperatures, given sufficient increases in greenhouse gases, but they have proved incapable of matching the low meridional gradients indicated by proxy data. A crucial step in resolving this 'low-gradient paradox' is uderstanding why climate models fail to reproduce the correct feedback between global mean temperature and its meridional gradient. Though models do achieve some reduction in temperature gradients, mostly through snow and sea-ice albedo feedback, the remaining discrepancy must be accounted for by either more exotic forms of radiative forcing feedback, which are not represented in current models, or by more efficient oceanic and/or atmospheric poleward heat transports, which the models for some reason do not capture. This latter feature is especially puzzling for the atmosphere, since there are plausible reasons to expect atmospheric energy transport to be be considerably more efficient in a warmer climate. We explore this issue by systematically studying the response of atmospheric heat transpor in a GCM to a very broad range of global mean temperatures and meridional gradients. We find that heat transport increases with global mean temperature when the latter is less than about 15C; above this value, heat transport saturates, becoming insensitive to surface temperature. This behavior has a dynamical origin traceble to changes in the structure of the atmosphere's general circulation. Mean tropospheric static stability increases with surface temperature, reducing baroclinicity and suppressing storm-track eddy activity. Furthermore, as temperature increases the storm-tracks as a whole migrate poleward over cooler waters, and thus do not experience the full global-mean surface temperature increase. These

  18. Prevention and correction mechanisms behind anaphase synchrony: implications for the genesis of aneuploidy.

    Science.gov (United States)

    Matos, I; Maiato, H

    2011-01-01

    The perpetuation of the species' genomic identity strongly depends on the accurate maintenance of chromosome number through countless cell generations. The synchronous entry and progression of all chromosomes through anaphase is fundamental for the quality of mitosis and is guaranteed by error prevention and correction mechanisms that ultimately certify the bipolar attachment of chromosomes to the mitotic spindle, the uniform distribution of forces amongst different chromosomes, and the simultaneity of sister-chromatid separation. The existence of a kinetochore-attachment checkpoint (KAC; also known as spindle-assembly checkpoint) ensures a delay in anaphase onset if any kinetochore remains unattached or devoid of a proper complement of microtubules. The stochastic nature of microtubule-kinetochore interactions predisposes the mitotic process to mistakes, but different molecular players cooperate by detecting and releasing incorrect attachments and thus delaying checkpoint satisfaction. Conversely, correct microtubule-kinetochore interactions become selectively stabilized. Once anaphase onset is triggered, the segregation velocities achieved by each chromosome should be similar, so that none of the chromosomes is lagged behind. This reflects the uniformity of forces acting on the different chromosomes and relies on a conspicuous mitotic spindle property known as microtubule poleward flux. Importantly, not all incorrect attachments are detected and resolved prior to anaphase leading to asynchronous chromosome segregation, but several mechanisms are in place to prevent aneuploidy. One of these mechanisms relies on anaphase spindle forces and another, known as the NoCut checkpoint, delays cell cleavage during cytokinesis until chromosomes can free the spindle mid-region. In this review we discuss how these different mechanisms act in concert to ensure the fidelity of the mitotic process.

  19. Can molecular cell biology explain chromosome motions?

    Directory of Open Access Journals (Sweden)

    Gagliardi L

    2011-05-01

    Full Text Available Abstract Background Mitotic chromosome motions have recently been correlated with electrostatic forces, but a lingering "molecular cell biology" paradigm persists, proposing binding and release proteins or molecular geometries for force generation. Results Pole-facing kinetochore plates manifest positive charges and interact with negatively charged microtubule ends providing the motive force for poleward chromosome motions by classical electrostatics. This conceptual scheme explains dynamic tracking/coupling of kinetochores to microtubules and the simultaneous depolymerization of kinetochore microtubules as poleward force is generated. Conclusion We question here why cells would prefer complex molecular mechanisms to move chromosomes when direct electrostatic interactions between known bound charge distributions can accomplish the same task much more simply.

  20. Epigenetic histone marks of extended meta-polycentric centromeres of Lathyrus and Pisum chromosomes

    Directory of Open Access Journals (Sweden)

    Pavel eNeumann

    2016-03-01

    Full Text Available Species of the legume genera Lathyrus and Pisum possess chromosomes that exhibit a unique structure of their centromeric regions, which is clearly apparent during metaphase by the formation of extended primary constrictions which span up to a third of the length of the chromosome. In addition, these species express two different variants of the CenH3 protein which are co-localized in multiple domains along the poleward surface of the primary constrictions. Here we show that the constrictions represent a distinct type of chromatin differing from the chromosome arms. In metaphase, histone phosphorylation patterns including H3S10ph, H3S28ph and H3T3ph were observed along the entire constriction, in a way similar to holocentric chromosomes. On the other hand, distribution of phosphorylated H2AT120 was different from that previously reported from either, holocentric and monocentric chromosomes, occurring at chromatin surrounding but not overlapping CenH3 domains. Since some of these phosphorylations play a role in chromatid cohesion, it can be assumed that they facilitate correct chromosome segregation by ensuring that multiple separate CenH3 domains present on the same chromatid are oriented towards the same pole. The constrictions also displayed distinct patterns of histone methylation marks, being enriched in H3K9me2 and depleted in H3K4me3 and H3K27me2 compared to the chromosome arms. High resolution fluorescence microscopy revealed that although both CenH3 protein variants are present in all CenH3 domains detected on metaphase chromosomes, they are only partially co-localized while there are chromatin subdomains which are mostly made of only one CenH3 variant. Taken together, these data revealed specific features of extended primary constrictions of Lathyrus and Pisum and support the idea that they may represent an intermediate stage between monocentric and holocentric chromosomes.

  1. Synchronizing chromosome segregation by flux-dependent force equalization at kinetochores.

    Science.gov (United States)

    Matos, Irina; Pereira, António J; Lince-Faria, Mariana; Cameron, Lisa A; Salmon, Edward D; Maiato, Helder

    2009-07-13

    The synchronous movement of chromosomes during anaphase ensures their correct inheritance in every cell division. This reflects the uniformity of spindle forces acting on chromosomes and their simultaneous entry into anaphase. Although anaphase onset is controlled by the spindle assembly checkpoint, it remains unknown how spindle forces are uniformly distributed among different chromosomes. In this paper, we show that tension uniformity at metaphase kinetochores and subsequent anaphase synchrony in Drosophila S2 cells are promoted by spindle microtubule flux. These results can be explained by a mechanical model of the spindle where microtubule poleward translocation events associated with flux reflect relaxation of the kinetochore-microtubule interface, which accounts for the redistribution and convergence of kinetochore tensions in a timescale comparable to typical metaphase duration. As predicted by the model, experimental acceleration of mitosis precludes tension equalization and anaphase synchrony. We propose that flux-dependent equalization of kinetochore tensions ensures a timely and uniform maturation of kinetochore-microtubule interfaces necessary for error-free and coordinated segregation of chromosomes in anaphase.

  2. Lagrangian transport in poleward breaking Rossby waves in the North Atlantic - Europe tropopause region

    Energy Technology Data Exchange (ETDEWEB)

    Bartels, J.; Peters, D. [Rostock Univ. (Germany). Inst. fuer Atmosphaerenphysik

    1997-12-31

    The poleward advection of upper-tropospheric air is investigated for poleward Rossby wave breaking events. During boreal winter months the isentropic deformations of the tropopause are examined using maps of Ertel`s potential vorticity (EPV) and contour advection (CA) calculations. The role of ambient baro-tropic flow is further examined by idealized numerical models. In the vicinity of the tropopause the characteristic Lagrangian transport of air masses for ECMWF-analysis data are compared with high resolution (T106) ECHAM4 experiments. (author) 3 refs.

  3. Poleward propagating subinertial alongshore surface currents off the U.S. West Coast

    KAUST Repository

    Kim, Sung Yong

    2013-12-01

    The network comprising 61 high-frequency radar systems along the U.S. West Coast (USWC) provides a unique, high resolution, and broad scale view of ocean surface circulation. Subinertial alongshore surface currents show poleward propagating signals with phase speeds of O(10) and O(100-300) km d -1 that are consistent with historical in situ observations off the USWC and that can be possibly interpreted as coastally trapped waves (CTWs). The propagating signals in the slow mode are partly observed in southern California, which may result from scattering and reflection of higher-mode CTWs due to curvature of shoreline and bathymetry near Point Conception, California. On the other hand, considering the order of the phase speed in the slow mode, the poleward propagating signals may be attributed to alongshore advection or pressure-driven flows. A statistical regression of coastal winds at National Data Buoy Center buoys on the observed surface currents partitions locally and remotely wind-forced components, isolates footprints of the equatorward propagating storm events in winter off the USWC, and shows the poleward propagating signals year round. Key Points A unique resource to examine synoptic-scale alongshore variability Isolation of equatorward wind events in winter using a statistical model Poleward propagating surface signals year-round © 2013. American Geophysical Union. All Rights Reserved.

  4. A Study of the Different classes of Poleward-Moving Auroral Forms

    Science.gov (United States)

    Kononenko, K.; Fasel, G. J.; Rothballer, A.; Angelo, A.; Alyami, M.; Brandt, T. G.; Fox, B.; Grissom, A. G.; Gribble, M.; Lysenstoen, K.; Sigernes, F.; Lorentzen, D. A.; Green, D.; Freeman, M. P. P.

    2015-12-01

    During periods when the z-component of the interplanetary magnetic field (IMF) becomes negative, the dayside auroral oval moves equatorward [Feldstein and Starkov, 1967; Horrwitz and Akasofu, 1977]. During these expansion periods poleward-auroral moving forms (PMAFs) are observed. PMAFs are also observed during periods when the auroral oval is expanded. PMAFs are not observed when the dayside auroral oval moves poleward of 79° [Lockwood et al., 1989]. Past studies of PMAFs show that they drift poleward and fade [Vorobjev et al., 1975; Horwitz and Akasofu, 1977; Sandholt et al., 1986, 1989, 1990; Rairden and Mende, 1989; Lockwood, 1991], rebrighten as they drift into the polar cap [Fasel et al., 1992, 1994; Fasel, 1995], or rebrighten and slow down while moving into the polar cap, eventually stopping while maintaining their luminosity at least 10 minutes [Fasel, 1995; Fasel et al., 1995]. Fasel [1995] classified these three types of PMAFs as PMAF1, PMAF2, PMAF3 events, respectively. This study looks at the three classes of PMAF events. The study will show the brightening histories of the PMAF events and their evolution as they move into the polar cap. PMAF1 events usually do not drift as far poleward as PMAF2 and PMAF3 events. The lifetime of PMAF1 events are shorter than those of PMAF2 and PMAF3 events. At least two rebrightenings are observed in PMAF2 and PMAF3 events as they drift into the polar cap.

  5. IMP 8 observations of a poleward plasma circulation: Evidence of entry into the plasma mantle?

    Science.gov (United States)

    Kolpak, M. A.; Paularena, K. I.; Richardson, J. D.; Siscoe, G. L.

    Plasma data from IMP 8 are used to map the spatial structure of plasma flow in Earth's magnetosheath. Plasma and magnetic field data from instruments on ISEE-3 and WIND are used to normalize the IMP 8 magnetosheath data to upstream solar wind conditions. For the majority of the data, the magnitude and direction of plasma flow inside the magnetosheath agree well with gas-dynamic models. About 8% of the ISEE-3-normalized velocity vectors and 3% of the WIND-normalized velocity vectors exhibit a poleward circulation in the YZ plane. The observed circulation is consistent with predictions for flow within the plasma mantle. The occurrence frequency of these poleward flows increases further down the tail, consistent with predictions that the mantle width increases tailward. Densities are lower where this flow is observed, consistent with expectations for the plasma mantle, but temperatures are higher and the magnetic field magnitudes lower, the opposite of theoretical expectations.

  6. Identification of the poleward boundary of the auroral oval using characteristics of ion precipitation

    Energy Technology Data Exchange (ETDEWEB)

    Troshichev, O.A.; Shishkina, E.M. [Arctic and Antartic Research Institute, St. Petersburg (Russian Federation); Meng, C.I.; Newell, P.T. [Johns Hopkins Univ., Laurel, MD (United States)

    1996-03-01

    The authors look for characteristics to identify the poleward edge of the auroral oval, by looking at precipitation properties of electrons and ions from DMSP F6 and F7 crossings of this region. They average the readings over 1/2 degree in latitude, and normalize them to flux maxima for each pass. The precipitation data clearly indicates the presence of the auroral oval. As one moves poleward then dependent upon the interplanetary magnetic field orientation, the precipitation falls off one or more orders of magnitude when B{sub z}>0, or when B{sub z}<0, it degenerates to an unstructured type of polar rain, with no clear ion precipitation evident. For B{sub z}>0 there are clear markers for identifying the inner edge of the oval, which are not so evident for southward fields. They discuss the significance of this boundary layer.

  7. Poleward eddy heat flux anomalies associated with recent Arctic sea ice loss

    Science.gov (United States)

    Hoshi, Kazuhira; Ukita, Jinro; Honda, Meiji; Iwamoto, Katsushi; Nakamura, Tetsu; Yamazaki, Koji; Dethloff, Klaus; Jaiser, Ralf; Handorf, Dörthe

    2017-01-01

    Details of the characteristics of upward planetary wave propagation associated with Arctic sea ice loss under present climate conditions are examined using reanalysis data and simulation results. Recent Arctic sea ice loss results in increased stratospheric poleward eddy heat fluxes in the eastern and central Eurasia regions and enhanced upward propagation of planetary-scale waves in the stratosphere. A linear decomposition scheme reveals that this modulation of the planetary waves arises from coupling of the climatological planetary wavefield with temperature anomalies for the eastern Eurasia region and with meridional wind anomalies for the central Eurasia region. Propagation of stationary Rossby wave packets results in a dynamic link between these temperature and meridional wind anomalies with sea ice loss over the Barents-Kara Sea. The results provide strong evidence that recent Arctic sea ice loss significantly modulates atmospheric circulation in winter to modify poleward eddy heat fluxes so as to drive stratosphere-troposphere coupling processes.

  8. Bub3-BubR1-dependent sequestration of Cdc20Fizzy at DNA breaks facilitates the correct segregation of broken chromosomes.

    Science.gov (United States)

    Derive, Nicolas; Landmann, Cedric; Montembault, Emilie; Claverie, Marie-Charlotte; Pierre-Elies, Priscillia; Goutte-Gattat, Damien; Founounou, Nabila; McCusker, Derek; Royou, Anne

    2015-11-09

    The presence of DNA double-strand breaks during mitosis is particularly challenging for the cell, as it produces broken chromosomes lacking a centromere. This situation can cause genomic instability resulting from improper segregation of the broken fragments into daughter cells. We recently uncovered a process by which broken chromosomes are faithfully transmitted via the BubR1-dependent tethering of the two broken chromosome ends. However, the mechanisms underlying BubR1 recruitment and function on broken chromosomes were largely unknown. We show that BubR1 requires interaction with Bub3 to localize on the broken chromosome fragments and to mediate their proper segregation. We also find that Cdc20, a cofactor of the E3 ubiquitin ligase anaphase-promoting complex/cyclosome (APC/C), accumulates on DNA breaks in a BubR1 KEN box-dependent manner. A biosensor for APC/C activity demonstrates a BubR1-dependent local inhibition of APC/C around the segregating broken chromosome. We therefore propose that the Bub3-BubR1 complex on broken DNA inhibits the APC/C locally via the sequestration of Cdc20, thus promoting proper transmission of broken chromosomes.

  9. Are Calanus spp. shifting poleward in the North Atlantic? A habitat modelling approach

    KAUST Repository

    Chust, Guillem

    2013-09-16

    In the last decade, the analysis based on Continuous Plankton Recorder survey in the eastern North Atlantic Ocean detected one of the most striking examples of marine poleward migration related to sea warming. The main objective of this study is to verify the poleward shift of zooplankton species (Calanus finmarchicus, C. glacialis, C. helgolandicus, C. hyperboreus) for which distributional changes have been recorded in the North Atlantic Ocean and to assess how much of this shift was triggered by sea warming, using Generalized Additive Models. To this end, the population gravity centre of observed data was compared with that of a series of simulation experiments: (i) a model using only climate factors (i.e. niche-based model) to simulate species habitat suitability, (ii) a model using only temporal and spatial terms to reconstruct the population distribution, and (iii) a model using both factors combined, using a subset of observations as independent dataset for validation. Our findings show that only C. finmarchicus had a consistent poleward shift, triggered by sea warming, estimated in 8.1 km per decade in the North Atlantic (16.5 per decade for the northeast), which is substantially lower than previous works at the assemblage level and restricted to the Northeast Atlantic. On the contrary, C. helgolandicus is expanding in all directions, although its northern distribution limit in the North Sea has shifted northward. Calanus glacialis and C. hyperboreus, which have the geographic centres of populations mainly in the NW Atlantic, showed a slight southward shift, probably responding to cool water penetrating southward in the Labrador Current. Our approach, supported by high model accuracy, shows its power in detecting species latitudinal shifts and identifying its causes, since the trend of occurrence observed data is influenced by the sampling frequency, which has progressively concentrated to lower latitudes with time. © 2013 © 2013 International Council for

  10. Has the East Asian Westerly Jet Experienced a Poleward Displacement in Recent Decades?

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yaocun; HUANG Danqing

    2011-01-01

    Previous studies have suggested a poleward shift of the zonally averaged jet stream due to rapid warming over continents.However,the regional characteristics of the change in the jet stream are not yet understood.Here,we present evidence suggesting that the East Asian westerly jet did not shift poleward in past decades (1980-2004 relative to 1958-1979),both in winter and summer.Rather,the jet axis has moved southward in summer,but its meridional position is steady in winter.The main change of the jet stream in winter is the enhancement of its intensity.These changes in both summer and winter are consistent with the corresponding changes in the large meridional tropospheric temperature-gradient zone.Based on these results,we suggest that the changes of the jet stream over East Asia are unique and are different from the zonal mean jet stream over the Northern Hemisphere and over the North Atlantic region.

  11. The poleward migration of the location of tropical cyclone maximum intensity.

    Science.gov (United States)

    Kossin, James P; Emanuel, Kerry A; Vecchi, Gabriel A

    2014-05-15

    Temporally inconsistent and potentially unreliable global historical data hinder the detection of trends in tropical cyclone activity. This limits our confidence in evaluating proposed linkages between observed trends in tropical cyclones and in the environment. Here we mitigate this difficulty by focusing on a metric that is comparatively insensitive to past data uncertainty, and identify a pronounced poleward migration in the average latitude at which tropical cyclones have achieved their lifetime-maximum intensity over the past 30 years. The poleward trends are evident in the global historical data in both the Northern and the Southern hemispheres, with rates of 53 and 62 kilometres per decade, respectively, and are statistically significant. When considered together, the trends in each hemisphere depict a global-average migration of tropical cyclone activity away from the tropics at a rate of about one degree of latitude per decade, which lies within the range of estimates of the observed expansion of the tropics over the same period. The global migration remains evident and statistically significant under a formal data homogenization procedure, and is unlikely to be a data artefact. The migration away from the tropics is apparently linked to marked changes in the mean meridional structure of environmental vertical wind shear and potential intensity, and can plausibly be linked to tropical expansion, which is thought to have anthropogenic contributions.

  12. Marker chromosomes.

    Science.gov (United States)

    Rao, Kiran Prabhaker; Belogolovkin, Victoria

    2013-04-01

    Marker chromosomes are a morphologically heterogeneous group of structurally abnormal chromosomes that pose a significant challenge in prenatal diagnosis. Phenotypes associated with marker chromosomes are highly variable and range from normal to severely abnormal. Clinical outcomes are very difficult to predict when marker chromosomes are detected prenatally. In this review, we outline the classification, etiology, cytogenetic characterization, and clinical consequences of marker chromosomes, as well as practical approaches to prenatal diagnosis and genetic counseling.

  13. Scintillation and loss of signal lock from poleward moving auroral forms in the cusp ionosphere

    CERN Document Server

    Oksavik, K; Lorentzen, D A; Baddeley, L J; Moen, J

    2016-01-01

    We present two examples from the cusp ionosphere over Svalbard,where poleward moving auroral forms (PMAFs) are causing significant phase scintillation in signals from navigation satellites. The data were obtained using a combination of ground-based optical instruments and a newly installed multiconstellation navigation signal receiver at Longyearbyen. Both events affected signals from GPS and Global Navigation Satellite System (GLONASS). When one intense PMAF appeared, the signal from one GPS spacecraft also experienced a temporary loss of signal lock. Although several polar cap patches were also observed in the area as enhancements in total electron content, the most severe scintillation and loss of signal lock appear to be attributed to very intense PMAF activity. This shows that PMAFs are locations of strong ionospheric irregularities, which at times may cause more severe disturbances in the cusp ionosphere for navigation signals than polar cap patches.

  14. Arctic cut-off high drives the poleward shift of a new Greenland melting record

    Science.gov (United States)

    Tedesco, M.; Mote, T.; Fettweis, X.; Hanna, E.; Jeyaratnam, J.; Booth, J. F.; Datta, R.; Briggs, K.

    2016-06-01

    Large-scale atmospheric circulation controls the mass and energy balance of the Greenland ice sheet through its impact on radiative budget, runoff and accumulation. Here, using reanalysis data and the outputs of a regional climate model, we show that the persistence of an exceptional atmospheric ridge, centred over the Arctic Ocean, was responsible for a poleward shift of runoff, albedo and surface temperature records over the Greenland during the summer of 2015. New records of monthly mean zonal winds at 500 hPa and of the maximum latitude of ridge peaks of the 5,700+/-50 m isohypse over the Arctic were associated with the formation and persistency of a cutoff high. The unprecedented (1948-2015) and sustained atmospheric conditions promoted enhanced runoff, increased the surface temperatures and decreased the albedo in northern Greenland, while inhibiting melting in the south, where new melting records were set over the past decade.

  15. Arctic Cut-Off High Drives the Poleward Shift of a New Greenland Melting Record

    Science.gov (United States)

    Tedesco, M.; Mote, T.; Fettweis, X.; Hanna, E.; Jeyaratnam, J.; Booth, J. F.; Datta, R.; Briggs, K.

    2016-01-01

    Large-scale atmospheric circulation controls the mass and energy balance of the Greenland ice sheet through its impact on radiative budget, runoff and accumulation. Here, using reanalysis data and the outputs of a regional climate model, we show that the persistence of an exceptional atmospheric ridge, centered over the Arctic Ocean, was responsible for a poleward shift of runoff, albedo and surface temperature records over the Greenland during the summer of 2015. New records of monthly mean zonal winds at 500 hPa and of the maximum latitude of ridge peaks of the 5,700+/-50 m isohypse over the Arctic were associated with the formation and persistency of a cutoff high. The unprecedented (1948-2015) and sustained atmospheric conditions promoted enhanced runoff, increased the surface temperatures and decreased the albedo in northern Greenland, while inhibiting melting in the south, where new melting records were set over the past decade. Subject terms: Earth sciences Atmospheric science Climate science

  16. Upstream drivers of poleward moving auroral forms by satellite-imager coordinated observations

    Science.gov (United States)

    Wang, B.; Nishimura, T.; Lyons, L. R.; Angelopoulos, V.; Frey, H. U.; Mende, S. B.

    2015-12-01

    Poleward moving auroral forms (PMAFs) are observed near the dayside poleward auroral oval boundary. PMAFs are thought to be an ionospheric signature of dayside reconnection and flux transfer events. PMAFs tend to occur when the IMF is southward. Although a limited number of PMAFs has been found in association with IMF southward turning, events without appreciable changes in IMF have also been reported. While those PMAFs could be triggered spontaneously, many of the past studies used solar wind measurements far away from the bow shock nose and may have used inaccurate time shift or missed small-scale structures in the solar wind. To examine how often PMAFs are triggered by upstream structures using solar wind measurements close to the bow shock nose, we use the AGO all sky imager in Antarctic and THEMIS B and C satellites in 2008, 2009 and 2011. We identified 24 conjunction events, where at least one of the THEMIS satellites is in the solar wind and the AGO imager is located within 3 MLT from the THEMIS MLT. We found that, in 14 out of 24 conjunction events, PMAFs occur soon after IMF southward turning, indicating that IMF southward turning could be the major triggering of PMAFs. Interestingly, among these 14 cases, there are 7 cases with different IMF structures between THEMIS B/C and OMNI, which obtained IMF information from WIND and ACE. And the larger correlation coefficients between PMAFs and IMFs observed by THMEIS B/C than OMNI present the advantages of THEMIS B/C. Among the 10 cases without correlating with IMF structures, PMAFs in two events are shown to have good correlation with reflected ions in the foreshock. Based on all the conjunction events we identified, IMF southward turning is the major trigger of PMAFs and reflected ions have minor effects. The rest of the cases could be spontaneous PMAFs, although foreshock activities, even if exists, may be missed due to the IMF orientation.

  17. The future demographic niche of a declining grassland bird fails to shift poleward in response to climate change

    Science.gov (United States)

    Lisa A. McCauley; Christine A. Ribic; Lars Y. Pomara; Benjamin Zuckerberg

    2017-01-01

    Context Temperate grasslands and their dependent species are exposed to high variability in weather and climate due to the lack of natural buffers such as forests. Grassland birds are particularly vulnerable to this variability, yet have failed to shift poleward in response to recent climate change like other bird species in North America. However, there have been few...

  18. Investigation of triggering of poleward moving auroral forms using satellite-imager coordinated observations

    Science.gov (United States)

    Wang, Boyi; Nishimura, Yukitoshi; Zou, Ying; Lyons, Larry R.; Angelopoulos, Vassilis; Frey, Harald; Mende, Stephen

    2016-11-01

    Poleward moving auroral forms (PMAFs) are thought to be an ionospheric signature of dayside magnetic reconnection. While PMAFs are more likely to occur when the interplanetary magnetic field (IMF) is southward, how often PMAFs are triggered by changes in solar wind parameters is still an open question. To address this issue, we used one of the Automatic Geophysical Observatories all-sky imagers in Antarctica and the Time History of Events and Macroscale Interactions during Substorms (THEMIS) B and C satellites, which can give solar wind measurements much closer to the subsolar bow shock than by Wind or ACE, to examine if PMAFs occurred in association with IMF orientation changes. We identified 60 PMAFs in conjunction with THEMIS B and C during 2008, 2009, and 2011 and 70% of events show reduction of Bz before PMAF onset indicating that IMF southward turning plays an important role in triggering a majority of PMAFs. In contrast, the magnitude of the IMF Bz reduction in OMNI data was smaller and the reduction occurred in a slightly smaller percentage of events (40-60%). This suggests that solar wind structures that missed the L1 point or evolution of solar wind between the L1 point and THEMIS may be important for identifying IMF changes responsible for transient dayside reconnection. Additionally, 17 PMAFs that did not have substantial IMF southward turnings are correlated well with foreshock events, indicating that foreshock phenomena may also play a role in triggering PMAFs.

  19. Faster poleward range shifts in moths with more variable colour patterns

    Science.gov (United States)

    Forsman, Anders; Betzholtz, Per-Eric; Franzén, Markus

    2016-11-01

    Range shifts have been documented in many organisms, and climate change has been implicated as a contributing driver of latitudinal and altitudinal range modifications. However, little is known about what species trait(s) allow for faster environmental tracking and improved capacity for distribution expansions. We used data for 416 species of moths, and show that range limits in Sweden have shifted to the north by on average 52.4 km per decade between 1973 and 2014. When also including non-expanding species, average expansion rate was 23.2 km per decade. The rate of boundary shifts increased with increasing levels of inter-individual variation in colour patterns and decreased with increasing latitude. The association with colour patterns indicate that variation in this functionally important trait enables species to cope with novel and changing conditions. Northern range limits also increased with average abundance and decreased with increasing year-to-year abundance fluctuations, implicating production of dispersers as a driver of range dynamics. Studies of terrestrial animals show that rates of poleward shifts differ between taxonomic groups, increase over time, and depend on study duration and latitude. Knowledge of how distribution shifts change with time, location, and species characteristics may improve projections of responses to climate change and aid the protection of biodiversity.

  20. Modeling Chromosomes

    Science.gov (United States)

    Robertson, Carol

    2016-01-01

    Learning about chromosomes is standard fare in biology classrooms today. However, students may find it difficult to understand the relationships among the "genome", "chromosomes", "genes", a "gene locus", and "alleles". In the simple activity described in this article, which follows the 5E approach…

  1. Correct end use during end joining of multiple chromosomal double strand breaks is influenced by repair protein RAD50, DNA-dependent protein kinase DNA-PKcs, and transcription context.

    Science.gov (United States)

    Gunn, Amanda; Bennardo, Nicole; Cheng, Anita; Stark, Jeremy M

    2011-12-09

    During repair of multiple chromosomal double strand breaks (DSBs), matching the correct DSB ends is essential to limit rearrangements. To investigate the maintenance of correct end use, we examined repair of two tandem noncohesive DSBs generated by endonuclease I-SceI and the 3' nonprocessive exonuclease Trex2, which can be expressed as an I-SceI-Trex2 fusion. We examined end joining (EJ) repair that maintains correct ends (proximal-EJ) versus using incorrect ends (distal-EJ), which provides a relative measure of incorrect end use (distal end use). Previous studies showed that ATM is important to limit distal end use. Here we show that DNA-PKcs kinase activity and RAD50 are also important to limit distal end use, but that H2AX is dispensable. In contrast, we find that ATM, DNA-PKcs, and RAD50 have distinct effects on repair events requiring end processing. Furthermore, we developed reporters to examine the effects of the transcription context on DSB repair, using an inducible promoter. We find that a DSB downstream from an active promoter shows a higher frequency of distal end use, and a greater reliance on ATM for limiting incorrect end use. Conversely, DSB transcription context does not affect end processing during EJ, the frequency of homology-directed repair, or the role of RAD50 and DNA-PKcs in limiting distal end use. We suggest that RAD50, DNA-PKcs kinase activity, and transcription context are each important to limit incorrect end use during EJ repair of multiple DSBs, but that these factors and conditions have distinct roles during repair events requiring end processing.

  2. First observations of poleward large-scale traveling ionospheric disturbances over the African sector during geomagnetic storm conditions

    Science.gov (United States)

    Habarulema, John Bosco; Katamzi, Zama Thobeka; Yizengaw, Endawoke

    2015-08-01

    This paper presents first observations of poleward traveling ionospheric disturbances (TIDs) during strong geomagnetic conditions over the African sector. By analyzing different data sets we have observed both positive and negative ionospheric responses during the storm period of 08-10 March 2012. Considering the African region as a whole, three longitudinal sectors were strategically selected to establish the entire regional response. On both sides of the geomagnetic equator, results show poleward shift in peak total electron content (TEC) enhancements/depletions at different times which are associated to large-scale TIDs. The observed phenomena are linked to the global ionospheric response and electrodynamics. The understanding has been established using data from International GNSS Service receiver network, radio occultation electron density profiles, derived E×B drift measurements from magnetometer observations and regional ground-based and satellite data. Contrary to other related studies, generated regional TEC perturbation maps were not enough to show obvious directions of the large-scale TIDs due to insufficient data over the northern hemispheric part of the African sector. There appears to be a switch between positive and negative storm phases during the same storm period especially in the Southern Hemisphere part of the African region where "enough" data were available. However, a detailed analysis revealed that the positive storm phase corresponded to the expansion of the equatorial ionization anomaly (EIA) toward some parts of midlatitude regions (and possibly with the contribution from low-latitude electrodynamics associated to equatorial electrojet), while the other part recorded a negative storm phase due to storm-induced changes from the auroral origin. We have observed a simultaneous occurrence of both poleward and equatorward propagating TIDs over the African sector during the same geomagnetic storm period. Our results show that short-lived large

  3. Reply to Comment on ‘Roles of interbasin frequency changes in the poleward shifts of maximum intensity location of tropical cyclones’

    Science.gov (United States)

    Moon, Il-Ju; Kim, Sung-Hun; Klotzbach, Phil; Chan, Johnny C. L.

    2016-06-01

    Recently a pronounced global poleward shift in the latitude at which the maximum intensities of tropical cyclones (TC) occur has been identified. Moon et al (2015 Environ. Res. Lett. 10 104004) reported that the poleward migration is significantly influenced by changes in interbasin frequency. These frequency changes are a larger contributor to the poleward shift than the intrabasin migration component. The strong role of interbasin frequency changes in the poleward migration also suggest that the poleward trend could be changed to an opposite equatorward trend in the future due to multi-decadal variability that significantly impacts Northern Hemisphere TC frequency. In the accompanying comment, Kossin et al (2016 Environ. Res. Lett. 11 068001) questioned the novelty and robustness of our results by raising issues associated with subsampling, contributions from some basins to poleward migration, and data dependency. Here, we explain the originality and importance of our main findings, which are different from those of Kossin et al (2014 Nature 509 349-52) and reaffirm that our conclusions are maintained regardless of the issues that were raised.

  4. Synthetic chromosomes.

    Science.gov (United States)

    Schindler, Daniel; Waldminghaus, Torsten

    2015-11-01

    What a living organism looks like and how it works and what are its components-all this is encoded on DNA, the genetic blueprint. Consequently, the way to change an organism is to change its genetic information. Since the first pieces of recombinant DNA have been used to transform cells in the 1970s, this approach has been enormously extended. Bigger and bigger parts of the genetic information have been exchanged or added over the years. Now we are at a point where the construction of entire chromosomes becomes a reachable goal and first examples appear. This development leads to fundamental new questions, for example, about what is possible and desirable to build or what construction rules one needs to follow when building synthetic chromosomes. Here we review the recent progress in the field, discuss current challenges and speculate on the appearance of future synthetic chromosomes.

  5. Body size, growth and life span: implications for the polewards range shift of Octopus tetricus in south-eastern Australia.

    Directory of Open Access Journals (Sweden)

    Jorge E Ramos

    Full Text Available Understanding the response of any species to climate change can be challenging. However, in short-lived species the faster turnover of generations may facilitate the examination of responses associated with longer-term environmental change. Octopus tetricus, a commercially important species, has undergone a recent polewards range shift in the coastal waters of south-eastern Australia, thought to be associated with the southerly extension of the warm East Australian Current. At the cooler temperatures of a polewards distribution limit, growth of a species could be slower, potentially leading to a bigger body size and resulting in a slower population turnover, affecting population viability at the extreme of the distribution. Growth rates, body size, and life span of O. tetricus were examined at the leading edge of a polewards range shift in Tasmanian waters (40°S and 147°E throughout 2011. Octopus tetricus had a relatively small body size and short lifespan of approximately 11 months that, despite cooler temperatures, would allow a high rate of population turnover and may facilitate the population increase necessary for successful establishment in the new extended area of the range. Temperature, food availability and gender appear to influence growth rate. Individuals that hatched during cooler and more productive conditions, but grew during warming conditions, exhibited faster growth rates and reached smaller body sizes than individuals that hatched into warmer waters but grew during cooling conditions. This study suggests that fast growth, small body size and associated rapid population turnover may facilitate the range shift of O. tetricus into Tasmanian waters.

  6. Body size, growth and life span: implications for the polewards range shift of Octopus tetricus in south-eastern Australia.

    Science.gov (United States)

    Ramos, Jorge E; Pecl, Gretta T; Moltschaniwskyj, Natalie A; Strugnell, Jan M; León, Rafael I; Semmens, Jayson M

    2014-01-01

    Understanding the response of any species to climate change can be challenging. However, in short-lived species the faster turnover of generations may facilitate the examination of responses associated with longer-term environmental change. Octopus tetricus, a commercially important species, has undergone a recent polewards range shift in the coastal waters of south-eastern Australia, thought to be associated with the southerly extension of the warm East Australian Current. At the cooler temperatures of a polewards distribution limit, growth of a species could be slower, potentially leading to a bigger body size and resulting in a slower population turnover, affecting population viability at the extreme of the distribution. Growth rates, body size, and life span of O. tetricus were examined at the leading edge of a polewards range shift in Tasmanian waters (40°S and 147°E) throughout 2011. Octopus tetricus had a relatively small body size and short lifespan of approximately 11 months that, despite cooler temperatures, would allow a high rate of population turnover and may facilitate the population increase necessary for successful establishment in the new extended area of the range. Temperature, food availability and gender appear to influence growth rate. Individuals that hatched during cooler and more productive conditions, but grew during warming conditions, exhibited faster growth rates and reached smaller body sizes than individuals that hatched into warmer waters but grew during cooling conditions. This study suggests that fast growth, small body size and associated rapid population turnover may facilitate the range shift of O. tetricus into Tasmanian waters.

  7. Chromosome Analysis

    Science.gov (United States)

    1998-01-01

    Perceptive Scientific Instruments, Inc., provides the foundation for the Powergene line of chromosome analysis and molecular genetic instrumentation. This product employs image processing technology from NASA's Jet Propulsion Laboratory and image enhancement techniques from Johnson Space Center. Originally developed to send pictures back to earth from space probes, digital imaging techniques have been developed and refined for use in a variety of medical applications, including diagnosis of disease.

  8. Chromosome segregation in plant meiosis

    Science.gov (United States)

    Zamariola, Linda; Tiang, Choon Lin; De Storme, Nico; Pawlowski, Wojtek; Geelen, Danny

    2014-01-01

    Faithful chromosome segregation in meiosis is essential for ploidy stability over sexual life cycles. In plants, defective chromosome segregation caused by gene mutations or other factors leads to the formation of unbalanced or unreduced gametes creating aneuploid or polyploid progeny, respectively. Accurate segregation requires the coordinated execution of conserved processes occurring throughout the two meiotic cell divisions. Synapsis and recombination ensure the establishment of chiasmata that hold homologous chromosomes together allowing their correct segregation in the first meiotic division, which is also tightly regulated by cell-cycle dependent release of cohesin and monopolar attachment of sister kinetochores to microtubules. In meiosis II, bi-orientation of sister kinetochores and proper spindle orientation correctly segregate chromosomes in four haploid cells. Checkpoint mechanisms acting at kinetochores control the accuracy of kinetochore-microtubule attachment, thus ensuring the completion of segregation. Here we review the current knowledge on the processes taking place during chromosome segregation in plant meiosis, focusing on the characterization of the molecular factors involved. PMID:24987397

  9. Chromosome segregation in plant meiosis

    Directory of Open Access Journals (Sweden)

    Linda eZamariola

    2014-06-01

    Full Text Available Faithful chromosome segregation in meiosis is essential for ploidy stability over sexual life cycles. In plants, defective chromosome segregation caused by gene mutations or other factors leads to the formation of unbalanced or unreduced gametes creating aneuploid or polyploid progeny, respectively. Accurate segregation requires the coordinated execution of conserved processes occurring throughout the two meiotic cell divisions. Synapsis and recombination ensure the establishment of chiasmata that hold homologous chromosomes together allowing their correct segregation in the first meiotic division, which is also tightly regulated by cell-cycle dependent release of cohesin and monopolar attachment of sister kinetochores to microtubules. In meiosis II, bi-orientation of sister kinetochores and proper spindle orientation correctly segregate chromosomes in four haploid cells. Checkpoint mechanisms acting at kinetochores control the accuracy of kinetochore-microtubule attachment, thus ensuring the completion of segregation. Here we review the current knowledge on the processes taking place during chromosome segregation in plant meiosis, focusing on the characterization of the molecular factors involved.

  10. Severe and localized GNSS scintillation at the poleward edge of the nightside auroral oval during intense substorm aurora

    CERN Document Server

    van der Meeren, Christer; Lorentzen, Dag A; Rietveld, Michael T; Clausen, Lasse B N

    2016-01-01

    In this paper we study how GPS, GLONASS, and Galileo navigation signals are compromised by strong irregularities causing severe phase scintillation ($\\mathit{\\sigma }_{\\phi }$ > 1) in the nightside high-latitude ionosphere during a substorm on 3 November 2013. Substorm onset and a later intensification coincided with polar cap patches entering the auroral oval to become auroral blobs. Using Global Navigation Satellite Systems (GNSS) receivers and optical data, we show severe scintillation driven by intense auroral emissions in the line of sight between the receiver and the satellites. During substorm expansion, the area of scintillation followed the intense poleward edge of the auroral oval. The intense auroral emissions were colocated with polar cap patches (blobs). The patches did not contain strong irregularities, neither before entering the auroral oval nor after the aurora had faded. Signals from all three GNSS constellations were similarly affected by the irregularities. Furthermore, two receivers space...

  11. Suborbital Holocene Climate Variability over Continental Western Eurasia Coupled with Poleward Heat Transport to the Northeastern Atlantic Ocean

    Science.gov (United States)

    Baker, J. L.; Lachniet, M. S.; Asmerom, Y.; Polyak, V. J.

    2016-12-01

    The centennial-scale coupling between the Holocene paleoclimate of Eurasia and ocean-atmosphere dynamics in the North Atlantic sector remains weakly understood, due to a paucity of high-resolution data from the continental interior. To investigate these links, we detrended a composite record of stalagmite δ18O from Kinderlinskaya Cave (southern Urals Mountains), which exhibits long-term warming from 11.7 ka to present. The chronologies of two stalagmites were constrained by 29 U-Th dates obtained through MC-ICP-MS analysis. Stable-isotope analysis at 0.5-mm resolution along the growth axes resulted in an average sampling frequency of 12.5 years. Stalagmite δ18O reflects multidecadal changes in the δ18O of winter half-year precipitation, which is highly sensitive to AO/NAO-like shifts in the strength and position of mid-latitude westerlies. Spectral density and wavelet analysis of the detrended record revealed significant periodicities near 2.4 ka, 1.4 ka, and 1.0 ka, which are common in northern hemispheric paleoclimate records and possibly related to solar and oceanic forcing during the Holocene. Coherent hemispheric coupling of continental and oceanic paleoclimate at suborbital timescales is demonstrated by comparison of our record with reconstructions of sea-surface temperature (SST) and meridional flow strength in the North Atlantic sector. Specifically, SST at cores MD-23258 and LO09-14 in the Barents Sea and Reykjanes Ridge, respectively, exhibit opposite phasing during the Holocene, due to alternating strength between the eastern and western branches of the North Atlantic Current, a major component of AMOC. Estimating the SST gradient between these sites as a proxy for poleward heat transport to the northeastern Atlantic Ocean, we find a strong covariance with detrended stalagmite δ18O. This relationship suggests that persistent strengthening (weakening) of wintertime westerlies, analogous to positive (negative) phases of the AO/NAO, was forced by

  12. Mangrove expansion and contraction at a poleward range limit: Climate extremes and land-ocean temperature gradients

    Science.gov (United States)

    Osland, Michael J.; Day, Richard H.; Hall, Courtney T.; Brumfield, Marisa D; Dugas, Jason; Jones, William R.

    2017-01-01

    Within the context of climate change, there is a pressing need to better understand the ecological implications of changes in the frequency and intensity of climate extremes. Along subtropical coasts, less frequent and warmer freeze events are expected to permit freeze-sensitive mangrove forests to expand poleward and displace freeze-tolerant salt marshes. Here, our aim was to better understand the drivers of poleward mangrove migration by quantifying spatiotemporal patterns in mangrove range expansion and contraction across land-ocean temperature gradients. Our work was conducted in a freeze-sensitive mangrove-marsh transition zone that spans a land-ocean temperature gradient in one of the world's most wetland-rich regions (Mississippi River Deltaic Plain; Louisiana, USA). We used historical air temperature data (1893-2014), alternative future climate scenarios, and coastal wetland coverage data (1978-2011) to investigate spatiotemporal fluctuations and climate-wetland linkages. Our analyses indicate that changes in mangrove coverage have been controlled primarily by extreme freeze events (i.e., air temperatures below a threshold zone of -6.3 to -7.6 °C). We expect that in the past 121 years, mangrove range expansion and contraction has occurred across land-ocean temperature gradients. Mangrove resistance, resilience, and dominance were all highest in areas closer to the ocean where temperature extremes were buffered by large expanses of water and saturated soil. Under climate change, these areas will likely serve as local hotspots for mangrove dispersal, growth, range expansion, and displacement of salt marsh. Collectively, our results show that the frequency and intensity of freeze events across land-ocean temperature gradients greatly influences spatiotemporal patterns of range expansion and contraction of freeze-sensitive mangroves. We expect that, along subtropical coasts, similar processes govern the distribution and abundance of other freeze

  13. Co-segregation of sex chromosomes in the male black widow spider Latrodectus mactans (Araneae, Theridiidae).

    Science.gov (United States)

    Ault, Jeffrey G; Felt, Kristen D; Doan, Ryan N; Nedo, Alexander O; Ellison, Cassondra A; Paliulis, Leocadia V

    2017-02-23

    During meiosis I, homologous chromosomes join together to form bivalents. Through trial and error, bivalents achieve stable bipolar orientations (attachments) on the spindle that eventually allow the segregation of homologous chromosomes to opposite poles. Bipolar orientations are stable through tension generated by poleward forces to opposite poles. Unipolar orientations lack tension and are stereotypically not stable. The behavior of sex chromosomes during meiosis I in the male black widow spider Latrodectus mactans (Araneae, Theridiidae) challenges the principles governing such a scenario. We found that male L. mactans has two distinct X chromosomes, X1 and X2. The X chromosomes join together to form a connection that is present in prometaphase I but is lost during metaphase I, before the autosomes disjoin at anaphase I. We found that both X chromosomes form stable unipolar orientations to the same pole that assure their co-segregation at anaphase I. Using micromanipulation, immunofluorescence microscopy, and electron microscopy, we studied this unusual chromosome behavior to explain how it may fit the current dogma of chromosome distribution during cell division.

  14. Chromosome Partitioning in Escherichia coli in the Absence of Dam-Directed Methylation

    OpenAIRE

    1992-01-01

    Escherichia coli dam mutants, lacking the GATC DNA methylase, do not produce anucleate cells at high frequencies, suggesting that hemimethylation of the chromosome origin of replication, oriC, is not essential for correct chromosome partitioning.

  15. CHROMOSOME ABNORMALITIES IN INFERTILITY

    Directory of Open Access Journals (Sweden)

    Mateja Smogavec

    2009-08-01

    Conclusions Chromosomal analysis is an important method in diagnostic procedures of infertility, because chromosomal abnormalities could play the important role in etiology of infertility and are more frequently detected in this group of patients compared to general population. In the infertile couples balanced chromosomal abnormalities are the main cause of spontaneous abortions. Sex chromosome aneuploidies are highly correlated to infertility of females and males.

  16. Spindly/CCDC99 is required for efficient chromosome congression and mitotic checkpoint regulation.

    Science.gov (United States)

    Barisic, Marin; Sohm, Bénédicte; Mikolcevic, Petra; Wandke, Cornelia; Rauch, Veronika; Ringer, Thomas; Hess, Michael; Bonn, Günther; Geley, Stephan

    2010-06-15

    Spindly recruits a fraction of cytoplasmic dynein to kinetochores for poleward movement of chromosomes and control of mitotic checkpoint signaling. Here we show that human Spindly is a cell cycle-regulated mitotic phosphoprotein that interacts with the Rod/ZW10/Zwilch (RZZ) complex. The kinetochore levels of Spindly are regulated by microtubule attachment and biorientation induced tension. Deletion mutants lacking the N-terminal half of the protein (NDelta253), or the conserved Spindly box (DeltaSB), strongly localized to kinetochores and failed to respond to attachment or tension. In addition, these mutants prevented the removal of the RZZ complex and that of MAD2 from bioriented chromosomes and caused cells to arrest at metaphase, showing that RZZ-Spindly has to be removed from kinetochores to terminate mitotic checkpoint signaling. Depletion of Spindly by RNAi, however, caused cells to arrest in prometaphase because of a delay in microtubule attachment. Surprisingly, this defect was alleviated by codepletion of ZW10. Thus, Spindly is not only required for kinetochore localization of dynein but is a functional component of a mechanism that couples dynein-dependent poleward movement of chromosomes to their efficient attachment to microtubules.

  17. Plasma structure within poleward-moving cusp/cleft auroral transients: EISCAT Svalbard radar observations and an explanation in terms of large local time extent of events

    Directory of Open Access Journals (Sweden)

    M. Lockwood

    Full Text Available We report high-resolution observations of the southward-IMF cusp/cleft ionosphere made on December 16th 1998 by the EISCAT (European incoherent scatter Svalbard radar (ESR, and compare them with observations of dayside auroral luminosity, as seen at a wavelength of 630 nm by a meridian scanning photometer at Ny Ålesund, and of plasma flows, as seen by the CUTLASS (co-operative UK twin location auroral sounding system Finland HF radar. The optical data reveal a series of poleward-moving transient red-line (630 nm enhancements, events that have been associated with bursts in the rate of magnetopause reconnection generating new open flux. The combined observations at this time have strong similarities to predictions of the effects of soft electron precipitation modulated by pulsed reconnection, as made by Davis and Lockwood (1996; however, the effects of rapid zonal flow in the ionosphere, caused by the magnetic curvature force on the newly opened field lines, are found to be a significant additional factor. In particular, it is shown how enhanced plasma loss rates induced by the rapid convection can explain two outstanding anomalies of the 630 nm transients, namely how minima in luminosity form between the poleward-moving events and how events can re-brighten as they move poleward. The observations show how cusp/cleft aurora and transient poleward-moving auroral forms appear in the ESR data and the conditions which cause enhanced 630 nm emission in the transients: they are an important first step in enabling the ESR to identify these features away from the winter solstice when supporting auroral observations are not available.

    Key words: Ionosphere (polar ionosphere - Magnetospheric physics (magnetopause; cusp and boundary layers; solar wind-magnetosphere interactions

  18. Undetected sex chromosome aneuploidy by chromosomal microarray.

    Science.gov (United States)

    Markus-Bustani, Keren; Yaron, Yuval; Goldstein, Myriam; Orr-Urtreger, Avi; Ben-Shachar, Shay

    2012-11-01

    We report on a case of a female fetus found to be mosaic for Turner syndrome (45,X) and trisomy X (47,XXX). Chromosomal microarray analysis (CMA) failed to detect the aneuploidy because of a normal average dosage of the X chromosome. This case represents an unusual instance in which CMA may not detect chromosomal aberrations. Such a possibility should be taken into consideration in similar cases where CMA is used in a clinical setting.

  19. Paternal isodisomy of chromosome 6 in association with a maternal supernumerary marker chromosome (6)

    Energy Technology Data Exchange (ETDEWEB)

    James, R.S.; Crolla, J.A.; Sitch, F.L. [Salisbury District Hospital, Wiltshire (United Kingdom)] [and others

    1994-09-01

    Uniparental disomy may arise by a number of different mechanisms of aneuploidy correction. A population that has been identified as being at increased risk of aneuploidy are those individuals bearing supernumerary marker chromosomes (SMCs). There have been a number of cases reported of trisomy 21 in association with bi-satellited marker chromosomes have described two individuals with small inv dup (15) markers. One had paternal isodisomy of chromosome 15 and Angelman syndrome. The other had maternal heterodisomy (15) and Prader-Willi syndrome. At the Wessex Regional Genetics Laboratory we have conducted a search for uniparental disomy of the normal homologues of the chromosomes from which SMCs originated. Our study population consists of 39 probands with SMCs originating from a number of different autosomes, including 17 with SMCs of chromosome 15 origin. Using PCR amplification of microsatellite repeat sequences located distal to the regions included in the SMCs we have determined the parental origin of the two normal homologues in each case. We have identified paternal isodisomy of chromosome 6 in a female child with a supernumerary marker ring chromosome 6 in approximately 70% of peripheral blood lymphocytes. The marker was found to be of maternal origin. This is the second case of paternal isodisomy of chromosome 6 to be reported, and the first in association with a SMC resulting in a partial trisomy for a portion of the short arm of chromosome 6. In spite of this, the patient appears to be functioning appropriately for her age.

  20. Modulating crossover positioning by introducing large structural changes in chromosomes

    NARCIS (Netherlands)

    Ederveen, A.; Lai, Y.; Van Driel, M.A.; Gerats, T.; Peters, J.L.

    2015-01-01

    Background Crossing over assures the correct segregation of the homologous chromosomes to both poles of the dividing meiocyte. This exchange of DNA creates new allelic combinations thus increasing the genetic variation present in offspring. Crossovers are not uniformly distributed along chromosomes;

  1. Chromosome Disorder Outreach

    Science.gov (United States)

    ... BLOG Join Us Donate You are not alone. Chromosome Disorder Outreach, Inc. is a non-profit organization, ... Support For all those diagnosed with any rare chromosome disorder. Since 1992, CDO has supported the parents ...

  2. Chromosome painting in plants.

    NARCIS (Netherlands)

    Schubert, I.; Fransz, P.F.; Fuchs, J.; Jong, de J.H.

    2001-01-01

    The current 'state-of-art' as to chromosome painting in plants is reviewed. We define different situations described as painting so far: i) Genomic in situ hybridisation (GISH) with total genomic DNA to distinguish alien chromosomes on the basis of divergent dispersed repeats, ii) 'Chromosomal in si

  3. ZEBRAFISH CHROMOSOME-BANDING

    NARCIS (Netherlands)

    PIJNACKER, LP; FERWERDA, MA

    1995-01-01

    Banding techniques were carried out on metaphase chromosomes of zebrafish (Danio rerio) embryos. The karyotypes with the longest chromosomes consist of 12 metacentrics, 26 submetacentrics, and 12 subtelocentrics (2n = 50). All centromeres are C-band positive. Eight chromosomes have a pericentric C-b

  4. Chromosome painting in plants.

    NARCIS (Netherlands)

    Schubert, I.; Fransz, P.F.; Fuchs, J.; Jong, de J.H.

    2001-01-01

    The current 'state-of-art' as to chromosome painting in plants is reviewed. We define different situations described as painting so far: i) Genomic in situ hybridisation (GISH) with total genomic DNA to distinguish alien chromosomes on the basis of divergent dispersed repeats, ii) 'Chromosomal in

  5. Modelling the Influence of Tropically-Excited Poleward Propagating Rossby Waves and their influence on recent Arctic Climate Change.

    Science.gov (United States)

    McCrystall, M.; Hosking, J. S.; Maycock, A.; Pyle, J. A.

    2016-12-01

    Identifying the key drivers of Arctic climate is essential for understanding the recent changes in local climate and the mechanisms for these changes. Remote sea-surface temperatures (SSTs) have been identified by Ding et al. (2014) as a driver of these recent changes by inducing surface and mid-tropospheric warming and increase in 200 hPa geopotential heights (Z200), particularly over northern Canada and Greenland. This work further investigates the robustness of the Tropical-Arctic teleconnection by assessing the role of tropical SSTs in exciting planetary scale Rossby waves, and determining their effect on Arctic climate. We analyse a series of sensitivity experiments, using the Met Office HadGEM3 atmospheric model, forced by observed changes in SSTs between the periods 1979-1988 and 2003-2012 imposed for; [i] the entire tropics, [ii] the tropical Pacific Ocean and [iii] the tropical Atlantic Ocean. The spatial patterns of Z200 anomalies in the experiments are quantitatively compared to the 27-year Z200 trends from ERA-Interim reanalysis data and the model results of Ding et al. (2014). In contrast to their results, we found negative Z200 anomalies over northern Canada and Greenland in boreal winter in response to recent changes in tropical SSTs. We capture, however, an increase in Z200 of around 20 m over Scandinavia and the Aleutian Islands. To understand the direct influence of the tropical SST forcing on high latitudes, we analyse 3D wave activity flux anomalies, based on Plumb (1985). There is large variability in northern hemisphere wave flux anomalies but we do identify a Rossby wave train from the tropical Atlantic projecting onto the anomalous Z200 over Scandinavia. The results suggest changes in tropical SSTs can affect regional Arctic climate through their effect on poleward propagating Rossby waves, however from these experiments, it appears that this process has not contributed to the recent observed Z200 trends over northern Canada and Greenland

  6. Structural organization of very small chromosomes: study on a single-celled evolutionary distant eukaryote Giardia intestinalis.

    Science.gov (United States)

    Tůmová, Pavla; Uzlíková, Magdalena; Wanner, Gerhard; Nohýnková, Eva

    2015-03-01

    During mitotic prophase, chromosomes of the pathogenic unicellular eukaryote Giardia intestinalis condense in each of the cell's two nuclei. In this study, Giardia chromosomes were investigated using light microscopy, high-resolution field emission scanning electron microscopy, and in situ hybridization. For the first time, we describe the overall morphology, condensation stages, and mitotic segregation of these chromosomes. Despite the absence of several genes involved in the cohesion and condensation pathways in the Giardia genome, we observed chromatin organization similar to those found in eukaryotes, i.e., 10-nm nucleosomal fibrils, 30-nm fibrils coiled to chromomeres or in parallel arrangements, and closely aligned sister chromatids. DNA molecules of Giardia terminate with telomeric repeats that we visualized on each of the four chromatid endings of metaphase chromosomes. Giardia chromosomes lack primary and secondary constrictions, thus preventing their classification based on the position of the centromere. The anaphase poleward segregation of sister chromatids is atypical in orientation and tends to generate lagging chromatids between daughter nuclei. In the Giardia genome database, we identified two putative members of the kleisin family thought to be responsible for condensin ring establishment. Thus far, Giardia chromosomes (300 nm to 1.5 μm) are the smallest chromosomes that were analyzed at the ultrastructural level. This study complements the existing molecular and sequencing data on Giardia chromosomes with cytological and ultrastructural information.

  7. Mapping strategies: Chromosome 16 workshop

    Energy Technology Data Exchange (ETDEWEB)

    1989-01-01

    The following topics from a workshop on chromosome 16 are briefly discussed: genetic map of chromosome 16; chromosome breakpoint map of chromosome 16; integrated physical/genetic map of chromosome 16; pulsed field map of the 16p13.2--p13.3 region (3 sheets); and a report of the HGM10 chromosome 16 committee.

  8. Engineering of plant chromosomes.

    Science.gov (United States)

    Mette, Michael Florian; Houben, Andreas

    2015-02-01

    Engineered minimal chromosomes with sufficient mitotic and meiotic stability have an enormous potential as vectors for stacking multiple genes required for complex traits in plant biotechnology. Proof of principle for essential steps in chromosome engineering such as truncation of chromosomes by T-DNA-mediated telomere seeding and de novo formation of centromeres by cenH3 fusion protein tethering has been recently obtained. In order to generate robust protocols for application in plant biotechnology, these steps need to be combined and supplemented with additional methods such as site-specific recombination for the directed transfer of multiple genes of interest on the minichromosomes. At the same time, the development of these methods allows new insight into basic aspects of plant chromosome functions such as how centromeres assure proper distribution of chromosomes to daughter cells or how telomeres serve to cap the chromosome ends to prevent shortening of ends over DNA replication cycles and chromosome end fusion.

  9. Chromosomal instability in meningiomas.

    Science.gov (United States)

    van Tilborg, Angela A G; Al Allak, Bushra; Velthuizen, Sandra C J M; de Vries, Annie; Kros, Johan M; Avezaat, Cees J J; de Klein, Annelies; Beverloo, H Berna; Zwarthoff, Ellen C

    2005-04-01

    Approximately 60% of sporadic meningiomas are caused by inactivation of the NF2 tumor suppressor gene on chromosome 22. No causative gene is known for the remaining 40%. Cytogenetic analysis shows that meningiomas caused by inactivation of the NF2 gene can be divided into tumors that show monosomy 22 as the sole abnormality and tumors with a more complex karyotype. Meningiomas not caused by the NF2 gene usually have a diploid karyotype. Here we report that, besides the clonal chromosomal aberrations, the chromosome numbers in many meningiomas varied from one metaphase spread to the other, a feature that is indicative of chromosomal instability. Unexpectedly and regardless of genotype, a subgroup of tumors was observed with an average number of 44.9 chromosomes and little variation in the number of chromosomes per metaphase spread. In addition, a second subgroup was recognized with a hyperdiploid number of chromosomes (average 48.5) and considerable variation in numbers per metaphase. However, this numerical instability resulted in a clonal karyotype with chromosomal gains and losses in addition to loss of chromosome 22 only in meningiomas caused by inactivation of the NF2 gene. In cultured cells of all tumor groups, bi- and multinucleated cells were seen, as well as anaphase bridges, residual chromatid strings, multiple spindle poles, and unseparated chromatids, suggesting defects in the mitotic apparatus or kinetochore. Thus, we conclude that even a benign and slow-growing tumor like a meningioma displays chromosomal instability.

  10. Complete kinetochore tracking reveals error-prone homologous chromosome biorientation in mammalian oocytes.

    Science.gov (United States)

    Kitajima, Tomoya S; Ohsugi, Miho; Ellenberg, Jan

    2011-08-19

    Chromosomes must establish stable biorientation prior to anaphase to achieve faithful segregation during cell division. The detailed process by which chromosomes are bioriented and how biorientation is coordinated with spindle assembly and chromosome congression remain unclear. Here, we provide complete 3D kinetochore-tracking datasets throughout cell division by high-resolution imaging of meiosis I in live mouse oocytes. We show that in acentrosomal oocytes, chromosome congression forms an intermediate chromosome configuration, the prometaphase belt, which precedes biorientation. Chromosomes then invade the elongating spindle center to form the metaphase plate and start biorienting. Close to 90% of all chromosomes undergo one or more rounds of error correction of their kinetochore-microtubule attachments before achieving correct biorientation. This process depends on Aurora kinase activity. Our analysis reveals the error-prone nature of homologous chromosome biorientation, providing a possible explanation for the high incidence of aneuploid eggs observed in mammals, including humans.

  11. A model for the regulatory network controlling the dynamics of kinetochore microtubule plus-ends and poleward flux in metaphase.

    Science.gov (United States)

    Fernandez, Nicolas; Chang, Qiang; Buster, Daniel W; Sharp, David J; Ma, Ao

    2009-05-12

    Tight regulation of kinetochore microtubule dynamics is required to generate the appropriate position and movement of chromosomes on the mitotic spindle. A widely studied but mysterious aspect of this regulation occurs during metaphase when polymerization of kinetochore microtubule plus-ends is balanced by depolymerization at their minus-ends. Thus, kinetochore microtubules maintain a constant net length, allowing chromosomes to persist at the spindle equator, but consist of tubulin subunits that continually flux toward spindle poles. Here, we construct a feasible network of regulatory proteins for controlling kinetochore microtubule plus-end dynamics, which was combined with a Monte Carlo algorithm to simulate metaphase tubulin flux. We also test the network model by combining it with a force-balancing model explicitly taking force generators into account. Our data reveal how relatively simple interrelationships among proteins that stimulate microtubule plus-end polymerization, depolymerization, and dynamicity can induce robust flux while accurately predicting apparently contradictory results of knockdown experiments. The model also provides a simple and robust physical mechanism through which the regulatory networks at kinetochore microtubule plus- and minus-ends could communicate.

  12. Analysis of plant meiotic chromosomes by chromosome painting.

    Science.gov (United States)

    Lysak, Martin A; Mandáková, Terezie

    2013-01-01

    Chromosome painting (CP) refers to visualization of large chromosome regions, entire chromosome arms, or entire chromosomes via fluorescence in situ hybridization (FISH). For CP in plants, contigs of chromosome-specific bacterial artificial chromosomes (BAC) from the target species or from a closely related species (comparative chromosome painting, CCP) are typically applied as painting probes. Extended pachytene chromosomes provide the highest resolution of CP in plants. CP enables identification and tracing of particular chromosome regions and/or entire chromosomes throughout all meiotic stages as well as corresponding chromosome territories in premeiotic interphase nuclei. Meiotic pairing and structural chromosome rearrangements (typically inversions and translocations) can be identified by CP. Here, we describe step-by-step protocols of CP and CCP in plant species including chromosome preparation, BAC DNA labeling, and multicolor FISH.

  13. Mechanisms for chromosome segregation.

    Science.gov (United States)

    Bouet, Jean-Yves; Stouf, Mathieu; Lebailly, Elise; Cornet, François

    2014-12-01

    Bacteria face the problem of segregating their gigantic chromosomes without a segregation period restricted in time and space, as Eukaryotes do. Segregation thus involves multiple activities, general or specific of a chromosome region and differentially controlled. Recent advances show that these various mechanisms conform to a “pair and release” rule, which appears as a general rule in DNA segregation. We describe the latest advances in segregation of bacterial chromosomes with emphasis on the different pair and release mechanisms.

  14. The Precarious Prokaryotic Chromosome

    OpenAIRE

    Kuzminov, Andrei

    2014-01-01

    Evolutionary selection for optimal genome preservation, replication, and expression should yield similar chromosome organizations in any type of cells. And yet, the chromosome organization is surprisingly different between eukaryotes and prokaryotes. The nuclear versus cytoplasmic accommodation of genetic material accounts for the distinct eukaryotic and prokaryotic modes of genome evolution, but it falls short of explaining the differences in the chromosome organization. I propose that the t...

  15. A novel nucleoid-associated protein coordinates chromosome replication and chromosome partition.

    Science.gov (United States)

    Taylor, James A; Panis, Gaël; Viollier, Patrick H; Marczynski, Gregory T

    2017-09-06

    We searched for regulators of chromosome replication in the cell cycle model Caulobacter crescentus and found a novel DNA-binding protein (GapR) that selectively aids the initiation of chromosome replication and the initial steps of chromosome partitioning. The protein binds the chromosome origin of replication (Cori) and has higher-affinity binding to mutated Cori-DNA that increases Cori-plasmid replication in vivo. gapR gene expression is essential for normal rapid growth and sufficient GapR levels are required for the correct timing of chromosome replication. Whole genome ChIP-seq identified dynamic DNA-binding distributions for GapR, with the strongest associations at the partitioning (parABS) locus near Cori. Using molecular-genetic and fluorescence microscopy experiments, we showed that GapR also promotes the first steps of chromosome partitioning, the initial separation of the duplicated parS loci following replication from Cori. This separation occurs before the parABS-dependent partitioning phase. Therefore, this early separation, whose mechanisms is not known, coincides with the poorly defined mechanism(s) that establishes chromosome asymmetry: C. crescentus chromosomes are partitioned to distinct cell-poles which develop into replicating and non-replicating cell-types. We propose that GapR coordinates chromosome replication with asymmetry-establishing chromosome separation, noting that both roles are consistent with the phylogenetic restriction of GapR to asymmetrically dividing bacteria. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

  16. Chromosome oscillations in mitosis

    Science.gov (United States)

    Campas, Otger

    2008-03-01

    Successful cell division necessitates a tight regulation of chromosome movement via the activity of molecular motors. Many of the key players at the origin of the forces generating the motion have been identified, but their spatial and temporal organization remains elusive. In animal cells, chromosomes periodically switch between phases of movement towards and away from the pole. This characteristic oscillatory behaviour cannot be explained by the current models of chromosome positioning and congression. We perform a self-contained theoretical analysis in which the motion of mono-oriented chromosomes results from the competition between the activity of the kinetochore and chromokinesin motors on the chromosome arms. Our analysis, consistent with the available experimental data, proposes that the interplay between the aster-like morphology of the spindle and the collective kinetics of molecular motors is at the origin of chromosome oscillations, positioning and congression. It provides a natural explanation for the so-called chromosome directional instability and for the mechanism by which chromosomes sense their position in space. In addition, we estimate the in vivo velocity of chromokinesins at vanishing load and propose new experiments to assess the mechanism at the origin of chromosome movement in cell division.

  17. Bacterial chromosome segregation.

    Science.gov (United States)

    Possoz, Christophe; Junier, Ivan; Espeli, Olivier

    2012-01-01

    Dividing cells have mechanisms to ensure that their genomes are faithfully segregated into daughter cells. In bacteria, the description of these mechanisms has been considerably improved in the recent years. This review focuses on the different aspects of bacterial chromosome segregation that can be understood thanks to the studies performed with model organisms: Escherichia coli, Bacillus subtilis, Caulobacter crescentus and Vibrio cholerae. We describe the global positionning of the nucleoid in the cell and the specific localization and dynamics of different chromosomal loci, kinetic and biophysic aspects of chromosome segregation are presented. Finally, a presentation of the key proteins involved in the chromosome segregation is made.

  18. Fetal chromosome analysis: screening for chromosome disease?

    DEFF Research Database (Denmark)

    Philip, J; Tabor, Ann; Bang, J

    1983-01-01

    The aim of the study was to investigate the rationale of the current indications for fetal chromosome analysis. 5372 women had 5423 amniocentesis performed, this group constituting a consecutive sample at the chromosome laboratory, Rigshospitalet, Copenhagen from March 1973 to September 1980 (Group...... to women having amniocentesis, although considered not to have any increased risk of fetal chromosome abnormality (1390 pregnancies, group B). They were also compared with 750 consecutive pregnancies in women 25-34 years of age, in whom all heritable diseases were excluded (group C). The risk of unbalanced...... with women without elevated risk. Spontaneous abortion rate and prematurity rate did not differ from rates expected without amniocentesis. It is concluded that current indications may be characterized as a mixture of evident high risk factors and factors with only a minor influence on risk. Indications...

  19. A review of metaphase chromosome image selection techniques for automatic karyotype generation.

    Science.gov (United States)

    Arora, Tanvi; Dhir, Renu

    2016-08-01

    The karyotype is analyzed to detect the genetic abnormalities. It is generated by arranging the chromosomes after extracting them from the metaphase chromosome images. The chromosomes are non-rigid bodies that contain the genetic information of an individual. The metaphase chromosome image spread contains the chromosomes, but these chromosomes are not distinct bodies; they can either be individual chromosomes or be touching one another; they may be bent or even may be overlapping and thus forming a cluster of chromosomes. The extraction of chromosomes from these touching and overlapping chromosomes is a very tedious process. The segmentation of a random metaphase chromosome image may not give us correct and accurate results. Therefore, before taking up a metaphase chromosome image for analysis, it must be analyzed for the orientation of the chromosomes it contains. The various reported methods for metaphase chromosome image selection for automatic karyotype generation are compared in this paper. After analysis, it has been concluded that each metaphase chromosome image selection method has its advantages and disadvantages.

  20. XYY chromosome anomaly and schizophrenia.

    Science.gov (United States)

    Rajagopalan, M; MacBeth, R; Varma, S L

    1998-02-07

    Sex chromosome anomalies have been associated with psychoses, and most of the evidence is linked to the presence of an additional X chromosome. We report a patient with XYY chromosome anomaly who developed schizophrenia.

  1. Electochemical detection of chromosome translocation

    DEFF Research Database (Denmark)

    Kwasny, Dorota; Dimaki, Maria; Silahtaroglu, Asli

    2014-01-01

    Cytogenetics is a study of the cell structure with a main focus on chromosomes content and their structure. Chromosome abnormalities, such as translocations may cause various genetic disorders and heametological malignancies. Chromosome translocations are structural rearrangements of two chromoso...

  2. Mitosin/CENP-F is a conserved kinetochore protein subjected to cytoplasmic dynein-mediated poleward transport

    Institute of Scientific and Technical Information of China (English)

    ZHEN YE YANG; JING GUO; NING LI; MIN QIAN; SHENG NIAN WANG; XUE LIANG ZHU

    2003-01-01

    Mitosin/CENP-F is a human nuclear protein transiently associated with the outer kinetochore plate in M phase and is involved in M phase progression. LEK1 and CMF1, which are its murine and chicken orthologs, however, are implicated in muscle differentiation and reportedly not distributed at kinetochores.We therefore conducted several assays to clarify this issue. The typical centromere staining patterns were observed in mitotic cells from both human primary culture and murine, canine, and mink cell lines. A C-terminal portion of LEK1 also conferred centromere localization. Our analysis further suggests conserved kinetochore localization of mammalian mitosin orthologs. Moreover, mitosin was associated preferentially with kinetochores of unaligned chromosomes. It was also constantly transported from kinetochores to spindle poles by cytoplasmic dynein. These properties resemble those of other kinetochore proteins important for the spindle checkpoint, thus implying a role of mitosin in this checkpoint. Therefore, mitosin family may serve as multifunctional proteins involved in both mitosis and differentiation.

  3. Chromosomal mosaicism goes global

    Directory of Open Access Journals (Sweden)

    Yurov Yuri B

    2008-11-01

    Full Text Available Intercellular differences of chromosomal content in the same individual are defined as chromosomal mosaicism (alias intercellular or somatic genomic variations or, in a number of publications, mosaic aneuploidy. It has long been suggested that this phenomenon poorly contributes both to intercellular (interindividual diversity and to human disease. However, our views have recently become to change due to a series of communications demonstrated a higher incidence of chromosomal mosaicism in diseased individuals (major psychiatric disorders and autoimmune diseases as well as depicted chromosomal mosaicism contribution to genetic diversity, the central nervous system development, and aging. The later has been produced by significant achievements in the field of molecular cytogenetics. Recently, Molecular Cytogenetics has published an article by Maj Hulten and colleagues that has provided evidences for chromosomal mosaicism to underlie formation of germline aneuploidy in human female gametes using trisomy 21 (Down syndrome as a model. Since meiotic aneuploidy is suggested to be the leading genetic cause of human prenatal mortality and postnatal morbidity, these data together with previous findings define chromosomal mosaicism not as a casual finding during cytogenetic analyses but as a more significant biological phenomenon than previously recognized. Finally, the significance of chromosomal mosaicism can be drawn from the fact, that this phenomenon is involved in genetic diversity, normal and abnormal prenatal development, human diseases, aging, and meiotic aneuploidy, the intrinsic cause of which remains, as yet, unknown.

  4. Sequential cloning of chromosomes

    Science.gov (United States)

    Lacks, S.A.

    1995-07-18

    A method for sequential cloning of chromosomal DNA of a target organism is disclosed. A first DNA segment homologous to the chromosomal DNA to be sequentially cloned is isolated. The first segment has a first restriction enzyme site on either side. A first vector product is formed by ligating the homologous segment into a suitably designed vector. The first vector product is circularly integrated into the target organism`s chromosomal DNA. The resulting integrated chromosomal DNA segment includes the homologous DNA segment at either end of the integrated vector segment. The integrated chromosomal DNA is cleaved with a second restriction enzyme and ligated to form a vector-containing plasmid, which is replicated in a host organism. The replicated plasmid is then cleaved with the first restriction enzyme. Next, a DNA segment containing the vector and a segment of DNA homologous to a distal portion of the previously isolated DNA segment is isolated. This segment is then ligated to form a plasmid which is replicated within a suitable host. This plasmid is then circularly integrated into the target chromosomal DNA. The chromosomal DNA containing the circularly integrated vector is treated with a third, retrorestriction (class IIS) enzyme. The cleaved DNA is ligated to give a plasmid that is used to transform a host permissive for replication of its vector. The sequential cloning process continues by repeated cycles of circular integration and excision. The excision is carried out alternately with the second and third enzymes. 9 figs.

  5. DNA microarray profiling of a diverse collection of nosocomial methicillin-resistant staphylococcus aureus isolates assigns the majority to the correct sequence type and staphylococcal cassette chromosome mec (SCCmec) type and results in the subsequent identification and characterization of novel SCCmec-SCCM1 composite islands.

    LENUS (Irish Health Repository)

    Shore, Anna C

    2012-10-01

    One hundred seventy-five isolates representative of methicillin-resistant Staphylococcus aureus (MRSA) clones that predominated in Irish hospitals between 1971 and 2004 and that previously underwent multilocus sequence typing (MLST) and staphylococcal cassette chromosome mec (SCCmec) typing were characterized by spa typing (175 isolates) and DNA microarray profiling (107 isolates). The isolates belonged to 26 sequence type (ST)-SCCmec types and subtypes and 35 spa types. The array assigned all isolates to the correct MLST clonal complex (CC), and 94% (100\\/107) were assigned an ST, with 98% (98\\/100) correlating with MLST. The array assigned all isolates to the correct SCCmec type, but subtyping of only some SCCmec elements was possible. Additional SCCmec\\/SCC genes or DNA sequence variation not detected by SCCmec typing was detected by array profiling, including the SCC-fusidic acid resistance determinant Q6GD50\\/fusC. Novel SCCmec\\/SCC composite islands (CIs) were detected among CC8 isolates and comprised SCCmec IIA-IIE, IVE, IVF, or IVg and a ccrAB4-SCC element with 99% DNA sequence identity to SCC(M1) from ST8\\/t024-MRSA, SCCmec VIII, and SCC-CI in Staphylococcus epidermidis. The array showed that the majority of isolates harbored one or more superantigen (94%; 100\\/107) and immune evasion cluster (91%; 97\\/107) genes. Apart from fusidic acid and trimethoprim resistance, the correlation between isolate antimicrobial resistance phenotype and the presence of specific resistance genes was ≥97%. Array profiling allowed high-throughput, accurate assignment of MRSA to CCs\\/STs and SCCmec types and provided further evidence of the diversity of SCCmec\\/SCC. In most cases, array profiling can accurately predict the resistance phenotype of an isolate.

  6. DNA Microarray Profiling of a Diverse Collection of Nosocomial Methicillin-Resistant Staphylococcus aureus Isolates Assigns the Majority to the Correct Sequence Type and Staphylococcal Cassette Chromosome mec (SCCmec) Type and Results in the Subsequent Identification and Characterization of Novel SCCmec-SCCM1 Composite Islands

    Science.gov (United States)

    Brennan, Orla M.; Deasy, Emily C.; Rossney, Angela S.; Kinnevey, Peter M.; Ehricht, Ralf; Monecke, Stefan; Coleman, David C.

    2012-01-01

    One hundred seventy-five isolates representative of methicillin-resistant Staphylococcus aureus (MRSA) clones that predominated in Irish hospitals between 1971 and 2004 and that previously underwent multilocus sequence typing (MLST) and staphylococcal cassette chromosome mec (SCCmec) typing were characterized by spa typing (175 isolates) and DNA microarray profiling (107 isolates). The isolates belonged to 26 sequence type (ST)-SCCmec types and subtypes and 35 spa types. The array assigned all isolates to the correct MLST clonal complex (CC), and 94% (100/107) were assigned an ST, with 98% (98/100) correlating with MLST. The array assigned all isolates to the correct SCCmec type, but subtyping of only some SCCmec elements was possible. Additional SCCmec/SCC genes or DNA sequence variation not detected by SCCmec typing was detected by array profiling, including the SCC-fusidic acid resistance determinant Q6GD50/fusC. Novel SCCmec/SCC composite islands (CIs) were detected among CC8 isolates and comprised SCCmec IIA-IIE, IVE, IVF, or IVg and a ccrAB4-SCC element with 99% DNA sequence identity to SCCM1 from ST8/t024-MRSA, SCCmec VIII, and SCC-CI in Staphylococcus epidermidis. The array showed that the majority of isolates harbored one or more superantigen (94%; 100/107) and immune evasion cluster (91%; 97/107) genes. Apart from fusidic acid and trimethoprim resistance, the correlation between isolate antimicrobial resistance phenotype and the presence of specific resistance genes was ≥97%. Array profiling allowed high-throughput, accurate assignment of MRSA to CCs/STs and SCCmec types and provided further evidence of the diversity of SCCmec/SCC. In most cases, array profiling can accurately predict the resistance phenotype of an isolate. PMID:22869569

  7. Sequential cloning of chromosomes

    Energy Technology Data Exchange (ETDEWEB)

    Lacks, S.A.

    1991-12-31

    A method for sequential cloning of chromosomal DNA and chromosomal DNA cloned by this method are disclosed. The method includes the selection of a target organism having a segment of chromosomal DNA to be sequentially cloned. A first DNA segment, having a first restriction enzyme site on either side. homologous to the chromosomal DNA to be sequentially cloned is isolated. A first vector product is formed by ligating the homologous segment into a suitably designed vector. The first vector product is circularly integrated into the target organism`s chromosomal DNA. The resulting integrated chromosomal DNA segment includes the homologous DNA segment at either end of the integrated vector segment. The integrated chromosomal DNA is cleaved with a second restriction enzyme and ligated to form a vector-containing plasmid, which is replicated in a host organism. The replicated plasmid is then cleaved with the first restriction enzyme. Next, a DNA segment containing the vector and a segment of DNA homologous to a distal portion of the previously isolated DNA segment is isolated. This segment is then ligated to form a plasmid which is replicated within a suitable host. This plasmid is then circularly integrated into the target chromosomal DNA. The chromosomal DNA containing the circularly integrated vector is treated with a third, retrorestriction enzyme. The cleaved DNA is ligated to give a plasmid that is used to transform a host permissive for replication of its vector. The sequential cloning process continues by repeated cycles of circular integration and excision. The excision is carried out alternately with the second and third enzymes.

  8. Simultaneous observation of the poleward expansion of substorm electrojet activity and the tailward expansion of current sheet disruption in the near-earth magnetotail

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, R.E. (Univ. of Maryland, College Park (United States)); Koskinen, H.E.J.; Pulkkinen, T.I. (Finnish Meteorological Inst., Helsinki (Finland)); Boesinger, T. (Univ. of Oulu (Finland)); McEntire, R.W.; Potemra, T.A. (Johns Hopkins Univ., Laurel, MD (United States))

    1993-06-01

    This paper reports on observations of a magnetospheric substorm on June 7, 1985. This event was observed simultaneously by a number of different systems. Particle and magnetic field data were collected by AMPTE/CCE, located near the neutral sheet; magnetic field data was monitored by the EISCAT magnetometer cross; STARE radar data was also collected; and Pi 1 data from Sodankyla. The ground based systems observed the poleward and westward expansion of electrojet activity at the start of the storm. The satellite was able to see the storms onset, and record perturbations in the current sheet at the onset of the substorm, in addition to later perturbations, which the authors argue originates tailward of the satellite. Satellite measurements are shown to occur in conjunction with ground events.

  9. CHROMOSOMES OF AMERICAN MARSUPIALS.

    Science.gov (United States)

    BIGGERS, J D; FRITZ, H I; HARE, W C; MCFEELY, R A

    1965-06-18

    Studies of the chromosomes of four American marsupials demonstrated that Caluromys derbianus and Marmosa mexicana have a diploid number of 14 chromosomes, and that Philander opossum and Didelphis marsupialis have a diploid number of 22. The karyotypes of C. derbianus and M. mexicana are similar, whereas those of P. opossum and D. marsupialis are dissimilar. If the 14-chromosome karyotype represents a reduction from a primitive number of 22, these observations suggest that the change has occurred independently in the American and Australasian forms.

  10. Chromosomal abnormalities and autism

    Directory of Open Access Journals (Sweden)

    Farida El-Baz

    2016-01-01

    Conclusion: Chromosomal abnormalities were not detected in the studied autistic children, and so the relation between the genetics and autism still needs further work up with different study methods and techniques.

  11. Feedback control of chromosome separation by a midzone Aurora B gradient

    Science.gov (United States)

    Pereira, António J.; Aguiar, Paulo; Lampson, Michael A.; Maiato, Helder

    2017-01-01

    Accurate chromosome segregation during mitosis requires the physical separation of sister chromatids before nuclear envelope reassembly (NER). However, how these two processes are coordinated remains unknown. Here, we identified a conserved feedback control mechanism that delays chromosome decondensation and NER in response to incomplete chromosome separation during anaphase. A midzone-associated Aurora B gradient was found to monitor chromosome position along the division axis and to prevent premature chromosome decondensation by retaining Condensin I. PP1/PP2A phosphatases counteracted this gradient and promoted chromosome decondensation and NER. Thus, an Aurora B gradient appears to mediate a surveillance mechanism that prevents chromosome decondensation and NER until effective separation of sister chromatids is achieved. This allows the correction and reintegration of lagging chromosomes in the main nuclei before completion of NER. PMID:24925910

  12. Back to the roots: segregation of univalent sex chromosomes in meiosis.

    Science.gov (United States)

    Fabig, Gunar; Müller-Reichert, Thomas; Paliulis, Leocadia V

    2016-06-01

    In males of many taxa, univalent sex chromosomes normally segregate during the first meiotic division, and analysis of sex chromosome segregation was foundational for the chromosome theory of inheritance. Correct segregation of single or multiple univalent sex chromosomes occurs in a cellular environment where every other chromosome is a bivalent that is being partitioned into homologous chromosomes at anaphase I. The mechanics of univalent chromosome segregation vary among animal taxa. In some, univalents establish syntelic attachment of sister kinetochores to the spindle. In others, amphitelic attachment is established. Here, we review how this problem of segregation of unpaired chromosomes is solved in different animal systems. In addition, we give a short outlook of how mechanistic insights into this process could be gained by explicitly studying model organisms, such as Caenorhabditis elegans.

  13. [Sex chromosomes and meiosis].

    Science.gov (United States)

    Guichaoua, M-R; Geoffroy-Siraudin, C; Tassistro, V; Ghalamoun-Slaimi, R; Perrin, J; Metzler-Guillemain, C

    2009-01-01

    Sex chromosome behaviour fundamentally differs between male and female meiosis. In oocyte, X chromosomes synapse giving a XX bivalent which is not recognizable in their morphology and behaviour from autosomal bivalents. In human male, X and Y chromosomes differ from one another in their morphology and their genetic content, leading to a limited pairing and preventing genetic recombination, excepted in homologous region PAR1. During pachytene stage of the first meiotic prophase, X and Y chromosomes undergo a progressive condensation and form a transcriptionally silenced peripheral XY body. The condensation of the XY bivalent during pachytene stage led us to describe four pachytene substages and to localize the pachytene checkpoint between substages 2 and 3. We also defined the pachytene index (PI=P1+P2/P1+P2+P3+P4) which is always less than 0.50 in normal meiosis. XY body undergoes decondensation at diplotene stage, but transcriptional inactivation of the two sex chromosomes or Meiotic Sex Chromosome Inactivation (MSCI) persists through to the end of spermatogenesis. Sex chromosome inactivation involves several proteins, some of them were now identified. Two isoforms of the HP1 protein, HP1beta and HP1gamma, are involved in the facultative heterochromatinization of the XY body, but the initiation of this process involves the phosphorylation of the protein H2AX by the kinase ATR whose recruitment depends on BRCA1. Extensive researches on the inactivation of the sex chromosomes during male meiosis will allow to a better understanding of some male infertilities.

  14. Chromosome doubling method

    Science.gov (United States)

    Kato, Akio

    2006-11-14

    The invention provides methods for chromosome doubling in plants. The technique overcomes the low yields of doubled progeny associated with the use of prior techniques for doubling chromosomes in plants such as grasses. The technique can be used in large scale applications and has been demonstrated to be highly effective in maize. Following treatment in accordance with the invention, plants remain amenable to self fertilization, thereby allowing the efficient isolation of doubled progeny plants.

  15. Activation of X Chromosome Inactivation

    NARCIS (Netherlands)

    C.M. Maduro (Cheryl)

    2016-01-01

    markdownabstractIn mammals, males are the heterogametic sex having an X chromosome and a Y chromosome whereas females have two X chromosomes. Despite originating from an ancient homologous autosomal pair, the X and Y chromosome now differ greatly in size and gene content after ~180 MY of evolution.

  16. Activation of X Chromosome Inactivation

    NARCIS (Netherlands)

    C.M. Maduro (Cheryl)

    2016-01-01

    markdownabstractIn mammals, males are the heterogametic sex having an X chromosome and a Y chromosome whereas females have two X chromosomes. Despite originating from an ancient homologous autosomal pair, the X and Y chromosome now differ greatly in size and gene content after ~180 MY of evolution.

  17. Vibrio chromosomes share common history

    Directory of Open Access Journals (Sweden)

    Gevers Dirk

    2010-05-01

    Full Text Available Abstract Background While most gamma proteobacteria have a single circular chromosome, Vibrionales have two circular chromosomes. Horizontal gene transfer is common among Vibrios, and in light of this genetic mobility, it is an open question to what extent the two chromosomes themselves share a common history since their formation. Results Single copy genes from each chromosome (142 genes from chromosome I and 42 genes from chromosome II were identified from 19 sequenced Vibrionales genomes and their phylogenetic comparison suggests consistent phylogenies for each chromosome. Additionally, study of the gene organization and phylogeny of the respective origins of replication confirmed the shared history. Conclusions Thus, while elements within the chromosomes may have experienced significant genetic mobility, the backbones share a common history. This allows conclusions based on multilocus sequence analysis (MLSA for one chromosome to be applied equally to both chromosomes.

  18. Evidence that Aurora B is implicated in spindle checkpoint signalling independently of error correction

    OpenAIRE

    Santaguida, Stefano; Vernieri, Claudio; Villa, Fabrizio; Ciliberto, Andrea; Musacchio, Andrea

    2011-01-01

    Fidelity of chromosome segregation is ensured by a tension-dependent error correction system that prevents stabilization of incorrect chromosome–microtubule attachments. Unattached or incorrectly attached chromosomes also activate the spindle assembly checkpoint, thus delaying mitotic exit until all chromosomes are bioriented. The Aurora B kinase is widely recognized as a component of error correction. Conversely, its role in the checkpoint is controversial. Here, we report an analysis of the...

  19. Rapid screening for chromosomal aneuploidies using array-MLPA

    Directory of Open Access Journals (Sweden)

    van Beuningen Rinie

    2011-05-01

    Full Text Available Abstract Background Chromosome abnormalities, especially trisomy of chromosome 21, 13, or 18 as well as sex chromosome aneuploidy, are a well-established cause of pregnancy loss. Cultured cell karyotype analysis and FISH have been considered reliable detectors of fetal abnormality. However, results are usually not available for 3-4 days or more. Multiplex ligation-dependent probe amplification (MLPA has emerged as an alternative rapid technique for detection of chromosome aneuploidies. However, conventional MLPA does not allow for relative quantification of more than 50 different target sequences in one reaction and does not detect mosaic trisomy. A multiplexed MLPA with more sensitive detection would be useful for fetal genetic screening. Methods We developed a method of array-based MLPA to rapidly screen for common aneuploidies. We designed 116 universal tag-probes covering chromosomes 13, 18, 21, X, and Y, and 8 control autosomal genes. We performed MLPA and hybridized the products on a 4-well flow-through microarray system. We determined chromosome copy numbers by analyzing the relative signals of the chromosome-specific probes. Results In a blind study of 161 peripheral blood and 12 amniotic fluid samples previously karyotyped, 169 of 173 (97.7% including all the amniotic fluid samples were correctly identified by array-MLPA. Furthermore, we detected two chromosome X monosomy mosaic cases in which the mosaism rates estimated by array-MLPA were basically consistent with the results from karyotyping. Additionally, we identified five Y chromosome abnormalities in which G-banding could not distinguish their origins for four of the five cases. Conclusions Our study demonstrates the successful application and strong potential of array-MLPA in clinical diagnosis and prenatal testing for rapid and sensitive chromosomal aneuploidy screening. Furthermore, we have developed a simple and rapid procedure for screening copy numbers on chromosomes 13, 18

  20. "Chromosome": a knowledge-based system for the chromosome classification.

    Science.gov (United States)

    Ramstein, G; Bernadet, M

    1993-01-01

    Chromosome, a knowledge-based analysis system has been designed for the classification of human chromosomes. Its aim is to perform an optimal classification by driving a tool box containing the procedures of image processing, pattern recognition and classification. This paper presents the general architecture of Chromosome, based on a multiagent system generator. The image processing tool box is described from the met aphasic enhancement to the fine classification. Emphasis is then put on the knowledge base intended for the chromosome recognition. The global classification process is also presented, showing how Chromosome proceeds to classify a given chromosome. Finally, we discuss further extensions of the system for the karyotype building.

  1. First trimester ultrasound screening of chromosomal abnormalities

    Directory of Open Access Journals (Sweden)

    Trninić-Pjević Aleksandra

    2007-01-01

    Full Text Available Introduction: A retrocervical subcutaneous collection of fluid at 11-14 weeks of gestation, can be visualized by ultrasound as nuchal translucency (NT. Objective. To examine the distribution of fetal nuchal translucency in low risk population, to determine the detection rate of chromosomal abnormalities in the population of interest based on maternal age and NT measurement. Method. Screening for chromosomal defects, advocated by The Fetal Medicine Foundation (FMF, was performed in 1,341 pregnancies in the period January 2000 - April 2004. Initial risk for chromosomal defects (based on maternal and gestational age and corrected risk, after the NT measurement, were calculated. Complete data were collected from 1,048 patients. Results. Out of 1,048 pregnancies followed, 8 cases of Down’s syndrome were observed, 7 were detected antenatally and 6 out of 7 were detected due to screening that combines maternal age and NT measurement. According to our results, sensitivity of the screening for aneuploidies based on maternal age alone was 12.5% and false positive rate 13.1%, showing that screening based on NT measurement is of great importance. Screening by a combination of maternal age and NT, and selecting a screening-positive group for invasive testing enabled detection of 75% of fetuses with trisomy 21. Conclusion. In screening for chromosomal abnormalities, an approach which combines maternal age and NT is effective and increases the detection rate compared to the use of any single test. .

  2. Coordinated Cluster, ground-based instrumentation and low-altitude satellite observations of transient poleward-moving events in the ionosphere and in the tail lobe

    Directory of Open Access Journals (Sweden)

    M. Lockwood

    Full Text Available During the interval between 8:00–9:30 on 14 January 2001, the four Cluster spacecraft were moving from the central magnetospheric lobe, through the dusk sector mantle, on their way towards intersecting the magnetopause near 15:00 MLT and 15:00 UT. Throughout this interval, the EISCAT Svalbard Radar (ESR at Longyearbyen observed a series of poleward-moving transient events of enhanced F-region plasma concentration ("polar cap patches", with a repetition period of the order of 10 min. Allowing for the estimated solar wind propagation delay of 75 ( ± 5 min, the interplanetary magnetic field (IMF had a southward component during most of the interval. The magnetic footprint of the Cluster spacecraft, mapped to the ionosphere using the Tsyganenko T96 model (with input conditions prevailing during this event, was to the east of the ESR beams. Around 09:05 UT, the DMSP-F12 satellite flew over the ESR and showed a sawtooth cusp ion dispersion signature that also extended into the electrons on the equatorward edge of the cusp, revealing a pulsed magnetopause reconnection. The consequent enhanced ionospheric flow events were imaged by the SuperDARN HF backscatter radars. The average convection patterns (derived using the AMIE technique on data from the magnetometers, the EISCAT and SuperDARN radars, and the DMSP satellites show that the associated poleward-moving events also convected over the predicted footprint of the Cluster spacecraft. Cluster observed enhancements in the fluxes of both electrons and ions. These events were found to be essentially identical at all four spacecraft, indicating that they had a much larger spatial scale than the satellite separation of the order of 600 km. Some of the events show a correspondence between the lowest energy magnetosheath electrons detected by the PEACE instrument on Cluster (10–20 eV and the topside ionospheric enhancements seen by the ESR (at 400–700 km. We suggest that a potential barrier at the

  3. Those amazing dinoflagellate chromosomes

    Institute of Scientific and Technical Information of China (English)

    PETER J RIZZO

    2003-01-01

    Dinoflagellates are a very large and diverse group of eukaryotic algae that play a major role in aquatic food webs of both fresh water and marine habitats. Moreover, the toxic members of this group pose a health threat in the form of red tides. Finally, dinoflagellates are of great evolutionary importance,because of their taxonomic position, and their unusual chromosome structure and composition. While the cytoplasm of dinoflagellates is typically eukaryotic, the nucleus is unique when compared to the nucleus of other eukaryotes. More specifically, while the chromosomes of all other eukaryotes contain histones,dinoflagellate chromosomes lack histones completely. There are no known exceptions to this observation: all dinoflagellates lack histones, and all other eukaryotes contain histones. Nevertheless, dinoflagellates remain a relatively unstudied group of eukaryotes.

  4. Chromosome numbers in Bromeliaceae

    Directory of Open Access Journals (Sweden)

    Cotias-de-Oliveira Ana Lúcia Pires

    2000-01-01

    Full Text Available The present study reports chromosome numbers of 17 species of Bromeliaceae, belonging to the genera Encholirium, Bromelia, Orthophytum, Hohenbergia, Billbergia, Neoglaziovia, Aechmea, Cryptanthus and Ananas. Most species present 2n = 50, however, Bromelia laciniosa, Orthophytum burle-marxii and O. maracasense are polyploids with 2n = 150, 2n = 100 and 2n = 150, respectively, while for Cryptanthus bahianus, 2n = 34 + 1-4B. B chromosomes were observed in Bromelia plumieri and Hohenbergia aff. utriculosa. The chromosome number of all species was determined for the first time, except for Billbergia chlorosticta and Cryptanthus bahianus. Our data supports the hypothesis of a basic number of x = 25 for the Bromeliaceae family and decreasing aneuploidy in the genus Cryptanthus.

  5. Assessment of aneuploidy in human oocytes and preimplantation embryos by chromosome painting

    Energy Technology Data Exchange (ETDEWEB)

    Rougier, N.; Viegas-Pequignot, E.; Plachot, M. [Hospital Necker, Paris (France)] [and others

    1994-09-01

    The poor quality of chromosome preparations often observed after fixation of oocytes and embryos did not usually allow accurate identification of chromosomes involved in non-disjunctions. We, therefore, used chromosome painting to determine the incidence of abnormalities for chromosomes 1 and 7. A total of 50 oocytes inseminated for IVF and showing no signs of fertilization as well as 37 diploid embryos donated for research were fixed according to the Dyban`s technique. Fluorescence in situ hybridization was carried out using whole chromosome painting DNA probes specific for human chromosome 1 and 7. The incidence of aneuploidy was 28%, 10% and 60% for metaphase II, polar body and sperm chromosomes, respectively. The high incidence of aneuploidy observed in sperm prematurely condensed sperm chromosomes is due to the fact that usually far less than 23 sperm chromatids are observed, maybe as a consequence of incomplete chromosome condensation. Thirty seven embryos were analyzed with the same probes. 48% of early embryos were either monosomic 1 or 7 or mosaics comprising blastomeres with 1, 2 or 3 signals. Thus, 8 among the 11 abnormal embryos had hypodiploid cells (25 to 37 chromosomes) indicating either an artefactual loss of chromosomes or a complex anomaly of nuclear division (maltinucleated blastomeres, abnormal migration of chromosomes at anaphase). We therefore calculated a {open_quotes}corrected{close_quotes} incidence of aneuploidy for chromosomes 1 or 7 in early embryos: 18%. 86% of the blastocysts showed mosaicism 2n/3 or 4n as a consequence of the formation of the syncitiotrophoblast. To conclude, chromosome painting is an efficient method to accurately identify chromosomes involved in aneuploidy. This technique should allow us to evaluate the incidence of non-disjunction for all chromosome pairs. Our results confirm the high incidence of chromosome abnormalities occurring as a consequence of meiotic or mitotic non-disjunctions in human oocytes and embryos.

  6. DNA Repair Defects and Chromosomal Aberrations

    Science.gov (United States)

    Hada, Megumi; George, K. A.; Huff, J. L.; Pluth, J. M.; Cucinotta, F. A.

    2009-01-01

    Yields of chromosome aberrations were assessed in cells deficient in DNA doublestrand break (DSB) repair, after exposure to acute or to low-dose-rate (0.018 Gy/hr) gamma rays or acute high LET iron nuclei. We studied several cell lines including fibroblasts deficient in ATM (ataxia telangiectasia mutated; product of the gene that is mutated in ataxia telangiectasia patients) or NBS (nibrin; product of the gene mutated in the Nijmegen breakage syndrome), and gliomablastoma cells that are proficient or lacking in DNA-dependent protein kinase (DNA-PK) activity. Chromosomes were analyzed using the fluorescence in situ hybridization (FISH) chromosome painting method in cells at the first division post irradiation, and chromosome aberrations were identified as either simple exchanges (translocations and dicentrics) or complex exchanges (involving >2 breaks in 2 or more chromosomes). Gamma irradiation induced greater yields of both simple and complex exchanges in the DSB repair-defective cells than in the normal cells. The quadratic dose-response terms for both simple and complex chromosome exchanges were significantly higher for the ATM- and NBS-deficient lines than for normal fibroblasts. However, in the NBS cells the linear dose-response term was significantly higher only for simple exchanges. The large increases in the quadratic dose-response terms in these repair-defective cell lines points the importance of the functions of ATM and NBS in chromatin modifications to facilitate correct DSB repair and minimize the formation of aberrations. The differences found between ATM- and NBS-deficient cells at low doses suggest that important questions should with regard to applying observations of radiation sensitivity at high dose to low-dose exposures. For aberrations induced by iron nuclei, regression models preferred purely linear dose responses for simple exchanges and quadratic dose responses for complex exchanges. Relative biological effectiveness (RBE) factors of all of

  7. DNA Repair Defects and Chromosomal Aberrations

    Science.gov (United States)

    Hada, Megumi; George, K. A.; Huff, J. L.; Pluth, J. M.; Cucinotta, F. A.

    2009-01-01

    Yields of chromosome aberrations were assessed in cells deficient in DNA doublestrand break (DSB) repair, after exposure to acute or to low-dose-rate (0.018 Gy/hr) gamma rays or acute high LET iron nuclei. We studied several cell lines including fibroblasts deficient in ATM (ataxia telangiectasia mutated; product of the gene that is mutated in ataxia telangiectasia patients) or NBS (nibrin; product of the gene mutated in the Nijmegen breakage syndrome), and gliomablastoma cells that are proficient or lacking in DNA-dependent protein kinase (DNA-PK) activity. Chromosomes were analyzed using the fluorescence in situ hybridization (FISH) chromosome painting method in cells at the first division post irradiation, and chromosome aberrations were identified as either simple exchanges (translocations and dicentrics) or complex exchanges (involving >2 breaks in 2 or more chromosomes). Gamma irradiation induced greater yields of both simple and complex exchanges in the DSB repair-defective cells than in the normal cells. The quadratic dose-response terms for both simple and complex chromosome exchanges were significantly higher for the ATM- and NBS-deficient lines than for normal fibroblasts. However, in the NBS cells the linear dose-response term was significantly higher only for simple exchanges. The large increases in the quadratic dose-response terms in these repair-defective cell lines points the importance of the functions of ATM and NBS in chromatin modifications to facilitate correct DSB repair and minimize the formation of aberrations. The differences found between ATM- and NBS-deficient cells at low doses suggest that important questions should with regard to applying observations of radiation sensitivity at high dose to low-dose exposures. For aberrations induced by iron nuclei, regression models preferred purely linear dose responses for simple exchanges and quadratic dose responses for complex exchanges. Relative biological effectiveness (RBE) factors of all of

  8. Chromosomal rearrangements in cattle and pigs revealed by chromosome microdissection and chromosome painting

    Directory of Open Access Journals (Sweden)

    Yerle Martine

    2003-11-01

    Full Text Available Abstract A pericentric inversion of chromosome 4 in a boar, as well as a case of (2q-;5p+ translocation mosaicism in a bull were analysed by chromosome painting using probes generated by conventional microdissection. For the porcine inversion, probes specific for p arms and q arms were produced and hybridised simultaneously on metaphases of a heterozygote carrier. In the case of the bovine translocation, two whole chromosome probes (chromosome 5, and derived chromosome 5 were elaborated and hybridised independently on chromosomal preparations of the bull who was a carrier of the mosaic translocation. The impossibility of differentiating chromosomes 2 and der(2 from other chromosomes of the metaphases did not allow the production of painting probes for these chromosomes. For all experiments, the quality of painting was comparable to that usually observed with probes obtained from flow-sorted chromosomes. The results obtained allowed confirmation of the interpretations proposed with G-banding karyotype analyses. In the bovine case, however, the reciprocity of the translocation could not be proven. The results presented in this paper show the usefulness of the microdissection technique for characterising chromosomal rearrangements in species for which commercial probes are not available. They also confirmed that the main limiting factor of the technique is the quality of the chromosomal preparations, which does not allow the identification of target chromosomes or chromosome fragments in all cases.

  9. Chromosomal rearrangement interferes with meiotic X chromosome inactivation

    OpenAIRE

    Homolka, David; Ivanek, Robert; Capkova, Jana; Jansa, Petr; Forejt, Jiri

    2007-01-01

    Heterozygosity for certain mouse and human chromosomal rearrangements is characterized by the incomplete meiotic synapsis of rearranged chromosomes, by their colocalization with the XY body in primary spermatocytes, and by male-limited sterility. Previously, we argued that such X–autosomal associations could interfere with meiotic sex chromosome inactivation. Recently, supporting evidence has reported modifications of histones in rearranged chromosomes by a process called the meiotic silencin...

  10. Daily scale winter-time sea surface temperature variability and the Iberian Poleward Current in the southern Bay of Biscay from 1981 to 2010

    Directory of Open Access Journals (Sweden)

    G. Esnaola

    2012-12-01

    Full Text Available The combination of remotely sensed gappy sea surface temperature (SST images with the missing data filling Data Interpolating EOFs (DINEOF technique followed by a Principal Component Analysis of the reconstructed data, has been used to identify the time evolution and the daily scale variability of the winter-time surface signal of the Iberian Poleward Current (IPC during the 1981–2010 period. An exhaustive comparison with the existing bibliography, and the vertical temperature and salinity profiles related to its extremes over the Bay of Biscay area, show that the obtained time series accurately reflect the variability of the IPC. A physical mechanism involving both atmospheric and oceanic variables is proposed in relation to the variability of the IPC. It jointly takes into account several mechanisms that have separately been related to the variability of the IPC, i.e. the south-westerly winds, the Joint Effect of Baroclinicity And Relief (JEBAR effect, the topographic β effect and a weakened North Atlantic Gyre. This mechanism emerges from an atmospheric 500 hPa circulation anomaly that has not a simple relationship with any of the most common North Atlantic teleconnection patterns. It then generates mutually coherent SST and sea level anomaly patterns in the North Atlantic area due to the action of anomalous wind-stress and heat-fluxes, and locally, it also generates the conditions for the mentioned mechanisms in the Bay of Biscay area.

  11. Bacterial Artificial Chromosome Mutagenesis Using Recombineering

    Directory of Open Access Journals (Sweden)

    Kumaran Narayanan

    2011-01-01

    Full Text Available Gene expression from bacterial artificial chromosome (BAC clones has been demonstrated to facilitate physiologically relevant levels compared to viral and nonviral cDNA vectors. BACs are large enough to transfer intact genes in their native chromosomal setting together with flanking regulatory elements to provide all the signals for correct spatiotemporal gene expression. Until recently, the use of BACs for functional studies has been limited because their large size has inherently presented a major obstacle for introducing modifications using conventional genetic engineering strategies. The development of in vivo homologous recombination strategies based on recombineering in E. coli has helped resolve this problem by enabling facile engineering of high molecular weight BAC DNA without dependence on suitably placed restriction enzymes or cloning steps. These techniques have considerably expanded the possibilities for studying functional genetics using BACs in vitro and in vivo.

  12. Chromosomes, cancer and radiosensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Samouhos, E.

    1983-08-01

    Some specific chromosomal abnormalities are associated with certain cancers. The earliest description of such a specific association is the one of the Philadelphia chromosome and myelogenous leukemia (1960). Other congenital karyotype abnormalities are associated with specific cancers. Examples of these are Down's syndrome with leukemia and Klinefelter's syndrome with male breast cancer. Genetic diseases of increased chromosome breakage, or of defective chromosome repair, are associated with greatly increased cancer incidence. Three such diseases have been recognized: 1) Fanconi's anemia, associated with leukemias and lymphomas, 2) Bloom's syndrome, associated with acute leukemias and lymphosarcoma, and 3) ataxia telangiectasia, associated with Hodgkin's disease, leukemia, and lymphosarcomas. Ten percent of individuals with ataxia telangiectasia will develop one of these neoplasms. Individuals with certain of these syndromes display an unusually high radiosensitivity. Radiation therapy for cancers has been fatal in patients who received as low as 3000 rad. This remarkable radiosensitivity has been quantitated in cell cultures from such cases. Evidence suggests that the apparent sensitivity may reflect subnormal ability to repair radiation damage. The rapid proliferation of information in this field stems from the interdigitation of many disciplines and specialties, including cytogenetics, cell biology, molecular biology, epidemiology, radiobiology, and several others. This paper is intended for clinicians; it presents a structured analytic scheme for correlating and classifying this multidisciplinary information as it becomes available.

  13. Ring chromosome 13

    DEFF Research Database (Denmark)

    Brandt, C A; Hertz, Jens Michael; Petersen, M B;

    1992-01-01

    A stillborn male child with anencephaly and multiple malformations was found to have the karyotype 46,XY,r(13) (p11q21.1). The breakpoint at 13q21.1, determined by high resolution banding, is the most proximal breakpoint ever reported in patients with ring chromosome 13. In situ hybridisation...

  14. The Y Chromosome

    Science.gov (United States)

    Offner, Susan

    2010-01-01

    The Y chromosome is of great interest to students and can be used to teach about many important biological concepts in addition to sex determination. This paper discusses mutation, recombination, mammalian sex determination, sex determination in general, and the evolution of sex determination in mammals. It includes a student activity that…

  15. Why Chromosome Palindromes?

    Directory of Open Access Journals (Sweden)

    Esther Betrán

    2012-01-01

    Full Text Available We look at sex-limited chromosome (Y or W evolution with particular emphasis on the importance of palindromes. Y chromosome palindromes consist of inverted duplicates that allow for local recombination in an otherwise nonrecombining chromosome. Since palindromes enable intrachromosomal gene conversion that can help eliminate deleterious mutations, they are often highlighted as mechanisms to protect against Y degeneration. However, the adaptive significance of recombination resides in its ability to decouple the evolutionary fates of linked mutations, leading to both a decrease in degeneration rate and an increase in adaptation rate. Our paper emphasizes the latter, that palindromes may exist to accelerate adaptation by increasing the potential targets and fixation rates of incoming beneficial mutations. This hypothesis helps reconcile two enigmatic features of the “palindromes as protectors” view: (1 genes that are not located in palindromes have been retained under purifying selection for tens of millions of years, and (2 under models that only consider deleterious mutations, gene conversion benefits duplicate gene maintenance but not initial fixation. We conclude by looking at ways to test the hypothesis that palindromes enhance the rate of adaptive evolution of Y-linked genes and whether this effect can be extended to palindromes on other chromosomes.

  16. The Y Chromosome

    Science.gov (United States)

    Offner, Susan

    2010-01-01

    The Y chromosome is of great interest to students and can be used to teach about many important biological concepts in addition to sex determination. This paper discusses mutation, recombination, mammalian sex determination, sex determination in general, and the evolution of sex determination in mammals. It includes a student activity that…

  17. Chromosome Variations And Human Behavior

    Science.gov (United States)

    Soudek, D.

    1974-01-01

    Article focused on the science of cytogenetics, which studied the transmission of the units of heredity called chromosomes, and considered the advantage of proper diagnosis of genetic diseases, treated on the chromosomal level. (Author/RK)

  18. [Dicentric Y chromosome].

    Science.gov (United States)

    Abdelmoula, N Bouayed; Amouri, A

    2005-01-01

    Dicentric Y chromosomes are the most common Y structural abnormalities and their influence on gonadal and somatic development is extremely variable. Here, we report the third comprehensive review of the literature concerning dicentric Y chromosomes reported since 1994. We find 78 new cases for which molecular studies (PCR or FISH) have been widely applied to investigate SRY (68% of cases), GBY, ZFY, RFS4Y, GCY and different genes at AZF region. For dic(Yq), all cases (n = 20) were mosaic for 45,X and 4 of them were also mosaic for a 46,XY cell line. When breakpoints were available (15/20 cases), they were in Yp11. 50% of cases were phenotypic female and 20% phenotypic male while 20% of cases were reported with gonadal dysgenesis. Gonadal histology was defined in 8 cases but only in one case, gonadal tissu was genetically investigated because of gonadoblastoma. For dic(Yp) (n = 55), mosaicism concerned only 45,X cell line and was found in 50 cases while the remainder five cases were homogeneous. When breakpoints were available, it was at Yq11 in 50 cases and at Yq12 in two cases. 54% of cases were phenotypic female, 26% were phenotypic male and 18% were associated with genitalia ambiguous. SRY was analyzed in 33 cases, sequenced in 9 cases and was muted in only one case. Gonads were histologically explored in 34 cases and genetically investigated in 8 cases. Gonadoblastoma was found in only two cases. Through this review, it seems that phenotype-genotype correlations are still not possible and that homogeneous studies of dic(Y) in more patients using molecular tools for structural characterization of the rearranged Y chromosome and assessment of mosaicism in many organs are necessary to clarify the basis of the phenotypic heterogeneity of dicentric Y chromosomes and then to help phenotypic prediction of such chromosome rearrangement.

  19. Telomere dysfunction and chromosome instability

    Energy Technology Data Exchange (ETDEWEB)

    Murnane, John P., E-mail: jmurnane@radonc.ucsf.edu [Department of Radiation Oncology, University of California San Francisco, 2340 Sutter Street, San Francisco, CA 94143-1331 (United States)

    2012-02-01

    The ends of chromosomes are composed of a short repeat sequence and associated proteins that together form a cap, called a telomere, that keeps the ends from appearing as double-strand breaks (DSBs) and prevents chromosome fusion. The loss of telomeric repeat sequences or deficiencies in telomeric proteins can result in chromosome fusion and lead to chromosome instability. The similarity between chromosome rearrangements resulting from telomere loss and those found in cancer cells implicates telomere loss as an important mechanism for the chromosome instability contributing to human cancer. Telomere loss in cancer cells can occur through gradual shortening due to insufficient telomerase, the protein that maintains telomeres. However, cancer cells often have a high rate of spontaneous telomere loss despite the expression of telomerase, which has been proposed to result from a combination of oncogene-mediated replication stress and a deficiency in DSB repair in telomeric regions. Chromosome fusion in mammalian cells primarily involves nonhomologous end joining (NHEJ), which is the major form of DSB repair. Chromosome fusion initiates chromosome instability involving breakage-fusion-bridge (B/F/B) cycles, in which dicentric chromosomes form bridges and break as the cell attempts to divide, repeating the process in subsequent cell cycles. Fusion between sister chromatids results in large inverted repeats on the end of the chromosome, which amplify further following additional B/F/B cycles. B/F/B cycles continue until the chromosome acquires a new telomere, most often by translocation of the end of another chromosome. The instability is not confined to a chromosome that loses its telomere, because the instability is transferred to the chromosome donating a translocation. Moreover, the amplified regions are unstable and form extrachromosomal DNA that can reintegrate at new locations. Knowledge concerning the factors promoting telomere loss and its consequences is

  20. Fourth international workshop on human chromosome 5. Final progress report

    Energy Technology Data Exchange (ETDEWEB)

    McPherson, J.D.

    1996-12-31

    The Fourth International Workshop on Human Chromosome 5 was held in Manchester, UK on November 9--10, 1996 and was hosted by the University of Manchester. The major goals of the workshop were: (1) to collate the various genetic, cytogenetic and physical maps of human chromosome 5; (2) to integrate these maps and identify/correct discrepancies between them wherever possible; (3) to catalogue the sequence-ready contigs of the chromosome; (4) to co-ordinate the various sequencing efforts to avoid future duplication; (5) to establish the first (to the author`s knowledge) web site for the human chromosome 5 community which contains the above information in a readily accessible form.

  1. Dynamical scenarios for chromosome bi-orientation.

    Science.gov (United States)

    Zhang, Tongli; Oliveira, Raquel A; Schmierer, Bernhard; Novák, Béla

    2013-06-18

    Chromosome bi-orientation at the metaphase spindle is essential for precise segregation of the genetic material. The process is error-prone, and error-correction mechanisms exist to switch misaligned chromosomes to the correct, bi-oriented configuration. Here, we analyze several possible dynamical scenarios to explore how cells might achieve correct bi-orientation in an efficient and robust manner. We first illustrate that tension-mediated feedback between the sister kinetochores can give rise to a bistable switch, which allows robust distinction between a loose attachment with low tension and a strong attachment with high tension. However, this mechanism has difficulties in explaining how bi-orientation is initiated starting from unattached kinetochores. We propose four possible mechanisms to overcome this problem (exploiting molecular noise; allowing an efficient attachment of kinetochores already in the absence of tension; a trial-and-error oscillation; and a stochastic bistable switch), and assess their impact on the bi-orientation process. Based on our results and supported by experimental data, we put forward a trial-and-error oscillation and a stochastic bistable switch as two elegant mechanisms with the potential to promote bi-orientation both efficiently and robustly.

  2. Dynamics of X Chromosome Inactivation

    NARCIS (Netherlands)

    F. Loos (Friedemann)

    2015-01-01

    markdownabstract__Abstract__ Dosage compensation evolved to account for the difference in expression of sex chromosome-linked genes. In mammals dosage compensation is achieved by inactivation of one X chromosome during early female embryogenesis in a process called X chromosome inactivation (XCI).

  3. Chromosomal evolution of the PKD1 gene family in primates

    Directory of Open Access Journals (Sweden)

    Krawczak Michael

    2009-01-01

    Full Text Available Abstract Correction to Kirsch S, Pasantes J, Wolf A, Bogdanova N, Münch C, Pennekamp P, Krawczak M, Dworniczak B, Schempp W: Chromosomal evolution of the PKD1 gene family in primates. BMC Evolutionary Biology 2008, 8:263 (doi:10.1186/1471-2148-8-263

  4. Chromosomal breakpoints characterization of two supernumerary ring chromosomes 20.

    Science.gov (United States)

    Guediche, N; Brisset, S; Benichou, J-J; Guérin, N; Mabboux, P; Maurin, M-L; Bas, C; Laroudie, M; Picone, O; Goldszmidt, D; Prévot, S; Labrune, P; Tachdjian, G

    2010-02-01

    The occurrence of an additional ring chromosome 20 is a rare chromosome abnormality, and no common phenotype has been yet described. We report on two new patients presenting with a supernumerary ring chromosome 20 both prenatally diagnosed. The first presented with intrauterine growth retardation and some craniofacial dysmorphism, and the second case had a normal phenotype except for obesity. Conventional cytogenetic studies showed for each patient a small supernumerary marker chromosome (SMC). Using fluorescence in situ hybridization, these SMCs corresponded to ring chromosomes 20 including a part of short and long arms of chromosome 20. Detailed molecular cytogenetic characterization showed different breakpoints (20p11.23 and 20q11.23 for Patient 1 and 20p11.21 and 20q11.21 for Patient 2) and sizes of the two ring chromosomes 20 (13.6 Mb for case 1 and 4.8 Mb for case 2). Review of the 13 case reports of an extra r(20) ascertained postnatally (8 cases) and prenatally (5 cases) showed varying degrees of phenotypic abnormalities. We document a detailed molecular cytogenetic chromosomal breakpoints characterization of two cases of supernumerary ring chromosomes 20. These results emphasize the need to characterize precisely chromosomal breakpoints of supernumerary ring chromosomes 20 in order to establish genotype-phenotype correlation. This report may be helpful for prediction of natural history and outcome, particularly in prenatal diagnosis.

  5. Familial complex chromosomal rearrangement resulting in a recombinant chromosome.

    Science.gov (United States)

    Berend, Sue Ann; Bodamer, Olaf A F; Shapira, Stuart K; Shaffer, Lisa G; Bacino, Carlos A

    2002-05-15

    Familial complex chromosomal rearrangements (CCRs) are rare and tend to involve fewer breakpoints and fewer chromosomes than CCRs that are de novo in origin. We report on a CCR identified in a child with congenital heart disease and dysmorphic features. Initially, the child's karyotype was thought to involve a straightforward three-way translocation between chromosomes 3, 8, and 16. However, after analyzing the mother's chromosomes, the mother was found to have a more complex rearrangement that resulted in a recombinant chromosome in the child. The mother's karyotype included an inverted chromosome 2 and multiple translocations involving chromosomes 3, 5, 8, and 16. No evidence of deletion or duplication that could account for the clinical findings in the child was identified.

  6. Chromosome 19 International Workshop

    Energy Technology Data Exchange (ETDEWEB)

    Pericak-Vance, M.A. (Duke Univ., Durham, NC (United States). Medical Center); Ropers, H.H. (Univ. Hospital Nijmegen, (The Netherlands). Dept. of Human Genetics); Carrano, A.J. (Lawrence Livermore National Lab., CA (United States))

    1993-01-04

    The Second International Workshop on Human Chromosome 19 was hosted on January 25 and 26, 1992, by the Department of Human Genetics, University Hospital Nijmegen, The Netherlands, at the 'Meerdal Conference Center'. The workshop was supported by a grant from the European Community obtained through HUGO, the Dutch Research Organization (NWO) and the Muscular Dystrophy Association (MDA). Travel support for American participants was provided by the Department of Energy. The goals of this workshop were to produce genetic, physical and integrated maps of chromosome 19, to identify inconsistencies and gaps, and to discuss and exchange resources and techniques available for the completion of these maps. The second day of the meeting was largely devoted to region or disease specific efforts. In particular, the meeting served as a platform for assessing and discussing the recent progress made into the molecular elucidation of myotonic dystrophy.

  7. Motion of the dayside polar cap boundary during substorm cycles: II. Generation of poleward-moving events and polar cap patches by pulses in the magnetopause reconnection rate

    Directory of Open Access Journals (Sweden)

    M. Lockwood

    2005-12-01

    Full Text Available Using data from the EISCAT (European Incoherent Scatter VHF and CUTLASS (Co-operative UK Twin-Located Auroral Sounding System HF radars, we study the formation of ionospheric polar cap patches and their relationship to the magnetopause reconnection pulses identified in the companion paper by Lockwood et al. (2005. It is shown that the poleward-moving, high-concentration plasma patches observed in the ionosphere by EISCAT on 23 November 1999, as reported by Davies et al. (2002, were often associated with corresponding reconnection rate pulses. However, not all such pulses generated a patch and only within a limited MLT range (11:00-12:00 MLT did a patch result from a reconnection pulse. Three proposed mechanisms for the production of patches, and of the concentration minima that separate them, are analysed and evaluated: (1 concentration enhancement within the patches by cusp/cleft precipitation; (2 plasma depletion in the minima between the patches by fast plasma flows; and (3 intermittent injection of photoionisation-enhanced plasma into the polar cap. We devise a test to distinguish between the effects of these mechanisms. Some of the events repeat too frequently to apply the test. Others have sufficiently long repeat periods and mechanism (3 is shown to be the only explanation of three of the longer-lived patches seen on this day. However, effect (2 also appears to contribute to some events. We conclude that plasma concentration gradients on the edges of the larger patches arise mainly from local time variations in the subauroral plasma, via the mechanism proposed by Lockwood et al. (2000.

  8. Lack of response to unaligned chromosomes in mammalian female gametes.

    Science.gov (United States)

    Sebestova, Jaroslava; Danylevska, Anna; Novakova, Lucia; Kubelka, Michal; Anger, Martin

    2012-08-15

    Chromosome segregation errors are highly frequent in mammalian female meiosis, and their incidence gradually increases with maternal age. The fate of aneuploid eggs is obviously dependent on the stringency of mechanisms for detecting unattached or repairing incorrectly attached kinetochores. In case of their failure, the newly formed embryo will inherit the impaired set of chromosomes, which will have severe consequences for its further development. Whether spindle assembly checkpoint (SAC) in oocytes is capable of arresting cell cycle progression in response to unaligned kinetochores was discussed for a long time. It is known that abolishing SAC increases frequency of chromosome segregation errors and causes precocious entry into anaphase; SAC, therefore, seems to be essential for normal chromosome segregation in meiosis I. However, it was also reported that for anaphase-promoting complex (APC) activation, which is a prerequisite for entering anaphase; alignment of only a critical mass of kinetochores on equatorial plane is sufficient. This indicates that the function of SAC and of cooperating chromosome attachment correction mechanisms in oocytes is different from somatic cells. To analyze this phenomenon, we used live cell confocal microscopy to monitor chromosome movements, spindle formation, APC activation and polar body extrusion (PBE) simultaneously in individual oocytes at various time points during first meiotic division. Our results, using oocytes from aged animals and interspecific crosses, demonstrate that multiple unaligned kinetochores and severe congression defects are tolerated at the metaphase to anaphase transition, although such cells retain sensitivity to nocodazole. This indicates that checkpoint mechanisms, operating in oocytes at this point, are essential for accurate timing of APC activation in meiosis I, but they are insufficient in detection or correction of unaligned chromosomes, preparing thus conditions for propagation of the aneuploidy

  9. Chromosome assortment in Saccharum.

    Science.gov (United States)

    Al-Janabi, S M; Honeycutt, R J; Sobral, B W

    1994-12-01

    Recent work has revealed random chromosome pairing and assortment in Saccharum spontaneum L., the most widely distributed, and morphologically and cytologically variable of the species of Saccharum. This conclusion was based on the analysis of a segregating population from across between S. spontaneum 'SES 208' and a spontaneously-doubled haploid of itself, derived from anther culture. To determine whether polysomic inheritance is common in Saccharum and whether it is observed in a typical biparental cross, we studied chromosome pairing and assortment in 44 progeny of a cross between euploid, meiotically regular, 2n=80 forms of Saccharum officinarum 'LA Purple' and Saccharum robustum ' Mol 5829'. Papuan 2n=80 forms of S. robustum have been suggested as the immediate progenitor species for cultivated sugarcane (S. officinarum). A total of 738 loci in LA Purple and 720 loci in Mol 5829 were amplified and typed in the progeny by arbitrarily primed PCR using 45 primers. Fifty and 33 single-dose polymorphisms were identified in the S. officinarum and S. robustum genomes, respectively (χ 2 at 98%). Linkage analysis of single-dose polymorphisms in both genomes revealed linkages in repulsion and coupling phases. In the S. officinarum genome, a map hypothesis gave 7 linkage groups with 17 linked and 33 unlinked markers. Four of 13 pairwise linkages were in repulsion phase and 9 were in coupling phase. In the S. robustum genome, a map hypothesis gave 5 linkage groups, defined by 12 markers, with 21 markers unlinked, and 2 of 9 pairwise linkages were in repulsion phase. Therefore, complete polysomic inheritance was not observed in either species, suggesting that chromosomal behavior is different from that observed by linkage analysis of over 500 markers in the S. spontaneum map. Implications of this finding for evolution and breeding are discussed.

  10. Intraspecific chromosome variability

    Directory of Open Access Journals (Sweden)

    N Dubinin

    2010-12-01

    Full Text Available (Editorial preface. The publication is presented in order to remind us of one of dramatic pages of the history of genetics. It re-opens for the contemporary reader a comprehensive work marking the priority change from plant cytogenetics to animal cytogenetics led by wide population studies which were conducted on Drosophila polytene chromosomes. The year of the publication (1937 became the point of irretrievable branching between the directions of Old World and New World genetics connected with the problems of chromosome variability and its significance for the evolution of the species. The famous book of T. Dobzhansky (1937 was published by Columbia University in the US under the title “Genetics and the origin of species”, and in the shadow of this American ‘skybuilding’ all other works grew dim. It is remarkable that both Dobzhansky and Dubinin come to similar conclusions about the role of chromosomes in speciation. This is not surprising given that they both might be considered as representatives of the Russian genetic school, by their birth and education. Interestingly, Dobzhansky had never referred to the full paper of Dubinin et al. (1937, though a previous short communication in Nature (1936 was included together with all former papers on the related subject. In full, the volume of the original publication printed in the Biological Journal in Moscow comprised 47 pages, in that number 41 pages of the Russian text accompanied by 16 Figs, a table and reference list, and, above all, 6 pages of the English summary. This final part in English is now reproduced in the authors’ version with the only addition being the reference list in the originally printed form.

  11. Vibrio chromosome-specific families

    DEFF Research Database (Denmark)

    Lukjancenko, Oksana; Ussery, David

    2014-01-01

    families, 1169 and 153 are uniquely found in chromosomes 1 and 2, respectively. Gene ontology (GO) terms for each of the protein families were determined, and the different sets for each chromosome were compared. A total of 363 different "Molecular Function" GO categories were found for chromosome 1......We have compared chromosome-specific genes in a set of 18 finished Vibrio genomes, and, in addition, also calculated the pan- and core-genomes from a data set of more than 250 draft Vibrio genome sequences. These genomes come from 9 known species and 2 unknown species. Within the finished...

  12. Chromosomal rearrangement interferes with meiotic X chromosome inactivation.

    Science.gov (United States)

    Homolka, David; Ivanek, Robert; Capkova, Jana; Jansa, Petr; Forejt, Jiri

    2007-10-01

    Heterozygosity for certain mouse and human chromosomal rearrangements is characterized by the incomplete meiotic synapsis of rearranged chromosomes, by their colocalization with the XY body in primary spermatocytes, and by male-limited sterility. Previously, we argued that such X-autosomal associations could interfere with meiotic sex chromosome inactivation. Recently, supporting evidence has reported modifications of histones in rearranged chromosomes by a process called the meiotic silencing of unsynapsed chromatin (MSUC). Here, we report on the transcriptional down-regulation of genes within the unsynapsed region of the rearranged mouse chromosome 17, and on the subsequent disturbance of X chromosome inactivation. The partial transcriptional suppression of genes in the unsynapsed chromatin was most prominent prior to the mid-pachytene stage of primary spermatocytes. Later, during the mid-late pachytene, the rearranged autosomes colocalized with the XY body, and the X chromosome failed to undergo proper transcriptional silencing. Our findings provide direct evidence on the MSUC acting at the mRNA level, and implicate that autosomal asynapsis in meiosis may cause male sterility by interfering with meiotic sex chromosome inactivation.

  13. Chromosome Connections: Compelling Clues to Common Ancestry

    Science.gov (United States)

    Flammer, Larry

    2013-01-01

    Students compare banding patterns on hominid chromosomes and see striking evidence of their common ancestry. To test this, human chromosome no. 2 is matched with two shorter chimpanzee chromosomes, leading to the hypothesis that human chromosome 2 resulted from the fusion of the two shorter chromosomes. Students test that hypothesis by looking for…

  14. Corrective Jaw Surgery

    Medline Plus

    Full Text Available ... Corrective Jaw Surgery Corrective Jaw Surgery Orthognathic surgery is performed to correct the misalignment of jaws and ... Implant Surgery Dental Implant Surgery Dental implant surgery is, of course, surgery, and is best performed by ...

  15. Corrective Jaw Surgery

    Medline Plus

    Full Text Available ... and Craniofacial Surgery Cleft Lip/Palate and Craniofacial Surgery A cleft lip may require one or more ... find out more. Corrective Jaw Surgery Corrective Jaw Surgery Orthognathic surgery is performed to correct the misalignment ...

  16. Corrective Jaw Surgery

    Science.gov (United States)

    ... and Craniofacial Surgery Cleft Lip/Palate and Craniofacial Surgery A cleft lip may require one or more ... find out more. Corrective Jaw Surgery Corrective Jaw Surgery Orthognathic surgery is performed to correct the misalignment ...

  17. The relation between the axial complex of meiotic prophase chromosomes and chromosome pairing in a salamander (Plethodon cinereus).

    Science.gov (United States)

    MOSES, M J

    1958-09-25

    An investigation of the structure of meiotic chromosomes from primary spermatocytes of two salamanders, Plethodon cinereus and Desmognathus fusca, has been made using correlated light and electron microscopy. Feulgen squashes were compared with stained sections and these related to adjacent thin sections in the electron microscope. A transition from the familiar cytological preparation to the electron image was thus effected. A linear complex consisting of three parallel strands has been observed with the electron microscope, passing along the central axis of primary spermatocyte chromosomes. The complex is similar to that found in comparable chromosomes from at least a dozen animal species. The structure in Plethodon is described in detail. Synapsis has been positively identified as the stage of meiotic prophase at which the complex occurs. Thus the complex is a part of bivalent chromosomes. It has not been seen in other stages or other divisions and is thus thought to be exclusively of synaptic occurrence. The term synaptinemal complex is suggested for the entire structure. By virtue of the material condensed around it, the complex is also seen in the light microscope where it appears as a fine, densely Feulgen-positive central core along the chromosome. The complex is thus closely associated with DNA, if not at least in part, composed of it. In the stages studied, homologous chromosomes are not always completely paired. The lateral elements of the complex separate and follow the single chromosome axes at these points. The central element disappears and thus may be a phenomenon of pairing. It is concluded that the lateral elements of the synaptinemal complex may more correctly be a "core" of the single meiotic prophase chromosome, possibly being concerned with its linear organization.

  18. A stochastic model of kinetochore-microtubule attachment accurately describes fission yeast chromosome segregation.

    Science.gov (United States)

    Gay, Guillaume; Courtheoux, Thibault; Reyes, Céline; Tournier, Sylvie; Gachet, Yannick

    2012-03-19

    In fission yeast, erroneous attachments of spindle microtubules to kinetochores are frequent in early mitosis. Most are corrected before anaphase onset by a mechanism involving the protein kinase Aurora B, which destabilizes kinetochore microtubules (ktMTs) in the absence of tension between sister chromatids. In this paper, we describe a minimal mathematical model of fission yeast chromosome segregation based on the stochastic attachment and detachment of ktMTs. The model accurately reproduces the timing of correct chromosome biorientation and segregation seen in fission yeast. Prevention of attachment defects requires both appropriate kinetochore orientation and an Aurora B-like activity. The model also reproduces abnormal chromosome segregation behavior (caused by, for example, inhibition of Aurora B). It predicts that, in metaphase, merotelic attachment is prevented by a kinetochore orientation effect and corrected by an Aurora B-like activity, whereas in anaphase, it is corrected through unbalanced forces applied to the kinetochore. These unbalanced forces are sufficient to prevent aneuploidy.

  19. Cohesin in determining chromosome architecture

    Energy Technology Data Exchange (ETDEWEB)

    Haering, Christian H., E-mail: christian.haering@embl.de [Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Heidelberg (Germany); Jessberger, Rolf, E-mail: rolf.jessberger@tu-dresden.de [Institute of Physiological Chemistry, Dresden University of Technology, Dresden (Germany)

    2012-07-15

    Cells use ring-like structured protein complexes for various tasks in DNA dynamics. The tripartite cohesin ring is particularly suited to determine chromosome architecture, for it is large and dynamic, may acquire different forms, and is involved in several distinct nuclear processes. This review focuses on cohesin's role in structuring chromosomes during mitotic and meiotic cell divisions and during interphase.

  20. Resolution of Multimeric Forms of Circular Plasmids and Chromosomes.

    Science.gov (United States)

    Crozat, Estelle; Fournes, Florian; Cornet, François; Hallet, Bernard; Rousseau, Philippe

    2014-10-01

    One of the disadvantages of circular plasmids and chromosomes is their high sensitivity to rearrangements caused by homologous recombination. Odd numbers of crossing-over occurring during or after replication of a circular replicon result in the formation of a dimeric molecule in which the two copies of the replicon are fused. If they are not converted back to monomers, the dimers of replicons may fail to correctly segregate at the time of cell division. Resolution of multimeric forms of circular plasmids and chromosomes is mediated by site-specific recombination, and the enzymes that catalyze this type of reaction fall into two families of proteins: the serine and tyrosine recombinase families. Here we give an overview of the variety of site-specific resolution systems found on circular plasmids and chromosomes.

  1. Chromosome choreography: the meiotic ballet.

    Science.gov (United States)

    Page, Scott L; Hawley, R Scott

    2003-08-08

    The separation of homologous chromosomes during meiosis in eukaryotes is the physical basis of Mendelian inheritance. The core of the meiotic process is a specialized nuclear division (meiosis I) in which homologs pair with each other, recombine, and then segregate from each other. The processes of chromosome alignment and pairing allow for homolog recognition. Reciprocal meiotic recombination ensures meiotic chromosome segregation by converting sister chromatid cohesion into mechanisms that hold homologous chromosomes together. Finally, the ability of sister kinetochores to orient to a single pole at metaphase I allows the separation of homologs to two different daughter cells. Failures to properly accomplish this elegant chromosome dance result in aneuploidy, a major cause of miscarriage and birth defects in human beings.

  2. Bacterial chromosome organization and segregation.

    Science.gov (United States)

    Badrinarayanan, Anjana; Le, Tung B K; Laub, Michael T

    2015-01-01

    If fully stretched out, a typical bacterial chromosome would be nearly 1 mm long, approximately 1,000 times the length of a cell. Not only must cells massively compact their genetic material, but they must also organize their DNA in a manner that is compatible with a range of cellular processes, including DNA replication, DNA repair, homologous recombination, and horizontal gene transfer. Recent work, driven in part by technological advances, has begun to reveal the general principles of chromosome organization in bacteria. Here, drawing on studies of many different organisms, we review the emerging picture of how bacterial chromosomes are structured at multiple length scales, highlighting the functions of various DNA-binding proteins and the impact of physical forces. Additionally, we discuss the spatial dynamics of chromosomes, particularly during their segregation to daughter cells. Although there has been tremendous progress, we also highlight gaps that remain in understanding chromosome organization and segregation.

  3. Schizophrenia and chromosomal deletions

    Energy Technology Data Exchange (ETDEWEB)

    Lindsay, E.A.; Baldini, A. [Baylor College of Medicine, Houston, TX (United States); Morris, M. A. [Univ. of Geneva School of Medicine, NY (United States)] [and others

    1995-06-01

    Recent genetic linkage analysis studies have suggested the presence of a schizophrenia locus on the chromosomal region 22q11-q13. Schizophrenia has also been frequently observed in patients affected with velo-cardio-facial syndrome (VCFS), a disorder frequently associated with deletions within 22q11.1. It has been hypothesized that psychosis in VCFS may be due to deletion of the catechol-o-methyl transferase gene. Prompted by these observations, we screened for 22q11 deletions in a population of 100 schizophrenics selected from the Maryland Epidemiological Sample. Our results show that there are schizophrenic patients carrying a deletion of 22q11.1 and a mild VCFS phenotype that might remain unrecognized. These findings should encourage a search for a schizophrenia-susceptibility gene within the deleted region and alert those in clinical practice to the possible presence of a mild VCFS phenotype associated with schizophrenia. 9 refs.

  4. Genetics Home Reference: Y chromosome infertility

    Science.gov (United States)

    ... Home Health Conditions Y chromosome infertility Y chromosome infertility Enable Javascript to view the expand/collapse boxes. ... PDF Open All Close All Description Y chromosome infertility is a condition that affects the production of ...

  5. The chromosomal passenger complex activates Polo kinase at centromeres.

    Directory of Open Access Journals (Sweden)

    Mar Carmena

    2012-01-01

    Full Text Available The coordinated activities at centromeres of two key cell cycle kinases, Polo and Aurora B, are critical for ensuring that the two sister kinetochores of each chromosome are attached to microtubules from opposite spindle poles prior to chromosome segregation at anaphase. Initial attachments of chromosomes to the spindle involve random interactions between kinetochores and dynamic microtubules, and errors occur frequently during early stages of the process. The balance between microtubule binding and error correction (e.g., release of bound microtubules requires the activities of Polo and Aurora B kinases, with Polo promoting stable attachments and Aurora B promoting detachment. Our study concerns the coordination of the activities of these two kinases in vivo. We show that INCENP, a key scaffolding subunit of the chromosomal passenger complex (CPC, which consists of Aurora B kinase, INCENP, Survivin, and Borealin/Dasra B, also interacts with Polo kinase in Drosophila cells. It was known that Aurora A/Bora activates Polo at centrosomes during late G2. However, the kinase that activates Polo on chromosomes for its critical functions at kinetochores was not known. We show here that Aurora B kinase phosphorylates Polo on its activation loop at the centromere in early mitosis. This phosphorylation requires both INCENP and Aurora B activity (but not Aurora A activity and is critical for Polo function at kinetochores. Our results demonstrate clearly that Polo kinase is regulated differently at centrosomes and centromeres and suggest that INCENP acts as a platform for kinase crosstalk at the centromere. This crosstalk may enable Polo and Aurora B to achieve a balance wherein microtubule mis-attachments are corrected, but proper attachments are stabilized allowing proper chromosome segregation.

  6. The chromosomal passenger complex activates Polo kinase at centromeres.

    Science.gov (United States)

    Carmena, Mar; Pinson, Xavier; Platani, Melpi; Salloum, Zeina; Xu, Zhenjie; Clark, Anthony; Macisaac, Fiona; Ogawa, Hiromi; Eggert, Ulrike; Glover, David M; Archambault, Vincent; Earnshaw, William C

    2012-01-01

    The coordinated activities at centromeres of two key cell cycle kinases, Polo and Aurora B, are critical for ensuring that the two sister kinetochores of each chromosome are attached to microtubules from opposite spindle poles prior to chromosome segregation at anaphase. Initial attachments of chromosomes to the spindle involve random interactions between kinetochores and dynamic microtubules, and errors occur frequently during early stages of the process. The balance between microtubule binding and error correction (e.g., release of bound microtubules) requires the activities of Polo and Aurora B kinases, with Polo promoting stable attachments and Aurora B promoting detachment. Our study concerns the coordination of the activities of these two kinases in vivo. We show that INCENP, a key scaffolding subunit of the chromosomal passenger complex (CPC), which consists of Aurora B kinase, INCENP, Survivin, and Borealin/Dasra B, also interacts with Polo kinase in Drosophila cells. It was known that Aurora A/Bora activates Polo at centrosomes during late G2. However, the kinase that activates Polo on chromosomes for its critical functions at kinetochores was not known. We show here that Aurora B kinase phosphorylates Polo on its activation loop at the centromere in early mitosis. This phosphorylation requires both INCENP and Aurora B activity (but not Aurora A activity) and is critical for Polo function at kinetochores. Our results demonstrate clearly that Polo kinase is regulated differently at centrosomes and centromeres and suggest that INCENP acts as a platform for kinase crosstalk at the centromere. This crosstalk may enable Polo and Aurora B to achieve a balance wherein microtubule mis-attachments are corrected, but proper attachments are stabilized allowing proper chromosome segregation.

  7. Genes and chromosomes: control of development

    Directory of Open Access Journals (Sweden)

    Oleg Serov

    2004-09-01

    Full Text Available The past decade has witnessed immense progress in research into the molecular basis behind the developmental regulation of genes. Sets of genes functioning under hierarchical control have been identified, evolutionary conserved systems of genes effecting the cell-to-cell transmission of transmembrane signals and assigned a central role in morphogenesis have been intensively studied; the concept of genomic regulatory networks coordinating expression of many genes has been introduced, to mention some of the major breakthroughs. It should be noted that the temporal and tissue-specific parameters of gene expression are correctly regulated in development only in the context of the chromosome and that they are to a great extent dependent on the position of the gene on the chromosome or the interphase nucleus. Moreover epigenetic inheritance of the gene states through successive cell generations has been conducted exclusively at the chromosome level by virtue of cell or chromosome memory. The ontogenetic memory is an inherent property of the chromosome and cis-regulation has a crucial role in its maintenance.Durante a última década houve imenso progresso na pesquisa sobre as bases moleculares da regulação gênica durante o desenvolvimento. Foram identificados grupos de genes funcionando sob controle hierárquico, sistemas de genes conservados ao longo da evolução atuando na transmissão célula a célula de sinais transmembrana e com uma função central na morfogênese foram intensamente estudados e o conceito de redes genômicas regulatórias coordenando a expressão de diversos genes foi introduzido, para citar apenas alguns dos principais avanços. Deve-se notar que os parâmetros tempo e tecido-específicos da expressão gênica são corretamente regulados durante o desenvolvimento apenas no contexto do cromossomo e que são amplamente dependentes da posição do gene no cromossomo ou no núcleo em interfase. Além do mais, a herança epigen

  8. Mitotic chromosome condensation in vertebrates

    Energy Technology Data Exchange (ETDEWEB)

    Vagnarelli, Paola, E-mail: P.Vagnarelli@ed.ac.uk

    2012-07-15

    Work from several laboratories over the past 10-15 years has revealed that, within the interphase nucleus, chromosomes are organized into spatially distinct territories [T. Cremer, C. Cremer, Chromosome territories, nuclear architecture and gene regulation in mammalian cells, Nat. Rev. Genet. 2 (2001) 292-301 and T. Cremer, M. Cremer, S. Dietzel, S. Muller, I. Solovei, S. Fakan, Chromosome territories-a functional nuclear landscape, Curr. Opin. Cell Biol. 18 (2006) 307-316]. The overall compaction level and intranuclear location varies as a function of gene density for both entire chromosomes [J.A. Croft, J.M. Bridger, S. Boyle, P. Perry, P. Teague,W.A. Bickmore, Differences in the localization and morphology of chromosomes in the human nucleus, J. Cell Biol. 145 (1999) 1119-1131] and specific chromosomal regions [N.L. Mahy, P.E. Perry, S. Gilchrist, R.A. Baldock, W.A. Bickmore, Spatial organization of active and inactive genes and noncoding DNA within chromosome territories, J. Cell Biol. 157 (2002) 579-589] (Fig. 1A, A'). In prophase, when cyclin B activity reaches a high threshold, chromosome condensation occurs followed by Nuclear Envelope Breakdown (NEB) [1]. At this point vertebrate chromosomes appear as compact structures harboring an attachment point for the spindle microtubules physically recognizable as a primary constriction where the two sister chromatids are held together. The transition from an unshaped interphase chromosome to the highly structured mitotic chromosome (compare Figs. 1A and B) has fascinated researchers for several decades now; however a definite picture of how this process is achieved and regulated is not yet in our hands and it will require more investigation to comprehend the complete process. From a biochemical point of view a vertebrate mitotic chromosomes is composed of DNA, histone proteins (60%) and non-histone proteins (40%) [6]. I will discuss below what is known to date on the contribution of these two different classes

  9. Chromatid Painting for Chromosomal Inversion Detection Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose the continued development of a novel approach to the detection of chromosomal inversions. Transmissible chromosome aberrations (translocations and...

  10. Chromatid Painting for Chromosomal Inversion Detection Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose a novel approach to the detection of chromosomal inversions. Transmissible chromosome aberrations (translocations and inversions) have profound genetic...

  11. CHROMOSOMAL MAPPING IN STRAINS OF STAPHYLOCOCCUS AUREUS,

    Science.gov (United States)

    STAPHYLOCOCCUS AUREUS , CHROMOSOMES), (*CHROMOSOMES, MAPPING), NITROSO COMPOUNDS, GUANIDINES, GENETICS, MUTATIONS, DRUGS, TOLERANCES(PHYSIOLOGY), TEST METHODS, DEOXYRIBONUCLEIC ACIDS, INHIBITION, RESISTANCE(BIOLOGY).

  12. pain2: A neuropathic pain QTL identified on rat chromosome 2.

    Science.gov (United States)

    Nissenbaum, Jonathan; Shpigler, Hagai; Pisanté, Anne; DelCanho, Sonia; Minert, Anne; Seltzer, Ze'ev; Devor, Marshall; Darvasi, Ariel

    2008-03-01

    We aimed to locate a chronic pain-associated QTL in the rat (Rattus norvegicus) based on previous findings of a QTL (pain1) on chromosome 15 of the mouse (Mus musculus). The work was based on rat selection lines HA (high autotomy) and LA (low autotomy) which show a contrasting pain phenotype in response to nerve injury in the neuroma model of neuropathic pain. An F(2) segregating population was generated from HA and LA animals. Phenotyped F(2) rats were genotyped on chromosome 7 and chromosome 2, regions that share a partial homology with mouse chromosome 15. Our interval mapping analysis revealed a LOD score value of 3.63 (corresponding to p=0.005 after correcting for multiple testing using permutations) on rat chromosome 2, which is suggestive of the presence of a QTL affecting the predisposition to neuropathic pain. This QTL was mapped to the 14-26cM interval of chromosome 2. Interestingly, this region is syntenic to mouse chromosome 13, rather than to the region of mouse chromosome 15 that contains pain1. This chromosomal position indicates that it is possibly a new QTL, and hence we name it pain2. Further work is needed to replicate and to uncover the underlying gene(s) in both species.

  13. Gametocidal chromosomes enhancing chromosome aberration in common wheat induced by 5-azacytidine.

    Science.gov (United States)

    Su, W-Y; Cong, W-W; Shu, Y-J; Wang, D; Xu, G-H; Guo, C-H

    2013-07-08

    The gametocidal (Gc) chromosome from Aegilops spp induces chromosome mutation, which is introduced into common wheat as a tool of chromosome manipulation for genetic improvement. The Gc chromosome functions similar to a restriction-modification system in bacteria, in which DNA methylation is an important regulator. We treated root tips of wheat carrying Gc chromosomes with the hypomethylation agent 5-azacytidine; chromosome breakage and micronuclei were observed in these root tips. The frequency of aberrations differed in wheat containing different Gc chromosomes, suggesting different functions inducing chromosome breakage. Gc chromosome 3C caused the greatest degree of chromosome aberration, while Gc chromosome 3C(SAT) and 2C caused only slight chromosome aberration. Gc chromosome 3C induced different degrees of chromosome aberration in wheat varieties Triticum aestivum var. Chinese Spring and Norin 26, demonstrating an inhibition function in common wheat.

  14. Chromosome segregation in Vibrio cholerae.

    Science.gov (United States)

    Ramachandran, Revathy; Jha, Jyoti; Chattoraj, Dhruba K

    2014-01-01

    The study of chromosome segregation is currently one of the most exciting research frontiers in cell biology. In this review, we discuss our current knowledge of the chromosome segregation process in Vibrio cholerae, based primarily on findings from fluorescence microscopy experiments. This bacterium is of special interest because of its eukaryotic feature of having a divided genome, a feature shared with 10% of known bacteria. We also discuss how the segregation mechanisms of V. cholerae compare with those in other bacteria, and highlight some of the remaining questions regarding the process of bacterial chromosome segregation.

  15. Numerous transitions of sex chromosomes in Diptera.

    Science.gov (United States)

    Vicoso, Beatriz; Bachtrog, Doris

    2015-04-01

    Many species groups, including mammals and many insects, determine sex using heteromorphic sex chromosomes. Diptera flies, which include the model Drosophila melanogaster, generally have XY sex chromosomes and a conserved karyotype consisting of six chromosomal arms (five large rods and a small dot), but superficially similar karyotypes may conceal the true extent of sex chromosome variation. Here, we use whole-genome analysis in 37 fly species belonging to 22 different families of Diptera and uncover tremendous hidden diversity in sex chromosome karyotypes among flies. We identify over a dozen different sex chromosome configurations, and the small dot chromosome is repeatedly used as the sex chromosome, which presumably reflects the ancestral karyotype of higher Diptera. However, we identify species with undifferentiated sex chromosomes, others in which a different chromosome replaced the dot as a sex chromosome or in which up to three chromosomal elements became incorporated into the sex chromosomes, and others yet with female heterogamety (ZW sex chromosomes). Transcriptome analysis shows that dosage compensation has evolved multiple times in flies, consistently through up-regulation of the single X in males. However, X chromosomes generally show a deficiency of genes with male-biased expression, possibly reflecting sex-specific selective pressures. These species thus provide a rich resource to study sex chromosome biology in a comparative manner and show that similar selective forces have shaped the unique evolution of sex chromosomes in diverse fly taxa.

  16. Numerous transitions of sex chromosomes in Diptera.

    Directory of Open Access Journals (Sweden)

    Beatriz Vicoso

    2015-04-01

    Full Text Available Many species groups, including mammals and many insects, determine sex using heteromorphic sex chromosomes. Diptera flies, which include the model Drosophila melanogaster, generally have XY sex chromosomes and a conserved karyotype consisting of six chromosomal arms (five large rods and a small dot, but superficially similar karyotypes may conceal the true extent of sex chromosome variation. Here, we use whole-genome analysis in 37 fly species belonging to 22 different families of Diptera and uncover tremendous hidden diversity in sex chromosome karyotypes among flies. We identify over a dozen different sex chromosome configurations, and the small dot chromosome is repeatedly used as the sex chromosome, which presumably reflects the ancestral karyotype of higher Diptera. However, we identify species with undifferentiated sex chromosomes, others in which a different chromosome replaced the dot as a sex chromosome or in which up to three chromosomal elements became incorporated into the sex chromosomes, and others yet with female heterogamety (ZW sex chromosomes. Transcriptome analysis shows that dosage compensation has evolved multiple times in flies, consistently through up-regulation of the single X in males. However, X chromosomes generally show a deficiency of genes with male-biased expression, possibly reflecting sex-specific selective pressures. These species thus provide a rich resource to study sex chromosome biology in a comparative manner and show that similar selective forces have shaped the unique evolution of sex chromosomes in diverse fly taxa.

  17. Chromosome fragility in Freemartin cattle

    Directory of Open Access Journals (Sweden)

    V. Barbieri

    2010-04-01

    Full Text Available The aim of the present study was to verify chromosome fragility in freemartin cattle using chromosome aberration (CA and sister chromatid exchange (SCE tests. A total of eighteen co-twins were investigated. Fourteen animals were identified as cytogenetically chimeric (2n=60, XX/XY while 4 were classified as normal. Freemartin cattle showed a higher percentage of aneuploid cells (18.64% and highly significant statistical differences (P < 0.001 in mean values of gaps (4.53 ± 2.05, chromatid breaks (0.26 ± 0.51, and significant statistical differences (P < 0.005 in mean values of chromosome breaks (0.12 ± 0.43 when compared to 10 control animals from single births (aneuploid cells, 11.20%; gaps, 2.01 ± 1.42; chromatid breaks, 0.05 ± 0.22; chromosome breaks, 0.02 ± 0.14.

  18. Chromosome Segregation in Vibrio cholerae

    OpenAIRE

    Ramachandran, R.; Jha, J.; Chattoraj, DK

    2014-01-01

    The study of chromosome segregation is currently one of the most exciting research frontiers in cell biology. In this review, we discuss our current knowledge of the chromosome segregation process in Vibrio cholerae, based primarily on findings from fluorescence microscopy experiments. This bacterium is of special interest because of its eukaryotic feature of having a divided genome, a feature shared with 10% of known bacteria. We also discuss how the segregation mechanisms of V. cholerae com...

  19. B chromosomes and sex in animals.

    Science.gov (United States)

    Camacho, J P M; Schmid, M; Cabrero, J

    2011-01-01

    Supernumerary (B) chromosomes are dispensable elements found in many eukaryote genomes in addition to standard (A) chromosomes. In many respects, B chromosomes resemble sex chromosomes, so that a common ancestry for them has frequently been suggested. For instance, B chromosomes in grasshoppers, and other insects, show a pycnotic cycle of condensation-decondensation during meiosis remarkably similar to that of the X chromosome. In some cases, B chromosome size is even very similar to that of the X chromosome. These resemblances have led to suggest the X as the B ancestor in many cases. In addition, sex chromosome origin from B chromosomes has also been suggested. In this article, we review the existing evidence for both evolutionary pathways, as well as sex differences for B frequency at adult and embryo progeny levels, B chromosome effects or B chromosome transmission. In addition, we review cases found in the literature showing sex-ratio distortion associated with B chromosome presence, the most extreme case being the paternal sex ratio (PSR) chromosomes in some Hymenoptera. We finally analyse the possibility of B chromosome regularisation within the host genome and, as a consequence of it, whether B chromosomes can become regular members of the host genome.

  20. Origin and domestication of papaya Yh chromosome

    Science.gov (United States)

    Sex in papaya is controlled by a pair of nascent sex chromosomes. Females are XX, and two slightly different Y chromosomes distinguish males (XY) and hermaphrodites (XYh). The hermaphrodite-specific region of the Yh chromosome (HSY) and its X chromosome counterpart were sequenced and analyzed previo...

  1. Centromeric Non-coding Transcription: Opening the Black Box of Chromosomal Instability?

    Science.gov (United States)

    Cáceres-Gutiérrez, Rodrigo; Herrera, Luis A

    2017-06-01

    In eukaryotes, mitosis is tightly regulated to avoid the generation of numerical chromosome aberrations, or aneuploidies. The aneuploid phenotype is a consequence of chromosomal instability (CIN), i.e., an enhanced rate of chromosome segregation errors, which is frequently found in cancer cells and is associated with tumor aggressiveness and increased tumor cell survival potential. To avoid the generation of aneuploidies, cells rely on the spindle assembly checkpoint (SAC), a widely conserved mechanism that protects the genome against this type of error. This signaling pathway stops mitotic pro-gression before anaphase until all chromosomes are correctly attached to spindle microtubules. Howev-er, impairment of the SAC cannot account for the establishment of CIN because cells bearing this phe-notype have a functional SAC. Hence, in cells with CIN, anaphase is not triggered until all chromo-somes are correctly attached to spindle microtubules and congressed at the metaphase plate. Thus, an in-teresting question arises: What mechanisms actually mediate CIN in cancer cells? Recent research has shown that some pathways involved in chromosome segregation are closely associated to centromere-encoded non-coding RNA (cencRNA) and that these RNAs are deregulated in abnormal conditions, such as cancer. These mechanisms may provide new explanations for chromosome segregation errors. The present review discusses some of these findings and proposes novel mechanisms for the establish-ment of CIN based on regulation by cencRNA.

  2. Numerically abnormal chromosome constitutions in humans

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1993-12-31

    Chapter 24, discusses numerically abnormal chromosome constitutions in humans. This involves abnormalities of human chromosome number, including polyploidy (when the number of sets of chromosomes increases) and aneuploidy (when the number of individual normal chromosomes changes). Chapter sections discuss the following chromosomal abnormalities: human triploids, imprinting and uniparental disomy, human tetraploids, hydatidiform moles, anomalies caused by chromosomal imbalance, 13 trisomy (D{sub 1} trisomy, Patau syndrome), 21 trisomy (Down syndrome), 18 trisomy syndrome (Edwards syndrome), other autosomal aneuploidy syndromes, and spontaneous abortions. The chapter concludes with remarks on the nonrandom participation of chromosomes in trisomy. 69 refs., 3 figs., 4 tabs.

  3. NWS Corrections to Observations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Form B-14 is the National Weather Service form entitled 'Notice of Corrections to Weather Records.' The forms are used to make corrections to observations on forms...

  4. Flow karyotyping and sorting of human chromosomes

    Energy Technology Data Exchange (ETDEWEB)

    Gray, J.W.; Lucas, J.; Peters, D.; Pinkel, D.; Trask, B.; van den Engh, G.; Van Dilla, M.A.

    1986-07-16

    Flow cytometry and sorting are becoming increasingly useful as tools for chromosome classfication and for the detection of numerical and structural chromosome aberrations. Chromosomes of a single type can be purified with these tools to facilitate gene mapping or production of chromosome specific recombinant DNA libraries. For analysis of chromosomes with flow cytometry, the chromosomes are extracted from mitotic cells, stained with one or more fluorescent dyes and classified one-by-one according to their dye content(s). Thus, the flow approach is fundamentally different than conventional karyotyping where chromosomes are classified within the context of a metaphase spread. Flow sorting allows purification of chromosomes that can be distinguished flow cytometrically. The authors describe the basic principles of flow cytometric chromosome classification i.e. flow karyotyping, and chromosome sorting and describe several applications. 30 refs., 8 figs.

  5. Error Correction in Classroom

    Institute of Scientific and Technical Information of China (English)

    Dr. Grace Zhang

    2000-01-01

    Error correction is an important issue in foreign language acquisition. This paper investigates how students feel about the way in which error correction should take place in a Chinese-as-a foreign-language classroom, based on empirical data of a large scale. The study shows that there is a general consensus that error correction is necessary. In terms of correction strategy, the students preferred a combination of direct and indirect corrections, or a direct only correction. The former choice indicates that students would be happy to take either so long as the correction gets done.Most students didn't mind peer correcting provided it is conducted in a constructive way. More than halfofthe students would feel uncomfortable ifthe same error they make in class is corrected consecutively more than three times. Taking these findings into consideration, we may want to cncourage peer correcting, use a combination of correction strategies (direct only if suitable) and do it in a non-threatening and sensitive way. It is hoped that this study would contribute to the effectiveness of error correction in a Chinese language classroom and it may also have a wider implication on other languages.

  6. Human chromosomes: Structure, behavior, and effects

    Energy Technology Data Exchange (ETDEWEB)

    Therman, E.; Susman, M.

    1993-12-31

    The book `Human Chromosomes: Structure, Behavior, and Effects` covers the most important topics regarding human chromosomes and current research in cytogenetics. Attention is given both to structure and function of autosomes and sex chromosomes, as well as definitions and causes of chromosomal aberrations. This often involves discussion about various aspects of the cell cycle (both mitosis and meiosis). Methods and techniques involved in researching and mapping human chromosomes are also discussed.

  7. Computer simulations predict that chromosome movements and rotations accelerate mitotic spindle assembly without compromising accuracy.

    Science.gov (United States)

    Paul, Raja; Wollman, Roy; Silkworth, William T; Nardi, Isaac K; Cimini, Daniela; Mogilner, Alex

    2009-09-15

    The mitotic spindle self-assembles in prometaphase by a combination of centrosomal pathway, in which dynamically unstable microtubules search in space until chromosomes are captured, and a chromosomal pathway, in which microtubules grow from chromosomes and focus to the spindle poles. Quantitative mechanistic understanding of how spindle assembly can be both fast and accurate is lacking. Specifically, it is unclear how, if at all, chromosome movements and combining the centrosomal and chromosomal pathways affect the assembly speed and accuracy. We used computer simulations and high-resolution microscopy to test plausible pathways of spindle assembly in realistic geometry. Our results suggest that an optimal combination of centrosomal and chromosomal pathways, spatially biased microtubule growth, and chromosome movements and rotations is needed to complete prometaphase in 10-20 min while keeping erroneous merotelic attachments down to a few percent. The simulations also provide kinetic constraints for alternative error correction mechanisms, shed light on the dual role of chromosome arm volume, and compare well with experimental data for bipolar and multipolar HT-29 colorectal cancer cells.

  8. Inherited unbalanced structural chromosome abnormalities at prenatal chromosome analysis are rarely ascertained through recurrent miscarriage

    NARCIS (Netherlands)

    Franssen, M. T. M.; Korevaar, J. C.; Tjoa, W. M.; Leschot, N. J.; Bossuyt, P. M. M.; Knegt, A. C.; Suykerbuyk, R. F.; Hochstenbach, R.; van der Veen, F.; Goddijn, M.

    2008-01-01

    Objective To determine the mode of ascertainment of inherited unbalanced structural chromosome abnormalities detected at prenatal chromosome analysis. Methods From the databases of three centres for clinical genetics in the Netherlands, all cases of inherited unbalanced structural chromosome abnorma

  9. Inherited unbalanced structural chromosome abnormalities at prenatal chromosome analysis are rarely ascertained through recurrent miscarriage

    NARCIS (Netherlands)

    Franssen, M. T. M.; Korevaar, J. C.; Tjoa, W. M.; Leschot, N. J.; Bossuyt, P. M. M.; Knegt, A. C.; Suykerbuyk, R. F.; Hochstenbach, R.; van der Veen, F.; Goddijn, M.

    2008-01-01

    Objective To determine the mode of ascertainment of inherited unbalanced structural chromosome abnormalities detected at prenatal chromosome analysis. Methods From the databases of three centres for clinical genetics in the Netherlands, all cases of inherited unbalanced structural chromosome abnorma

  10. Dean flow fractionation of chromosomes

    Science.gov (United States)

    Hockin, Matt; Sant, Himanshu J.; Capecchi, Mario; Gale, Bruce K.

    2016-03-01

    Efforts to transfer intact mammalian chromosomes between cells have been attempted for more than 50 years with the consistent result being transfer of sub unit length pieces regardless of method. Inertial microfluidics is a new field that has shown much promise in addressing the fractionation of particles in the 2-20 μm size range (with unknown limits) and separations are based upon particles being carried by curving confined flows (within a spiral shaped, often rectangular flow chamber) and migrating to stable "equilibrium" positions of varying distance from a chamber wall depending on the balance of dean and lift forces. We fabricated spiral channels for inertial microfluidic separations using a standard soft lithography process. The concentration of chromosomes, small contaminant DNA and large cell debris in each outlets were evaluated using microscope (60X) and a flow cytometer. Using Dean Flow Fractionation, we were able to focus 4.5 times more chromosomes in outlet 2 compared to outlet 4 where most of the large debris is found. We recover 16% of the chromosomes in outlet #1- 50% in 2, 23% in 3 and 11% in 4. It should be noted that these estimates of recovery do not capture one piece of information- it actually may be that the chromosomes at each outlet are physically different and work needs to be done to verify this potential.

  11. The Reduction of Chromosome Number in Meiosis Is Determined by Properties Built into the Chromosomes

    OpenAIRE

    Paliulis, Leocadia V.; Nicklas, R. Bruce

    2000-01-01

    In meiosis I, two chromatids move to each spindle pole. Then, in meiosis II, the two are distributed, one to each future gamete. This requires that meiosis I chromosomes attach to the spindle differently than meiosis II chromosomes and that they regulate chromosome cohesion differently. We investigated whether the information that dictates the division type of the chromosome comes from the whole cell, the spindle, or the chromosome itself. Also, we determined when chromosomes can switch from ...

  12. Somatic Mosaicism in Cases with Small Supernumerary Marker Chromosomes

    Science.gov (United States)

    Liehr, Thomas; Karamysheva, Tatyana; Merkas, Martina; Brecevic, Lukrecija; Hamid, Ahmed B.; Ewers, Elisabeth; Mrasek, Kristin; Kosyakova, Nadezda; Weise, Anja

    2010-01-01

    Somatic mosaicism is something that is observed in everyday lives of cytogeneticists. Chromosome instability is one of the leading causes of large-scale genome variation analyzable since the correct human chromosome number was established in 1956. Somatic mosaicism is also a well-known fact to be present in cases with small supernumerary marker chromosomes (sSMC), i.e. karyotypes of 47,+mar/46. In this study, the data available in the literature were collected concerning the frequency mosaicism in different subgroups of patients with sSMC. Of 3124 cases with sSMC 1626 (52%) present with somatic mosaicism. Some groups like patients with Emanuel-, cat-eye- or i(18p)- syndrome only tend rarely to develop mosaicism, while in Pallister-Killian syndrome every patient is mosaic. In general, acrocentric and non-acrocentric derived sSMCs are differently susceptible to mosaicism; non-acrocentric derived ones are hereby the less stable ones. Even though, in the overwhelming majority of the cases, somatic mosaicism does not have any detectable clinical effects, there are rare cases with altered clinical outcomes due to mosaicism. This is extremely important for prenatal genetic counseling. Overall, as mosaicism is something to be considered in at least every second sSMC case, array-CGH studies cannot be offered as a screening test to reliably detect this kind of chromosomal aberration, as low level mosaic cases and cryptic mosaics are missed by that. PMID:21358988

  13. VHL loss causes spindle misorientation and chromosome instability.

    Science.gov (United States)

    Thoma, Claudio R; Toso, Alberto; Gutbrodt, Katrin L; Reggi, Sabina P; Frew, Ian J; Schraml, Peter; Hergovich, Alexander; Moch, Holger; Meraldi, Patrick; Krek, Wilhelm

    2009-08-01

    Error-free mitosis depends on fidelity-monitoring checkpoint systems that ensure correct temporal and spatial coordination of chromosome segregation by the microtubule spindle apparatus. Defects in these checkpoint systems can lead to genomic instability, an important aspect of tumorigenesis. Here we show that the von Hippel-Lindau (VHL) tumour suppressor protein, pVHL, which is inactivated in hereditary and sporadic forms of renal cell carcinoma, localizes to the mitotic spindle in mammalian cells and its functional inactivation provokes spindle misorientation, spindle checkpoint weakening and chromosomal instability. Spindle misorientation is linked to unstable astral microtubules and is supressed by the restoration of wild-type pVHL in pVHL-deficient cells, but not in naturally-occurring VHL disease mutants that are defective in microtubule stabilization. Impaired spindle checkpoint function and chromosomal instability are the result of reduced Mad2 (mitotic arrest deficient 2) levels actuated by pVHL-inactivation and are rescued by re-expression of either Mad2 or pVHL in VHL-defective cells. An association between VHL inactivation, reduced Mad2 levels and increased aneuploidy was also found in human renal cancer, implying that the newly identified functions of pVHL in promoting proper spindle orientation and chromosomal stability probably contribute to tumour suppression.

  14. Diophantine Correct Open Induction

    CERN Document Server

    Raffer, Sidney

    2010-01-01

    We give an induction-free axiom system for diophantine correct open induction. We relate the problem of whether a finitely generated ring of Puiseux polynomials is diophantine correct to a problem about the value-distribution of a tuple of semialgebraic functions with integer arguments. We use this result, and a theorem of Bergelson and Leibman on generalized polynomials, to identify a class of diophantine correct subrings of the field of descending Puiseux series with real coefficients.

  15. Chromosome-specific families in Vibrio genomes

    Directory of Open Access Journals (Sweden)

    Oksana eLukjancenko

    2014-03-01

    Full Text Available We have compared chromosome-specific genes in a set of 18 finished Vibrio genomes, and, in addition, also calculated the pan- and core-genomes from a data set of more than 250 draft Vibrio genome sequences. These genomes come from 9 known species and 2 unknown species. Within the finished chromosomes, we find a core set of 1269 encoded protein families for chromosome 1, and a core of 252 encoded protein families for chromosome 2. Many of these core proteins are also found in the draft genomes (although which chromosome they are located on is unknown. Of the chromosome specific core protein families, 1169 and 153 are uniquely found in chromosomes 1 and 2, respectively. Gene ontology (GO terms for each of the protein families were determined, and the different sets for each chromosome were compared. A total of 363 different `Molecular Function` GO categories were found for chromosome 1 specific protein families, and these include several broad activities: pyridoxine 5' phosphate synthetase, glucosylceramidase, heme transport, DNA ligase, amino acid binding, and ribosomal components; in contrast, chromosome 2 specific protein families have only 66 Molecular Function GO terms and include many membrane-associated activities, such as ion channels, transmembrane transporters, and electron transport chain proteins. Thus, it appears that whilst there are many 'housekeeping systems' encoded in chromosome 1, there are far fewer core functions found in chromosome 2. However, the presence of many membrane-associated encoded proteins in chromosome 2 is surprising.

  16. Chromosome synteny in cucumis species

    Science.gov (United States)

    Cucumber, Cucumis sativus L. (2n = 2x = 14) and melon, C. melo L. (2n = 2x = 24) are two important vegetable species in the genus Cucumis (family Cucurbitaceae). Two inter-fertile botanical varieties with 14 chromosomes, the cultivated C. sativus var. sativus L. and the wild C. sativus var. hardwick...

  17. Chromosome Territory Modeller and Viewer.

    Science.gov (United States)

    Tkacz, Magdalena A; Chromiński, Kornel; Idziak-Helmcke, Dominika; Robaszkiewicz, Ewa; Hasterok, Robert

    2016-01-01

    This paper presents ChroTeMo, a tool for chromosome territory modelling, accompanied by ChroTeVi-a chromosome territory visualisation software that uses the data obtained by ChroTeMo. These tools have been developed in order to complement the molecular cytogenetic research of interphase nucleus structure in a model grass Brachypodium distachyon. Although the modelling tool has been initially created for one particular species, it has universal application. The proposed version of ChroTeMo allows for generating a model of chromosome territory distribution in any given plant or animal species after setting the initial, species-specific parameters. ChroTeMo has been developed as a fully probabilistic modeller. Due to this feature, the comparison between the experimental data on the structure of a nucleus and the results obtained from ChroTeMo can indicate whether the distribution of chromosomes inside a nucleus is also fully probabilistic or is subjected to certain non-random patterns. The presented tools have been written in Python, so they are multiplatform, portable and easy to read. Moreover, if necessary they can be further developed by users writing their portions of code. The source code, documentation, and wiki, as well as the issue tracker and the list of related articles that use ChroTeMo and ChroTeVi, are accessible in a public repository at Github under GPL 3.0 license.

  18. Chromosomal disorders and male infertility

    Institute of Scientific and Technical Information of China (English)

    Gary L Harton; Helen G Tempest

    2012-01-01

    infertility in humans is surprisingly common occurring in approximately 15% of the population wishing to start a family.Despite this,the molecular and genetic factors underlying the cause of infertility remain largely undiscovered.Nevertheless,more and more genetic factors associated with infertility are being identified.This review will focus on our current understanding of the chromosomal basis of male infertility specifically:chromosomal aneuploidy,structural and numerical karyotype abnormalities and Y chromosomal microdeletions.Chromosomal aneuploidy is the leading cause of pregnancy loss and developmental disabilities in humans.Aneuploidy is predominantly maternal in origin,but concerns have been raised regarding the safety of intracytoplasmic sperm injection as infertile men have significantly higher levels of sperm aneuploidy compared to their fertile counterparts.Males with numerical or structural karyotype abnormalities are also at an increased risk of producing aneuploid sperm.Our current understanding of how sperm aneuploidy translates to embryo aneuploidy will be reviewed,as well as the application of preimplantation genetic diagnosis (PGD) in such cases.Clinical recommendations where possible will be made,as well as discussion of the use of emerging array technology in PGD and its potential applications in male infertility.

  19. Chromosome 5 and Parkinson disease.

    Science.gov (United States)

    Foroud, Tatiana; Pankratz, Nathan; Martinez, Maria

    2006-10-01

    Parkinson disease (PD) is the second most common neurodegenerative disorder. Despite the identification of five causative genes, the majority of PD etiology is still unknown. A region on chromosome 5q is one of the few regions of the genome found linked in multiple studies of familial PD. Analyses were performed using genotypic data from two independent research studies to evaluate rigorously the evidence of linkage on chromosome 5. The combined sample consisting of 1238 affected individuals from 569 multiplex PD families were genotyped for a common set of 20 microsatellite markers spanning an 80 cM region on chromosome 5q. Two disease models were employed and model-free linkage analyses were performed to detect linkage to a PD susceptibility gene and also to detect linkage to a quantitative phenotype, age of onset of PD. There was little evidence of linkage using either a narrower or broader disease definition (lod <0.5). Analyses employing age of onset of PD as the phenotype produced a lod score of 1.8. These results in a very large sample of familial PD suggest that it is unlikely that a PD susceptibility gene is located on chromosome 5q. Evidence for a locus contributing to the age of onset of PD is modest at best (empirical P-value=0.07).

  20. CHROMOSOMAL MULTIPLICITY IN BURKHOLDERIA CEPACIA

    Science.gov (United States)

    We have used CHEF gel electrophoresis to screen preparations of large DNA from different Burkholderia cepacia isolates for the presence of DNA species corresponding to the linearized forms of the three chromosomes of 3.4,2.5, and 0.9 Mb identified in B. cepacia strain 17616. DNA ...

  1. Chromosomal disorders and male infertility.

    Science.gov (United States)

    Harton, Gary L; Tempest, Helen G

    2012-01-01

    Infertility in humans is surprisingly common occurring in approximately 15% of the population wishing to start a family. Despite this, the molecular and genetic factors underlying the cause of infertility remain largely undiscovered. Nevertheless, more and more genetic factors associated with infertility are being identified. This review will focus on our current understanding of the chromosomal basis of male infertility specifically: chromosomal aneuploidy, structural and numerical karyotype abnormalities and Y chromosomal microdeletions. Chromosomal aneuploidy is the leading cause of pregnancy loss and developmental disabilities in humans. Aneuploidy is predominantly maternal in origin, but concerns have been raised regarding the safety of intracytoplasmic sperm injection as infertile men have significantly higher levels of sperm aneuploidy compared to their fertile counterparts. Males with numerical or structural karyotype abnormalities are also at an increased risk of producing aneuploid sperm. Our current understanding of how sperm aneuploidy translates to embryo aneuploidy will be reviewed, as well as the application of preimplantation genetic diagnosis (PGD) in such cases. Clinical recommendations where possible will be made, as well as discussion of the use of emerging array technology in PGD and its potential applications in male infertility.

  2. Sex chromosome rearrangements in Polyphaga beetles.

    Science.gov (United States)

    Dutrillaux, A M; Dutrillaux, B

    2009-01-01

    The presence of a parachute sex chromosome bivalent (Xyp) at metaphase I of male meiosis is a well-known characteristic of Coleoptera, present in almost all families of this order and assumed to represent their ancestral sex chromosome formula. Sex chromosomes appear to be manifold more frequently involved in inter-chromosomal rearrangements than the average of the nine autosomal pairs usually forming their karyotype. This leads to various formulae such as neo-sex, multiple sex and perhaps unique sex chromosomes. These rearrangements alter the intimate association between sex chromosomes and nucleolar proteins, which are usual components of the Xyp. Different situations, selected in a series of 125 mitotic and meiotic cytogenetic studies of Polyphaga beetle species, are reported and discussed, with the aim to improve our knowledge on the mechanisms of sex chromosome rearrangements, the relationships with nucleoli and the consequences on dosage compensation and chromosome segregation.

  3. Association of recurrent pregnancy loss with chromosomal ...

    African Journals Online (AJOL)

    EB

    Results: Parental chromosomal abnormality was detected in 28 cases (2.8% of all cases, 5.7% of the couples) most of which ... Key words: chromosomal abnormality, recurrent pregnancy loss, thrombophilia ..... significant role in infertility.

  4. CORRECTING WRITTEN WORK

    Institute of Scientific and Technical Information of China (English)

    1994-01-01

    Introduction During the teaching and learning process, teachers often check how much students have understood through written assignments. In this article I’d like to describe one method of correcting students’ written work by using a variety of symbols to indicate where students have gone wrong, then asking students to correct their work themselves.

  5. Association analysis of chromosome 1 migraine candidate genes

    Directory of Open Access Journals (Sweden)

    MacMillan John

    2007-08-01

    Full Text Available Abstract Background Migraine with aura (MA is a subtype of typical migraine. Migraine with aura (MA also encompasses a rare severe subtype Familial Hemiplegic Migraine (FHM with several known genetic loci. The type 2 FHM (FHM-2 susceptibility locus maps to chromosome 1q23 and mutations in the ATP1A2 gene at this site have recently been implicated. We have previously provided evidence of linkage of typical migraine (predominantly MA to microsatellite markers on chromosome 1, in the 1q31 and 1q23 regions. In this study, we have undertaken a large genomic investigation involving candidate genes that lie within the chromosome 1q23 and 1q31 regions using an association analysis approach. Methods We have genotyped a large population of case-controls (243 unrelated Caucasian migraineurs versus 243 controls examining a set of 5 single nucleotide polymorphisms (SNPs and the Fas Ligand dinucleotide repeat marker, located within the chromosome 1q23 and 1q31 regions. Results Several genes have been studied including membrane protein (ATP 1 subtype A4 and FasL, cytoplasmic glycoprotein (CASQ 1 genes and potassium (KCN J9 and KCN J10 and calcium (CACNA1E channel genes in 243 migraineurs (including 85% MA and 15% of migraine without aura (MO and 243 matched controls. After correction for multiple testing, chi-square results showed non-significant P values (P > 0.008 across all SNPs (and a CA repeat tested in these different genes, however results with the KCN J10 marker gave interesting results (P = 0.02 that may be worth exploring further in other populations. Conclusion These results do not show a significant role for the tested candidate gene variants and also do not support the hypothesis that a common chromosome 1 defective gene influences both FHM and the more common forms of migraine.

  6. Cyclin G-associated kinase promotes microtubule outgrowth from chromosomes during spindle assembly.

    Science.gov (United States)

    Tanenbaum, Marvin E; Vallenius, Tea; Geers, Erica F; Greene, Lois; Mäkelä, Tomi P; Medema, Rene H

    2010-08-01

    During mitosis, all chromosomes must attach to microtubules of the mitotic spindle to ensure correct chromosome segregation. Microtubule attachment occurs at specialized structures at the centromeric region of chromosomes, called kinetochores. These kinetochores can generate microtubule attachments through capture of centrosome-derived microtubules, but in addition, they can generate microtubules themselves, which are subsequently integrated with centrosome-derived microtubules to form the mitotic spindle. Here, we have performed a large scale RNAi screen and identify cyclin G-associated kinase (GAK) as a novel regulator of microtubule generation at kinetochores/chromatin. This function of GAK requires its C-terminal J-domain, which is essential for clathrin recycling from endocytic vesicles. Consistently, cells lacking GAK show strongly reduced levels of clathrin on the mitotic spindle, and reduction of clathrin levels also inhibits microtubule generation at kinetochores/chromosomes. Finally, we present evidence that association of clathrin with the spindle is promoted by a signal coming from the chromosomes. These results identify a role for GAK and clathrin in microtubule outgrowth from kinetochores/chromosomes and suggest that GAK acts through clathrin to control microtubule outgrowth around chromosomes.

  7. Chromosome protein framework from proteome analysis of isolated human metaphase chromosomes.

    Science.gov (United States)

    Fukui, Kiichi; Uchiyama, Susumu

    2007-01-01

    We have presented a structural model of the chromosome based on its constituent proteins. Development of a method of mass isolation for intact human metaphase chromosomes and proteome analysis by mass spectrometry of the isolated chromosomal proteins enabled us to develop a four-layer structural model of human metaphase chromosomes. The model consists of four layers, each with different chromosomal protein sets, i.e., chromosome coating proteins (CCPs), chromosome peripheral proteins (CPPs), chromosome structural proteins (CSPs), and chromosome fibrous proteins (CFPs). More than 200 identified proteins have been classified and assigned to the four layers with each layer occupying a distinct region of the chromosome. CCPs are localized at the most outer regions of the chromosomes and they attach to the regions tentatively and occasionally. CCPs include mostly mitochondrial and cytoplasmic proteins, e.g., 70 kDa heat shock protein 9B and Hsp60. CPPs are also localized at the peripheral regions of the chromosomes, but as the essential part of the chromosomes. CPPs include nucleolin, lamin A/C, fibrillarin, etc. CSPs are the primary chromosomal structure proteins, and include topoisomerase IIalpha, condensin subunits, histones, etc. CFPs have a fibrous nature, e.g., beta-actin, vimentin, myosin II, tublin, etc. A data set of these proteins, which we developed, contains essential chromosome proteins with classified information based on this four-layer model and presents useful leads for further studies on chromosomal structure and function.

  8. Familial transmission of a ring chromosome 21

    DEFF Research Database (Denmark)

    Hertz, Jens Michael

    1987-01-01

    A ring chromosome 21 was found in a phenotypically normal mother and her son. The clinical findings in the son were bilateral retention of the testes and a slightly delayed puberty onset. Consequences of a ring formation of a chromosome 21 in phenotypically normal patients are presented...... and discussed, and the previously reported cases of familially transmitted G-group ring chromosomes are reviewed....

  9. Female meiotic sex chromosome inactivation in chicken

    NARCIS (Netherlands)

    S. Schoenmakers (Sam); E. Wassenaar (Evelyne); J.W. Hoogerbrugge (Jos); J.S.E. Laven (Joop); J.A. Grootegoed (Anton); W.M. Baarends (Willy)

    2009-01-01

    textabstractDuring meiotic prophase in male mammals, the heterologous X and Y chromosomes remain largely unsynapsed, and meiotic sex chromosome inactivation (MSCI) leads to formation of the transcriptionally silenced XY body. In birds, the heterogametic sex is female, carrying Z and W chromosomes (Z

  10. A Plain English Map of the Human Chromosomes.

    Science.gov (United States)

    Offner, Susan

    1992-01-01

    Presents a chromosome map for 19 known chromosomes in human genetics. Describes the characteristics attributed to the genetic codes for each of the chromosomes and discusses the teaching applications of the chromosome map. (MDH)

  11. A novel method for sex determination by detecting the number of X chromosomes.

    Science.gov (United States)

    Nakanishi, Hiroaki; Shojo, Hideki; Ohmori, Takeshi; Hara, Masaaki; Takada, Aya; Adachi, Noboru; Saito, Kazuyuki

    2015-01-01

    A novel method for sex determination, based on the detection of the number of X chromosomes, was established. Current methods, based on the detection of the Y chromosome, can directly identify an unknown sample as male, but female gender is determined indirectly, by not detecting the Y chromosome. Thus, a direct determination of female gender is important because the quality (e.g., fragmentation and amelogenin-Y null allele) of the Y chromosome DNA may lead to a false result. Thus, we developed a novel sex determination method by analyzing the number of X chromosomes using a copy number variation (CNV) detection technique (the comparative Ct method). In this study, we designed a primer set using the amelogenin-X gene without the CNV region as the target to determine the X chromosome copy number, to exclude the influence of the CNV region from the comparative Ct value. The number of X chromosomes was determined statistically using the CopyCaller software with real-time PCR. All DNA samples from participants (20 males, 20 females) were evaluated correctly using this method with 1-ng template DNA. A minimum of 0.2-ng template DNA was found to be necessary for accurate sex determination with this method. When using ultraviolet-irradiated template DNA, as mock forensic samples, the sex of the samples could not be determined by short tandem repeat (STR) analysis but was correctly determined using our method. Thus, we successfully developed a method of sex determination based on the number of X chromosomes. Our novel method will be useful in forensic practice for sex determination.

  12. Y-chromosome polymorphism: Possible largest Y chromosome in man?

    Energy Technology Data Exchange (ETDEWEB)

    Murthy, D.S.K.; Al-Awadi, S.A.; Bastaki, L. [Kuwait Medical Genetics Centre, Sulaibikat (Kuwait)] [and others

    1994-09-01

    The role of variations (inversions/deletion or duplication) in the heterochromatin in gonadal development and function, reproductive fitness, and malignant disease has been extensively studied. However, the causal-relationship of large Y (Yqh+) and repeated fetal loss has not been established unequivocally. An Arab couple (?Bedouin origin) with a history of repeated abortions were investigated. Karyotype analysis of the husband showed a very large Y chromosome, confirmed by GTG-, QFQ- and CBG-banding techniques. C-banding showed discontinuous distribution of the heterochromatin blocks separated by pale bands. The origin of the large heterochromatin segment could be due to tandem duplication of the Yq region or translocation (Yq:Yq). No other relatives (males) of the propositus have been available for investigation. Polymorphism of the Y chromosome could be attributed to evolutionary changes from an ancestral type, either by deletion or duplication of the heterochromatin segment. More detailed studies on isolated, aboriginal/tribal human populations will enable us to better understand the significance of the Y chromosome polymorphism.

  13. Chromosomal instability in Streptomyces avermitilis: major deletion in the central region and stable circularized chromosome

    Directory of Open Access Journals (Sweden)

    Wen Ying

    2010-07-01

    Full Text Available Abstract Background The chromosome of Streptomyces has been shown to be unstable, frequently undergoing gross chromosomal rearrangements. However, the mechanisms underlying this phenomenon remain unclear, with previous studies focused on two chromosomal ends as targets for rearrangements. Here we investigated chromosomal instability of Streptomyces avermitilis, an important producer of avermectins, and characterized four gross chromosomal rearrangement events, including a major deletion in the central region. The present findings provide a valuable contribution to the mechanistic study of genetic instability in Streptomyces. Results Thirty randomly-selected "bald" mutants derived from the wild-type strain all contained gross chromosomal rearrangements of various types. One of the bald mutants, SA1-8, had the same linear chromosomal structure as the high avermectin-producing mutant 76-9. Chromosomes of both strains displayed at least three independent chromosomal rearrangements, including chromosomal arm replacement to form new 88-kb terminal inverted repeats (TIRs, and two major deletions. One of the deletions eliminated the 36-kb central region of the chromosome, but surprisingly did not affect viability of the cells. The other deletion (74-kb was internal to the right chromosomal arm. The chromosome of another bald mutant, SA1-6, was circularized with deletions at both ends. No obvious homology was found in all fusion sequences. Generational stability analysis showed that the chromosomal structure of SA1-8 and SA1-6 was stable. Conclusions Various chromosomal rearrangements, including chromosomal arm replacement, interstitial deletions and chromosomal circularization, occurred in S. avermitilis by non-homologous recombination. The finding of an inner deletion involving in the central region of S. avermitilis chromosome suggests that the entire Streptomyces chromosome may be the target for rearrangements, which are not limited, as previously

  14. The origin of human chromosome 2 analyzed by comparative chromosome mapping with a DNA microlibrary

    OpenAIRE

    Wienberg, Johannes; Jauch, Anna; Lüdecke, H J; Senger, G.; Horsthemke, B; Claussen, U.; Cremer, Thomas; Arnold, N; Lengauer, Christoph

    1994-01-01

    Fluorescencein situ hybridization (FISH) of microlibraries established from distinct chromosome subregions can test the evolutionary conservation of chromosome bands as well as chromosomal rearrangements that occurred during primate evolution and will help to clarify phylogenetic relationships. We used a DNA library established by microdissection and microcloning from the entire long arm of human chromosome 2 for fluorescencein situ hybridization and comparative mapping of the chromosomes of ...

  15. Probabilistic quantum error correction

    CERN Document Server

    Fern, J; Fern, Jesse; Terilla, John

    2002-01-01

    There are well known necessary and sufficient conditions for a quantum code to correct a set of errors. We study weaker conditions under which a quantum code may correct errors with probabilities that may be less than one. We work with stabilizer codes and as an application study how the nine qubit code, the seven qubit code, and the five qubit code perform when there are errors on more than one qubit. As a second application, we discuss the concept of syndrome quality and use it to suggest a way that quantum error correction can be practically improved.

  16. [From conventional cytogenetics to microarrays. Fifty years of Philadelphia chromosome].

    Science.gov (United States)

    Hernández, Jesús M; Granada, Isabel; Solé, Francesc

    2011-07-23

    In 1960 Ph-chromosome was found associated with the presence of chronic myelogenous leukemia. In these 50 years an increasing number of cytogenetic abnormalities have been found associated with hematological malignancies. The presence of these abnormalities is not only important for the diagnosis of the patient, but it also contributes to the prognosis of patients with leukemia or lymphoma. For this reason the WHO classification of hematological disease has included these studies for the correct characterization of leukemias and lymphomas. In addition, the use of FISH and micromatrix methodologies have refined the genetic lesions present in these malignancies. The cytogenetic changes observed also provide further information in relation to the therapy.

  17. Mapping strategies: Chromosome 16 workshop. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    1989-12-31

    The following topics from a workshop on chromosome 16 are briefly discussed: genetic map of chromosome 16; chromosome breakpoint map of chromosome 16; integrated physical/genetic map of chromosome 16; pulsed field map of the 16p13.2--p13.3 region (3 sheets); and a report of the HGM10 chromosome 16 committee.

  18. The Chromosomes of Birds during Meiosis.

    Science.gov (United States)

    Pigozzi, María I

    2016-01-01

    The cytological analysis of meiotic chromosomes is an exceptional tool to approach complex processes such as synapsis and recombination during the division. Chromosome studies of meiosis have been especially valuable in birds, where naturally occurring mutants or experimental knock-out animals are not available to fully investigate the basic mechanisms of major meiotic events. This review highlights the main contributions of synaptonemal complex and lampbrush chromosome research to the current knowledge of avian meiosis, with special emphasis on the organization of chromosomes during prophase I, the impact of chromosome rearrangements during meiosis, and distinctive features of the ZW pair.

  19. Polymer models of chromosome (re)organization

    Science.gov (United States)

    Mirny, Leonid

    Chromosome Conformation Capture technique (Hi-C) provides comprehensive information about frequencies of spatial interactions between genomic loci. Inferring 3D organization of chromosomes from these data is a challenging biophysical problem. We develop a top-down approach to biophysical modeling of chromosomes. Starting with a minimal set of biologically motivated interactions we build ensembles of polymer conformations that can reproduce major features observed in Hi-C experiments. I will present our work on modeling organization of human metaphase and interphase chromosomes. Our works suggests that active processes of loop extrusion can be a universal mechanism responsible for formation of domains in interphase and chromosome compaction in metaphase.

  20. Chromosome painting of Z and W sex chromosomes in Characidium (Characiformes, Crenuchidae).

    Science.gov (United States)

    Pazian, Marlon F; Shimabukuro-Dias, Cristiane Kioko; Pansonato-Alves, José Carlos; Oliveira, Claudio; Foresti, Fausto

    2013-03-01

    Some species of the genus Characidium have heteromorphic ZZ/ZW sex chromosomes with a totally heterochromatic W chromosome. Methods for chromosome microdissection associated with chromosome painting have become important tools for cytogenetic studies in Neotropical fish. In Characidium cf. fasciatum, the Z chromosome contains a pericentromeric heterochromatin block, whereas the W chromosome is completely heterochromatic. Therefore, a probe was produced from the W chromosome through microdissection and degenerate oligonucleotide-primed polymerase chain reaction amplification. FISH was performed using the W probe on the chromosomes of specimens of this species. This revealed expressive marks in the pericentromeric region of the Z chromosome as well as a completely painted W chromosome. When applying the same probe on chromosome preparations of C. cf. gomesi and Characidium sp., a pattern similar to C. cf. fasciatum was found, while C. cf. zebra, C. cf. lagosantense and Crenuchus spilurus species showed no hybridization signals. Structural changes in the chromosomes of an ancestral sexual system in the group that includes the species C. cf. gomesi, C. cf. fasciatum and Characidium sp., could have contributed to the process of speciation and could represent a causal mechanism of chromosomal diversification in this group. The heterochromatinization process possibly began in homomorphic and homologous chromosomes of an ancestral form, and this process could have given rise to the current patterns found in the species with sex chromosome heteromorphism.

  1. STAG2 promotes error correction in mitosis by regulating kinetochore-microtubule attachments.

    Science.gov (United States)

    Kleyman, Marianna; Kabeche, Lilian; Compton, Duane A

    2014-10-01

    Mutations in the STAG2 gene are present in ∼20% of tumors from different tissues of origin. STAG2 encodes a subunit of the cohesin complex, and tumors with loss-of-function mutations are usually aneuploid and display elevated frequencies of lagging chromosomes during anaphase. Lagging chromosomes are a hallmark of chromosomal instability (CIN) arising from persistent errors in kinetochore-microtubule (kMT) attachment. To determine whether the loss of STAG2 increases the rate of formation of kMT attachment errors or decreases the rate of their correction, we examined mitosis in STAG2-deficient cells. STAG2 depletion does not impair bipolar spindle formation or delay mitotic progression. Instead, loss of STAG2 permits excessive centromere stretch along with hyperstabilization of kMT attachments. STAG2-deficient cells display mislocalization of Bub1 kinase, Bub3 and the chromosome passenger complex. Importantly, strategically destabilizing kMT attachments in tumor cells harboring STAG2 mutations by overexpression of the microtubule-destabilizing enzymes MCAK (also known as KIF2C) and Kif2B decreased the rate of lagging chromosomes and reduced the rate of chromosome missegregation. These data demonstrate that STAG2 promotes the correction of kMT attachment errors to ensure faithful chromosome segregation during mitosis.

  2. Epigenetic-genetic chromosome dosage approach for fetal trisomy 21 detection using an autosomal genetic reference marker.

    Directory of Open Access Journals (Sweden)

    Yu K Tong

    Full Text Available BACKGROUND: The putative promoter of the holocarboxylase synthetase (HLCS gene on chromosome 21 is hypermethylated in placental tissues and could be detected as a fetal-specific DNA marker in maternal plasma. Detection of fetal trisomy 21 (T21 has been demonstrated by an epigenetic-genetic chromosome dosage approach where the amount of hypermethylated HLCS in maternal plasma is normalized using a fetal genetic marker on the Y chromosome as a chromosome dosage reference marker. We explore if this method can be applied on both male and female fetuses with the use of a paternally-inherited fetal single nucleotide polymorphism (SNP allele on a reference chromosome for chromosome dosage normalization. METHODOLOGY: We quantified hypermethylated HLCS molecules using methylation-sensitive restriction endonuclease digestion followed by real-time or digital PCR analyses. For chromosome dosage analysis, we compared the amount of digestion-resistant HLCS to that of a SNP allele (rs6636, a C/G SNP that the fetus has inherited from the father but absent in the pregnant mother. PRINCIPAL FINDINGS: Using a fetal-specific SNP allele on a reference chromosome, we analyzed 20 euploid and nine T21 placental tissue samples. All samples with the fetal-specific C allele were correctly classified. One sample from each of the euploid and T21 groups were misclassified when the fetal-specific G allele was used as the reference marker. We then analyzed 33 euploid and 14 T21 maternal plasma samples. All but one sample from each of the euploid and T21 groups were correctly classified using the fetal-specific C allele, while correct classification was achieved for all samples using the fetal-specific G allele as the reference marker. CONCLUSIONS: As a proof-of-concept study, we have demonstrated that the epigenetic-genetic chromosome dosage approach can be applied to the prenatal diagnosis of trisomy 21 for both male and female fetuses.

  3. Analysis of morphine responses in mice reveals a QTL on Chromosome 7 [version 1; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Wim E. Crusio

    2016-09-01

    Full Text Available In this study we identified a quantitative trait locus (QTL on mouse Chromosome 7 associated with locomotor activity and rearing post morphine treatment. This QTL was revealed after correcting for the effects of another QTL peak on Chromosome 10 using composite interval mapping. The positional candidate genes are Syt9 and Ppfibp2. Several other genes within the interval are linked to neural processes, locomotor activity, and the defensive response to harmful stimuli.

  4. Analysis of morphine responses in mice reveals a QTL on Chromosome 7 [version 2; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Wim E. Crusio

    2016-10-01

    Full Text Available In this study we identified a quantitative trait locus (QTL on mouse Chromosome 7 associated with locomotor activity and rearing post morphine treatment. This QTL was revealed after correcting for the effects of another QTL peak on Chromosome 10 using composite interval mapping. The positional candidate genes are Syt9 and Ppfibp2. Several other genes within the interval are linked to neural processes, locomotor activity, and the defensive response to harmful stimuli.

  5. Chromosome X aneuploidy in Brazilian schizophrenic patients.

    Science.gov (United States)

    de Moraes, Leopoldo Silva; Khayat, André Salim; de Lima, Patrícia Danielle Lima; Lima, Eleonidas Moura; Pinto, Giovanny Rebouças; Leal, Mariana Ferreira; de Arruda Cardoso Smith, Marília; Burbano, Rommel Rodríguez

    2010-01-01

    The identification of cytogenetic abnormalities in schizophrenic patients may provide clues to the genes involved in this disease. For this reason, a chromosomal analysis of samples from 62 schizophrenics and 70 controls was performed with trypsin-Giemsa banding and fluorescence in situ hybridization of the X chromosome. A clonal pericentric inversion on chromosome 9 was detected in one male patient, and we also discovered mosaicism associated with X chromosome aneuploidy in female patients, primarily detected in schizophrenic and normal female controls over 40 years old. When compared with age-matched female controls, the frequency of X chromosome loss was not significantly different between schizophrenics and controls, except for the 40- to 49-year-old age group. Our findings suggest that the X chromosome loss seen in schizophrenic patients is inherent to the normal cellular aging process. However, our data also suggest that X chromosome gain may be correlated with schizophrenia in this Brazilian population.

  6. Flow cytometric detection of aberrant chromosomes

    Energy Technology Data Exchange (ETDEWEB)

    Gray, J.W.; Lucas, J.; Yu, L.C.; Langlois, R.

    1983-05-11

    This report describes the quantification of chromosomal aberrations by flow cytometry. Both homogeneously and heterogeneously occurring chromosome aberrations were studied. Homogeneously occurring aberrations were noted in chromosomes isolated from human colon carcinoma (LoVo) cells, stained with Hoechst 33258 and chromomycin A3 and analyzed using dual beam flow cytometry. The resulting bivariate flow karyotype showed a homogeneously occurring marker chromosome of intermediate size. Heterogeneously occurring aberrations were quantified by slit-scan flow cytometry in chromosomes isolated from control and irradiated Chinese hamster cells and stained with propidium iodide. Heterogeneously occurring dicentric chromosomes were detected by their shapes (two centrometers). The frequencies of such chromosomes estimated by slit-scan flow cytometry correlated well with the frequencies determined by visual microscopy.

  7. Dynamics of chromosome segregation in Escherichia coli

    DEFF Research Database (Denmark)

    Nielsen, Henrik Jørck

    2007-01-01

    in the cell by labeling specific parts of it. Later the dynamics of chromosome segregation was included. Investigating chromosome organization by labeling of specific loci was already a widely used technique when I started on this thesis, but the data acquisition and treatment was slow and generally poorly......, and it is obvious that structured cellular actions are required to unpack it, as required for its replication, and refold the two daughter chromosomes separately without getting them entangled in the process each generation. The intention of the study was initially to find out how the chromosome is organized....... Adding the results of the thesis together with known data results in the following description of the chromosome dynamics of slowly growing E.coli cells: The chromosome of slow growing cells is organized with the origin at the cell center when it is newborn. It has one chromosomal arm on one side...

  8. Chromosomal patterns in human malignant astrocytomas.

    Science.gov (United States)

    Rey, J A; Bello, M J; de Campos, J M; Kusak, M E; Ramos, C; Benitez, J

    1987-12-01

    Cytogenetic analysis by direct and/or in vitro preparations was performed on 34 malignant astrocytomas. Thirty tumors showed near-diploid chromosome numbers, whereas, tritetraploid chromosome complements were present in four tumors. The most frequent chromosomal changes implied numerical deviations by a gain of chromosomes #7, #19, and #20, and by losses of #10, #22, and Y. Structural rearrangements were present in stem- or side lines of 24 tumors. Although no common chromosomal rearrangement seems to exist among those tumors, chromosomes #1, #6, #7, and #9 were predominantly involved. Polysomy and structural rearrangements of chromosome #7 could be related to the overexpression of epidermal growth factor gene, previously observed in some malignant gliomas.

  9. Entropy as the driver of chromosome segregation.

    Science.gov (United States)

    Jun, Suckjoon; Wright, Andrew

    2010-08-01

    We present a new physical biology approach to understanding the relationship between the organization and segregation of bacterial chromosomes. We posit that replicated Escherichia coli daughter strands will spontaneously demix as a result of entropic forces, despite their strong confinement within the cell; in other words, we propose that entropy can act as a primordial physical force which drives chromosome segregation under the right physical conditions. Furthermore, proteins implicated in the regulation of chromosome structure and segregation may in fact function primarily in supporting such an entropy-driven segregation mechanism by regulating the physical state of chromosomes. We conclude that bacterial chromosome segregation is best understood in terms of spontaneous demixing of daughter strands. Our concept may also have important implications for chromosome segregation in eukaryotes, in which spindle-dependent chromosome movement follows an extended period of sister chromatid demixing and compaction.

  10. CHROMOSOMAL ABNORMALITIES IN PATIENTS WITH RECURRENT MISCARRIAGE

    Directory of Open Access Journals (Sweden)

    Daniela Mierla

    2012-06-01

    Full Text Available Chromosomal abnormalities are involved in the etiology of recurrent spontaneous pregnancy loss and sub-fertility. The purpose of this study was to determine the frequency and contribution of chromosomal abnormalities in recurrent miscarriages. The results obtained and literature review are helpful in understanding the importance of cytogenetics analysis of female infertility. To investigate the distribution of chromosomal abnormalities in the Romanian population with recurrent miscarriage, karyotype analysis by G-banding was performed from peripheral blood in 967 women infertility. Results: Chromosomal abnormalities were found to 79 women (8,17%. The percentage of chromosomal abnormalities in the studied population correlates with the data in the literature. Chromosomal abnormalities could play the important role in etiology of infertility and are more frequently detected in this group of patients compared to general population. In the infertile couples balanced chromosomal abnormalities are the main cause of spontaneous abortions.

  11. Corrective Jaw Surgery

    Medline Plus

    Full Text Available ... It can also invite bacteria that lead to gum disease. Click here to find out more. Who We ... It can also invite bacteria that lead to gum disease. Click here to find out more. Corrective Jaw ...

  12. Correction of Neonatal Hypovolemia

    Directory of Open Access Journals (Sweden)

    V. V. Moskalev

    2007-01-01

    Full Text Available Objective: to evaluate the efficiency of hydroxyethyl starch solution (6% refortane, Berlin-Chemie versus fresh frozen plasma used to correct neonatal hypovolemia.Materials and methods. In 12 neonatal infants with hypoco-agulation, hypovolemia was corrected with fresh frozen plasma (10 ml/kg body weight. In 13 neonates, it was corrected with 6% refortane infusion in a dose of 10 ml/kg. Doppler echocardiography was used to study central hemodynamic parameters and Doppler study was employed to examine regional blood flow in the anterior cerebral and renal arteries.Results. Infusion of 6% refortane and fresh frozen plasma at a rate of 10 ml/hour during an hour was found to normalize the parameters of central hemodynamics and regional blood flow.Conclusion. Comparative analysis of the findings suggests that 6% refortane is the drug of choice in correcting neonatal hypovolemia. Fresh frozen plasma should be infused in hemostatic disorders. 

  13. Corrected Age for Preemies

    Science.gov (United States)

    ... Spread the Word Shop AAP Find a Pediatrician Ages & Stages Prenatal Baby Bathing & Skin Care Breastfeeding Crying & ... Listen Español Text Size Email Print Share Corrected Age For Preemies Page Content Article Body If your ...

  14. Self-correction in human embryos%胚胎自我修复

    Institute of Scientific and Technical Information of China (English)

    徐艳文

    2013-01-01

    Reanalysis of aneuploid embryos diagnosed by preimplantation genetic screening (PGS) using fluorescence in situ hybridization(FISH) showed that part or all cells in some human cleavage-stage embryos may undergo self-correction during preimplantation development. Putative embryo self-correction mechanisms include embryonic mosaicism, preferential segregation of chromosomal abnormalities to the trophectoderm and extrusion or duplication of aneuploid chromosomes resulting in uniparental disomy. However, embryo self-correction has not been proved in the study using a single nucleotide polymorphism (SNP)microarray-based 24 chromosome aneuploidy screening technology. Neither preferential segregation of aneuploidy to trophectoderm nor uniparental disomy was found. Further study to improve the accuracy of karyotyping on cleavage-stage embryos is definitely needed.

  15. Environmental pollution, chromosomes, and health

    Science.gov (United States)

    Bell, Peter M.

    In mid-May, 1980, President Carter declared a state of emergency at the Love Canal area, near Niagara Falls, New York. The reason for this was for the U.S. to underwrite the relocation costs ($3-5 million) of some 2500 residents who, according to a report by the EPA (Environmental Protection Agency) may have suffered damaged chromosomes. These injuries were apparently caused by contact with toxic wastes that had been dumped in the area in the years prior to development for housing.That the toxic compounds exist in the Love Canal and Niagara Falls subsurface zones, including public water supplies, appears to be established fact. That the residents of the Love Canal area suffered chromosomal damage may be established fact as well. Whether or not these two findings can be linked to ill health of the residents is another matter. Recently, the EPA report has been described as having ‘close to zero scientific significance,’ and has been ‘discredited’(Science, 208, 123a, 1980). The reasons for this disparity go beyond differences of opinion, beyond possible inadequacies of the EPA study, and even beyond problems that probably will arise from future studies, including those now in the planning stages. The problem is that even if victims have easily recognizable injuries from toxic substances (injury that apparently has not occurred to Love Canal residents), medical science usually cannot show a causal relationship. Even chromosomal damage is, at best, difficult to interpret. In ideal studies of significant populations and control groups, the association of toxic chemical to chromosome damage and to cancer and birth defects is indirect and, up to now, has been shown to have little or no significance to an individual member of the exposed population.

  16. Bacterial Chromosome Organization and Segregation

    OpenAIRE

    Toro, Esteban; Shapiro, Lucy

    2010-01-01

    Bacterial chromosomes are generally ∼1000 times longer than the cells in which they reside, and concurrent replication, segregation, and transcription/translation of this crowded mass of DNA poses a challenging organizational problem. Recent advances in cell-imaging technology with subdiffraction resolution have revealed that the bacterial nucleoid is reliably oriented and highly organized within the cell. Such organization is transmitted from one generation to the next by progressive segrega...

  17. Correctness is not enough

    CERN Document Server

    Pryor, Louise

    2008-01-01

    The usual aim of spreadsheet audit is to verify correctness. There are two problems with this: first, it is often difficult to tell whether the spreadsheets in question are correct, and second, even if they are, they may still give the wrong results. These problems are explained in this paper, which presents the key criteria for judging a spreadsheet and discusses how those criteria can be achieved

  18. Adaptable DC offset correction

    Science.gov (United States)

    Golusky, John M. (Inventor); Muldoon, Kelly P. (Inventor)

    2009-01-01

    Methods and systems for adaptable DC offset correction are provided. An exemplary adaptable DC offset correction system evaluates an incoming baseband signal to determine an appropriate DC offset removal scheme; removes a DC offset from the incoming baseband signal based on the appropriate DC offset scheme in response to the evaluated incoming baseband signal; and outputs a reduced DC baseband signal in response to the DC offset removed from the incoming baseband signal.

  19. Microdissection and chromosome painting of the alien chromosome in an addition line of wheat-Thinopyrum intermedium

    Science.gov (United States)

    The chromosome painting is an efficient tool for chromosome research. However, plant chromosome painting is relatively underdeveloped. In this study, chromosome painting was developed and used to identify alien chromosomes in TAi-27, a wheat-Thinopyrum intermedium addition line, and chromosomes of...

  20. Chromosome aberration assays in Allium

    Energy Technology Data Exchange (ETDEWEB)

    Grant, W.F.

    1982-01-01

    The common onion (Allium cepa) is an excellent plant for the assay of chromosome aberrations after chemical treatment. Other species of Allium (A. cepa var. proliferum, A. carinatum, A. fistulosum and A. sativum) have also been used but to a much lesser extent. Protocols have been given for using root tips from either bulbs or seeds of Allium cepa to study the cytological end-points, such as chromosome breaks and exchanges, which follow the testing of chemicals in somatic cells. It is considered that both mitotic and meiotic end-points should be used to a greater extent in assaying the cytogenetic effects of a chemical. From a literature survey, 148 chemicals are tabulated that have been assayed in 164 Allium tests for their clastogenic effect. Of the 164 assays which have been carried out, 75 are reported as giving a positive reaction, 49 positive and with a dose response, 1 positive and temperature-related, 9 borderline positive, and 30 negative; 76% of the chemicals gave a definite positive response. It is proposed that the Allium test be included among those tests routinely used for assessing chromosomal damage induced by chemicals.

  1. Chromosome segregation and aneuploidy. I

    Energy Technology Data Exchange (ETDEWEB)

    Vig, B.K. [Univ. of Nevada, Reno, NV (United States)

    1993-12-31

    Of all genetic afflictions of man, aneuploidy ranks as the most prevalent. Among liveborn babies aneuploidy exist to the extent of about 0.3%, to about 0.5% among stillborns and a dramatic 25% among miscarriages. The burden is too heavy to be taken lightly. Whereas cytogeneticists are capable of tracing the origin of the extra or missing chromosome to the contributing parent, it is not certain what factors are responsible for this {open_quote}epidemic{close_quote} affecting the human genome. The matter is complicated by the observation that, to the best of our knowledge, all chromosomes do not malsegregate with equal frequency. Chromosome number 16, for example, is the most prevalent among abortuses - one-third of all aneuploid miscarriages are due to trisomy 16 - yet it never appears in aneuploid constitution among the liveborn. Some chromsomes, number 1, for example, appear only rarely, if at all. In the latter case painstaking efforts have to be made to karyotype very early stages of embryonic development, as early as the 8-cell stage. Even though no convincing data are yet available, it is conceivable that the product of most aneuploid zygotes is lost before implantation.

  2. GSK-3 inhibitors induce chromosome instability

    Directory of Open Access Journals (Sweden)

    Staples Oliver D

    2007-08-01

    Full Text Available Abstract Background Several mechanisms operate during mitosis to ensure accurate chromosome segregation. However, during tumour evolution these mechanisms go awry resulting in chromosome instability. While several lines of evidence suggest that mutations in adenomatous polyposis coli (APC may promote chromosome instability, at least in colon cancer, the underlying mechanisms remain unclear. Here, we turn our attention to GSK-3 – a protein kinase, which in concert with APC, targets β-catenin for proteolysis – and ask whether GSK-3 is required for accurate chromosome segregation. Results To probe the role of GSK-3 in mitosis, we inhibited GSK-3 kinase activity in cells using a panel of small molecule inhibitors, including SB-415286, AR-A014418, 1-Azakenpaullone and CHIR99021. Analysis of synchronised HeLa cells shows that GSK-3 inhibitors do not prevent G1/S progression or cell division. They do, however, significantly delay mitotic exit, largely because inhibitor-treated cells have difficulty aligning all their chromosomes. Although bipolar spindles form and the majority of chromosomes biorient, one or more chromosomes often remain mono-oriented near the spindle poles. Despite a prolonged mitotic delay, anaphase frequently initiates without the last chromosome aligning, resulting in chromosome non-disjunction. To rule out the possibility of "off-target" effects, we also used RNA interference to selectively repress GSK-3β. Cells deficient for GSK-3β exhibit a similar chromosome alignment defect, with chromosomes clustered near the spindle poles. GSK-3β repression also results in cells accumulating micronuclei, a hallmark of chromosome missegregation. Conclusion Thus, not only do our observations indicate a role for GSK-3 in accurate chromosome segregation, but they also raise the possibility that, if used as therapeutic agents, GSK-3 inhibitors may induce unwanted side effects by inducing chromosome instability.

  3. Diagnosis of a constitutional five-chromosome rearrangement by fluorescent in situ hybridization (FISH)

    Energy Technology Data Exchange (ETDEWEB)

    Tsien, F.; Shapira, E. [Tulane Univ. School of Medicine, New Orleans, LA (United States); Carvalho, T. [Hospital Sarah Kubitschek, Brasilia (Brazil)] [and others

    1994-09-01

    Complex chromosomal rearrangements are structural rearrangements involving at least three chromosomes and three or more chromosome breakpoints. Such karyotypes are often acquired during cancer multi-step development and in chromosome instability syndromes. However, extremely rare constitutional forms have been reported, most of which are incompatible with life. We present a 2-year-old female with de novo complex rearrangement consisting of five chromosomes and nine breakpoints. Clinical evaluation at two years of age revealed a weight of 5 kg, length of 66 cm, and had circumference of 38 cm, all below the 5th percentile, microcephaly, trigonocephaly, epicanthal folds, inguinal hernia, left clubfoot, hypertonicity, and developmental delay. The neurological examination revealed chorea-acanthocytosis and psychomotor delay. Cultured lymphocytes and fibroblasts revealed a karyotype consisting of five derivative chromosomes. The metaphases were further analyzed by FISH using chromosome-specific libraries and telomeric probes in order to delineate the composition of the rearranged chromosomes; FISH results demonstrated a karyotype of: 46,XX,1pter{r_arrow}1q25::1q42.1{r_arrow}1qter, 2pter{r_arrow}q32.3::1q32.3{r_arrow}2q41::2q37.3{r_arrow}2qter, 7qter{r_arrow}7q21.2::6q22.3{r_arrow}6qter::1q31{r_arrow}1q32.3::6p23{r_arrow}6q22.3, 7pter{r_arrow}7q21.1::6p23{r_arrow}6pter, 2q33{r_arrow}2q37, 1::9p21{r_arrow}9qter. This analysis demonstrates the usefulness of FISH in characterizing complex chromosome rearrangements otherwise difficult to correctly interpret using classical cytogenetics alone.

  4. Mechanisms of Chromosome Congression during Mitosis

    Science.gov (United States)

    Maiato, Helder; Gomes, Ana Margarida; Sousa, Filipe; Barisic, Marin

    2017-01-01

    Chromosome congression during prometaphase culminates with the establishment of a metaphase plate, a hallmark of mitosis in metazoans. Classical views resulting from more than 100 years of research on this topic have attempted to explain chromosome congression based on the balance between opposing pulling and/or pushing forces that reach an equilibrium near the spindle equator. However, in mammalian cells, chromosome bi-orientation and force balance at kinetochores are not required for chromosome congression, whereas the mechanisms of chromosome congression are not necessarily involved in the maintenance of chromosome alignment after congression. Thus, chromosome congression and maintenance of alignment are determined by different principles. Moreover, it is now clear that not all chromosomes use the same mechanism for congressing to the spindle equator. Those chromosomes that are favorably positioned between both poles when the nuclear envelope breaks down use the so-called “direct congression” pathway in which chromosomes align after bi-orientation and the establishment of end-on kinetochore-microtubule attachments. This favors the balanced action of kinetochore pulling forces and polar ejection forces along chromosome arms that drive chromosome oscillatory movements during and after congression. The other pathway, which we call “peripheral congression”, is independent of end-on kinetochore microtubule-attachments and relies on the dominant and coordinated action of the kinetochore motors Dynein and Centromere Protein E (CENP-E) that mediate the lateral transport of peripheral chromosomes along microtubules, first towards the poles and subsequently towards the equator. How the opposite polarities of kinetochore motors are regulated in space and time to drive congression of peripheral chromosomes only now starts to be understood. This appears to be regulated by position-dependent phosphorylation of both Dynein and CENP-E and by spindle microtubule

  5. Mechanisms of Chromosome Congression during Mitosis

    Directory of Open Access Journals (Sweden)

    Helder Maiato

    2017-02-01

    Full Text Available Chromosome congression during prometaphase culminates with the establishment of a metaphase plate, a hallmark of mitosis in metazoans. Classical views resulting from more than 100 years of research on this topic have attempted to explain chromosome congression based on the balance between opposing pulling and/or pushing forces that reach an equilibrium near the spindle equator. However, in mammalian cells, chromosome bi-orientation and force balance at kinetochores are not required for chromosome congression, whereas the mechanisms of chromosome congression are not necessarily involved in the maintenance of chromosome alignment after congression. Thus, chromosome congression and maintenance of alignment are determined by different principles. Moreover, it is now clear that not all chromosomes use the same mechanism for congressing to the spindle equator. Those chromosomes that are favorably positioned between both poles when the nuclear envelope breaks down use the so-called “direct congression” pathway in which chromosomes align after bi-orientation and the establishment of end-on kinetochore-microtubule attachments. This favors the balanced action of kinetochore pulling forces and polar ejection forces along chromosome arms that drive chromosome oscillatory movements during and after congression. The other pathway, which we call “peripheral congression”, is independent of end-on kinetochore microtubule-attachments and relies on the dominant and coordinated action of the kinetochore motors Dynein and Centromere Protein E (CENP-E that mediate the lateral transport of peripheral chromosomes along microtubules, first towards the poles and subsequently towards the equator. How the opposite polarities of kinetochore motors are regulated in space and time to drive congression of peripheral chromosomes only now starts to be understood. This appears to be regulated by position-dependent phosphorylation of both Dynein and CENP-E and by spindle

  6. Pulsed flows at the high-altitude cusp poleward boundary, and associated ionospheric convection and particle signatures, during a Cluster - FAST - SuperDARN- Søndrestrøm conjunction under a southwest IMF

    Directory of Open Access Journals (Sweden)

    C. J. Farrugia

    2004-09-01

    Full Text Available Particle and magnetic field observations during a magnetic conjunction Cluster 1-FAST-Søndrestrøm within the field of view of SuperDARN radars on 21 January 2001 allow us to draw a detailed, comprehensive and self-consistent picture at three heights of signatures associated with transient reconnection under a steady south-westerly IMF (clock angle ≈130°. Cluster 1 was outbound through the high altitude (~12RE exterior northern cusp tailward of the bifurcation line (geomagnetic Bx>0 when a solar wind dynamic pressure release shifted the spacecraft into a boundary layer downstream of the cusp. The centerpiece of the investigation is a series of flow bursts observed there by the spacecraft, which were accompanied by strong field perturbations and tailward flow deflections. Analysis shows these to be Alfvén waves. We interpret these flow events as being due to a sequence of reconnected flux tubes, with field-aligned currents in the associated Alfvén waves carrying stresses to the underlying ionosphere, a view strengthened by the other observations. At the magnetic footprint of the region of Cluster flow bursts, FAST observed an ion energy-latitude disperison of the stepped cusp type, with individual cusp ion steps corresponding to individual flow bursts. Simultaneously, the SuperDARN Stokkseyri radar observed very strong poleward-moving radar auroral forms (PMRAFs which were conjugate to the flow bursts at Cluster. FAST was traversing these PMRAFs when it observed the cusp ion steps. The Søndrestrøm radar observed pulsed ionospheric flows (PIFs just poleward of the convection reversal boundary. As at Cluster, the flow was eastward (tailward, implying a coherent eastward (tailward motion of the hypothesized open flux tubes. The joint Søndrestrøm and FAST observations indicate that the open/closed field line boundary was equatorward of the convection reversal boundary by ~2°. The unprecedented accuracy

  7. Uniparental disomy of the entire X chromosome in Turner syndrome patient-specific induced pluripotent stem cells.

    Science.gov (United States)

    Luo, Yumei; Zhu, Detu; Du, Rong; Gong, Yu; Xie, Chun; Xu, Xiangye; Fan, Yong; Yu, Bolan; Sun, Xiaofang; Chen, Yaoyong

    2015-01-01

    The human induced pluripotent stem cell (iPSC) technique promises to provide an unlimited, reliable source of genetically matched pluripotent cells for personalized therapy and disease modeling. Recently, it is observed that cells with ring chromosomes 13 or 17 autonomously correct the defects via compensatory uniparental disomy during cellular reprogramming to iPSCs. This breakthrough finding suggests a potential therapeutic approach to repair large-scale chromosomal aberrations. However, due to the scarceness of ring chromosome samples, the reproducibility of this approach in different individuals is not carefully evaluated yet. Moreover, the underlying mechanism and the applicability to other types of chromosomal aberrations remain unknown. Here we generated iPSCs from four 45,X chorionic villous fibroblast lines and found that only one reprogrammed line acquired 46,XX karyotype via uniparental disomy of the entire X chromosome. The karyotype correction was reproducible in the same cell line by either retroviral or episomal reprogramming. The karyotype-corrected iPSCs were subject to X chromosome inactivation and obtained better colony morphology and higher proliferation rate than other uncorrected ones. Further transcriptomic comparison among the fibroblast lines identified a distinct expression pattern of cell cycle regulators in the uncorrectable ones. These findings demonstrate that the iPSC technique holds the potential to correct X monosomy, but the correction rate is very low, probably due to differential regulation of cell cycle genes between individuals. Our data strongly suggest that more systematic investigations are needed before defining the iPSC technique as a novel means of chromosome therapy.

  8. Chromosomal stickiness and related meiotic irregularities in Inula racemosa - a critically endangered medicinal herb of North Western Himalayas

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    Peerzada Arshid Shabir

    2013-07-01

    Full Text Available Background: The species Inula racemosa, a rare species of Kashmir Himalaya, has been included in the list of endangered species of India. In the present study, we aimed to make a more formal quantitative analysis of the fertility of I. racemosa, wild as well as transplanted populations, using a meiotic behaviour analysis and pollen viability test. Materials and Methods: Inflorescences at an ideal stage for meiotic study were collected and fixed in acetic ethanol (1:3 for 24 h and stored in 70% alcohol under refrigeration at 4˚C until use. For slide preparation the anthers were squashed in 2% acetocarmine. Results: The present study revealed a peculiar chromosomal stickiness and formation of interbivalent chromatin connections among 2-4 bivalents. This stickiness of chromosomes along with interbivalent chromatin connections impairs the correct segregation of chromosomes, as a result single and double chromosomal bridges of different thickness, different number of lagging chromosomes, unequal separation, and multipolarity were continuously observed from anaphase I to microspore stage. Consequent to stickiness and associated meiotic abnormalities, the pollen grains varied greatly in size, individuals show 24.05-38.83% pollen sterility. Conclusion: The presence of sticky chromosomes in I. racemosa impairs the correct segregation during anaphase which compromises the pollen viability of the species. Although the percentage of pollen sterility was not completely concord to the high rates of observed chromosomal abnormalities but the findings can aid in the successful conservation and management of the species.

  9. Whole chromosome painting of B chromosomes of the red-eye tetra Moenkhausia sanctaefilomenae (Teleostei, Characidae)

    Science.gov (United States)

    Scudeler, Patricia Elda Sobrinho; Diniz, Débora; Wasko, Adriane Pinto; Oliveira, Claudio; Foresti, Fausto

    2015-01-01

    Abstract B chromosomes are dispensable genomic elements found in different groups of animals and plants. In the present study, a whole chromosome probe was generated from a specific heterochromatic B chromosome occurring in cells of the characidae fish Moenkhausia sanctaefilomenae (Steindachner, 1907). The chromosome painting probes were used in fluorescence in situ hybridization (FISH) experiments for the assessment of metaphase chromosomes obtained from individuals from three populations of Moenkhausia sanctaefilomenae. The results revealed that DNA sequences were shared between a specific B chromosome and many chromosomes of the A complement in all populations analyzed, suggesting a possible intra-specific origin of these B chromosomes. However, no hybridization signals were observed in other B chromosomes found in the same individuals, implying a possible independent origin of B chromosome variants in this species. FISH experiments using 18S rDNA probes revealed the presence of non-active ribosomal genes in some B chromosomes and in some chromosomes of the A complement, suggesting that at least two types of B chromosomes had an independent origin. The role of heterochromatic segments and ribosomal sequences in the origin of B chromosomes were discussed. PMID:26753081

  10. Chromosomal divergence and evolutionary inferences in Rhodniini based on the chromosomal location of ribosomal genes

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    Sebastian Pita

    2013-05-01

    Full Text Available In this study, we used fluorescence in situ hybridisation to determine the chromosomal location of 45S rDNA clusters in 10 species of the tribe Rhodniini (Hemiptera: Reduviidae: Triatominae. The results showed striking inter and intraspecific variability, with the location of the rDNA clusters restricted to sex chromosomes with two patterns: either on one (X chromosome or both sex chromosomes (X and Y chromosomes. This variation occurs within a genus that has an unchanging diploid chromosome number (2n = 22, including 20 autosomes and 2 sex chromosomes and a similar chromosome size and genomic DNA content, reflecting a genome dynamic not revealed by these chromosome traits. The rDNA variation in closely related species and the intraspecific polymorphism in Rhodnius ecuadoriensis suggested that the chromosomal position of rDNA clusters might be a useful marker to identify recently diverged species or populations. We discuss the ancestral position of ribosomal genes in the tribe Rhodniini and the possible mechanisms involved in the variation of the rDNA clusters, including the loss of rDNA loci on the Y chromosome, transposition and ectopic pairing. The last two processes involve chromosomal exchanges between both sex chromosomes, in contrast to the widely accepted idea that the achiasmatic sex chromosomes of Heteroptera do not interchange sequences.

  11. Whole chromosome painting of B chromosomes of the red-eye tetra Moenkhausia sanctaefilomenae (Teleostei, Characidae).

    Science.gov (United States)

    Scudeler, Patricia Elda Sobrinho; Diniz, Débora; Wasko, Adriane Pinto; Oliveira, Claudio; Foresti, Fausto

    2015-01-01

    B chromosomes are dispensable genomic elements found in different groups of animals and plants. In the present study, a whole chromosome probe was generated from a specific heterochromatic B chromosome occurring in cells of the characidae fish Moenkhausia sanctaefilomenae (Steindachner, 1907). The chromosome painting probes were used in fluorescence in situ hybridization (FISH) experiments for the assessment of metaphase chromosomes obtained from individuals from three populations of Moenkhausia sanctaefilomenae. The results revealed that DNA sequences were shared between a specific B chromosome and many chromosomes of the A complement in all populations analyzed, suggesting a possible intra-specific origin of these B chromosomes. However, no hybridization signals were observed in other B chromosomes found in the same individuals, implying a possible independent origin of B chromosome variants in this species. FISH experiments using 18S rDNA probes revealed the presence of non-active ribosomal genes in some B chromosomes and in some chromosomes of the A complement, suggesting that at least two types of B chromosomes had an independent origin. The role of heterochromatic segments and ribosomal sequences in the origin of B chromosomes were discussed.

  12. Chromosome aberrations induced by zebularine in triticale.

    Science.gov (United States)

    Ma, Xuhui; Wang, Qing; Wang, Yanzhi; Ma, Jieyun; Wu, Nan; Ni, Shuang; Luo, Tengxiao; Zhuang, Lifang; Chu, Chenggen; Cho, Seong-Woo; Tsujimoto, Hisashi; Qi, Zengjun

    2016-07-01

    Chromosome engineering is an important approach for generating wheat germplasm. Efficient development of chromosome aberrations will facilitate the introgression and application of alien genes in wheat. In this study, zebularine, a DNA methylation transferase inhibitor, was successfully used to induce chromosome aberrations in the octoploid triticale cultivar Jinghui#1. Dry seeds were soaked in zebularine solutions (250, 500, and 750 μmol/L) for 24 h, and the 500 μmol/L treatment was tested in three additional treatment times, i.e., 12, 36, and 48 h. All treatments induced aberrations involving wheat and rye chromosomes. Of the 920 cells observed in 67 M1 plants, 340 (37.0%) carried 817 aberrations with an average of 0.89 aberrations per cell (range: 0-12). The aberrations included probable deletions, telosomes and acentric fragments (49.0%), large segmental translocations (28.9%), small segmental translocations (17.1%), intercalary translocations (2.6%), long chromosomes that could carry more than one centromere (2.0%), and ring chromosomes (0.5%). Of 510 M2 plants analyzed, 110 (21.6%) were found to carry stable aberrations. Such aberrations included 79 with varied rye chromosome numbers, 7 with wheat and rye chromosome translocations, 15 with possible rye telosomes/deletions, and 9 with complex aberrations involving variation in rye chromosome number and wheat-rye translocations. These indicated that aberrations induced by zebularine can be steadily transmitted, suggesting that zebularine is a new efficient agent for chromosome manipulation.

  13. The importance of having two X chromosomes.

    Science.gov (United States)

    Arnold, Arthur P; Reue, Karen; Eghbali, Mansoureh; Vilain, Eric; Chen, Xuqi; Ghahramani, Negar; Itoh, Yuichiro; Li, Jingyuan; Link, Jenny C; Ngun, Tuck; Williams-Burris, Shayna M

    2016-02-19

    Historically, it was thought that the number of X chromosomes plays little role in causing sex differences in traits. Recently, selected mouse models have been used increasingly to compare mice with the same type of gonad but with one versus two copies of the X chromosome. Study of these models demonstrates that mice with one X chromosome can be strikingly different from those with two X chromosomes, when the differences are not attributable to confounding group differences in gonadal hormones. The number of X chromosomes affects adiposity and metabolic disease, cardiovascular ischaemia/reperfusion injury and behaviour. The effects of X chromosome number are likely the result of inherent differences in expression of X genes that escape inactivation, and are therefore expressed from both X chromosomes in XX mice, resulting in a higher level of expression when two X chromosomes are present. The effects of X chromosome number contribute to sex differences in disease phenotypes, and may explain some features of X chromosome aneuploidies such as in Turner and Klinefelter syndromes.

  14. Chromosome analysis of arsenic affected cattle

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    S. Shekhar

    2014-10-01

    Full Text Available Aim: The aim was to study the chromosome analysis of arsenic affected cattle. Materials and Methods: 27 female cattle (21 arsenic affected and 6 normal were selected for cytogenetical study. The blood samples were collected, incubated, and cultured using appropriate media and specific methods. The samples were analyzed for chromosome number and morphology, relative length of the chromosome, arm ratio, and centromere index of X chromosome and chromosomal abnormalities in arsenic affected cattle to that of normal ones. Results: The diploid number of metaphase chromosomes in arsenic affected cattle as well as in normal cattle were all 2n=60, 58 being autosomes and 2 being sex chromosomes. From the centromeric position, karyotyping studies revealed that all the 29 pair of autosomes was found to be acrocentric or telocentric, and the sex chromosomes (XX were submetacentric in both normal and arsenic affected cattle. The relative length of all the autosome pairs and sex chrosomosome pair was found to be higher in normal than that of arsenic affected cattle. The mean arm ratio of X-chromosome was higher in normal than that of arsenic affected cattle, but it is reverse in case of centromere index value of X-chromosome. There was no significant difference of arm ratio and centromere index of X-chromosomes between arsenic affected and normal cattle. No chromosomal abnormalities were found in arsenic affected cattle. Conclusion: The chromosome analysis of arsenic affected cattle in West Bengal reported for the first time in this present study which may serve as a guideline for future studies in other species. These reference values will also help in comparison of cytological studies of arsenic affected cattle to that of various toxicants.

  15. Ultrasound screening program for chromosomal abnormalities: The first 2000 women

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    Novakov-Mikić Aleksandra

    2007-01-01

    Full Text Available Introduction Screening for chromosomal abnormalities identifies the group of women at higher risk for having a fetus with chromosomal abnormalities and the need for fetal karyotyping. In order to provide high quality screening, strict criteria for certification of operators are introduced, issued by the Fetal Medicine Foundation (FMF, which enables annual external control of results. The aim of this study was to review the results of five-year prenatal screening for chromosomal abnormalities in Novi Sad, Serbia. Material and methods Ultrasound screening at 11-15 weeks gestation was performed, assessing fetal morphology, crowner-rump length and nuchal translucency (NT according to the FMF guidelines. Risk for chromosomal abnormalities included the initial risk, based on maternal age, gestational age and anamnestic data, and corrected risk, which took into account the initial risk and the value of the nuchal translucency. The corrected risk was issued by the computer program issued by the FMF. Results During the period 1999 - 2004, 4580 pregnant women were scanned. The risk for chromosomal abnormality was calculated using the FMF program in 2245 cases and the outcome was known in 1406 cases. The majority of women were between 25 and 29 years of age (37%, and 12% were older than 35 years. NT was below the median in 43% of cases and above in 57%, 3.7% of cases were above the 95th centile. 89% of women were younger than 35, and the risk was reduced in 97% of cases. There were three false negative cases. In 3% of women from this group the risk was increased, out of which there were five cases of trisomy 21 and two terminations were done due to major anomalies. In the group of women over 35 years, the risk was reduced in 95% of cases and in all of them but two the karyotype was normal. In one of the two cases there was a large omphalocele and the karyotype was trisomy 18, and in the other fetus appeared normal, but after amniocentesis due to maternal

  16. Sgo1 regulates both condensin and Ipl1/Aurora B to promote chromosome biorientation.

    Directory of Open Access Journals (Sweden)

    Karolina Peplowska

    2014-06-01

    Full Text Available Correct chromosome segregation is essential in order to prevent aneuploidy. To segregate sister chromatids equally to daughter cells, the sisters must attach to microtubules emanating from opposite spindle poles. This so-called biorientation manifests itself by increased tension and conformational changes across kinetochores and pericentric chromatin. Tensionless attachments are dissolved by the activity of the conserved mitotic kinase Aurora B/Ipl1, thereby promoting the formation of correctly attached chromosomes. Recruitment of the conserved centromeric protein shugoshin is essential for biorientation, but its exact role has been enigmatic. Here, we identify a novel function of shugoshin (Sgo1 in budding yeast that together with the protein phosphatase PP2A-Rts1 ensures localization of condensin to the centromeric chromatin in yeast Saccharomyces cerevisiae. Failure to recruit condensin results in an abnormal conformation of the pericentric region and impairs the correction of tensionless chromosome attachments. Moreover, we found that shugoshin is required for maintaining Aurora B/Ipl1 localization on kinetochores during metaphase. Thus, shugoshin has a dual function in promoting biorientation in budding yeast: first, by its ability to facilitate condensin recruitment it modulates the conformation of the pericentric chromatin. Second, shugoshin contributes to the maintenance of Aurora B/Ipl1 at the kinetochore during gradual establishment of bipolarity in budding yeast mitosis. Our findings identify shugoshin as a versatile molecular adaptor that governs chromosome biorientation.

  17. CORRECTING STUDENTS’ HOMEWORK

    Institute of Scientific and Technical Information of China (English)

    1996-01-01

    IntroductionI have been teaching English for ten years and like many other teachers in middle schools.I teach threebig classes each year.Before I had the opportunity to further my study in the SMSTT project run jointlyby the British Council and the State Education Commission of China at Southwest China TeachersUniversity.I found it somewhat difficult to correct students homework since I had so many students.Now I still have three big classes.but I have found it casier to correct students homework since I havebeen combining the techniques learned in the project with my own successful experience.In this article.I attempt to discuss my approach to correcting students homework.I hope that it will be of some use tothose who have not vet had the opportunity to further their training.

  18. Model Correction Factor Method

    DEFF Research Database (Denmark)

    Christensen, Claus; Randrup-Thomsen, Søren; Morsing Johannesen, Johannes

    1997-01-01

    The model correction factor method is proposed as an alternative to traditional polynomial based response surface techniques in structural reliability considering a computationally time consuming limit state procedure as a 'black box'. The class of polynomial functions is replaced by a limit...... statebased on an idealized mechanical model to be adapted to the original limit state by the model correction factor. Reliable approximations are obtained by iterative use of gradient information on the original limit state function analogously to previous response surface approaches. However, the strength...... of the model correction factor method, is that in simpler form not using gradient information on the original limit state function or only using this information once, a drastic reduction of the number of limit state evaluation is obtained together with good approximations on the reliability. Methods...

  19. Deciphering evolutionary strata on plant sex chromosomes and fungal mating-type chromosomes through compositional segmentation.

    Science.gov (United States)

    Pandey, Ravi S; Azad, Rajeev K

    2016-03-01

    Sex chromosomes have evolved from a pair of homologous autosomes which differentiated into sex determination systems, such as XY or ZW system, as a consequence of successive recombination suppression between the gametologous chromosomes. Identifying the regions of recombination suppression, namely, the "evolutionary strata", is central to understanding the history and dynamics of sex chromosome evolution. Evolution of sex chromosomes as a consequence of serial recombination suppressions is well-studied for mammals and birds, but not for plants, although 48 dioecious plants have already been reported. Only two plants Silene latifolia and papaya have been studied until now for the presence of evolutionary strata on their X chromosomes, made possible by the sequencing of sex-linked genes on both the X and Y chromosomes, which is a requirement of all current methods that determine stratum structure based on the comparison of gametologous sex chromosomes. To circumvent this limitation and detect strata even if only the sequence of sex chromosome in the homogametic sex (i.e. X or Z chromosome) is available, we have developed an integrated segmentation and clustering method. In application to gene sequences on the papaya X chromosome and protein-coding sequences on the S. latifolia X chromosome, our method could decipher all known evolutionary strata, as reported by previous studies. Our method, after validating on known strata on the papaya and S. latifolia X chromosome, was applied to the chromosome 19 of Populus trichocarpa, an incipient sex chromosome, deciphering two, yet unknown, evolutionary strata. In addition, we applied this approach to the recently sequenced sex chromosome V of the brown alga Ectocarpus sp. that has a haploid sex determination system (UV system) recovering the sex determining and pseudoautosomal regions, and then to the mating-type chromosomes of an anther-smut fungus Microbotryum lychnidis-dioicae predicting five strata in the non

  20. Scaling Chromosomes for an Evolutionary Karyotype: A Chromosomal Tradeoff between Size and Number across Woody Species.

    Science.gov (United States)

    Liang, Guolu; Chen, Hong

    2015-01-01

    This study aims to examine the expected scaling relationships between chromosome size and number across woody species and to clarify the importance of the scaling for the maintenance of chromosome diversity by analyzing the scaling at the inter- & intra-chromosomal level. To achieve for the goals, chromosome trait data were extracted for 191 woody species (including 56 evergreen species and 135 deciduous species) from the available literature. Cross-species analyses revealed a tradeoff among chromosomes between chromosome size and number, demonstrating there is selective mechanism crossing chromosomes among woody species. And the explanations for the result were presented from intra- to inter-chromosome contexts that the scaling may be compromises among scale symmetry, mechanical requirements, and resource allocation across chromosomes. Therein, a 3/4 scaling pattern was observed between total chromosomes and m-chromosomes within nucleus which may imply total chromosomes may evolve from more to less. In addition, the primary evolutionary trend of karyotype and the role of m-chromosomes in the process of karyotype evolution were also discussed.

  1. Microdissection and chromosome painting of X and B chromosomes in Locusta migratoria.

    Science.gov (United States)

    Teruel, María; Cabrero, Josefa; Montiel, Eugenia E; Acosta, Manuel J; Sánchez, Antonio; Camacho, Juan Pedro M

    2009-01-01

    Acquisition of knowledge of the nature and DNA content of B chromosomes has been triggered by a collection of molecular techniques, one of which, microdissection, has provided interesting results in a number of B chromosome systems. Here we provide the first data on the molecular composition of B chromosomes in Locusta migratoria, after microdissection of the B and X chromosomes, DNA amplification by one (B) or two (X) different methods, and chromosome painting. The results showed that B chromosomes share at least two types of repetitive DNA sequences with the A chromosomes, suggesting that Bs in this species most likely arose intraspecifically. One of these repetitive DNAs is located on the heterochromatic distal half of the B chromosome and in the pericentromeric regions of about half of the A chromosomes, including the X. The other type of repetitive DNA is located interspersedly over the non-centromeric euchromatic regions of all A chromosomes and in an interstitial part of the proximal euchromatic half of the B chromosome. Chromosome painting, however, did not provide results sufficiently reliable to determine, in this species, which A chromosome gave rise to the B; this might be done by detailed analysis of the microdissected DNA sequences.

  2. Chromosome-specific segmentation revealed by structural analysis of individually isolated chromosomes.

    Science.gov (United States)

    Kitada, Kunio; Taima, Akira; Ogasawara, Kiyomoto; Metsugi, Shouichi; Aikawa, Satoko

    2011-04-01

    Analysis of structural rearrangements at the individual chromosomal level is still technologically challenging. Here we optimized a chromosome isolation method using fluorescent marker-assisted laser-capture and laser-beam microdissection and applied it to structural analysis of two aberrant chromosomes found in a lung cancer cell line. A high-density array-comparative genomic hybridization (array-CGH) analysis of DNA samples prepared from each of the chromosomes revealed that these two chromosomes contained 296 and 263 segments, respectively, ranging from 1.5 kb to 784.3 kb in size, derived from different portions of chromosome 8. Among these segments, 242 were common in both aberrant chromosomes, but 75 were found to be chromosome-specific. Sequences of 263 junction sites connecting the ends of segments were determined using a PCR/Sanger-sequencing procedure. Overlapping microhomologies were found at 169 junction sites. Junction partners came from various portions of chromosome 8 and no biased pattern in the positional distribution of junction partners was detected. These structural characteristics suggested the occurrence of random fragmentation of the entire chromosome 8 followed by random rejoining of these fragments. Based on that, we proposed a model to explain how these aberrant chromosomes are formed. Through these structural analyses, it was demonstrated that the optimized chromosome isolation method described here can provide high-quality chromosomal DNA for high resolution array-CGH analysis and probably for massively parallel sequencing analysis.

  3. Automating dicentric chromosome detection from cytogenetic biodosimetry data.

    Science.gov (United States)

    Rogan, Peter K; Li, Yanxin; Wickramasinghe, Asanka; Subasinghe, Akila; Caminsky, Natasha; Khan, Wahab; Samarabandu, Jagath; Wilkins, Ruth; Flegal, Farrah; Knoll, Joan H

    2014-06-01

    We present a prototype software system with sufficient capacity and speed to estimate radiation exposures in a mass casualty event by counting dicentric chromosomes (DCs) in metaphase cells from many individuals. Top-ranked metaphase cell images are segmented by classifying and defining chromosomes with an active contour gradient vector field (GVF) and by determining centromere locations along the centreline. The centreline is extracted by discrete curve evolution (DCE) skeleton branch pruning and curve interpolation. Centromere detection minimises the global width and DAPI-staining intensity profiles along the centreline. A second centromere is identified by reapplying this procedure after masking the first. Dicentrics can be identified from features that capture width and intensity profile characteristics as well as local shape features of the object contour at candidate pixel locations. The correct location of the centromere is also refined in chromosomes with sister chromatid separation. The overall algorithm has both high sensitivity (85 %) and specificity (94 %). Results are independent of the shape and structure of chromosomes in different cells, or the laboratory preparation protocol followed. The prototype software was recoded in C++/OpenCV; image processing was accelerated by data and task parallelisation with Message Passaging Interface and Intel Threading Building Blocks and an asynchronous non-blocking I/O strategy. Relative to a serial process, metaphase ranking, GVF and DCE are, respectively, 100 and 300-fold faster on an 8-core desktop and 64-core cluster computers. The software was then ported to a 1024-core supercomputer, which processed 200 metaphase images each from 1025 specimens in 1.4 h.

  4. A Pair of Maternal Chromosomes Derived from Meiotic Nondisjunction in Trisomy 21 Affects Nuclear Architecture and Transcriptional Regulation.

    Science.gov (United States)

    Omori, Sayaka; Tanabe, Hideyuki; Banno, Kimihiko; Tsuji, Ayumi; Nawa, Nobutoshi; Hirata, Katsuya; Kawatani, Keiji; Kokubu, Chikara; Takeda, Junji; Taniguchi, Hidetoshi; Arahori, Hitomi; Wada, Kazuko; Kitabatake, Yasuji; Ozono, Keiichi

    2017-04-10

    Eukaryotic genomes are organised into complex higher-order structures within the nucleus, and the three-dimensional arrangement of chromosomes is functionally important for global gene regulation. The existence of supernumerary chromosome 21 in Down syndrome may perturb the nuclear architecture at different levels, which is normally optimised to maintain the physiological balance of gene expression. However, it has not been clearly elucidated whether and how aberrant configuration of chromosomes affects gene activities. To investigate the effects of trisomy 21 on nuclear organisation and gene expression, we performed three-dimensional fluorescent imaging analysis of chromosome-edited human induced pluripotent stem cells (iPSCs), which enabled identification of the parental origin of the three copies of chromosome 21. We found that two copies of maternal chromosomes resulting from meiotic nondisjunction had a higher tendency to form an adjacent pair and were located relatively distant from the nuclear membrane, suggesting the conserved interaction between these homologous chromosomes. Transcriptional profiling of parental-origin-specific corrected disomy 21 iPSC lines indicated upregulated expression of the maternal alleles for a group of genes, which was accompanied by a fluctuating expression pattern. These results suggest the unique effects of a pair of maternal chromosomes in trisomy 21, which may contribute to the pathological phenotype.

  5. Correction of ocular dystopia.

    Science.gov (United States)

    Janecka, I P

    1996-04-01

    The purpose of this study was to examine results with elective surgical correction of enophthalmos. The study was a retrospective assessment in a university-based referral practice. A consecutive sample of 10 patients who developed ocular dystopia following orbital trauma was examined. The main outcome measures were a subjective evaluation by patients and objective measurements of patients' eye position. The intervention was three-dimensional orbital reconstruction with titanium plates. It is concluded that satisfactory correction of enophthalmos and ocular dystopia can be achieved with elective surgery using titanium plates. In addition, intraoperative measurements of eye position in three planes increases the precision of surgery.

  6. Evidence that Aurora B is implicated in spindle checkpoint signalling independently of error correction.

    Science.gov (United States)

    Santaguida, Stefano; Vernieri, Claudio; Villa, Fabrizio; Ciliberto, Andrea; Musacchio, Andrea

    2011-04-20

    Fidelity of chromosome segregation is ensured by a tension-dependent error correction system that prevents stabilization of incorrect chromosome-microtubule attachments. Unattached or incorrectly attached chromosomes also activate the spindle assembly checkpoint, thus delaying mitotic exit until all chromosomes are bioriented. The Aurora B kinase is widely recognized as a component of error correction. Conversely, its role in the checkpoint is controversial. Here, we report an analysis of the role of Aurora B in the spindle checkpoint under conditions believed to uncouple the effects of Aurora B inhibition on the checkpoint from those on error correction. Partial inhibition of several checkpoint and kinetochore components, including Mps1 and Ndc80, strongly synergizes with inhibition of Aurora B activity and dramatically affects the ability of cells to arrest in mitosis in the presence of spindle poisons. Thus, Aurora B might contribute to spindle checkpoint signalling independently of error correction. Our results support a model in which Aurora B is at the apex of a signalling pyramid whose sensory apparatus promotes the concomitant activation of error correction and checkpoint signalling pathways.

  7. Sexual maldevelopment and sex reversal, chromosomal causes.

    Science.gov (United States)

    Magenis, R Ellen

    2006-01-01

    The SRY gene on the Y chromosome is the testis determining factor (TDF). It is therefore the initial male determining factor. However, phenotypic sex determination includes a cascade of genes located on autosomes as well as sex chromosomes. Aberrations of these genes may cause sexual maldevelopment or sex reversal. Abnormalities may include single gene mutations and gene loss or gain-changes may involve only sex organs or may be part of syndromes. These changes may also arise as chromosome abnormalities involving contiguous genes. Eight cases with chromosomal abnormalities involving different causative mechanisms are described herein. The most common cause is nondisjunction, including loss or gain of sex chromosomes. Less common causes are mispairing and crossing over in meiosis, chromosome breaks with repair, nonhomologous pairing due to low copy repeats and crossing over, and translocation (familial or de novo) with segregation. Cases include: [see: text].

  8. Chromosome engineering: power tools for plant genetics.

    Science.gov (United States)

    Chan, Simon W L

    2010-12-01

    The term "chromosome engineering" describes technologies in which chromosomes are manipulated to change their mode of genetic inheritance. This review examines recent innovations in chromosome engineering that promise to greatly increase the efficiency of plant breeding. Haploid Arabidopsis thaliana have been produced by altering the kinetochore protein CENH3, yielding instant homozygous lines. Haploid production will facilitate reverse breeding, a method that downregulates recombination to ensure progeny contain intact parental chromosomes. Another chromosome engineering success is the conversion of meiosis into mitosis, which produces diploid gametes that are clones of the parent plant. This is a key step in apomixis (asexual reproduction through seeds) and could help to preserve hybrid vigor in the future. New homologous recombination methods in plants will potentiate many chromosome engineering applications. Copyright © 2010 Elsevier Ltd. All rights reserved.

  9. Building bridges within the bacterial chromosome.

    Science.gov (United States)

    Song, Dan; Loparo, Joseph J

    2015-03-01

    All organisms must dramatically compact their genomes to accommodate DNA within the cell. Bacteria use a set of DNA-binding proteins with low sequence specificity called nucleoid-associated proteins (NAPs) to assist in chromosome condensation and organization. By bending or bridging DNA, NAPs also facilitate chromosome segregation and regulate gene expression. Over the past decade, emerging single-molecule and chromosome conformation capture techniques have investigated the molecular mechanisms by which NAPs remodel and organize the bacterial chromosome. In this review we describe how such approaches reveal the biochemical mechanisms of three NAPs that are believed to facilitate DNA bridging: histone-like nucleoid structuring protein (H-NS), ParB, and structural maintenance of chromosomes (SMC). These three proteins form qualitatively different DNA bridges, leading to varied effects on transcription and chromosome segregation.

  10. Fast chromosome karyotyping by auction algorithm.

    Science.gov (United States)

    Wu, Xiaolin; Dumitrescu, Sorina; Biyani, Pravesh; Wu, Qiang

    2005-01-01

    We consider the problem of automated classification of human chromosomes or karyotyping and study discrete optimisation algorithms to solve the problem as one of joint maximum likelihood classification. We demonstrate that the auction algorithm offers a simpler and more efficient solution for chromosome karyotyping than the previously known transportation algorithm, while still guaranteeing global optimality. This improvement in algorithm efficiency is made possible by first casting chromosome karyotyping into a problem of optimal assignment and then exploiting the sparsity of the assignment problem due to the inherent properties of chromosome data. Furthermore, the auction algorithm also works when the chromosome data in a cell are incomplete due to the exclusion of overlapped or severely bent chromosomes, as often encountered in routine quality data.

  11. The effect of maternal age on chromosomal anomaly rate and spectrum in recurrent miscarriage.

    Science.gov (United States)

    Grande, Maribel; Borrell, Antoni; Garcia-Posada, Raul; Borobio, Virginia; Muñoz, Miriam; Creus, Montserrat; Soler, Anna; Sanchez, Aurora; Balasch, Juan

    2012-10-01

    Is there any effect of maternal age on chromosomal anomaly rate and spectrum in recurrent miscarriage? There was no significant difference in the chromosome abnormality rate between sporadic and recurrent miscarriage but the chromosome abnormality rate increased significantly with maternal age. About 50-70% of non-recurrent miscarriages occur because of a chromosomal anomaly, but no agreement about the effect of either maternal age or the number of previous miscarriages on the chromosomal anomaly rate has been reached. A retrospective cohort of 353 miscarriages successfully karyotyped in the same center between 2002 and 2011, grouped according to the number of miscarriages and maternal age. Among the 353 women, 153 were below 35 years (73 with sporadic, 48 with two and 32 with recurrent miscarriage) and 200 were 35 years or more (81 with sporadic, 55 with two and 64 with recurrent miscarriage). The chromosomal anomaly rate and the anomaly spectrum were compared between sporadic and recurrent miscarriage, within the two maternal age groups, using the chi-square test and the Bonferroni correction for all the P-values. Risk of chromosomal anomaly was estimated for maternal age, number of miscarriages and previous live births by multivariate binary logistic regression analysis. Sporadic and recurrent miscarriage did not show significantly different chromosomal anomaly rates (68 versus 60%) and maternal age was the only statistically significant predictor of the chromosomal anomaly risk we identified. Some trends were observed in the chromosomal anomaly spectrum when sporadic was compared with recurrent miscarriage: recurrent miscarriage exhibited a decrease in viable trisomies (37 versus 11%) and an increase in non-viable trisomies (38 versus 57%) in women >35 years, together with an increase in unbalanced structural anomalies (4.9 versus 29%) in younger women. The mixed origin of our study population, and the limited number of recurrent miscarriages, particularly in

  12. Chromosomal rearrangements in Tourette syndrome

    DEFF Research Database (Denmark)

    Bertelsen, Birgitte; Debes, Nanette Mol; Hjermind, Lena E

    2013-01-01

    Tourette syndrome (TS) is a childhood-onset complex neurobiological disorder characterized by a combination of persistent motor and vocal tics and frequent presence of other neuropsychiatric comorbidities. TS shares the fate of other complex disorders, where the genetic etiology is largely unknown......, and identification of susceptibility genes through linkage and association studies has been complicated due to inherent difficulties such as no clear mode of inheritance, genetic heterogeneity, and apparently incomplete penetrance. Positional cloning through mapping of disease-related chromosome rearrangements has...

  13. Meiosis I: When Chromosomes Undergo Extreme Makeover

    OpenAIRE

    Miller, Matthew P; Amon, Angelika; Ünal, Elçin

    2013-01-01

    The ultimate success of cell division relies on the accurate partitioning of the genetic material. Errors in this process occur in nearly all tumors and are the leading cause of miscarriages and congenital birth defects in humans. Two cell divisions, mitosis and meiosis, use common as well as unique mechanisms to ensure faithful chromosome segregation. In mitosis, alternating rounds of DNA replication and chromosome segregation preserves the chromosome complement of the progenitor cell. In co...

  14. Research on automatic human chromosome image analysis

    Science.gov (United States)

    Ming, Delie; Tian, Jinwen; Liu, Jian

    2007-11-01

    Human chromosome karyotyping is one of the essential tasks in cytogenetics, especially in genetic syndrome diagnoses. In this thesis, an automatic procedure is introduced for human chromosome image analysis. According to different status of touching and overlapping chromosomes, several segmentation methods are proposed to achieve the best results. Medial axis is extracted by the middle point algorithm. Chromosome band is enhanced by the algorithm based on multiscale B-spline wavelets, extracted by average gray profile, gradient profile and shape profile, and calculated by the WDD (Weighted Density Distribution) descriptors. The multilayer classifier is used in classification. Experiment results demonstrate that the algorithms perform well.

  15. Genome architecture: domain organization of interphase chromosomes.

    Science.gov (United States)

    Bickmore, Wendy A; van Steensel, Bas

    2013-03-14

    The architecture of interphase chromosomes is important for the regulation of gene expression and genome maintenance. Chromosomes are linearly segmented into hundreds of domains with different protein compositions. Furthermore, the spatial organization of chromosomes is nonrandom and is characterized by many local and long-range contacts among genes and other sequence elements. A variety of genome-wide mapping techniques have made it possible to chart these properties at high resolution. Combined with microscopy and computational modeling, the results begin to yield a more coherent picture that integrates linear and three-dimensional (3D) views of chromosome organization in relation to gene regulation and other nuclear functions.

  16. Meiotic chromosome abnormalities in human spermatogenesis.

    Science.gov (United States)

    Martin, Renée H

    2006-08-01

    The last few years have witnessed an explosion in the information about chromosome abnormalities in human sperm and the meiotic events that predispose to these abnormalities. We have determined that all chromosomes are susceptible to nondisjunction, but chromosomes 21 and 22 and, especially, the sex chromosomes have an increased frequency of aneuploidy. Studies are just beginning on the effects of potential mutagens on the chromosomal constitution of human sperm. The effects of pesticides and cancer therapeutic agents have been reviewed. In the last decade, there has been a great impetus to study chromosome abnormalities in sperm from infertile men because the advent of intracytoplasmic sperm injection (ICSI) made it possible for these men to father pregnancies. A large number of studies have demonstrated that infertile men have an increased frequency of chromosomally abnormal sperm and children, even when they have a normal somatic karyotype. Meiotic studies on the pachytene stage of spermatogenesis have demonstrated that infertile men have impaired chromosome synapsis, a significantly decreased frequency of recombination, and an increased frequency of chromosomes completely lacking a recombination site. Such errors make these cells susceptible to meiotic arrest and the production of aneuploid gametes.

  17. Refraction corrections for surveying

    Science.gov (United States)

    Lear, W. M.

    1980-01-01

    Optical measurements of range and elevation angles are distorted by refraction of Earth's atmosphere. Theoretical discussion of effect, along with equations for determining exact range and elevation corrections, is presented in report. Potentially useful in optical site surveying and related applications, analysis is easily programmed on pocket calculator. Input to equation is measured range and measured elevation; output is true range and true elevation.

  18. Renormalons and Power Corrections

    CERN Document Server

    Beneke, Martin

    2000-01-01

    Even for short-distance dominated observables the QCD perturbation expansion is never complete. The divergence of the expansion through infrared renormalons provides formal evidence of this fact. In this article we review how this apparent failure can be turned into a useful tool to investigate power corrections to hard processes in QCD.

  19. Radiative Corrections and Z'

    CERN Document Server

    Erler, Jens

    2009-01-01

    Radiative corrections to parity violating deep inelastic electron scattering are reviewed including a discussion of the renormalization group evolution of the weak mixing angle. Recently obtained results on hypothetical Z' bosons - for which parity violating observables play an important role - are also presented.

  20. General forecasting correcting formula

    OpenAIRE

    Harin, Alexander

    2009-01-01

    A general forecasting correcting formula, as a framework for long-use and standardized forecasts, is created. The formula provides new forecasting resources and new possibilities for expansion of forecasting including economic forecasting into the areas of municipal needs, middle-size and small-size business and, even, to individual forecasting.

  1. ERRORS AND CORRECTION

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    To err is human . Since the 1960s, most second language teachers or language theorists have regarded errors as natural and inevitable in the language learning process . Instead of regarding them as terrible and disappointing, teachers have come to realize their value. This paper will consider these values, analyze some errors and propose some effective correction techniques.

  2. Corrective Jaw Surgery

    Medline Plus

    Full Text Available ... of jaws and teeth. Surgery can improve chewing, speaking and breathing. While the patient's appearance may be dramatically enhanced as a result of their surgery, orthognathic surgery is performed to correct functional problems. Jaw Surgery can have a dramatic effect on ...

  3. Corrective Jaw Surgery

    Medline Plus

    Full Text Available ... functional problems. Jaw Surgery can have a dramatic effect on many aspects of life. Following are some of the conditions that may indicate the need for corrective jaw surgery: Difficulty chewing, or biting food Difficulty swallowing Chronic jaw or jaw joint (TMJ) ...

  4. Corrections for collaborators

    NARCIS (Netherlands)

    NN,

    1953-01-01

    In the ”Directions and Hints” for collaborators in Flora Malesiana, which has been forwarded to all collaborators, two corrections should be made, viz: 1) p. 12; Omit the explanatory notes under Jamaica Plain, Mass., and Cambridge, Mass. 2) p. 13; Add as number 12a; Stockholm, Paleobotaniska Avdelni

  5. General forecasting correcting formula

    OpenAIRE

    2009-01-01

    A general forecasting correcting formula, as a framework for long-use and standardized forecasts, is created. The formula provides new forecasting resources and new possibilities for expansion of forecasting including economic forecasting into the areas of municipal needs, middle-size and small-size business and, even, to individual forecasting.

  6. The Philadelphia chromosome in leukemogenesis

    Institute of Scientific and Technical Information of China (English)

    ZhiJieKang; JinSongYan; QuentinLiu; YuFeiLiu; LingZhiXu; ZiJieLong; DanHuang; YaYang; BingLiu; JiuXingFeng; YuJiaPan

    2016-01-01

    The truncated chromosome 22 that results from the reciprocal translocation t(9;22)(q34;q11) is known as the Phila‑delphia chromosome (Ph) and is a hallmark of chronic myeloid leukemia (CML). In leukemia cells, Ph not only impairs the physiological signaling pathways but also disrupts genomic stability. This aberrant fusion gene encodes the breakpoint cluster region‑proto‑oncogene tyrosine‑protein kinase (BCR‑ABL1) oncogenic protein with persistently enhanced tyrosine kinase activity. The kinase activity is responsible for maintaining proliferation, inhibiting differentia‑tion, and conferring resistance to cell death. During the progression of CML from the chronic phase to the accelerated phase and then to the blast phase, the expression patterns of different BCR‑ABL1 transcripts vary. Each BCR‑ABL1 transcript is present in a distinct leukemia phenotype, which predicts both response to therapy and clinical outcome. Besides CML, the Ph is found in acute lymphoblastic leukemia, acute myeloid leukemia, and mixed‑phenotype acute leukemia. Here, we provide an overview of the clinical presentation and cellular biology of different phenotypes of Ph‑positive leukemia and highlight key ifndings regarding leukemogenesis.

  7. Chromosomal replicons of higher plants

    Energy Technology Data Exchange (ETDEWEB)

    Van' t Hof, J.

    1987-03-16

    This brief discussion of replicons of higher plants offers a glimpse into the properties of chromosomal DNA replication. It gives evidence that the S phase of unrelated plant species is comprised of temporally ordered replicon families that increase in number with genome size. This orderly process, which assures a normal inheritance of genetic material to recipient daughter cells, is maintained at the level of replicon clusters by two mutually exclusive mechanisms, one involving the rate at which single replicons replicate their allotment of DNA, and another by means of the tempo-pause. The same two mechanisms are used by cells to alter the pattern of chromosomal DNA replication just prior to and during normal development. Both mechanisms are genetically determined and produce genetic effects when disturbed of disrupted by additional non-conforming DNAs. Further insight into how these two mechanisms operate requires more molecular information about the nature of replicons and the factors that govern when a replicon family replicates. Plant material is a rich and ideal source for this information just awaiting exploitation. 63 refs.

  8. Increased chromosome radiosensitivity during pregnancy

    Energy Technology Data Exchange (ETDEWEB)

    Ricoul, Michelle; Sabatier, Laure; Dutrillaux, Bernard [Commissariat a l`Energie Atomique, Laboratoire de Radiobiologie et Oncologie, DRR, DSV, Fontenay aux roses (France)

    1997-03-04

    It was necessary to consider the risks of exposure of pregnant women, not only in relation to the child, but also in relation to their own hypersensitivity. We have demonstrated that pregnancy increases radiosensitivity of chromosome in the mouse at the end of gestation. This is of importance since it may have implications on radioprotection of pregnant women and give experimental guidelines to the problems of hypersensitivity to drugs and cancer aggravation during pregnancy. Blood obtained from women at various times of pregnancy was exposed to ionizing radiations. By comparison to non-pregnant women, an increase in chromosome breakage was observed in metaphases from lymphocytes, after short-term culture in the presence of the serum of the same donor. Immediately after delivery, this increase in radiosensitivity disappeared. In a prospective study, serial analyses showed a very strong correlation between the amount of pregnancy hormones, progesterone in particular, and the increase in radiosensitivity. Pregnant women may have an increased sensitivity to ionizing radiation during the second half of their pregnancy. This study provides the first evidence in human that radiosensitivity may vary in relation to physiological conditions.

  9. Chromosomal phenotypes and submicroscopic abnormalities

    Directory of Open Access Journals (Sweden)

    Devriendt Koen

    2004-01-01

    Full Text Available Abstract The finding, during the last decade, that several common, clinically delineated syndromes are caused by submicroscopic deletions or, more rarely, by duplications, has provided a powerful tool in the annotation of the human genome. Since most microdeletion/microduplication syndromes are defined by a common deleted/duplicated region, abnormal dosage of genes located within these regions can explain the phenotypic similarities among individuals with a specific syndrome. As such, they provide a unique resource towards the genetic dissection of complex phenotypes such as congenital heart defects, mental and growth retardation and abnormal behaviour. In addition, the study of phenotypic differences in individuals with the same microdeletion syndrome may also become a treasury for the identification of modifying factors for complex phenotypes. The molecular analysis of these chromosomal anomalies has led to a growing understanding of their mechanisms of origin. Novel tools to uncover additional submicroscopic chromosomal anomalies at a higher resolution and higher speed, as well as the novel tools at hand for deciphering the modifying factors and epistatic interactors, are 'on the doorstep' and will, besides their obvious diagnostic role, play a pivotal role in the genetic dissection of complex phenotypes.

  10. Chromosomal instability determines taxane response

    DEFF Research Database (Denmark)

    Swanton, C.; Nicke, B.; Schuett, M.

    2009-01-01

    Microtubule-stabilizing (MTS) agents, such as taxanes, are important chemotherapeutics with a poorly understood mechanism of action. We identified a set of genes repressed in multiple cell lines in response to MTS agents and observed that these genes are overexpressed in tumors exhibiting chromos...... resistance but carboplatin sensitivity, indicating that CIN may determine MTS response in vivo. Thus, pretherapeutic assessment of CIN may optimize treatment stratification and clinical trial design using these agents....... chromosomal instability (CIN). Silencing 22/50 of these genes, many of which are involved in DNA repair, caused cancer cell death, suggesting that these genes are involved in the survival of aneuploid cells. Overexpression of these "CIN-survival'' genes is associated with poor outcome in estrogen receptor......-positive breast cancer and occurs frequently in basal-like and Her2-positive cases. In diploid cells, but not in chromosomally unstable cells, paclitaxel causes repression of CIN-survival genes, followed by cell death. In the OV01 ovarian cancer clinical trial, a high level of CIN was associated with taxane...

  11. Conservation of chromosomes syntenic with avian autosomes in squamate reptiles revealed by comparative chromosome painting.

    Science.gov (United States)

    Pokorná, Martina; Giovannotti, Massimo; Kratochvíl, Lukáš; Caputo, Vincenzo; Olmo, Ettore; Ferguson-Smith, Malcolm A; Rens, Willem

    2012-08-01

    In contrast to mammals, birds exhibit a slow rate of chromosomal evolution. It is not clear whether high chromosome conservation is an evolutionary novelty of birds or was inherited from an earlier avian ancestor. The evolutionary conservatism of macrochromosomes between birds and turtles supports the latter possibility; however, the rate of chromosomal evolution is largely unknown in other sauropsids. In squamates, we previously reported strong conservatism of the chromosomes syntenic with the avian Z, which could reflect a peculiarity of this part of the genome. The chromosome 1 of iguanians and snakes is largely syntenic with chromosomes 3, 5 and 7 of the avian ancestral karyotype. In this project, we used comparative chromosome painting to determine how widely this synteny is conserved across nine families covering most of the main lineages of Squamata. The results suggest that the association of the avian ancestral chromosomes 3, 5 and 7 can be dated back to at least the early Jurassic and could be an ancestral characteristic for Unidentata (Serpentes, Iguania, Anguimorpha, Laterata and Scinciformata). In Squamata chromosome conservatism therefore also holds for the parts of the genome which are homologous to bird autosomes, and following on from this, a slow rate of chromosomal evolution could be a common characteristic of all sauropsids. The large evolutionary stasis in chromosome organization in birds therefore seems to be inherited from their ancestors, and it is particularly striking in comparison with mammals, probably the only major tetrapod lineage with an increased rate of chromosomal rearrangements as a whole.

  12. Chromosomal painting and ZW sex chromosomes differentiation in Characidium (Characiformes, Crenuchidae

    Directory of Open Access Journals (Sweden)

    Artoni Roberto F

    2011-07-01

    Full Text Available Abstract Background The Characidium (a Neotropical fish group have a conserved diploid number (2n = 50, but show remarkable differences among species and populations in relation to sex chromosome systems and location of nucleolus organizer regions (NOR. In this study, we isolated a W-specific probe for the Characidium and characterized six Characidium species/populations using cytogenetic procedures. We analyzed the origin and differentiation of sex and NOR-bearing chromosomes by chromosome painting in populations of Characidium to reveal their evolution, phylogeny, and biogeography. Results A W-specific probe for efficient chromosome painting was isolated by microdissection and degenerate oligonucleotide primed-polymerase chain reaction (DOP-PCR amplification of W chromosomes from C. gomesi. The W probe generated weak signals dispersed on the proto sex chromosomes in C. zebra, dispersed signals in both W and Z chromosomes in C. lauroi and, in C. gomesi populations revealed a proximal site on the long arms of the Z chromosome and the entire W chromosome. All populations showed small terminal W probe sites in some autosomes. The 18S rDNA revealed distinctive patterns for each analyzed species/population with regard to proto sex chromosome, sex chromosome pair, and autosome location. Conclusions The results from dual-color fluorescence in situ hybridization (dual-color FISH using W and 18S rDNA probes allowed us to infer the putative evolutionary pathways for the differentiation of sex chromosomes and NORs, from structural rearrangements in a sex proto-chromosome, followed by gene erosion and heterochromatin amplification, morphological differentiation of the sex chromosomal pair, and NOR transposition, giving rise to the distinctive patterns observed among species/populations of Characidium. Biogeographic isolation and differentiation of sex chromosomes seem to have played a major role in the speciation process in this group of fish.

  13. Development of a Drosophila cell-based error correction assay

    Directory of Open Access Journals (Sweden)

    Jeffrey D. Salemi

    2013-07-01

    Full Text Available Accurate transmission of the genome through cell division requires microtubules from opposing spindle poles to interact with protein super-structures called kinetochores that assemble on each sister chromatid. Most kinetochores establish erroneous attachments that are destabilized through a process called error correction. Failure to correct improper kinetochore-microtubule (kt-MT interactions before anaphase onset results in chromosomal instability (CIN, which has been implicated in tumorigenesis and tumor adaptation. Thus, it is important to characterize the molecular basis of error correction to better comprehend how CIN occurs and how it can be modulated. An error correction assay has been previously developed in cultured mammalian cells in which incorrect kt-MT attachments are created through the induction of monopolar spindle assembly via chemical inhibition of kinesin-5. Error correction is then monitored following inhibitor wash out. Implementing the error correction assay in Drosophila melanogaster S2 cells would be valuable because kt-MT attachments are easily visualized and the cells are highly amenable to RNAi and high-throughput screening. However, Drosophila kinesin-5 (Klp61F is unaffected by available small molecule inhibitors. To overcome this limitation, we have rendered S2 cells susceptible to kinesin-5 inhibitors by functionally replacing Klp61F with human kinesin-5 (Eg5. Eg5 expression rescued the assembly of monopolar spindles typically caused by Klp61F depletion. Eg5-mediated bipoles collapsed into monopoles due to the activity of kinesin-14 (Ncd when treated with the kinesin-5 inhibitor S-trityl-L-cysteine (STLC. Furthermore, bipolar spindles reassembled and error correction was observed after STLC wash out. Importantly, error correction in Eg5-expressing S2 cells was dependent on the well-established error correction kinase Aurora B. This system provides a powerful new cell-based platform for studying error correction and

  14. Development of a Drosophila cell-based error correction assay.

    Science.gov (United States)

    Salemi, Jeffrey D; McGilvray, Philip T; Maresca, Thomas J

    2013-01-01

    Accurate transmission of the genome through cell division requires microtubules from opposing spindle poles to interact with protein super-structures called kinetochores that assemble on each sister chromatid. Most kinetochores establish erroneous attachments that are destabilized through a process called error correction. Failure to correct improper kinetochore-microtubule (kt-MT) interactions before anaphase onset results in chromosomal instability (CIN), which has been implicated in tumorigenesis and tumor adaptation. Thus, it is important to characterize the molecular basis of error correction to better comprehend how CIN occurs and how it can be modulated. An error correction assay has been previously developed in cultured mammalian cells in which incorrect kt-MT attachments are created through the induction of monopolar spindle assembly via chemical inhibition of kinesin-5. Error correction is then monitored following inhibitor wash out. Implementing the error correction assay in Drosophila melanogaster S2 cells would be valuable because kt-MT attachments are easily visualized and the cells are highly amenable to RNAi and high-throughput screening. However, Drosophila kinesin-5 (Klp61F) is unaffected by available small molecule inhibitors. To overcome this limitation, we have rendered S2 cells susceptible to kinesin-5 inhibitors by functionally replacing Klp61F with human kinesin-5 (Eg5). Eg5 expression rescued the assembly of monopolar spindles typically caused by Klp61F depletion. Eg5-mediated bipoles collapsed into monopoles due, in part, to kinesin-14 (Ncd) activity when treated with the kinesin-5 inhibitor S-trityl-L-cysteine (STLC). Furthermore, bipolar spindles reassembled and error correction was observed after STLC wash out. Importantly, error correction in Eg5-expressing S2 cells was dependent on the well-established error correction kinase Aurora B. This system provides a powerful new cell-based platform for studying error correction and CIN.

  15. Radiative corrections to DIS

    CERN Document Server

    Krasny, Mieczyslaw Witold

    2008-01-01

    Early deep inelastic scattering (DIS) experiments at SLAC discovered partons, identified them as quarks and gluons, and restricted the set of the candidate theories for strong interactions to those exhibiting the asymptotic freedom property. The next generation DIS experiments at FNAL and CERN confirmed the predictions of QCD for the size of the scaling violation effects in the nucleon structure functions. The QCD fits to their data resulted in determining the momentum distributions of the point-like constituents of nucleons. Interpretation of data coming from all these experiments and, in the case of the SLAC experiments, even an elaboration of the running strategies, would not have been possible without a precise understanding of the electromagnetic radiative corrections. In this note I recollect the important milestones, achieved in the period preceding the HERA era, in the high precision calculations of the radiative corrections to DIS, and in the development of the methods of their experimental control. ...

  16. Aberration Corrected Emittance Exchange

    CERN Document Server

    Nanni, Emilio A

    2015-01-01

    Full exploitation of emittance exchange (EEX) requires aberration-free performance of a complex imaging system including active radio-frequency (RF) elements which can add temporal distortions. We investigate the performance of an EEX line where the exchange occurs between two dimensions with normalized emittances which differ by orders of magnitude. The transverse emittance is exchanged into the longitudinal dimension using a double dog-leg emittance exchange setup with a 5 cell RF deflector cavity. Aberration correction is performed on the four most dominant aberrations. These include temporal aberrations that are corrected with higher order magnetic optical elements located where longitudinal and transverse emittance are coupled. We demonstrate aberration-free performance of emittances differing by 4 orders of magnitude, i.e. an initial transverse emittance of $\\epsilon_x=1$ pm-rad is exchanged with a longitudinal emittance of $\\epsilon_z=10$ nm-rad.

  17. Correcting Duporcq's theorem☆

    Science.gov (United States)

    Nawratil, Georg

    2014-01-01

    In 1898, Ernest Duporcq stated a famous theorem about rigid-body motions with spherical trajectories, without giving a rigorous proof. Today, this theorem is again of interest, as it is strongly connected with the topic of self-motions of planar Stewart–Gough platforms. We discuss Duporcq's theorem from this point of view and demonstrate that it is not correct. Moreover, we also present a revised version of this theorem. PMID:25540467

  18. Congenitally corrected transposition

    Directory of Open Access Journals (Sweden)

    Debich-Spicer Diane

    2011-05-01

    Full Text Available Abstract Congenitally corrected transposition is a rare cardiac malformation characterized by the combination of discordant atrioventricular and ventriculo-arterial connections, usually accompanied by other cardiovascular malformations. Incidence has been reported to be around 1/33,000 live births, accounting for approximately 0.05% of congenital heart malformations. Associated malformations may include interventricular communications, obstructions of the outlet from the morphologically left ventricle, and anomalies of the tricuspid valve. The clinical picture and age of onset depend on the associated malformations, with bradycardia, a single loud second heart sound and a heart murmur being the most common manifestations. In the rare cases where there are no associated malformations, congenitally corrected transposition can lead to progressive atrioventricular valvar regurgitation and failure of the systemic ventricle. The diagnosis can also be made late in life when the patient presents with complete heart block or cardiac failure. The etiology of congenitally corrected transposition is currently unknown, and with an increase in incidence among families with previous cases of congenitally corrected transposition reported. Diagnosis can be made by fetal echocardiography, but is more commonly made postnatally with a combination of clinical signs and echocardiography. The anatomical delineation can be further assessed by magnetic resonance imaging and catheterization. The differential diagnosis is centred on the assessing if the patient is presenting with isolated malformations, or as part of a spectrum. Surgical management consists of repair of the associated malformations, or redirection of the systemic and pulmonary venous return associated with an arterial switch procedure, the so-called double switch approach. Prognosis is defined by the associated malformations, and on the timing and approach to palliative surgical care.

  19. Inheritance of a ring 14 chromosome.

    Science.gov (United States)

    Riley, S B; Buckton, K E; Ratcliffe, S G; Syme, J

    1981-06-01

    A family is described in which the mother, her two live offspring, and a therapeutically aborted fetus each had a ring 14 chromosomes. The two children were mentally retarded and the mother's intelligence was at the lower end of the normal range. In addition, the mother had two spontaneous abortions, one of which was shown to be chromosomally normal.

  20. Inheritance of a ring 14 chromosome.

    OpenAIRE

    Riley, S B; Buckton, K E; Ratcliffe, S G; Syme, J.

    1981-01-01

    A family is described in which the mother, her two live offspring, and a therapeutically aborted fetus each had a ring 14 chromosomes. The two children were mentally retarded and the mother's intelligence was at the lower end of the normal range. In addition, the mother had two spontaneous abortions, one of which was shown to be chromosomally normal.

  1. Chromosomal Aneuploidies and Early Embryonic Developmental Arrest

    Directory of Open Access Journals (Sweden)

    Maria Maurer

    2015-07-01

    Full Text Available Background: Selecting the best embryo for transfer, with the highest chance of achieving a vital pregnancy, is a major goal in current in vitro fertilization (IVF technology. The high rate of embryonic developmental arrest during IVF treatment is one of the limitations in achieving this goal. Chromosomal abnormalities are possibly linked with chromosomal arrest and selection against abnormal fertilization products. The objective of this study was to evaluate the frequency and type of chromosomal abnormalities in preimplantation embryos with developmental arrest. Materials and Methods: This cohort study included blastomeres of embryos with early developmental arrest that were biopsied and analyzed by fluorescence in-situ hybridization (FISH with probes for chromosomes 13, 16, 18, 21 and 22. Forty-five couples undergoing IVF treatment were included, and 119 arrested embryos were biopsied. All probes were obtained from the Kinderwunsch Zentrum, Linz, Austria, between August 2009 and August 2011. Results: Of these embryos, 31.6% were normal for all chromosomes tested, and 68.4% were abnormal. Eleven embryos were uniformly aneuploid, 20 were polyploid, 3 were haploid, 11 displayed mosaicism and 22 embryos exhibited chaotic chromosomal complement. Conclusion: Nearly 70% of arrested embryos exhibit chromosomal errors, making chromosomal abnormalities a major cause of embryonic arrest and may be a further explanation for the high developmental failure rates during culture of the embryos in the IVF setting.

  2. Genomic Dark Matter Illuminated: Anopheles Y Chromosomes.

    Science.gov (United States)

    Redmond, Seth N; Neafsey, Daniel E

    2016-08-01

    Hall et al. have strategically used long-read sequencing technology to characterize the structure and highly repetitive content of the Y chromosome in Anopheles malaria mosquitoes. Their work confirms that this important but elusive heterochromatic sex chromosome is evolving extremely rapidly and harbors a remarkably small number of genes.

  3. Non-disjunction of chromosome 13

    DEFF Research Database (Denmark)

    Bugge, Merete; Collins, Andrew; Hertz, Jens Michael

    2007-01-01

    recombination in both maternal MI and MII errors and the former is associated with a significant number of tetrads (33%) that are nullichiasmate, which do not appear to be a feature of normal chromosome 13 meiosis. This study supports the evidence for subtle chromosome-specific influences on the mechanisms...

  4. Chromosome condensation: weaving an untangled web.

    Science.gov (United States)

    Thadani, Rahul; Uhlmann, Frank

    2015-08-03

    The compaction of diffuse interphase chromatin into stable mitotic chromosomes enables the segregation of replicated DNA to daughter cells. Two new studies characterise, both in vivo and in vitro, the essential contribution of the vertebrate condensin complex to chromosome organisation.

  5. Chromosome Segregation: Organizing Overlap at the Midzone

    NARCIS (Netherlands)

    Janson, M.E.; Tran, P.T.

    2008-01-01

    Sets of overlapping microtubules support the segregation of chromosomes by linking the poles of mitotic spindles. Recent work examines the effect of putting these linkages under pressure by the activation of dicentric chromosomes and sheds new light on the structural role of several well-known spind

  6. Paradigm Lost: The Human Chromosome Story.

    Science.gov (United States)

    Unger, Lawrence; Blystone, Robert V.

    1996-01-01

    Discusses whether the discovery in 1956 that humans have a chromosome number of 46, as opposed to 47 or 48 as previously thought, fits into a paradigm shift of the Kuhnian type. Concludes that Kuhn probably would not have considered the chromosome number shift to be large enough to be a focus for one of his paradigms. (AIM)

  7. Human male meiotic sex chromosome inactivation

    NARCIS (Netherlands)

    Vries, M. de; Vosters, S.; Merkx, G.F.M.; Hauwers, K.W.M. d'; Wansink, D.G.; Ramos, L.; Boer, P. de

    2012-01-01

    In mammalian male gametogenesis the sex chromosomes are distinctive in both gene activity and epigenetic strategy. At first meiotic prophase the heteromorphic X and Y chromosomes are placed in a separate chromatin domain called the XY body. In this process, X,Y chromatin becomes highly phosphorylate

  8. Human male meiotic sex chromosome inactivation

    NARCIS (Netherlands)

    Vries, M. de; Vosters, S.; Merkx, G.F.M.; Hauwers, K.W.M. d'; Wansink, D.G.; Ramos, L.; Boer, P. de

    2012-01-01

    In mammalian male gametogenesis the sex chromosomes are distinctive in both gene activity and epigenetic strategy. At first meiotic prophase the heteromorphic X and Y chromosomes are placed in a separate chromatin domain called the XY body. In this process, X,Y chromatin becomes highly

  9. Chromosome morphometry in opisthorchiid species (Platyhelminthes, Trematoda).

    Science.gov (United States)

    Zadesenets, Kira S; Polyakov, Andrey V; Katokhin, Alexey V; Mordvinov, Viatcheslav A; Rubtsov, Nikolay B

    2017-08-01

    Few existing studies have dealt with cytogenetics in trematodes, largely due to the attendant technical difficulty of chromosome preparation. We performed a comparative analysis of chromosomes in five opistorchiid species, including Opisthorchis felineus Rivolta, 1884, Opisthorchis viverrini Poirier, 1886, Clonorchis sinensis Cobbold, 1875, Metorchis xanthosomus Creplin 1846, and Metorchis bilis (Braun, 1790) Odening, 1962. For some of these species, no detailed morphometric description of their karyotypes has yet been published; for the karyotype of Metorchis bilis this is the first-ever description. We found that opisthorchiids, like other trematodes, are characterized by karyotypic conservatism (N=6-7) and karyotype asymmetry, although comparison of chromosome morphometric traits did reveal differences between the karyotypes of the species. Moreover, to address certain a methodological issue in trematode chromosome preparation, we analyzed how the source of chromosomal material (partenitae or mature flukes) and the chromosome preparation techniques used (air-drying and cell suspension methods) affected chromosome spreading and size, concluding that the most reliable comparative method involves comparing relative parameters (relative length, arm ratio, centromeric index) of chromosomes prepared using the same technique. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  10. [CHROMOSOMAL ABNORMALITIES IN PATIENTS WITH INFERTILITY].

    Science.gov (United States)

    Pylyp, L Y; Spinenko, L O; Verhoglyad, N V; Kashevarova, O O; Zukin, V D

    2015-01-01

    To assess the frequency and structure of chromosomal abnormalities in patients with infertility, a retrospective analysis of cytogenetic studies of 3414 patients (1741 females and 1673 males), referred to the Clinic of reproductive medicine "Nadiya" from 2007 to 2012, was performed. Chromosomal abnormalities were detected in 2.37% patients: 2.79% in males and 1.95% in females. Balanced structural chromosomal abnormalities prevailed over numerical abnormalities and corresponded to 80.2% of all chromosomal abnormalities detected in the studied group. Sex chromosome abnormalities made up 23.5% of chromosomal pathology (19/81) and included gonosomal aneuploidies in 84% of cases (16/19) and structural abnormalities of chromosome Y in 16% of cases (3/19). The low level sex chromosome mosaicism was detected with the frequency of 0.55%. Our results highlight the importance of cytogenetic studies in patients seeking infertility treatment by assisted reproductive technologies, since an abnormal finding not only provide a firm diagnosis to couples with infertility, but also influences significantly the approach to infertility treatment in such patients.

  11. Zfy genes are required for efficient meiotic sex chromosome inactivation (MSCI) in spermatocytes.

    Science.gov (United States)

    Vernet, Nadège; Mahadevaiah, Shantha K; de Rooij, Dirk G; Burgoyne, Paul S; Ellis, Peter J I

    2016-10-13

    During spermatogenesis, germ cells that fail to synapse their chromosomes or fail to undergo meiotic sex chromosome inactivation (MSCI) are eliminated via apoptosis during mid-pachytene. Previous work showed that Y-linked genes Zfy1 and Zfy2 act as 'executioners' for this checkpoint, and that wrongful expression of either gene during pachytene triggers germ cell death. Here, we show that in mice, Zfy genes are also necessary for efficient MSCI and the sex chromosomes are not correctly silenced in Zfy-deficient spermatocytes. This unexpectedly reveals a triple role for Zfy at the mid-pachytene checkpoint in which Zfy genes first promote MSCI, then monitor its progress (since if MSCI is achieved, Zfy genes will be silenced), and finally execute cells with MSCI failure. This potentially constitutes a negative feedback loop governing this critical checkpoint mechanism.

  12. Small supernumerary marker chromosomes (sSMC) in humans; are there B chromosomes hidden among them

    OpenAIRE

    Ogilvie Caroline; Kosyakova Nadezda; Mrasek Kristin; Liehr Thomas; Vermeesch Joris; Trifonov Vladimir; Rubtsov Nikolai

    2008-01-01

    Abstract Background Small supernumerary marker chromosomes (sSMC) and B-chromosomes represent a heterogeneous collection of chromosomes added to the typical karyotype, and which are both small in size. They may consist of heterochromatic and/or euchromatic material. Also a predominance of maternal transmission was reported for both groups. Even though sSMC and B-chromosomes show some similarity it is still an open question if B-chromosomes are present among the heterogeneous group of sSMC. Ac...

  13. DETECTION OF CHROMOSOME ABERRATIONS IN TWELVE PRIMARY GASTRIC CANCERS BY DIRECT CHROMOSOME ANALYSIS AND FISH

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    Direct chromosome analysis and FISH were performed on twelve primary gastric carcinomas. Two of them had simple chromosome changes: 48,XX, +8, +20, and 49, XY, +2, +8, +9, and the others had complicated chromosome changes, which includes much more numerical and structural chromosome aberrations. Frequent structural changes in the complicated types involved chromosome 7, 3, 1, 5 and 12 etc. The del 7q was noted in eight cases. The del (3p) and del (1p) were noted in six and five cases, respectively. The results provide some important clues for isolation of the genes related to gastric cancer.

  14. Advances in understanding paternally transmitted Chromosomal Abnormalities

    Energy Technology Data Exchange (ETDEWEB)

    Marchetti, F; Sloter, E; Wyrobek, A J

    2001-03-01

    Multicolor FISH has been adapted for detecting the major types of chromosomal abnormalities in human sperm including aneuploidies for clinically-relevant chromosomes, chromosomal aberrations including breaks and rearrangements, and other numerical abnormalities. The various sperm FISH assays have been used to evaluate healthy men, men of advanced age, and men who have received mutagenic cancer therapy. The mouse has also been used as a model to investigate the mechanism of paternally transmitted genetic damage. Sperm FISH for the mouse has been used to detect chromosomally abnormal mouse sperm, while the PAINT/DAPI analysis of mouse zygotes has been used to evaluate the types of chromosomal defects that can be paternally transmitted to the embryo and their effects on embryonic development.

  15. Review of the Y chromosome and hypertension

    Directory of Open Access Journals (Sweden)

    D. Ely

    2000-06-01

    Full Text Available The Y chromosome from spontaneously hypertensive rats (SHR has a locus that raises blood pressure 20-25 mmHg. Associated with the SHR Y chromosome effect is a 4-week earlier pubertal rise of testosterone and dependence upon the androgen receptor for the full blood pressure effect. Several indices of enhanced sympathetic nervous system (SNS activity are also associated with the SHR Y chromosome. Blockade of SNS outflow reduced the blood pressure effect. Salt sensitivity was increased by the Y chromosome as was salt appetite which was SNS dependent. A strong correlation (r = 0.57, P<0.001 was demonstrable between plasma testosterone and angiotensin II. Coronary collagen increased with blood pressure and the presence of the SHR Y chromosome. A promising candidate gene for the Y effect is the Sry locus (testis determining factor, a transcription factor which may also have other functions.

  16. Temporal genomic evolution of bird sex chromosomes

    DEFF Research Database (Denmark)

    Wang, Zongji; Zhang, Jilin; Yang, Wei;

    2014-01-01

    BACKGROUND: Sex chromosomes exhibit many unusual patterns in sequence and gene expression relative to autosomes. Birds have evolved a female heterogametic sex system (male ZZ, female ZW), through stepwise suppression of recombination between chrZ and chrW. To address the broad patterns and complex...... driving forces of Z chromosome evolution, we analyze here 45 newly available bird genomes and four species' transcriptomes, over their course of recombination loss between the sex chromosomes. RESULTS: We show Z chromosomes in general have a significantly higher substitution rate in introns and synonymous...... changes with that of introns, between chrZ and autosomes or regions with increasing ages of becoming Z-linked, therefore codon usage bias in birds is probably driven by the mutational bias. On the other hand, Z chromosomes also evolve significantly faster at nonsynonymous sites relative to autosomes...

  17. Structure and dynamics of interphase chromosomes.

    Directory of Open Access Journals (Sweden)

    Angelo Rosa

    Full Text Available During interphase chromosomes decondense, but fluorescent in situ hybridization experiments reveal the existence of distinct territories occupied by individual chromosomes inside the nuclei of most eukaryotic cells. We use computer simulations to show that the existence and stability of territories is a kinetic effect that can be explained without invoking an underlying nuclear scaffold or protein-mediated interactions between DNA sequences. In particular, we show that the experimentally observed territory shapes and spatial distances between marked chromosome sites for human, Drosophila, and budding yeast chromosomes can be reproduced by a parameter-free minimal model of decondensing chromosomes. Our results suggest that the observed interphase structure and dynamics are due to generic polymer effects: confined Brownian motion conserving the local topological state of long chain molecules and segregation of mutually unentangled chains due to topological constraints.

  18. Energy Landscapes of Folding Chromosomes

    Science.gov (United States)

    Zhang, Bin

    The genome, the blueprint of life, contains nearly all the information needed to build and maintain an entire organism. A comprehensive understanding of the genome is of paramount interest to human health and will advance progress in many areas, including life sciences, medicine, and biotechnology. The overarching goal of my research is to understand the structure-dynamics-function relationships of the human genome. In this talk, I will be presenting our efforts in moving towards that goal, with a particular emphasis on studying the three-dimensional organization, the structure of the genome with multi-scale approaches. Specifically, I will discuss the reconstruction of genome structures at both interphase and metaphase by making use of data from chromosome conformation capture experiments. Computationally modeling of chromatin fiber at atomistic level from first principles will also be presented as our effort for studying the genome structure from bottom up.

  19. Unusual maternal uniparental isodisomic x chromosome mosaicism with asymmetric y chromosomal rearrangement.

    Science.gov (United States)

    Lee, B Y; Kim, S Y; Park, J Y; Choi, E Y; Kim, D J; Kim, J W; Ryu, H M; Cho, Y H; Park, S Y; Seo, J T

    2014-01-01

    Infertile men with azoospermia commonly have associated microdeletions in the azoospermia factor (AZF) region of the Y chromosome, sex chromosome mosaicism, or sex chromosome rearrangements. In this study, we describe an unusual 46,XX and 45,X mosaicism with a rare Y chromosome rearrangement in a phenotypically normal male patient. The patient's karyotype was 46,XX[50]/45,X[25]/46,X,der(Y)(pter→q11.222::p11.2→pter)[25]. The derivative Y chromosome had a deletion at Yq11.222 and was duplicated at Yp11.2. Two copies of the SRY gene were confirmed by fluorescence in situ hybridization analysis, and complete deletion of the AZFb and AZFc regions was shown by multiplex-PCR for microdeletion analysis. Both X chromosomes of the predominant mosaic cell line (46,XX) were isodisomic and derived from the maternal gamete, as determined by examination of short tandem repeat markers. We postulate that the derivative Y chromosome might have been generated during paternal meiosis or early embryogenesis. Also, we suggest that the very rare mosaicism of isodisomic X chromosomes might be formed during maternal meiosis II or during postzygotic division derived from the 46,X,der(Y)/ 45,X lineage because of the instability of the derivative Y chromosome. To our knowledge, this is the first confirmatory study to verify the origin of a sex chromosome mosaicism with a Y chromosome rearrangement.

  20. Genetic screening for chromosomal abnormalities and Y chromosome microdeletions in Chinese infertile men.

    Science.gov (United States)

    Fu, Li; Xiong, Da-Ke; Ding, Xian-Ping; Li, Chuang; Zhang, Li-Yuan; Ding, Min; Nie, Shuang-Shuang; Quan, Qiang

    2012-06-01

    To investigate the frequency and type of both chromosomal abnormalities and Y chromosome microdeletions and analyze their association with defective spermatogenesis in Chinese infertile men. This is a single center study. Karyotyping using G-banding and screening for Y chromosome microdeletion by multiplex polymerase chain reaction(PCR)were performed in 200 controls and 1,333 infertile men, including 945 patients with non-obstructive azoospermia and 388 patients with severe oligozoospermia. Out of 1,333 infertile patients, 154(11.55%) presented chromosomal abnormalities. Of these, 139 of 945 (14.71%) were from the azoospermic and 15 of 388 (3.87%) from the severe oligozoospermic patient groups. The incidence of sex chromosomal abnormalities in men with azoospermia was 11.53% compared with 1.03% in men with severe oligozoospermia (P chromosome microdeletions. The incidence of azoospermia factor(AZF) microdeletion was 11.75% and 8.51% in patients with azoospermia and severe oligozoospermia respectively. Deletion of AZFc was the most common and deletions in AZFa or AZFab or AZFabc were found in azoospermic men. In addition, 34 patients had chromosomal abnormalities among the 144 patients with Y chromosome microdeletions. No chromosomal abnormality and microdeletion in AZF region were detected in controls. There was a high incidence (19.80%) of chromosomal abnormalities and Y chromosomal microdeletions in Chinese infertile males with azoospermia or severe oligozoospermia. These findings strongly suggest that genetic screening should be advised to infertile men before starting assisted reproductive treatments.

  1. Impact of different patterns of sperm chromosomal abnormalities on the chromosomal constitution of preimplantation embryos.

    Science.gov (United States)

    Rodrigo, Lorena; Peinado, Vanessa; Mateu, Emilia; Remohí, José; Pellicer, Antonio; Simón, Carlos; Gil-Salom, Manuel; Rubio, Carmen

    2010-09-01

    To evaluate the effect of sperm chromosome abnormalities--disomy for sex chromosomes and diploidy--in the chromosomal constitution of preimplantation embryos. Retrospective cohort study. Infertility clinic. Three groups: 46,XY infertile men with increased incidence of sex chromosome disomy in sperm; 46,XY infertile men with increased diploidy rates in sperm; 47,XYY infertile men with increased sex chromosome disomy and diploidy rates in sperm. Sperm collection for fluorescence in situ hybridization analysis. Embryo biopsy for preimplantation genetic screening. Frequencies of numerical abnormalities in sperm for chromosomes 13, 18, 21, X, and Y, and in embryos for chromosomes 13, 16, 18, 21, 22, X, and Y. A significant increase of chromosomally abnormal and mosaic embryos was observed in the three study groups compared with controls. Those sperm samples with increased sex chromosome disomy rates produced significantly higher percentages of aneuploid embryos, with a threefold increase for sex chromosomes. Sperm samples with increased diploidy rates were mainly associated to the production of triploid embryos. A strong correlation between sperm and embryo chromosomal constitution has been shown in infertile men with 46,XY and 47,XYY karyotypes. Copyright (c) 2010 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  2. Comparative analysis by chromosome painting of the sex chromosomes in arvicolid rodents.

    Science.gov (United States)

    Acosta, M J; Romero-Fernández, I; Sánchez, A; Marchal, J A

    2011-01-01

    Sex chromosome evolution in mammals has been extensively investigated through chromosome-painting analyses. In some rodent species from the subfamily Arvicolinae the sex chromosomes contain remarkable features such as giant size, a consequence of heterochromatic enlargement, or asynaptic behaviour during male meiosis. Here, we have made a comparative study of the sex chromosomes in 6 arvicolid species using different probes from the X and Y chromosomes of 3 species, in order to gain knowledge about intra- or interspecific preservation of euchromatic regions. Our results clearly reveal poor conservation of the euchromatic region of the Y chromosome within these species, while the euchromatin on the X chromosome is extremely well preserved. Furthermore, we detected no clear correlation between the synaptic/asynaptic behaviour of the sex chromosomes, and the presence or absence of sequence homology within their euchromatic regions. Notably, our study has shown a new relationship between the giant sex chromosomes of 2 species, Microtus agrestis and Microtus cabrerae, that is, both X and Y share a novel region of common sequences in the euchromatin that is not present in the other species analysed. This interspecific euchromatic conservation, limited to the giant sex chromosomes, could point towards a common evolutionary origin for the heterochromatic enlargement process that has characterized the evolution of the sex chromosomes in some arvicolid species.

  3. New Y chromosomes and early stages of sex chromosome differentiation: sex determination in Megaselia

    Indian Academy of Sciences (India)

    Walther Traut

    2010-09-01

    The phorid fly Megaselia scalaris is a laboratory model for the turnover and early differentiation of sex chromosomes. Isolates from the field have an XY sex-determining mechanism with chromosome pair 2 acting as X and Y chromosomes. The sex chromosomes are homomorphic but display early signs of sex chromosome differentiation: a low level of molecular differences between X and Y. The male-determining function $(M)$, maps to the distal part of the Y chromosome’s short arm. In laboratory cultures, new Y chromosomes with no signs of a molecular differentiation arise at a low rate, probably by transposition of to these chromosomes. Downstream of the primary signal, the homologue of the Drosophila doublesex (dsx) is part of the sex-determining pathway while Sex-lethal (Sxl), though structurally conserved, is not.

  4. Novel gene acquisition on carnivore Y chromosomes.

    Directory of Open Access Journals (Sweden)

    William J Murphy

    2006-03-01

    Full Text Available Despite its importance in harboring genes critical for spermatogenesis and male-specific functions, the Y chromosome has been largely excluded as a priority in recent mammalian genome sequencing projects. Only the human and chimpanzee Y chromosomes have been well characterized at the sequence level. This is primarily due to the presumed low overall gene content and highly repetitive nature of the Y chromosome and the ensuing difficulties using a shotgun sequence approach for assembly. Here we used direct cDNA selection to isolate and evaluate the extent of novel Y chromosome gene acquisition in the genome of the domestic cat, a species from a different mammalian superorder than human, chimpanzee, and mouse (currently being sequenced. We discovered four novel Y chromosome genes that do not have functional copies in the finished human male-specific region of the Y or on other mammalian Y chromosomes explored thus far. Two genes are derived from putative autosomal progenitors, and the other two have X chromosome homologs from different evolutionary strata. All four genes were shown to be multicopy and expressed predominantly or exclusively in testes, suggesting that their duplication and specialization for testis function were selected for because they enhance spermatogenesis. Two of these genes have testis-expressed, Y-borne copies in the dog genome as well. The absence of the four newly described genes on other characterized mammalian Y chromosomes demonstrates the gene novelty on this chromosome between mammalian orders, suggesting it harbors many lineage-specific genes that may go undetected by traditional comparative genomic approaches. Specific plans to identify the male-specific genes encoded in the Y chromosome of mammals should be a priority.

  5. The X chromosome and immune associated genes.

    Science.gov (United States)

    Bianchi, Ilaria; Lleo, Ana; Gershwin, M Eric; Invernizzi, Pietro

    2012-05-01

    The X chromosome is known to contain the largest number of immune-related genes of the whole human genome. For this reason, X chromosome has recently become subject of great interest and attention and numerous studies have been aimed at understanding the role of genes on the X chromosome in triggering and maintaining the autoimmune aggression. Autoimmune diseases are indeed a growing heath burden affecting cumulatively up to 10% of the general population. It is intriguing that most X-linked primary immune deficiencies carry significant autoimmune manifestations, thus illustrating the critical role played by products of single gene located on the X chromosome in the onset, function and homeostasis of the immune system. Again, the plethora of autoimmune stigmata observed in patients with Turner syndrome, a disease due to the lack of one X chromosome or the presence of major X chromosome deletions, indicate that X-linked genes play a unique and major role in autoimmunity. There have been several reports on a role of X chromosome gene dosage through inactivation or duplication in women with autoimmune diseases, for example through a higher rate of circulating cells with a single X chromosome (i.e. with X monosomy). Finally, a challenge for researchers in the coming years will be to dissect the role for the large number of X-linked microRNAs from the perspective of autoimmune disease development. Taken together, X chromosome might well constitute the common trait of the susceptibility to autoimmune diseases, other than to explain the female preponderance of these conditions. This review will focus on the available evidence on X chromosome changes and discuss their potential implications and limitations.

  6. Recombinant protein expression by targeting pre-selected chromosomal loci

    Directory of Open Access Journals (Sweden)

    Krömer Wolfgang

    2009-12-01

    Full Text Available Abstract Background Recombinant protein expression in mammalian cells is mostly achieved by stable integration of transgenes into the chromosomal DNA of established cell lines. The chromosomal surroundings have strong influences on the expression of transgenes. The exploitation of defined loci by targeting expression constructs with different regulatory elements is an approach to design high level expression systems. Further, this allows to evaluate the impact of chromosomal surroundings on distinct vector constructs. Results We explored antibody expression upon targeting diverse expression constructs into previously tagged loci in CHO-K1 and HEK293 cells that exhibit high reporter gene expression. These loci were selected by random transfer of reporter cassettes and subsequent screening. Both, retroviral infection and plasmid transfection with eGFP or antibody expression cassettes were employed for tagging. The tagged cell clones were screened for expression and single copy integration. Cell clones producing > 20 pg/cell in 24 hours could be identified. Selected integration sites that had been flanked with heterologous recombinase target sites (FRTs were targeted by Flp recombinase mediated cassette exchange (RMCE. The results give proof of principle for consistent protein expression upon RMCE. Upon targeting antibody expression cassettes 90-100% of all resulting cell clones showed correct integration. Antibody production was found to be highly consistent within the individual cell clones as expected from their isogenic nature. However, the nature and orientation of expression control elements revealed to be critical. The impact of different promoters was examined with the tag-and-targeting approach. For each of the chosen promoters high expression sites were identified. However, each site supported the chosen promoters to a different extent, indicating that the strength of a particular promoter is dominantly defined by its chromosomal context

  7. SNP-based non-invasive prenatal testing detects sex chromosome aneuploidies with high accuracy

    Science.gov (United States)

    Samango-Sprouse, Carole; Banjevic, Milena; Ryan, Allison; Sigurjonsson, Styrmir; Zimmermann, Bernhard; Hill, Matthew; Hall, Megan P.; Westemeyer, Margaret; Saucier, Jennifer; Demko, Zachary; Rabinowitz, Matthew

    2013-01-01

    Objective To develop a single nucleotide polymorphism- and informatics-based non-invasive prenatal test that detects sex chromosome aneuploidies early in pregnancy. Methods Fifteen aneuploid samples, including thirteen 45,X, two 47,XXY, and one 47,XYY, along with 185 euploid controls, were analyzed. Cell-free DNA was isolated from maternal plasma, amplified in a single multiplex PCR assay that targeted 19,488 polymorphic loci covering chromosomes 13, 18, 21, X, and Y, and sequenced. Sequencing results were analyzed using a Bayesian-based maximum likelihood statistical method to determine copy number of interrogated chromosomes, calculating sample-specific accuracies. Results Of the samples that passed a stringent quality control metric (93%), the algorithm correctly identified copy number at all five chromosomes in all 187 samples, for 934/935 correct calls as early as 9.4 weeks of gestation. We detected 45,X with 91.7% sensitivity (CI: 61.5-99.8%) and 100% specificity (CI: 97.9-100%), and 47,XXY and 47,XYY. The average calculated accuracy was 99.78%. Conclusion This method non-invasively detected 45,X, 47,XXY, and 47,XYY fetuses from cfDNA isolated from maternal plasma with high calculated accuracies, and thus offers a non-invasive method with the potential to function as a routine screen allowing for early prenatal detection of rarely diagnosed yet commonly occurring sex aneuploidies. PMID:23712453

  8. Should the markers on X chromosome be used for genomic prediction?

    DEFF Research Database (Denmark)

    Su, Guosheng; Guldbrandtsen, Bernt; Aamand, Gert Pedersen;

    2013-01-01

    excluding the X chromosome.Averaged over 15 traits, the gains in reliability from the X chromosome rangedfrom 0.3% to 0.5% points among the three data sets and models. Using a model with a G-matrix accounting for sex-linkedrelationship appropriately or a model which divided genomic breeding value intoan......This study investigated theaccuracy of imputation from LD (7K) to 54K panel and compared accuracy ofgenomic prediction with or without the X chromosome information, based on data ofNordic Holstein bulls. Beagle and Findhap were used for imputation. Averagedover two imputation datasets, the allele...... correct rates of imputation usingFindhap were 98.2% for autosomal markers, 89.7% for markers on the pseudoautosomal region of the X chromosome, and 96.4% for X-specific markers. Theallele correct rates were 98.9%, 91.2% and 96.8%, respectively, when usingBeagle. Genomic predictions were carried out for 15...

  9. New image analysis methods for 3D visualization and assessment of mapping distance for chromosomes in interphase nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Ikizyan, I.; Burde, S.; Leary, J.F. (Univ. of Rochester, NY (United States))

    1993-01-01

    Confocal microscopy (Meridian Instruments, Inc.) images of interphase nuclei with portions or entire chromosomes singley- or doubly-labeled by fluorescence in situ hybridization were analyzed with newly-developed software on an 80486 PC equipped with an autostereoscopic display (Dimension Technologies, Inc.). The computer display is hologram-like with the ability to address points in 3D space using the associated mouse. Software was developed which allowed for reduction of background by a 19 voxel (3x3x3 voxel cube without corner voxels) median filtering algorithm followed by rendering of a 3D surface and skeleton figure of a chromosome. Visualization at multiple viewing angles by animation allows approximate coordinate locations to be obtained with a 3D mouse to guide the process thereby reducing significantly the required calculation times. Two biological applications under development include (1) correct counting of a given chromosome's copy number using centromere/chromosome-specific probes, and (2) visualization of painted chromosomes and subregion-specific probes at different locations on that chromosome for physical mapping. In either application, real-world distances within each confocal plane and between planes are calculable to give physical mapping distances in three dimensions and along the chromosome.

  10. Chicago aberration correction work

    Energy Technology Data Exchange (ETDEWEB)

    Beck, V.D., E-mail: vnlbeck@earthlink.net [1 Hobby Drive, Ridgefield, CT 06877-01922 (United States)

    2012-12-15

    The author describes from his personal involvement the many improvements to electron microscopy Albert Crewe and his group brought by minimizing the effects of aberrations. The Butler gun was developed to minimize aperture aberrations in a field emission electron gun. In the 1960s, Crewe anticipated using a spherical aberration corrector based on Scherzer's design. Since the tolerances could not be met mechanically, a method of moving the center of the octopoles electrically was developed by adding lower order multipole fields. Because the corrector was located about 15 cm ahead of the objective lens, combination aberrations would arise with the objective lens. This fifth order aberration would then limit the aperture of the microscope. The transformation of the off axis aberration coefficients of a round lens was developed and a means to cancel anisotropic coma was developed. A new method of generating negative spherical aberration was invented using the combination aberrations of hexapoles. Extensions of this technique to higher order aberrations were developed. An electrostatic electron mirror was invented, which allows the cancellation of primary spherical aberration and first order chromatic aberration. A reduction of chromatic aberration by two orders of magnitude was demonstrated using such a system. -- Highlights: Black-Right-Pointing-Pointer Crewe and his group made significant advances in aberration correction and reduction. Black-Right-Pointing-Pointer A deeper understanding of the quadrupole octopole corrector was developed. Black-Right-Pointing-Pointer A scheme to correct spherical aberration using hexapoles was developed. Black-Right-Pointing-Pointer Chromatic aberration was corrected using a uniform field mirror.

  11. HOW CORRECTION CAN MOTIVATE LEARNING

    Institute of Scientific and Technical Information of China (English)

    1996-01-01

    IntroductionMistakes and their correction generally follow one another in the language classroom.Most teachersthink that correction is a necessary part of teaching;while most students agree that making mistakesis a necessary part of learning.Although both teachers and students maintain that correction andmistakes are necessary,we often find that some correction helps students’ learning and some does not.Correction can make students lose confidence and interest in learning.In order to try and find outmore about why this happens I surveyed students attitudes towards mistakes and correction.

  12. Experimental repetitive quantum error correction.

    Science.gov (United States)

    Schindler, Philipp; Barreiro, Julio T; Monz, Thomas; Nebendahl, Volckmar; Nigg, Daniel; Chwalla, Michael; Hennrich, Markus; Blatt, Rainer

    2011-05-27

    The computational potential of a quantum processor can only be unleashed if errors during a quantum computation can be controlled and corrected for. Quantum error correction works if imperfections of quantum gate operations and measurements are below a certain threshold and corrections can be applied repeatedly. We implement multiple quantum error correction cycles for phase-flip errors on qubits encoded with trapped ions. Errors are corrected by a quantum-feedback algorithm using high-fidelity gate operations and a reset technique for the auxiliary qubits. Up to three consecutive correction cycles are realized, and the behavior of the algorithm for different noise environments is analyzed.

  13. Spo0A regulates chromosome copy number during sporulation by directly binding to the origin of replication in Bacillus subtilis

    NARCIS (Netherlands)

    Boonstra, Mirjam; de Jong, Imke G.; Scholefield, Graham; Murray, Heath; Kuipers, Oscar P.; Veening, Jan-Willem

    When starved, Bacillus subtilis cells can enter the developmental programme of endospore formation by activation of the master transcriptional regulator Spo0A. Correct chromosome copy number is crucial for the production of mature and fully resistant spores. The production and maintenance of one

  14. Calculating correct compilers

    DEFF Research Database (Denmark)

    Bahr, Patrick; Hutton, Graham

    2015-01-01

    In this article, we present a new approach to the problem of calculating compilers. In particular, we develop a simple but general technique that allows us to derive correct compilers from high-level semantics by systematic calculation, with all details of the implementation of the compilers...... falling naturally out of the calculation process. Our approach is based upon the use of standard equational reasoning techniques, and has been applied to calculate compilers for a wide range of language features and their combination, including arithmetic expressions, exceptions, state, various forms...

  15. [Correction of hypospadias].

    Science.gov (United States)

    Bianchi, M

    1998-12-01

    A thorough evaluation of both urethral and penile malformation are mandatory for the choice of the best surgical treatment of patients with hypospadias. The site and the size of the urethral meatus, the presence of a chordee and of a velamentous distal urethra must be carefully assessed. In distal (glandular and coronal) hypospadias, the meatal advancement with glanduloplasty is the treatment of choice. In proximal hypospadias with chordee, the transverse preputial island flap according to the Duckett's technique allows a one-stage hypospadias repair. The awareness of the possible psychologic impact of genital malformations in childhood recommends an early correction of hypospadias, if possible during the first year of life.

  16. [Correction of paralytic lagophthalmos].

    Science.gov (United States)

    Iskusnykh, N S; Grusha, Y O

    2015-01-01

    Current options for correction of paralytic lagophthalmos are either temporary (external eyelid weight placement, hyaluronic acid gel or botulinum toxin A injection) or permanent (various procedures for narrowing of the palpebral fissure, upper eyelid weights or spring implantation). Neuroplastic surgery (cross-facial nerve grafting, nerve anastomoses) and muscle transposition surgery is not effective enough. The majority of elderly and medically compromised patients should not be considered for such complicated and long procedures. Upper eyelid weight implantation thus appears the most reliable and simple treatment.

  17. Brain Image Motion Correction

    DEFF Research Database (Denmark)

    Jensen, Rasmus Ramsbøl; Benjaminsen, Claus; Larsen, Rasmus

    2015-01-01

    The application of motion tracking is wide, including: industrial production lines, motion interaction in gaming, computer-aided surgery and motion correction in medical brain imaging. Several devices for motion tracking exist using a variety of different methodologies. In order to use such devices...... offset and tracking noise in medical brain imaging. The data are generated from a phantom mounted on a rotary stage and have been collected using a Siemens High Resolution Research Tomograph for positron emission tomography. During acquisition the phantom was tracked with our latest tracking prototype...

  18. Assessing the applicability of FISH-based prematurely condensed dicentric chromosome assay in triage biodosimetry.

    Science.gov (United States)

    Suto, Yumiko; Gotoh, Takaya; Noda, Takashi; Akiyama, Miho; Owaki, Makiko; Darroudi, Firouz; Hirai, Momoki

    2015-03-01

    The dicentric chromosome assay (DCA) has been regarded as the gold standard of radiation biodosimetry. The assay, however, requires a 2-d peripheral blood lymphocyte culture before starting metaphase chromosome analyses to estimate biological doses. Other biological assays also have drawbacks with respect to the time needed to obtain dose estimates for rapid decision on the correct line of medical treatment. Therefore, alternative technologies that suit requirements for triage biodosimetry are needed. Radiation-induced DNA double strand breaks in G0 lymphocytes can be detected as interphase chromosome aberrations by the cell fusion-mediated premature chromosome condensation (PCC) method. The method, in combination with fluorescence in situ hybridization (FISH) techniques, has been proposed in early studies as a powerful tool for obtaining biological dose estimates without 2-d lymphocyte culture procedures. The present work assesses the applicability of FISH-based PCC techniques using pan-centromeric and telomeric peptide nucleic acid (PNA) probes in triage mode biodosimetry and demonstrates that an improved rapid procedure of the prematurely condensed dicentric chromosome (PCDC) assay has the potential for evaluating exposed radiation doses in as short as 6 h after the collection of peripheral blood specimens.

  19. Meiotic Recombination Analyses in Pigs Carrying Different Balanced Structural Chromosomal Rearrangements.

    Directory of Open Access Journals (Sweden)

    Nicolas Mary

    Full Text Available Correct pairing, synapsis and recombination between homologous chromosomes are essential for normal meiosis. All these events are strongly regulated, and our knowledge of the mechanisms involved in this regulation is increasing rapidly. Chromosomal rearrangements are known to disturb these processes. In the present paper, synapsis and recombination (number and distribution of MLH1 foci were studied in three boars (Sus scrofa domestica carrying different chromosomal rearrangements. One (T34he was heterozygote for the t(3;4(p1.3;q1.5 reciprocal translocation, one (T34ho was homozygote for that translocation, while the third (T34Inv was heterozygote for both the translocation and a pericentric inversion inv(4(p1.4;q2.3. All three boars were normal for synapsis and sperm production. This particular situation allowed us to rigorously study the impact of rearrangements on recombination. Overall, the rearrangements induced only minor modifications of the number of MLH1 foci (per spermatocyte or per chromosome and of the length of synaptonemal complexes for chromosomes 3 and 4. The distribution of MLH1 foci in T34he was comparable to that of the controls. Conversely, the distributions of MLH1 foci on chromosome 4 were strongly modified in boar T34Inv (lack of crossover in the heterosynaptic region of the quadrivalent, and crossover displaced to the chromosome extremities, and also in boar T34ho (two recombination peaks on the q-arms compared with one of higher magnitude in the controls. Analyses of boars T34he and T34Inv showed that the interference was propagated through the breakpoints. A different result was obtained for boar T34ho, in which the breakpoints (transition between SSC3 and SSC4 chromatin on the bivalents seemed to alter the transmission of the interference signal. Our results suggest that the number of crossovers and crossover interference could be regulated by partially different mechanisms.

  20. Developmental regulation of X-chromosome inactivation.

    Science.gov (United States)

    Payer, Bernhard

    2016-08-01

    With the emergence of sex-determination by sex chromosomes, which differ in composition and number between males and females, appeared the need to equalize X-chromosomal gene dosage between the sexes. Mammals have devised the strategy of X-chromosome inactivation (XCI), in which one of the two X-chromosomes is rendered transcriptionally silent in females. In the mouse, the best-studied model organism with respect to XCI, this inactivation process occurs in different forms, imprinted and random, interspersed by periods of X-chromosome reactivation (XCR), which is needed to switch between the different modes of XCI. In this review, I describe the recent advances with respect to the developmental control of XCI and XCR and in particular their link to differentiation and pluripotency. Furthermore, I review the mechanisms, which influence the timing and choice, with which one of the two X-chromosomes is chosen for inactivation during random XCI. This has an impact on how females are mosaics with regard to which X-chromosome is active in different cells, which has implications on the severity of diseases caused by X-linked mutations.

  1. Algorithms for reconstruction of chromosomal structures.

    Science.gov (United States)

    Lyubetsky, Vassily; Gershgorin, Roman; Seliverstov, Alexander; Gorbunov, Konstantin

    2016-01-19

    One of the main aims of phylogenomics is the reconstruction of objects defined in the leaves along the whole phylogenetic tree to minimize the specified functional, which may also include the phylogenetic tree generation. Such objects can include nucleotide and amino acid sequences, chromosomal structures, etc. The structures can have any set of linear and circular chromosomes, variable gene composition and include any number of paralogs, as well as any weights of individual evolutionary operations to transform a chromosome structure. Many heuristic algorithms were proposed for this purpose, but there are just a few exact algorithms with low (linear, cubic or similar) polynomial computational complexity among them to our knowledge. The algorithms naturally start from the calculation of both the distance between two structures and the shortest sequence of operations transforming one structure into another. Such calculation per se is an NP-hard problem. A general model of chromosomal structure rearrangements is considered. Exact algorithms with almost linear or cubic polynomial complexities have been developed to solve the problems for the case of any chromosomal structure but with certain limitations on operation weights. The computer programs are tested on biological data for the problem of mitochondrial or plastid chromosomal structure reconstruction. To our knowledge, no computer programs are available for this model. Exactness of the proposed algorithms and such low polynomial complexities were proved. The reconstructed evolutionary trees of mitochondrial and plastid chromosomal structures as well as the ancestral states of the structures appear to be reasonable.

  2. Engineered human dicentric chromosomes show centromere plasticity.

    Science.gov (United States)

    Higgins, Anne W; Gustashaw, Karen M; Willard, Huntington F

    2005-01-01

    The centromere is essential for the faithful distribution of a cell's genetic material to subsequent generations. Despite intense scrutiny, the precise genetic and epigenetic basis for centromere function is still unknown. Here, we have used engineered dicentric human chromosomes to investigate mammalian centromere structure and function. We describe three classes of dicentric chromosomes isolated in different cell lines: functionally monocentric chromosomes, in which one of the two genetically identical centromeres is consistently inactivated; functionally dicentric chromosomes, in which both centromeres are consistently active; and dicentric chromosomes heterogeneous with respect to centromere activity. A study of serial single cell clones from heterogeneous cell lines revealed that while centromere activity is usually clonal, the centromere state (i.e. functionally monocentric or dicentric) in some lines can switch within a growing population of cells. Because pulsed field gel analysis indicated that the DNA at the centromeres of these chromosomes did not change detectably, this switching of the centromere state is most likely due to epigenetic changes. Inactivation of one of the two active centromeres in a functionally dicentric chromosome was observed in a percentage of cells after treatment with Trichostatin A, an inhibitor of histone deacetylation. This study provides evidence that the activity of human centromeres, while largely stable, can be subject to dynamic change, most likely due to epigenetic modification.

  3. [Dosage compensation mechanism of X chromosome].

    Science.gov (United States)

    Wang, Yan-Yun; Chen, Mei; Li, Bin

    2012-08-01

    Dosage compensation mechanism is crucial for the balance expression of X chromosome genes, which ensures the protein or enzyme encoded by the X chromosome to be equal or almost equal expression amounts between males and females. However, different organisms have evolved distinct dosage compensation strategies, and so far three kinds of dosage compensation strategies among organisms have been reported. The first strategy is that the single male X chromosome expression is doubly activated; the second one is to inactivate one female X chromosome by leaving both sexes with one active allele; and the third one is to reduce the expression to half activity in both X chromosomes of the female. The study of dosage compensation will be useful to reveal the mechanism of regulation of X-linked genes as well as the evolution and the differentiation progress of the sex chromosome, and it can also contribute to illustrate mutation and distortion of sex chromosome. Therefore, this paper briefly reviewed and discussed the progresses and prospects of the important mechanism of dosage compensation.

  4. [Y chromosome structural abnormalities and Turner's syndrome].

    Science.gov (United States)

    Ravel, C; Siffroi, J-P

    2009-06-01

    Although specifically male, the human Y chromosome may be observed in female karyotypes, mostly in women with Turner syndrome stigmata. In women with isolated gonadal dysgenesis but otherwise normal stature, the testis determining factor or SRY gene may have been removed from the Y chromosome or may be mutated. In other women with Turner syndrome, the karyotype is usually abnormal and shows a frequent 45,X/46,XY mosaicism. In these cases, the phenotype depends on the ratio between Y positive and 45,X cell lines in the body. When in mosaicism, Y chromosomes are likely to carry structural abnormalities which explain mitotic instability, such as the existence of two centromeres. Dicentric Y isochromosomes for the short arm (idic[Yp]) or ring Y chromosomes (r[Y]) are the most frequent abnormal Y chromosomes found in infertile patients and in Turner syndrome in mosaic with 45,X cells. Although monocentric, deleted Y chromosomes for the long arm and those carrying microdeletions in the AZF region are also instable and are frequently associated with a 45,X cell line. Management of infertile patients carrying such abnormal Y chromosomes must take into account the risk and the consequences of a mosaicism in the offspring.

  5. Chromosome I duplications in Caenorhabditis elegans

    Energy Technology Data Exchange (ETDEWEB)

    McKim, K.S.; Rose, A.M. (Univ. of British Columbia, Vancouver (Canada))

    1990-01-01

    We have isolated and characterized 76 duplications of chromosome I in the genome of Caenorhabditis elegans. The region studied is the 20 map unit left half of the chromosome. Sixty-two duplications were induced with gamma radiation and 14 arose spontaneously. The latter class was apparently the result of spontaneous breaks within the parental duplication. The majority of duplications behave as if they are free. Three duplications are attached to identifiable sequences from other chromosomes. The duplication breakpoints have been mapped by complementation analysis relative to genes on chromosome I. Nineteen duplication breakpoints and seven deficiency breakpoints divide the left half of the chromosome into 24 regions. We have studied the relationship between duplication size and segregational stability. While size is an important determinant of mitotic stability, it is not the only one. We observed clear exceptions to a size-stability correlation. In addition to size, duplication stability may be influenced by specific sequences or chromosome structure. The majority of the duplications were stable enough to be powerful tools for gene mapping. Therefore the duplications described here will be useful in the genetic characterization of chromosome I and the techniques we have developed can be adapted to other regions of the genome.

  6. Using Online Annotations to Support Error Correction and Corrective Feedback

    Science.gov (United States)

    Yeh, Shiou-Wen; Lo, Jia-Jiunn

    2009-01-01

    Giving feedback on second language (L2) writing is a challenging task. This research proposed an interactive environment for error correction and corrective feedback. First, we developed an online corrective feedback and error analysis system called "Online Annotator for EFL Writing". The system consisted of five facilities: Document Maker,…

  7. New sequence-based data on the relative DNA contents of chromosomes in the normal male and female human diploid genomes for radiation molecular cytogenetics

    Directory of Open Access Journals (Sweden)

    Repin Mikhail V

    2009-06-01

    Full Text Available Abstract Background The objective of this work is to obtain the correct relative DNA contents of chromosomes in the normal male and female human diploid genomes for the use at FISH analysis of radiation-induced chromosome aberrations. Results The relative DNA contents of chromosomes in the male and female human diploid genomes have been calculated from the publicly available international Human Genome Project data. New sequence-based data on the relative DNA contents of human chromosomes were compared with the data recommended by the International Atomic Energy Agency in 2001. The differences in the values of the relative DNA contents of chromosomes obtained by using different approaches for 15 human chromosomes, mainly for large chromosomes, were below 2%. For the chromosomes 13, 17, 20 and 22 the differences were above 5%. Conclusion New sequence-based data on the relative DNA contents of chromosomes in the normal male and female human diploid genomes were obtained. This approach, based on the genome sequence, can be recommended for the use in radiation molecular cytogenetics.

  8. Analysis of chromosome conservation in Lemur catta studied by chromosome paints and BAC/PAC probes.

    Science.gov (United States)

    Cardone, Maria Francesca; Ventura, Mario; Tempesta, Sergio; Rocchi, Mariano; Archidiacono, Nicoletta

    2002-12-01

    A panel of human chromosome painting probes and bacterial and P1 artificial chromosome (BAC/PAC) clones were used in fluorescence in situ hybridization (FISH) experiments to investigate the chromosome conservation of the ring-tailed lemur (Lemur catta, LCA) with respect to human. Whole chromosome paints specific for human chromosomes 7, 9, 11, 13, 14, 17, 18, 20, 21, and X were found to identify a single chromosome or an uninterrupted chromosomal region in LCA. A large set of partial chromosome paints and BAC/PAC probes were then used to refine the characterization of the rearrangements differentiating the two karyotypes. The results were also used to reconstruct the ancestral Lemuridae karyotype. Lemur catta, indeed, can be used as an outgroup, allowing symplesiomorphic (ancestral) rearrangements to be distinguished from apomorphic (derived) rearrangements in lemurs. Some LCA chromosomes are difficult to distinguish morphologically. The 'anchorage' of most LCA chromosomes to specific probes will contribute to the standardization of the karyotype of this species.

  9. Large-scale reconstruction of 3D structures of human chromosomes from chromosomal contact data.

    Science.gov (United States)

    Trieu, Tuan; Cheng, Jianlin

    2014-04-01

    Chromosomes are not positioned randomly within a nucleus, but instead, they adopt preferred spatial conformations to facilitate necessary long-range gene-gene interactions and regulations. Thus, obtaining the 3D shape of chromosomes of a genome is critical for understanding how the genome folds, functions and how its genes interact and are regulated. Here, we describe a method to reconstruct preferred 3D structures of individual chromosomes of the human genome from chromosomal contact data generated by the Hi-C chromosome conformation capturing technique. A novel parameterized objective function was designed for modeling chromosome structures, which was optimized by a gradient descent method to generate chromosomal structural models that could satisfy as many intra-chromosomal contacts as possible. We applied the objective function and the corresponding optimization method to two Hi-C chromosomal data sets of both a healthy and a cancerous human B-cell to construct 3D models of individual chromosomes at resolutions of 1 MB and 200 KB, respectively. The parameters used with the method were calibrated according to an independent fluorescence in situ hybridization experimental data. The structural models generated by our method could satisfy a high percentage of contacts (pairs of loci in interaction) and non-contacts (pairs of loci not in interaction) and were compatible with the known two-compartment organization of human chromatin structures. Furthermore, structural models generated at different resolutions and from randomly permuted data sets were consistent.

  10. Chromosomal abnormalities and Y chromosome microdeletions in infertile men from Morocco.

    Science.gov (United States)

    Naasse, Yassine; Charoute, Hicham; El Houate, Brahim; Elbekkay, Chadli; Razoki, Lunda; Malki, Abderrahim; Barakat, Abdelhamid; Rouba, Hassan

    2015-09-18

    Male infertility is responsible for 50% of infertile couples. Thirty percent of male infertility is due to cytogenetic and genetic abnormalities. In Arab and North African populations, several studies have shown the association of these chromosomal abnormalities with male infertility. Our objective is to evaluate the frequency of chromosomal abnormalities and Y chromosome microdeletions in infertile men from Morocco. A total of 573 Moroccan infertile men (444 azoospermic and 129 oligozoospermic men) referred for cytogenetic analysis to the Department of Cytogenetics of the Pasteur Institute of Morocco, were screened for the presence of chromosomal abnormalities and Y chromosome microdeletions. Chromosomal abnormalities accounted for approximately 10.5% (60/573). Fifty six cases among them have sex chromosome abnormalities (93.34%), including Klinefelter's syndrome in 41 patients (68.34%). Autosomal chromosome abnormalities (6.66%) were observed in 4 patients. Chromosomal abnormalities were more prevalent in azoospermic men (13.06%) than in oligospermic men (1.55%). Y microdeletions were detected in 16 of 85 patients (AZFc: 14.12%, AZFbc: 4.70%), most of them where azoospermic men with no chromosomal abnormality. These results highlighted the need for efficient molecular genetic testing in male infertility diagnosis. In addition, a genetic screening should be performed in infertile men before starting assisted reproductive treatments.

  11. Aurora B prevents chromosome arm separation defects by promoting telomere dispersion and disjunction

    OpenAIRE

    Reyes, Céline; Serrurier, Céline; Gauthier, Tiphaine; Gachet, Yannick; Tournier, Sylvie

    2015-01-01

    The segregation of centromeres and telomeres at mitosis is coordinated at multiple levels to prevent the formation of aneuploid cells, a phenotype frequently observed in cancer. Mitotic instability arises from chromosome segregation defects, giving rise to chromatin bridges at anaphase. Most of these defects are corrected before anaphase onset by a mechanism involving Aurora B kinase, a key regulator of mitosis in a wide range of organisms. Here, we describe a new role for Aurora B in telomer...

  12. A stochastic model of kinetochore–microtubule attachment accurately describes fission yeast chromosome segregation

    OpenAIRE

    Gay, Guillaume; Courtheoux, Thibault; Reyes, Céline; Tournier, Sylvie; Gachet, Yannick

    2012-01-01

    In fission yeast, erroneous attachments of spindle microtubules to kinetochores are frequent in early mitosis. Most are corrected before anaphase onset by a mechanism involving the protein kinase Aurora B, which destabilizes kinetochore microtubules (ktMTs) in the absence of tension between sister chromatids. In this paper, we describe a minimal mathematical model of fission yeast chromosome segregation based on the stochastic attachment and detachment of ktMTs. The model accurately reproduce...

  13. Chromosomal aberrations in benign prostatic hyperplasia patients

    Directory of Open Access Journals (Sweden)

    Muammer Altok

    2016-01-01

    Full Text Available Purpose: To investigate the chromosomal changes in patients with benign prostatic hyperplasia (BPH. Materials and Methods: A total of 54 patients diagnosed with clinical BPH underwent transurethral prostate resection to address their primary urological problem. All patients were evaluated by use of a comprehensive medical history and rectal digital examination. The preoperative evaluation also included serum prostate-specific antigen (PSA measurement and ultrasonographic measurement of prostate volume. Prostate cancer was detected in one patient, who was then excluded from the study. We performed conventional cytogenetic analyses of short-term cultures of 53 peripheral blood samples obtained from the BPH patients. Results: The mean (±standard deviation age of the 53 patients was 67.8±9.4 years. The mean PSA value of the patients was 5.8±7.0 ng/mL. The mean prostate volume was 53.6±22.9 mL. Chromosomal abnormalities were noted in 5 of the 53 cases (9.4%. Loss of the Y chromosome was the most frequent chromosomal abnormality and was observed in three patients (5.7%. There was no statistically significant relationship among age, PSA, prostate volume, and chromosomal changes. Conclusions: Loss of the Y chromosome was the main chromosomal abnormality found in our study. However, this coexistence did not reach a significant level. Our study concluded that loss of the Y chromosome cannot be considered relevant for the diagnosis of BPH as it is for prostate cancer. Because BPH usually occurs in aging men, loss of the Y chromosome in BPH patients may instead be related to the aging process.

  14. PREVENTING THE CHROMOSOMAL TRANSLOCATIONS THAT CAUSE CANCER.

    Science.gov (United States)

    Hromas, Robert; Williamson, Elizabeth; Lee, Suk-Hee; Nickoloff, Jac

    2016-01-01

    Approximately half of all cancers harbor chromosomal translocations that can either contribute to their origin or govern their subsequent behavior. Chromosomal translocations by definition can only occur when there are two DNA double-strand breaks (DSBs) on distinct chromosomes that are repaired heterologously. Thus, chromosomal translocations are by their very nature problems of DNA DSB repair. Such DNA DSBs can be from internal or external sources. Internal sources of DNA DSBs that can lead to translocations can occur are inappropriate immune receptor gene maturation during V(D)J recombination or heavy-chain switching. Other internal DNA DSBs can come from aberrant DNA structures, or are generated at collapsed and reversed replication forks. External sources of DNA DSBs that can generate chromosomal translocations are ionizing radiation and cancer chemotherapy. There are several known nuclear and chromatin properties that enhance translocations over homologous chromosome DSB repair. The proximity of the region of the heterologous chromosomes to each other increases translocation rates. Histone methylation events at the DSB also influence translocation frequencies. There are four DNA DSB repair pathways, but it appears that only one, alternative non-homologous end-joining (a-NHEJ) can mediate chromosomal translocations. The rate-limiting, initial step of a-NHEJ is the binding of poly-adenosine diphosphate ribose polymerase 1 (PARP1) to the DSB. In our investigation of methods for preventing oncogenic translocations, we discovered that PARP1 was required for translocations. Significantly, the clinically approved PARP1 inhibitors can block the formation of chromosomal translocations, raising the possibility for the first time that secondary oncogenic translocations can be reduced in high risk patients.

  15. Chromosomal abnormalities and y chromosome microdeletions in infertile men with varicocele and idiopathic infertility of South Indian origin

    National Research Council Canada - National Science Library

    Rao, Lakshmi; Babu, Arvind; Kanakavalli, Murthy; Padmalatha, Venkata; Singh, Amarpal; Singh, Prashant Kumar; Deenadayal, Mamata; Singh, Lalji

    2004-01-01

    .... The objective of our present study was to investigate the chromosomal abnormalities and Y chromosome microdeletions in infertile men of South Indian origin with varicocele and idiopathic infertility...

  16. Chromosomal abnormalities in patients with sperm disorders

    Directory of Open Access Journals (Sweden)

    L. Y. Pylyp

    2013-02-01

    Full Text Available Chromosomal abnormalities are among the most common genetic causes of spermatogenic disruptions. Carriers of chromosomal abnormalities are at increased risk of infertility, miscarriage or birth of a child with unbalanced karyotype due to the production of unbalanced gametes. The natural selection against chromosomally abnormal sperm usually prevents fertilization with sperm barring in cases of serious chromosomal abnormalities. However, assisted reproductive technologies in general and intracytoplasmic sperm injection in particular, enable the transmission of chromosomal abnormalities to the progeny. Therefore, cytogenetic studies are important in patients with male factor infertility before assisted reproduction treatment. The purpose of the current study was to investigate the types and frequencies of chromosomal abnormalities in 724 patients with infertility and to estimate the risk of chromosomal abnormalities detection in subgroups of patients depending on the severity of spermatogenic disruption, aiming at identifying groups of patients in need of cytogenetic studies. Karyotype analysis was performed in 724 blood samples of men attending infertility clinic. Chromosomal preparation was performed by standard techniques. At least 20 GTG-banded metaphase plates with the resolution from 450 to 750 bands per haploid set were analysed in each case. When chromosomal mosaicism was suspected, this number was increased to 50. Abnormal karyotypes were observed in 48 (6.6% patients, including 67% of autosomal abnormalities and 33% of gonosomal abnormalities. Autosomal abnormalities were represented by structural rearrangements. Reciprocal translocations were the most common type of structural chromosomal abnormalities in the studied group, detected with the frequency of 2.6% (n = 19, followed by Robertsonian translocation, observed with the frequency of 1.2% (n = 9. The frequency of inversions was 0.6% (n = 4. Gonosomal abnormalities included 14 cases

  17. 78 FR 34245 - Miscellaneous Corrections

    Science.gov (United States)

    2013-06-07

    ... Federal Regulations is sold by the Superintendent of Documents. #0;Prices of new books are listed in the... office, correcting and adding missing cross-references, correcting grammatical errors, revising language... the name of its human capital office, correcting and adding missing cross-references,...

  18. Power corrections, renormalons and resummation

    Energy Technology Data Exchange (ETDEWEB)

    Beneke, M.

    1996-08-01

    I briefly review three topics of recent interest concerning power corrections, renormalons and Sudakov resummation: (a) 1/Q corrections to event shape observables in e(+)e(-) annihilation, (b) power corrections in Drell-Yan production and (c) factorial divergences that arise in resummation of large infrared (Sudakov) logarithms in moment or `real` space.

  19. Radiation camera motion correction system

    Science.gov (United States)

    Hoffer, P.B.

    1973-12-18

    The device determines the ratio of the intensity of radiation received by a radiation camera from two separate portions of the object. A correction signal is developed to maintain this ratio at a substantially constant value and this correction signal is combined with the camera signal to correct for object motion. (Official Gazette)

  20. 75 FR 16516 - Dates Correction

    Science.gov (United States)

    2010-04-01

    ... From the Federal Register Online via the Government Publishing Office ] NATIONAL ARCHIVES AND RECORDS ADMINISTRATION Office of the Federal Register Dates Correction Correction In the Notices section... through 15499, the date at the top of each page is corrected to read ``Monday, March 29, 2010''....

  1. Homologies between human and marmoset (Callithrix jacchus) chromosomes revealed by comparative chromosome painting

    Energy Technology Data Exchange (ETDEWEB)

    Sherlock, J.K.; Griffin, D.K.; Delhanty, J.D.A.; Parrington, J.M. [Univ. College London (United Kingdom)

    1996-04-15

    Regions of DNA homology between human and marmoset (Callithrix jacchus) chromosomes have been demonstrated using fluorescence in situ hybridization. All 24 chromosome paints and two centromere repeat sequences from Homo sapiens (HSA) have been annealed to previously G-banded metaphase spreads of Callithrix jacchus. All human paint probes, except Y, successfully hybridized to marmoset chromosomes. Fifteen of them hybridized to one region only, seven to two regions, and paint 1 to three regions. Homologies proposed from previous banding comparisons have been confirmed for HSA 2, 4-6, 10-12, 18, 19, 21, and X and partially confirmed for HSA 1 and 3, but were not in agreement for HSA 14 and 17. Human centromere repeat sequences for X and 18 did not hybridize to marmoset chromosomes. Because, at present, there is the confusing situation of several different numbering systems for marmoset chromosomes, we propose a new simpler nomenclature based on descending order of chromosome size. 25 refs., 3 figs.

  2. Anomaly corrected heterotic horizons

    Science.gov (United States)

    Fontanella, A.; Gutowski, J. B.; Papadopoulos, G.

    2016-10-01

    We consider supersymmetric near-horizon geometries in heterotic supergravity up to two loop order in sigma model perturbation theory. We identify the conditions for the horizons to admit enhancement of supersymmetry. We show that solutions which undergo supersymmetry enhancement exhibit an {s}{l}(2,{R}) symmetry, and we describe the geometry of their horizon sections. We also prove a modified Lichnerowicz type theorem, incorporating α' corrections, which relates Killing spinors to zero modes of near-horizon Dirac operators. Furthermore, we demonstrate that there are no AdS2 solutions in heterotic supergravity up to second order in α' for which the fields are smooth and the internal space is smooth and compact without boundary. We investigate a class of nearly supersymmetric horizons, for which the gravitino Killing spinor equation is satisfied on the spatial cross sections but not the dilatino one, and present a description of their geometry.

  3. Anomaly Corrected Heterotic Horizons

    CERN Document Server

    Fontanella, A; Papadopoulos, G

    2016-01-01

    We consider supersymmetric near-horizon geometries in heterotic supergravity up to two loop order in sigma model perturbation theory. We identify the conditions for the horizons to admit enhancement of supersymmetry. We show that solutions which undergo supersymmetry enhancement exhibit an sl(2,R) symmetry, and we describe the geometry of their horizon sections. We also prove a modified Lichnerowicz type theorem, incorporating $\\alpha'$ corrections, which relates Killing spinors to zero modes of near-horizon Dirac operators. Furthermore, we demonstrate that there are no AdS2 solutions in heterotic supergravity up to second order in $\\alpha'$ for which the fields are smooth and the internal space is smooth and compact without boundary. We investigate a class of nearly supersymmetric horizons, for which the gravitino Killing spinor equation is satisfied on the spatial cross sections but not the dilatino one, and present a description of their geometry.

  4. Catalytic quantum error correction

    CERN Document Server

    Brun, T; Hsieh, M H; Brun, Todd; Devetak, Igor; Hsieh, Min-Hsiu

    2006-01-01

    We develop the theory of entanglement-assisted quantum error correcting (EAQEC) codes, a generalization of the stabilizer formalism to the setting in which the sender and receiver have access to pre-shared entanglement. Conventional stabilizer codes are equivalent to dual-containing symplectic codes. In contrast, EAQEC codes do not require the dual-containing condition, which greatly simplifies their construction. We show how any quaternary classical code can be made into a EAQEC code. In particular, efficient modern codes, like LDPC codes, which attain the Shannon capacity, can be made into EAQEC codes attaining the hashing bound. In a quantum computation setting, EAQEC codes give rise to catalytic quantum codes which maintain a region of inherited noiseless qubits. We also give an alternative construction of EAQEC codes by making classical entanglement assisted codes coherent.

  5. EDITORIAL: Politically correct physics?

    Science.gov (United States)

    Pople Deputy Editor, Stephen

    1997-03-01

    If you were a caring, thinking, liberally minded person in the 1960s, you marched against the bomb, against the Vietnam war, and for civil rights. By the 1980s, your voice was raised about the destruction of the rainforests and the threat to our whole planetary environment. At the same time, you opposed discrimination against any group because of race, sex or sexual orientation. You reasoned that people who spoke or acted in a discriminatory manner should be discriminated against. In other words, you became politically correct. Despite its oft-quoted excesses, the political correctness movement sprang from well-founded concerns about injustices in our society. So, on balance, I am all for it. Or, at least, I was until it started to invade science. Biologists were the first to feel the impact. No longer could they refer to 'higher' and 'lower' orders, or 'primitive' forms of life. To the list of undesirable 'isms' - sexism, racism, ageism - had been added a new one: speciesism. Chemists remained immune to the PC invasion, but what else could you expect from a group of people so steeped in tradition that their principal unit, the mole, requires the use of the thoroughly unreconstructed gram? Now it is the turn of the physicists. This time, the offenders are not those who talk disparagingly about other people or animals, but those who refer to 'forms of energy' and 'heat'. Political correctness has evolved into physical correctness. I was always rather fond of the various forms of energy: potential, kinetic, chemical, electrical, sound and so on. My students might merge heat and internal energy into a single, fuzzy concept loosely associated with moving molecules. They might be a little confused at a whole new crop of energies - hydroelectric, solar, wind, geothermal and tidal - but they could tell me what devices turned chemical energy into electrical energy, even if they couldn't quite appreciate that turning tidal energy into geothermal energy wasn't part of the

  6. Chromosome repatterning in three representative parrots (Psittaciformes) inferred from comparative chromosome painting.

    Science.gov (United States)

    Nanda, I; Karl, E; Griffin, D K; Schartl, M; Schmid, M

    2007-01-01

    Parrots (order: Psittaciformes) are the most common captive birds and have attracted human fascination since ancient times because of their remarkable intelligence and ability to imitate human speech. However, their genome organization, evolution and genomic relation with other birds are poorly understood. Chromosome painting with DNA probes derived from the flow-sorted macrochromosomes (1-10) of chicken (Gallus gallus, GGA) has been used to identify and distinguish the homoeologous chromosomal segments in three species of parrots, i.e., Agapornis roseicollis (peach-faced lovebird); Nymphicus hollandicus (cockatiel) and Melopsittacus undulatus (budgerigar). The ten GGA macrochromosome paints unequivocally recognize 14 to 16 hybridizing regions delineating the conserved chromosomal segments for the respective chicken macrochromosomes in these representative parrot species. The cross-species chromosome painting results show that, unlike in many other avian karyotypes with high homology to chicken chromosomes, dramatic rearrangements of the macrochromosomes have occurred in parrot lineages. Among the larger GGA macrochromosomes (1-5), chromosomes 1 and 4 are conserved on two chromosomes in all three species. However, the hybridization pattern for GGA 4 in A. roseicollis and M. undulatus is in sharp contrast to the most common pattern known from hybridization of chicken macrochromosome 4 in other avian karyotypes. With the exception of A. roseicollis, chicken chromosomes 2, 3 and 5 hybridized either completely or partially to a single chromosome. In contrast, the smaller GGA macrochromosomes 6, 7 and 8 displayed a complex hybridization pattern: two or three of these macrochromosomes were found to be contiguously arranged on a single chromosome in all three parrot species. Overall, the study shows that translocations and fusions in conjunction with intragenomic rearrangements have played a major role in the karyotype evolution of parrots. Our inter-species chromosome

  7. Drug-induced premature chromosome condensation (PCC) protocols: cytogenetic approaches in mitotic chromosome and interphase chromatin.

    Science.gov (United States)

    Gotoh, Eisuke

    2015-01-01

    Chromosome analysis is a fundamental technique which is used in wide areas of cytogenetic study including karyotyping species, hereditary diseases diagnosis, or chromosome biology study. Chromosomes are usually prepared from mitotic cells arrested by colcemid block protocol. However, obtaining mitotic chromosomes is often hampered under several circumstances. As a result, cytogenetic analysis will be sometimes difficult or even impossible in such cases. Premature chromosome condensation (PCC) (see Note 1) is an alternative method that has proved to be a unique and useful way in chromosome analysis. Former, PCC has been achieved following cell fusion method (cell-fusion PCC) mediated either by fusogenic viruses (e.g., Sendai virus) or cell fusion chemicals (e.g., polyethylene glycol), but the cell fusion PCC has several drawbacks. The novel drug-induced PCC using protein phosphatase inhibitors was introduced about 20 years ago. This method is much simpler and easier even than the conventional mitotic chromosome preparation protocol use with colcemid block and furthermore obtained PCC index (equivalent to mitotic index for metaphase chromosome) is usually much higher than colcemid block method. Moreover, this method allows the interphase chromatin to be condensed to visualize like mitotic chromosomes. Therefore drug-induced PCC has opened the way for chromosome analysis not only in metaphase chromosomes but also in interphase chromatin. The drug-induced PCC has thus proven the usefulness in cytogenetics and other cell biology fields. For this second edition version, updated modifications/changes are supplemented in Subheadings 2, 3, and 4, and a new section describing the application of PCC in chromosome science fields is added with citation of updated references.

  8. Chromosome landmarks and autosome-sex chromosome translocations in Rumex hastatulus, a plant with XX/XY1Y2 sex chromosome system.

    Science.gov (United States)

    Grabowska-Joachimiak, Aleksandra; Kula, Adam; Książczyk, Tomasz; Chojnicka, Joanna; Sliwinska, Elwira; Joachimiak, Andrzej J

    2015-06-01

    Rumex hastatulus is the North American endemic dioecious plant with heteromorphic sex chromosomes. It is differentiated into two chromosomal races: Texas (T) race characterised by a simple XX/XY sex chromosome system and North Carolina (NC) race with a polymorphic XX/XY1Y2 sex chromosome system. The gross karyotype morphology in NC race resembles the derived type, but chromosomal changes that occurred during its evolution are poorly understood. Our C-banding/DAPI and fluorescence in situ hybridization (FISH) experiments demonstrated that Y chromosomes of both races are enriched in DAPI-positive sequences and that the emergence of polymorphic sex chromosome system was accompanied by the break of ancestral Y chromosome and switch in the localization of 5S rDNA, from autosomes to sex chromosomes (X and Y2). Two contrasting domains were detected within North Carolina Y chromosomes: the older, highly heterochromatinised, inherited from the original Y chromosome and the younger, euchromatic, representing translocated autosomal material. The flow-cytometric DNA estimation showed ∼3.5 % genome downsizing in the North Carolina race. Our results are in contradiction to earlier reports on the lack of heterochromatin within Y chromosomes of this species and enable unambiguous identification of autosomes involved in the autosome-heterosome translocation, providing useful chromosome landmarks for further studies on the karyotype and sex chromosome differentiation in this species.

  9. Genomic regulatory landscapes and chromosomal rearrangements

    DEFF Research Database (Denmark)

    Ladegaard, Elisabete L Engenheiro

    2008-01-01

    The main objectives of the PhD study are to identify and characterise chromosomal rearrangements within evolutionarily conserved regulatory landscapes around genes involved in the regulation of transcription and/or development (trans-dev genes). A frequent feature of trans-dev genes...... the complex spatio-temporal expression of the associated trans-dev gene. Rare chromosomal breakpoints that disrupt the integrity of these regulatory landscapes may be used as a tool, not only to make genotype-phenotype associations, but also to link the associated phenotype with the position and tissue...... specificity of the individual CNEs. In this PhD study I have studied several chromosomal rearrangements with breakpoints in the vicinity of trans-dev genes. This included chromosomal rearrangements compatible with known phenotype-genotype associations (Rieger syndrome-PITX2, Mowat-Wilson syndrome-ZEB2...

  10. Micro-Raman spectroscopy of chromosomes

    NARCIS (Netherlands)

    de Mul, F.F.M.; van Welle, A.G.M.; Otto, Cornelis; Greve, Jan

    1984-01-01

    Raman spectra of intact chromosomes (Chinese hamster), recorded with a microspectrometer, are reported. The spectra could be assigned to protein and DNA contributions. Protein and DNA conformations and the ratio of base pairs in DNA were determined.

  11. Control of chromosome replication in caulobacter crescentus.

    Science.gov (United States)

    Marczynski, Gregory T; Shapiro, Lucy

    2002-01-01

    Caulobacter crescentus permits detailed analysis of chromosome replication control during a developmental cell cycle. Its chromosome replication origin (Cori) may be prototypical of the large and diverse class of alpha-proteobacteria. Cori has features that both affiliate and distinguish it from the Escherichia coli chromosome replication origin. For example, requirements for DnaA protein and RNA transcription affiliate both origins. However, Cori is distinguished by several features, and especially by five binding sites for the CtrA response regulator protein. To selectively repress and limit chromosome replication, CtrA receives both protein degradation and protein phosphorylation signals. The signal mediators, proteases, response regulators, and kinases, as well as Cori DNA and the replisome, all show distinct patterns of temporal and spatial organization during cell cycle progression. Future studies should integrate our knowledge of biochemical activities at Cori with our emerging understanding of cytological dynamics in C. crescentus and other bacteria.

  12. Cognitive and medical features of chromosomal aneuploidy.

    Science.gov (United States)

    Hutaff-Lee, Christa; Cordeiro, Lisa; Tartaglia, Nicole

    2013-01-01

    This chapter describes the physical characteristics, medical complications, and cognitive and psychological profiles that are associated with chromosomal aneuploidy conditions, a group of conditions in which individuals are born with one or more additional chromosome. Overall, chromosomal aneuploidy conditions occur in approximately 1 in 250 children. Information regarding autosomal disorders including trisomy 21 (Down syndrome), trisomy 13 (Patau syndrome), and trisomy 18 (Edward syndrome) are presented. Sex chromosome aneuploidy conditions such as Klinefelter syndrome (47,XXY), XYY, trisomy X, and Turner syndrome (45,X), in addition to less frequently occurring tetrasomy and pentasomy conditions are also covered. Treatment recommendations and suggestions for future research directions are discussed. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. Temporal genomic evolution of bird sex chromosomes

    DEFF Research Database (Denmark)

    Wang, Zongji; Zhang, Jilin; Yang, Wei

    2014-01-01

    ('fast-Z' evolution). And species with a lower level of intronic heterozygosities tend to evolve even faster on the Z chromosome. Further analysis of fast-evolving genes' enriched functional categories and sex-biased expression patterns support that, fast-Z evolution in birds is mainly driven by genetic...... driving forces of Z chromosome evolution, we analyze here 45 newly available bird genomes and four species' transcriptomes, over their course of recombination loss between the sex chromosomes. RESULTS: We show Z chromosomes in general have a significantly higher substitution rate in introns and synonymous...... protein-coding sites than autosomes, driven by the male-to-female mutation bias ('male-driven evolution' effect). Our genome-wide estimate reveals that the degree of such a bias ranges from 1.6 to 3.8 among different species. G + C content of third codon positions exhibits the same trend of gradual...

  14. Genetics Home Reference: isodicentric chromosome 15 syndrome

    Science.gov (United States)

    ... isodicentric chromosome 15 syndrome include hyperactivity, anxiety, and frustration leading to tantrums. Other behaviors resemble features of ... Information from MedlinePlus (5 links) Diagnostic Tests Drug Therapy Genetic Counseling Palliative Care Surgery and Rehabilitation Related ...

  15. Chromosomal contact permits transcription between coregulated genes

    CSIR Research Space (South Africa)

    Fanucchi, Stephanie

    2013-10-01

    Full Text Available . To ask whether chromosomal contacts are required for cotranscription in multigene complexes, we devised a strategy using TALENs to cleave and disrupt gene loops in a well-characterized multigene complex. Monitoring this disruption using RNA FISH...

  16. Meiosis I: when chromosomes undergo extreme makeover.

    Science.gov (United States)

    Miller, Matthew P; Amon, Angelika; Ünal, Elçin

    2013-12-01

    The ultimate success of cell division relies on the accurate partitioning of the genetic material. Errors in this process occur in nearly all tumors and are the leading cause of miscarriages and congenital birth defects in humans. Two cell divisions, mitosis and meiosis, use common as well as unique mechanisms to ensure faithful chromosome segregation. In mitosis, alternating rounds of DNA replication and chromosome segregation preserve the chromosome complement of the progenitor cell. In contrast, during meiosis two consecutive rounds of nuclear division, meiosis I and meiosis II, follow a single round of DNA replication to reduce the chromosome complement by half. Meiosis likely evolved through changes to the mitotic cell division program. This review will focus on the recent findings describing the modifications that transform mitosis into meiosis. Copyright © 2013. Published by Elsevier Ltd.

  17. XYY chromosome abnormality in sexual homicide perpetrators.

    Science.gov (United States)

    Briken, Peer; Habermann, Niels; Berner, Wolfgang; Hill, Andreas

    2006-03-05

    In a retrospective investigation of the court reports about sexual homicide perpetrators chromosome analysis had been carried out in 13 of 166 (7.8%) men. Three men (1.8%) with XYY chromosome abnormality were found. This rate is much higher than that found in unselected samples of prisoners (0.7-0.9%) or in the general population (0.01%). The three men had shown prepubescent abnormalities, school problems, and had suffered from physical abuse. The chromosome analysis in all cases had been carried out in connection with the forensic psychiatric court report due to the sexual homicide. However, two men had earlier psychiatric referrals. All were diagnosed as sexual sadistic, showed a psychopathic syndrome or psychopathy according to the Psychopathy Checklist-Revised [Hare RD, 1991, The Hare Psychopathy Checklist-Revised, Toronto, Ontario, Canada: Multi-Health Systems]. Two were multiple murderers. Especially forensic psychiatrists should be vigilant of the possibility of XYY chromosome abnormalities in sexual offenders.

  18. A Revised Map of the Human Chromosomes.

    Science.gov (United States)

    Offner, Susan

    1993-01-01

    Presents an updated map of the human chromosomes, building on a "plain English map" that was previously published. A brief summary of genes research is included in the gene explanations accompanying the map. (PR)

  19. The chromosomes Damaliscus lunatus of the tsessebe

    African Journals Online (AJOL)

    Callianassa species found in the King's Beach transect. ... Africa with a key to South African species. Ann. S. Afr. Mus. ... described. The diploid chromosome number of 36 (NF = 61) ... dactyla, Carnivora, Proboscidea and Perissodactyla in.

  20. Chromosome replication and segregation in bacteria.

    Science.gov (United States)

    Reyes-Lamothe, Rodrigo; Nicolas, Emilien; Sherratt, David J

    2012-01-01

    In dividing cells, chromosome duplication once per generation must be coordinated with faithful segregation of newly replicated chromosomes and with cell growth and division. Many of the mechanistic details of bacterial replication elongation are well established. However, an understanding of the complexities of how replication initiation is controlled and coordinated with other cellular processes is emerging only slowly. In contrast to eukaryotes, in which replication and segregation are separate in time, the segregation of most newly replicated bacterial genetic loci occurs sequentially soon after replication. We compare the strategies used by chromosomes and plasmids to ensure their accurate duplication and segregation and discuss how these processes are coordinated spatially and temporally with growth and cell division. We also describe what is known about the three conserved families of ATP-binding proteins that contribute to chromosome segregation and discuss their inter-relationships in a range of disparate bacteria.

  1. Insect chromosomes preparing methods for genetic researches

    African Journals Online (AJOL)

    STORAGESEVER

    2009-01-05

    Jan 5, 2009 ... Key words: Fluorescence in situ hybridization (FISH), chromosome staining, g- banding, c – banding, ... accomplished by studying various aspects of the genetics ... is a private method in molecular cytogenetics, due to the.

  2. Dynamics of rye chromosome 1R regions with high or low crossover frequency in homology search and synapsis development.

    Directory of Open Access Journals (Sweden)

    Nohelia T Valenzuela

    Full Text Available In many organisms, homologous pairing and synapsis depend on the meiotic recombination machinery that repairs double-strand DNA breaks (DSBs produced at the onset of meiosis. The culmination of recombination via crossover gives rise to chiasmata, which locate distally in many plant species such as rye, Secale cereale. Although, synapsis initiates close to the chromosome ends, a direct effect of regions with high crossover frequency on partner identification and synapsis initiation has not been demonstrated. Here, we analyze the dynamics of distal and proximal regions of a rye chromosome introgressed into wheat to define their role on meiotic homology search and synapsis. We have used lines with a pair of two-armed chromosome 1R of rye, or a pair of telocentrics of its long arm (1RL, which were homozygous for the standard 1RL structure, homozygous for an inversion of 1RL that changes chiasma location from distal to proximal, or heterozygous for the inversion. Physical mapping of recombination produced in the ditelocentric heterozygote (1RL/1RL(inv showed that 70% of crossovers in the arm were confined to a terminal segment representing 10% of the 1RL length. The dynamics of the arms 1RL and 1RL(inv during zygotene demonstrates that crossover-rich regions are more active in recognizing the homologous partner and developing synapsis than crossover-poor regions. When the crossover-rich regions are positioned in the vicinity of chromosome ends, their association is facilitated by telomere clustering; when they are positioned centrally in one of the two-armed chromosomes and distally in the homolog, their association is probably derived from chromosome elongation. On the other hand, chromosome movements that disassemble the bouquet may facilitate chromosome pairing correction by dissolution of improper chromosome associations. Taken together, these data support that repair of DSBs via crossover is essential in both the search of the homologous partner

  3. Assembly of eukaryotic algal chromosomes in yeast

    OpenAIRE

    Karas, Bogumil J.; Molparia, Bhuvan; Jablanovic, Jelena; Hermann, Wolfgang J; Lin, Ying-Chi; Dupont, Christopher L.; Tagwerker, Christian; Yonemoto, Isaac T.; Noskov, Vladimir N.; Chuang, Ray-Yuan; Allen, Andrew E; Glass, John I.; Hutchison, Clyde A; Smith, Hamilton O; Venter, J Craig

    2013-01-01

    Background Synthetic genomic approaches offer unique opportunities to use powerful yeast and Escherichia coli genetic systems to assemble and modify chromosome-sized molecules before returning the modified DNA to the target host. For example, the entire 1 Mb Mycoplasma mycoides chromosome can be stably maintained and manipulated in yeast before being transplanted back into recipient cells. We have previously demonstrated that cloning in yeast of large (> ~ 150 kb), high G + C (55%) prokaryoti...

  4. Abnormal sex chromosome constitution and longitudinal growth

    DEFF Research Database (Denmark)

    Aksglaede, Lise; Skakkebaek, Niels E; Juul, Anders

    2008-01-01

    Growth is a highly complex process regulated by the interaction between sex steroids and the GH IGF-axis. However, other factors such as sex chromosome-related genes play independent roles.......Growth is a highly complex process regulated by the interaction between sex steroids and the GH IGF-axis. However, other factors such as sex chromosome-related genes play independent roles....

  5. Chromosomal organization and segregation in Pseudomonas aeruginosa.

    Directory of Open Access Journals (Sweden)

    Isabelle Vallet-Gely

    2013-05-01

    Full Text Available The study of chromosomal organization and segregation in a handful of bacteria has revealed surprising variety in the mechanisms mediating such fundamental processes. In this study, we further emphasized this diversity by revealing an original organization of the Pseudomonas aeruginosa chromosome. We analyzed the localization of 20 chromosomal markers and several components of the replication machinery in this important opportunistic γ-proteobacteria pathogen. This technique allowed us to show that the 6.3 Mb unique circular chromosome of P. aeruginosa is globally oriented from the old pole of the cell to the division plane/new pole along the oriC-dif axis. The replication machinery is positioned at mid-cell, and the chromosomal loci from oriC to dif are moved sequentially to mid-cell prior to replication. The two chromosomal copies are subsequently segregated at their final subcellular destination in the two halves of the cell. We identified two regions in which markers localize at similar positions, suggesting a bias in the distribution of chromosomal regions in the cell. The first region encompasses 1.4 Mb surrounding oriC, where loci are positioned around the 0.2/0.8 relative cell length upon segregation. The second region contains at least 800 kb surrounding dif, where loci show an extensive colocalization step following replication. We also showed that disrupting the ParABS system is very detrimental in P. aeruginosa. Possible mechanisms responsible for the coordinated chromosomal segregation process and for the presence of large distinctive regions are discussed.

  6. Fetal calcifications are associated with chromosomal abnormalities.

    Directory of Open Access Journals (Sweden)

    Ellika Sahlin

    Full Text Available The biological importance of calcifications occasionally noted in fetal tissues (mainly liver at autopsy or ultrasound is largely unexplored. Previous reports hint at an association to infection, circulatory compromise, malformations or chromosomal abnormalities. To identify factors associated with calcifications, we have performed a case-control study on the largest cohort of fetuses with calcifications described thus far.One-hundred and fifty-one fetuses with calcifications and 302 matched controls were selected from the archives of the Department of Pathology, Karolinska University Hospital. Chromosome analysis by karyotyping or quantitative fluorescence-polymerase chain reaction was performed. Autopsy and placenta reports were scrutinized for presence of malformations and signs of infection.Calcifications were mainly located in the liver, but also in heart, bowel, and other tissues. Fetuses with calcifications showed a significantly higher proportion of chromosomal abnormalities than controls; 50% vs. 20% (p<0.001. The most frequent aberrations among cases included trisomy 21 (33%, trisomy 18 (22%, and monosomy X (18%. A similar distribution was seen among controls. When comparing cases and controls with chromosomal abnormalities, the cases had a significantly higher prevalence of malformations (95% vs. 77%, p=0.004. Analyzed the other way around, cases with malformations had a significantly higher proportion of chromosomal abnormalities compared with controls, (66% vs. 31%, p<0.001.The presence of fetal calcifications is associated with high risk of chromosomal abnormality in combination with malformations. Identification of a calcification together with a malformation at autopsy more than doubles the probability of detecting a chromosomal abnormality, compared with identification of a malformation only. We propose that identification of a fetal tissue calcification at autopsy, and potentially also at ultrasound examination, should infer

  7. Female meiotic sex chromosome inactivation in chicken.

    Science.gov (United States)

    Schoenmakers, Sam; Wassenaar, Evelyne; Hoogerbrugge, Jos W; Laven, Joop S E; Grootegoed, J Anton; Baarends, Willy M

    2009-05-01

    During meiotic prophase in male mammals, the heterologous X and Y chromosomes remain largely unsynapsed, and meiotic sex chromosome inactivation (MSCI) leads to formation of the transcriptionally silenced XY body. In birds, the heterogametic sex is female, carrying Z and W chromosomes (ZW), whereas males have the homogametic ZZ constitution. During chicken oogenesis, the heterologous ZW pair reaches a state of complete heterologous synapsis, and this might enable maintenance of transcription of Z- and W chromosomal genes during meiotic prophase. Herein, we show that the ZW pair is transiently silenced, from early pachytene to early diplotene using immunocytochemistry and gene expression analyses. We propose that ZW inactivation is most likely achieved via spreading of heterochromatin from the W on the Z chromosome. Also, persistent meiotic DNA double-strand breaks (DSBs) may contribute to silencing of Z. Surprisingly, gammaH2AX, a marker of DSBs, and also the earliest histone modification that is associated with XY body formation in mammalian and marsupial spermatocytes, does not cover the ZW during the synapsed stage. However, when the ZW pair starts to desynapse, a second wave of gammaH2AX accumulates on the unsynapsed regions of Z, which also show a reappearance of the DSB repair protein RAD51. This indicates that repair of meiotic DSBs on the heterologous part of Z is postponed until late pachytene/diplotene, possibly to avoid recombination with regions on the heterologously synapsed W chromosome. Two days after entering diplotene, the Z looses gammaH2AX and shows reactivation. This is the first report of meiotic sex chromosome inactivation in a species with female heterogamety, providing evidence that this mechanism is not specific to spermatogenesis. It also indicates the presence of an evolutionary force that drives meiotic sex chromosome inactivation independent of the final achievement of synapsis.

  8. Abnormal Chromosome Segregation May Trigger Tumors

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    @@ Cancer is a primary threat to human health as it kills millions of people each year.Scientists have shown that 75% of human cancers have an abnormal number of chromosomes in cells,and the proportion of the cells with an abnormal chromosome number is tightly and positively related to malignance progression and metastasis of cancers. But the pathological mechanism behind the anomaly still remains unknown.

  9. Entropy as the driver of chromosome segregation

    OpenAIRE

    Jun, Suckjoon; Wright, Andrew

    2010-01-01

    We present a new physical biology approach to understanding the relationship between the organization and segregation of bacterial chromosomes. We posit that replicated Escherichia coli daughter strands will spontaneously demix as a result of entropic forces, despite their strong confinement within the cell; in other words, we propose that entropy can act as a primordial physical force which drives chromosome segregation under the right physical conditions. Furthermore, proteins implicated in...

  10. Plasmid and chromosome segregation in prokaryotes

    DEFF Research Database (Denmark)

    Møller-Jensen, Jakob; Bugge Jensen, Rasmus; Gerdes, Kenn

    2000-01-01

    Recent major advances in the understanding of prokaryotic DNA segregation have been achieved by using fluorescence microscopy to visualize the localization of cellular components. Plasmids and bacterial chromosomes are partitioned in a highly dynamic fashion, suggesting the presence of a mitotic......-like apparatus in prokaryotes. The identification of chromosomal homologues of the well-characterized plasmid partitioning genes indicates that there could be a general mechanism of bacterial DNA partitioning. Udgivelsesdato: July 1...

  11. Chromosomal profile of indigenous pig (Sus scrofa

    Directory of Open Access Journals (Sweden)

    P. Guru Vishnu

    2015-02-01

    Full Text Available Aim: The objective of this study was to investigate the chromosomal profile of indigenous pigs by computing morphometric measurements. Materials and Methods: A cytogenetic study was carried out in 60 indigenous pigs to analyze the chromosomal profile by employing the short term peripheral blood lymphocyte culture technique. Results: The modal chromosome number (2n in indigenous pigs was found to be 38 and a fundamental number of 64 as in the exotic. First chromosome was the longest pair, and thirteenth pair was the second largest while Y-chromosome was the smallest in the karyotype of the pig. The mean relative length, arm ratio, centromeric indices and morphological indices of chromosomes varied from 1.99±0.01 to 11.23±0.09, 1.04±0.05 to 2.95±0.02, 0.51±0.14 to 0.75±0.09 and 2.08±0.07 to 8.08±0.15%, respectively in indigenous pigs. Sex had no significant effect (p>0.05 on all the morphometric measurements studied. Conclusion: The present study revealed that among autosomes first five pairs were sub metacentric, next two pairs were sub telocentric (6-7, subsequent five pairs were metacentric (8-12 and remaining six pairs were telocentric (13-18, while both allosomes were metacentric. The chromosomal number, morphology and various morphometric measurements of the chromosomes of the indigenous pigs were almost similar to those established breeds reported in the literature.

  12. Chromosomal aberrations and aneuploidies of spermatozoa.

    Science.gov (United States)

    Piomboni, Paola; Stendardi, Anita; Gambera, Laura

    2014-01-01

    Chromosomal abnormalities are relevant causes of human infertility, affecting 2 -14 % of infertile males. Patients with seminal anomalies could be affected by improper meiotic recombination and increased sperm chromosome aneuploidy. Since the transmission of a haploid chromosomal asset is fundamental for embryo vitality and development, the study of sperm chromosomes has become fundamental because intracytoplasmic sperm injection allows fertilization in cases of severe male infertility.In this chapter we summarize the data on the incidence of sperm aneuploidy, detected by fluorescence in situ hybridization (FISH), in infertile men with normal or abnormal karyotype. The possibility of reducing sperm chromosomal imbalance is also reported.Among control males, the lowest aneuploidy rate was detected (range: 0.09 -0.14 % for autosomes; 0.04 -0.10 % for gonosomes). In infertile patients with normal karyotype, the severity of semen alteration is correlated with the frequency of aneuploidy, particularly for X and Y chromosomes. Among patients with abnormal karyotype, 47,XXY and 47,XYY carriers showed a high variability of sperm aneuploidy both for gonosomes and autosomes. In Robertsonian translocation carriers, the increase in aneuploidy rate was particularly evident for total sex disomy, and resulted mainly from interchromosomal effect (ICE). In reciprocal translocation carriers, a high percentage of unbalanced sperm (approximately 50 %) was detected, perhaps mostly related to ICE.Sperm chromosomal constitution could be analyzed to obtain more accurate information about the causes of male infertility. It would be worthwhile to evaluate the benefits of a therapy with recombinant Follicle Stimulating Hormone (rFSH) on sperm chromosome segregation in selected infertile males.

  13. Female meiotic sex chromosome inactivation in chicken.

    Directory of Open Access Journals (Sweden)

    Sam Schoenmakers

    2009-05-01

    Full Text Available During meiotic prophase in male mammals, the heterologous X and Y chromosomes remain largely unsynapsed, and meiotic sex chromosome inactivation (MSCI leads to formation of the transcriptionally silenced XY body. In birds, the heterogametic sex is female, carrying Z and W chromosomes (ZW, whereas males have the homogametic ZZ constitution. During chicken oogenesis, the heterologous ZW pair reaches a state of complete heterologous synapsis, and this might enable maintenance of transcription of Z- and W chromosomal genes during meiotic prophase. Herein, we show that the ZW pair is transiently silenced, from early pachytene to early diplotene using immunocytochemistry and gene expression analyses. We propose that ZW inactivation is most likely achieved via spreading of heterochromatin from the W on the Z chromosome. Also, persistent meiotic DNA double-strand breaks (DSBs may contribute to silencing of Z. Surprisingly, gammaH2AX, a marker of DSBs, and also the earliest histone modification that is associated with XY body formation in mammalian and marsupial spermatocytes, does not cover the ZW during the synapsed stage. However, when the ZW pair starts to desynapse, a second wave of gammaH2AX accumulates on the unsynapsed regions of Z, which also show a reappearance of the DSB repair protein RAD51. This indicates that repair of meiotic DSBs on the heterologous part of Z is postponed until late pachytene/diplotene, possibly to avoid recombination with regions on the heterologously synapsed W chromosome. Two days after entering diplotene, the Z looses gammaH2AX and shows reactivation. This is the first report of meiotic sex chromosome inactivation in a species with female heterogamety, providing evidence that this mechanism is not specific to spermatogenesis. It also indicates the presence of an evolutionary force that drives meiotic sex chromosome inactivation independent of the final achievement of synapsis.

  14. Application of chromosomal microdissection, polymerase chain reaction (PCR), and reverse chromosome painting in prenatal diagnosis

    Energy Technology Data Exchange (ETDEWEB)

    Wang, N.; Xu, J.; Cedrone, E. [Univ. of Rochester School of Medicine, Rochester, NY (United States)

    1994-09-01

    De novo marker chromosomes have been found in about 0.04% of amniotic fluid cultures. The origin of these marker chromosomes is difficult to identify by routine chromosome banding analysis. In the present study, we applied microdissection, PCR, and reverse chromosome painting to two amniotic fluid cases with a karyotype of 47,XX,+mar, and 47,XX,+?i(9p), respectively. Fluorescence in situ hybridization of the biotin-labeled DNA probe generated from 5 copies of the dissected marker chromosomes was applied to the normal metaphase spreads and revealed that the marker originated from the p arm of chromosomes 14 and 22, while the ?i(9p) was actually i(4p). Reverse painting of the same probe to the metaphase spreads of the patients completely painted the marker chromosomes in question, which confirms the accuracy of the analysis. Our study provides an example of the application of chromosome microdissection and molecular cytogenetics in prenatal diagnosis for the identification of marker chromosomes unidentifiable by routine analysis.

  15. Whole chromosome gain does not in itself confer cancer-like chromosomal instability.

    Science.gov (United States)

    Valind, Anders; Jin, Yuesheng; Baldetorp, Bo; Gisselsson, David

    2013-12-24

    Constitutional aneuploidy is typically caused by a single-event meiotic or early mitotic error. In contrast, somatic aneuploidy, found mainly in neoplastic tissue, is attributed to continuous chromosomal instability. More debated as a cause of aneuploidy is aneuploidy itself; that is, whether aneuploidy per se causes chromosomal instability, for example, in patients with inborn aneuploidy. We have addressed this issue by quantifying the level of somatic mosaicism, a proxy marker of chromosomal instability, in patients with constitutional aneuploidy by precise background-filtered dual-color FISH. In contrast to previous studies that used less precise methods, we find that constitutional trisomy, even for large chromosomes that are often trisomic in cancer, does not confer a significantly elevated rate of somatic chromosomal mosaicism in individual cases. Constitutional triploidy was associated with an increased level of somatic mosaicism, but this consisted mostly of reversion from trisomy to disomy and did not correspond to a proportionally elevated level of chromosome mis-segregation in triploids, indicating that the observed mosaicism resulted from a specific accumulation of cells with a hypotriploid chromosome number. In no case did the rate of somatic mosaicism in constitutional aneuploidy exceed that of "chromosomally stable" cancer cells. Our findings show that even though constitutional aneuploidy was in some cases associated with low-level somatic mosaicism, it was insufficient to generate the cancer-like levels expected if aneuploidy single-handedly triggered cancer-like chromosomal instability.

  16. Detection of chromosomal abnormality and Y chromosome microdeletion in patients with azoospermia and oligozoospermia

    Institute of Scientific and Technical Information of China (English)

    Shi Yun-fang; Shao Min-jie; Zhang Ying; Zhang Xiu-ling; Li Yan

    2008-01-01

    Objective:To investigate the chromosomal abnormality and Y chromosome microdeletion in patients with azoospermia and oligozoospermia.Methods:Cytogenetic karyotype analysis and multiplex PCR were used to detect chromosomal abnormality and Y chromosome microdeletion in 99 azoospermic and 57 oligospermic patients(total 156).45 fertile men were includ-ed as controls.Results:31 patients were found with chromosomal abnormalities in 156 cases(31/156,19.9 %),20 cases showed 47,XXY,2 cases showed 46,XY/47,XXY,7 cases had Y chromosome structural abnormalities and 2 had autosomal chromosome abnormalities.There were significant differences between the frequency of AZF microde-letion in 125 cases with normal karyotype and 45 controls(P0.05).AZFa,AZFb,AZFa+b,AZFb+c,AZFa+b+d and AZFb+c+d mierodeletions were found in azoospermic patients.AZFb,AZFc,AZFd,AZFb+c+d and AZFc+d microdeletions were found in oligo-spermic patients.Conxlusion:The frequency of chromosomal abnormality was 19.9% and the frequency of Y chromosome mi-crodeletion was 15.2% in patient with azoospermia and oligozoospermia.We should pay close attention to this prob-lem.

  17. Neo-sex chromosomes of Ronderosia bergi: insight into the evolution of sex chromosomes in grasshoppers.

    Science.gov (United States)

    Palacios-Gimenez, O M; Marti, D A; Cabral-de-Mello, D C

    2015-09-01

    Sex chromosomes have evolved many times from morphologically identical autosome pairs, most often presenting several recombination suppression events, followed by accumulation of repetitive DNA sequences. In Orthoptera, most species have an X0♂ sex chromosome system. However, in the subfamily Melanoplinae, derived variants of neo-sex chromosomes (neo-XY♂ or neo-X1X2Y♂) emerged several times. Here, we examined the differentiation of neo-sex chromosomes in a Melanoplinae species with a neo-XY♂/XX♀ system, Ronderosia bergi, using several approaches: (i) classical cytogenetic analysis, (ii) mapping via fluorescent in situ hybridization of some selected repetitive DNA sequences and microdissected sex chromosomes, and (iii) immunolocalization of distinct histone modifications. The microdissected sex chromosomes were also used as sources for Polymerase chain reaction (PCR) amplification of RNA-coding multigene families, to study variants related to the sex chromosomes. Our data suggest that the R. bergi neo-Y has become differentiated after its formation by a Robertsonian translocation and inversions, and has accumulated repetitive DNA sequences. Interestingly, the ex autosomes incorporated into the neo-sex chromosomes retain some autosomal post-translational histone modifications, at least in metaphase I, suggesting that the establishment of functional modifications in neo-sex chromosomes is slower than their sequence differentiation.

  18. Homomorphic sex chromosomes and the intriguing Y chromosome of Ctenomys rodent species (Rodentia, Ctenomyidae).

    Science.gov (United States)

    Suárez-Villota, Elkin Y; Pansonato-Alves, José C; Foresti, Fausto; Gallardo, Milton H

    2014-01-01

    Unlike the X chromosome, the mammalian Y chromosome undergoes evolutionary decay resulting in small size. This sex chromosomal heteromorphism, observed in most species of the fossorial rodent Ctenomys, contrasts with the medium-sized, homomorphic acrocentric sex chromosomes of closely related C. maulinus and C. sp. To characterize the sequence composition of these chromosomes, fluorescent banding, self-genomic in situ hybridization, and fluorescent in situ hybridization with an X painting probe were performed on mitotic and meiotic plates. High molecular homology between the sex chromosomes was detected on mitotic material as well as on meiotic plates immunodetected with anti-SYCP3 and anti-γH2AX. The Y chromosome is euchromatic, poor in repetitive sequences and differs from the X by the loss of a block of pericentromeric chromatin. Inferred from the G-banding pattern, an inversion and the concomitant prevention of recombination in a large asynaptic region seems to be crucial for meiotic X chromosome inactivation. These peculiar findings together with the homomorphism of Ctenomys sex chromosomes are discussed in the light of the regular purge that counteracts Muller's ratchet and the probable mechanisms accounting for their origin and molecular homology.

  19. Label Free Chromosome Translocation Detection with Silicon nanowires

    DEFF Research Database (Denmark)

    Kwasny, Dorota; Andersen, Karsten Brandt; Frøhling, Kasper Bayer;

    is a Fluorescent In Situ Hybridization, which is laborious and involves use of expensive reagents [1]. Here we present a label free technique for detection of chromosome translocations. As a proof of concept detection of chromosome translocation between chromosome 3 (Chr3) and chromosome 9 (Chr9) was chosen....

  20. The chromosome as a dynamic structure of the cell nucleus

    Institute of Scientific and Technical Information of China (English)

    WOLFGANGHENNIG

    1993-01-01

    Out view of eukaryotic chromosomes is still very much dictated by the classic ideas of geneticists and cytologists considering the chromosome just as a vehicle for genes. This one-sided view of chromosomes may have been strongly influenced by the many cytological observations made on polytene chromosomes.

  1. Chromosomes in the genesis and progression of ependymomas

    DEFF Research Database (Denmark)

    Rogatto, S R; Casartelli, C; Rainho, C A;

    1993-01-01

    chromosomes in three cases. Structural rearrangements of chromosome 2 were a finding for all cases and involved loss of material at 2q32-34. Other structural chromosome abnormalities detected involved chromosomes 4, 6, 10, 11, 12, and X. We also reviewed data on 22 cases previously reported....

  2. GeneBreak: detection of recurrent DNA copy number aberration-associated chromosomal breakpoints within genes [version 2; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Evert van den Broek

    2017-07-01

    Full Text Available Development of cancer is driven by somatic alterations, including numerical and structural chromosomal aberrations. Currently, several computational methods are available and are widely applied to detect numerical copy number aberrations (CNAs of chromosomal segments in tumor genomes. However, there is lack of computational methods that systematically detect structural chromosomal aberrations by virtue of the genomic location of CNA-associated chromosomal breaks and identify genes that appear non-randomly affected by chromosomal breakpoints across (large series of tumor samples. ‘GeneBreak’ is developed to systematically identify genes recurrently affected by the genomic location of chromosomal CNA-associated breaks by a genome-wide approach, which can be applied to DNA copy number data obtained by array-Comparative Genomic Hybridization (CGH or by (low-pass whole genome sequencing (WGS. First, ‘GeneBreak’ collects the genomic locations of chromosomal CNA-associated breaks that were previously pinpointed by the segmentation algorithm that was applied to obtain CNA profiles. Next, a tailored annotation approach for breakpoint-to-gene mapping is implemented. Finally, dedicated cohort-based statistics is incorporated with correction for covariates that influence the probability to be a breakpoint gene. In addition, multiple testing correction is integrated to reveal recurrent breakpoint events. This easy-to-use algorithm, ‘GeneBreak’, is implemented in R (www.cran.r-project.org and is available from Bioconductor (www.bioconductor.org/packages/release/bioc/html/GeneBreak.html.

  3. Small Supernumerary Marker Chromosomes in Human Infertility.

    Science.gov (United States)

    Armanet, Narjes; Tosca, Lucie; Brisset, Sophie; Liehr, Thomas; Tachdjian, Gérard

    2015-01-01

    Small supernumerary marker chromosomes (sSMC) are structurally abnormal chromosomes that cannot be unambiguously identified by banding cytogenetics. The objective of this study was to provide an overview of sSMC frequency and characterization in a context of infertility and to review the literature describing sSMC in relation with male and female infertility. Therefore, a systematic literature review on sSMC associated with infertility was conducted by means of a PubMed literature and a sSMC database (http://ssmc-tl.com/sSMC.html) search. A total of 234 patients with infertility were identified as carriers of sSMC. All chromosomes, except chromosomes 10, 19 and the X, were involved in sSMC, and in 72% the sSMC originated from acrocentric chromosomes. Euchromatic imbalances were caused by the presence of sSMC in 30% of the cases. Putative genes have been identified in only 1.2% of sSMC associated with infertility. The implication of sSMC in infertility could be due to a partial trisomy of some genes but also to mechanical effects perturbing meiosis. Further precise molecular and interphase-architecture studies on sSMC are needed in the future to characterize the relationship between this chromosomal anomaly and human infertility.

  4. Evolutionary stability of sex chromosomes in snakes

    Science.gov (United States)

    Rovatsos, Michail; Vukić, Jasna; Lymberakis, Petros; Kratochvíl, Lukáš

    2015-01-01

    Amniote vertebrates possess various mechanisms of sex determination, but their variability is not equally distributed. The large evolutionary stability of sex chromosomes in viviparous mammals and birds was believed to be connected with their endothermy. However, some ectotherm lineages seem to be comparably conserved in sex determination, but previously there was a lack of molecular evidence to confirm this. Here, we document a stability of sex chromosomes in advanced snakes based on the testing of Z-specificity of genes using quantitative PCR (qPCR) across 37 snake species (our qPCR technique is suitable for molecular sexing in potentially all advanced snakes). We discovered that at least part of sex chromosomes is homologous across all families of caenophidian snakes (Acrochordidae, Xenodermatidae, Pareatidae, Viperidae, Homalopsidae, Colubridae, Elapidae and Lamprophiidae). The emergence of differentiated sex chromosomes can be dated back to about 60 Ma and preceded the extensive diversification of advanced snakes, the group with more than 3000 species. The Z-specific genes of caenophidian snakes are (pseudo)autosomal in the members of the snake families Pythonidae, Xenopeltidae, Boidae, Erycidae and Sanziniidae, as well as in outgroups with differentiated sex chromosomes such as monitor lizards, iguanas and chameleons. Along with iguanas, advanced snakes are therefore another example of ectothermic amniotes with a long-term stability of sex chromosomes comparable with endotherms. PMID:26702042

  5. Sex chromosome inactivation in the male.

    Science.gov (United States)

    Yan, Wei; McCarrey, John R

    2009-10-01

    Mammalian females have two X chromosomes, while males have only one X plus a Y chromosome. In order to balance X-linked gene dosage between the sexes, one X chromosome undergoes inactivation during development of female embryos. This process has been termed X-chromosome inactivation (XCI). Inactivation of the single X chromosome also occurs in the male, but is transient and is confined to the late stages of first meiotic prophase during spermatogenesis. This phenomenon has been termed meiotic sex chromosome inactivation (MSCI). A substantial portion ( approximately 15-25%) of X-linked mRNA-encoding genes escapes XCI in female somatic cells. While no mRNA genes are known to escape MSCI in males, approximately 80% of X-linked miRNA genes have been shown to escape this process. Recent results have led to the proposal that the RNA interference mechanism may be involved in regulating XCI in female cells. We suggest that some MSCI-escaping miRNAs may play a similar role in regulating MSCI in male germ cells.

  6. The genomics of plant sex chromosomes.

    Science.gov (United States)

    Vyskot, Boris; Hobza, Roman

    2015-07-01

    Around six percent of flowering species are dioecious, with separate female and male individuals. Sex determination is mostly based on genetics, but morphologically distinct sex chromosomes have only evolved in a few species. Of these, heteromorphic sex chromosomes have been most clearly described in the two model species - Silene latifolia and Rumex acetosa. In both species, the sex chromosomes are the largest chromosomes in the genome. They are hence easily distinguished, can be physically separated and analyzed. This review discusses some recent experimental data on selected model dioecious species, with a focus on S. latifolia. Phylogenetic analyses show that dioecy in plants originated independently and repeatedly even within individual genera. A cogent question is whether there is genetic degeneration of the non-recombining part of the plant Y chromosome, as in mammals, and, if so, whether reduced levels of gene expression in the heterogametic sex are equalized by dosage compensation. Current data provide no clear conclusion. We speculate that although some transcriptome analyses indicate the first signs of degeneration, especially in S. latifolia, the evolutionary processes forming plant sex chromosomes in plants may, to some extent, differ from those in animals.

  7. Chromosome distribution studies after inorganic lead exposure

    Energy Technology Data Exchange (ETDEWEB)

    Verschaeve, L.; Driesen, M.; Kirsch-Volders, M.; Hens, L.; Susanne, C.

    1979-06-19

    We studied the chromosome distribution in persons professionally exposed to inorganic lead. The degree of lead exposure was evaluated by biochemical measurements and cytogenetic analysis. The chromosome distribution was analyzed from trypsin banded karyotypes; in particular we studied centromere distances (delta2) and centromere-metaphase-center distances (d2) which were obtained by computer-aided mathematical transformation of the individual metaphase coordinates. Higher concentrations of blood lead and urine delta-ALA and a statistically significant increase in aneuploidy, hypoploidy, and type-B chromosome aberrations revealed appreciable exposure although none of the subjects showed signs of excessive lead absorption. However, study of the chromosome distribution showed no major differences with that of the controls indicating that lead acts preferentially (directly or indirectly) on the chromosomes rather than on the spindle apparatus. A dissociation of the acrocentric chromosomes was observed in the lead group when compared with the controls. This is thought to reflect a secondary action of lead on the nucleolar organizer regions.

  8. Evolutionary stability of sex chromosomes in snakes.

    Science.gov (United States)

    Rovatsos, Michail; Vukić, Jasna; Lymberakis, Petros; Kratochvíl, Lukáš

    2015-12-22

    Amniote vertebrates possess various mechanisms of sex determination, but their variability is not equally distributed. The large evolutionary stability of sex chromosomes in viviparous mammals and birds was believed to be connected with their endothermy. However, some ectotherm lineages seem to be comparably conserved in sex determination, but previously there was a lack of molecular evidence to confirm this. Here, we document a stability of sex chromosomes in advanced snakes based on the testing of Z-specificity of genes using quantitative PCR (qPCR) across 37 snake species (our qPCR technique is suitable for molecular sexing in potentially all advanced snakes). We discovered that at least part of sex chromosomes is homologous across all families of caenophidian snakes (Acrochordidae, Xenodermatidae, Pareatidae, Viperidae, Homalopsidae, Colubridae, Elapidae and Lamprophiidae). The emergence of differentiated sex chromosomes can be dated back to about 60 Ma and preceded the extensive diversification of advanced snakes, the group with more than 3000 species. The Z-specific genes of caenophidian snakes are (pseudo)autosomal in the members of the snake families Pythonidae, Xenopeltidae, Boidae, Erycidae and Sanziniidae, as well as in outgroups with differentiated sex chromosomes such as monitor lizards, iguanas and chameleons. Along with iguanas, advanced snakes are therefore another example of ectothermic amniotes with a long-term stability of sex chromosomes comparable with endotherms.

  9. Chromosome tips damaged in anaphase inhibit cytokinesis.

    Directory of Open Access Journals (Sweden)

    Norman M Baker

    Full Text Available Genome maintenance is ensured by a variety of biochemical sensors and pathways that repair accumulated damage. During mitosis, the mechanisms that sense and resolve DNA damage remain elusive. Studies have demonstrated that damage accumulated on lagging chromosomes can activate the spindle assembly checkpoint. However, there is little known regarding damage to DNA after anaphase onset. In this study, we demonstrate that laser-induced damage to chromosome tips (presumptive telomeres in anaphase of Potorous tridactylis cells (PtK2 inhibits cytokinesis. In contrast, equivalent irradiation of non-telomeric chromosome regions or control irradiations in either the adjacent cytoplasm or adjacent to chromosome tips near the spindle midzone during anaphase caused no change in the eventual completion of cytokinesis. Damage to only one chromosome tip caused either complete absence of furrow formation, a prolonged delay in furrow formation, or furrow regression. When multiple chromosome tips were irradiated in the same cell, the cytokinesis defects increased, suggesting a potential dose-dependent mechanism. These results suggest a mechanism in which dysfunctional telomeres inhibit mitotic exit.

  10. Classifier-assisted metric for chromosome pairing.

    Science.gov (United States)

    Ventura, Rodrigo; Khmelinskii, Artem; Sanches, J

    2010-01-01

    Cytogenetics plays a central role in the detection of chromosomal abnormalities and in the diagnosis of genetic diseases. A karyogram is an image representation of human chromosomes arranged in order of decreasing size and paired in 23 classes. In this paper we propose an approach to automatically pair the chromosomes into a karyogram, using the information obtained in a rough SVM-based classification step, to help the pairing process mainly based on similarity metrics between the chromosomes. Using a set of geometric and band pattern features extracted from the chromosome images, the algorithm is formulated on a Bayesian framework, combining the similarity metric with the results from the classifier. The solution is obtained solving a mixed integer program. Two datasets with contrasting quality levels and 836 chromosomes each were used to test and validate the algorithm. Relevant improvements with respect to the algorithm described by the authors in [1] were obtained with average paring rates above 92%, close to the rates obtained by human operators.

  11. Fluorescence imaging of chromosomal DNA using click chemistry

    Science.gov (United States)

    Ishizuka, Takumi; Liu, Hong Shan; Ito, Kenichiro; Xu, Yan

    2016-09-01

    Chromosome visualization is essential for chromosome analysis and genetic diagnostics. Here, we developed a click chemistry approach for multicolor imaging of chromosomal DNA instead of the traditional dye method. We first demonstrated that the commercially available reagents allow for the multicolor staining of chromosomes. We then prepared two pro-fluorophore moieties that served as light-up reporters to stain chromosomal DNA based on click reaction and visualized the clear chromosomes in multicolor. We applied this strategy in fluorescence in situ hybridization (FISH) and identified, with high sensitivity and specificity, telomere DNA at the end of the chromosome. We further extended this approach to observe several basic stages of cell division. We found that the click reaction enables direct visualization of the chromosome behavior in cell division. These results suggest that the technique can be broadly used for imaging chromosomes and may serve as a new approach for chromosome analysis and genetic diagnostics.

  12. A Geometric Approach For Fully Automatic Chromosome Segmentation

    CERN Document Server

    Minaee, Shervin; Khalaj, Babak Hossein

    2011-01-01

    Chromosome segmentation is a fundamental task in human chromosome analysis. Most of previous methods for separation between touching chromosomes require human intervention. In this paper, a geometry based method is used for automatic chromosome segmentation. This method can be divided into two phases. In the first phase, chromosome clusters are detected using three geometric criteria and in the second phase chromosome clusters are separated using a proper cut line. However, most earlier methods do not work well with chromosome clusters that contain more than two chromosomes. Our method, on the other hand, has a high efficiency in separation of chromosome clusters in such scenarios. Another advantage of the proposed method is that it can easily apply to any type of images such as binary images. This is due to the fact that the proposed scheme uses the geometric features of chromosomes which are independent of the type of images. The performance of the proposed scheme is demonstrated on a database containing to...

  13. Fluorescence imaging of chromosomal DNA using click chemistry

    Science.gov (United States)

    Ishizuka, Takumi; Liu, Hong Shan; Ito, Kenichiro; Xu, Yan

    2016-01-01

    Chromosome visualization is essential for chromosome analysis and genetic diagnostics. Here, we developed a click chemistry approach for multicolor imaging of chromosomal DNA instead of the traditional dye method. We first demonstrated that the commercially available reagents allow for the multicolor staining of chromosomes. We then prepared two pro-fluorophore moieties that served as light-up reporters to stain chromosomal DNA based on click reaction and visualized the clear chromosomes in multicolor. We applied this strategy in fluorescence in situ hybridization (FISH) and identified, with high sensitivity and specificity, telomere DNA at the end of the chromosome. We further extended this approach to observe several basic stages of cell division. We found that the click reaction enables direct visualization of the chromosome behavior in cell division. These results suggest that the technique can be broadly used for imaging chromosomes and may serve as a new approach for chromosome analysis and genetic diagnostics. PMID:27620982

  14. Maternal uniparental disomy for chromosome 14 by secondary nondisjunction of a initial trisomy

    Energy Technology Data Exchange (ETDEWEB)

    Morichon-Delvallez, N.; Segues, B.; Pinson, M.P. [Hopital Necker-Enfants Malades, Paris (France)] [and others

    1994-09-01

    Three cases of maternal uniparental disomy for chromosome 14 (UD 14) have been described in the literature. In all three cases, the UD was found in carriers of Robertsonian translocations (13q14q or 14q and 14q). Here, we report on a new case of UD for chromosome 14 in a fetus in which the UD arose presumably by secondary nondisjunction of a trisomy 14. Prenatal diagnosis was performed on a 40-year-old woman by trans-abdominal chorionic villi sampling. Cytogenetic analysis showed a confined placental mosaicism (CPM) for trisomy 14 (100% of cells trisomic in short term preparations and 20% trisomic in cultured villi). The ultrasound examination was normal and after counselling the parents agreed to continue the pregnancy. Amniocentesis was performed and a normal 46,XX karyotype was found in the 70 cells examined. Molecular analysis of the parental origin of the fetus`s chromosome 14 was performed using microsatellite DNA markers evenly distributed on chromosome 14. Molecular results suggested a maternal heterodisomy. Another ultrasound examination was normal and after genetic counselling based on the small number of cases reported in the literature, the parents decided to keep the pregnancy. At birth, the clinical examination was normal. In conclusion, among the different mechanisms leading to UD, the correction of an initial trisomy by secondary nondisjunction might also be an important one. CPM is observed in about 2% of CVS studies and theoretically 1/3 of corrected trisomies could result in UD for the chromosomal pair that was originally trisomic. In order to provide adequate genetic counselling in these cases, it will be important to undergo molecular studies in the instances of confined placental mosaicism.

  15. An Allometric Analysis of Sex and Sex Chromosome Dosage Effects on Subcortical Anatomy in Humans.

    Science.gov (United States)

    Reardon, Paul Kirkpatrick; Clasen, Liv; Giedd, Jay N; Blumenthal, Jonathan; Lerch, Jason P; Chakravarty, M Mallar; Raznahan, Armin

    2016-02-24

    Structural neuroimaging of humans with typical and atypical sex-chromosome complements has established the marked influence of both Yand X-/Y-chromosome dosage on total brain volume (TBV) and identified potential cortical substrates for the psychiatric phenotypes associated with sex-chromosome aneuploidy (SCA). Here, in a cohort of 354 humans with varying karyotypes (XX, XY, XXX, XXY, XYY, XXYY, XXXXY), we investigate sex and SCA effects on subcortical size and shape; focusing on the striatum, pallidum and thalamus. We find large effect-size differences in the volume and shape of all three structures as a function of sex and SCA. We correct for TBV effects with a novel allometric method harnessing normative scaling rules for subcortical size and shape in humans, which we derive here for the first time. We show that all three subcortical volumes scale sublinearly with TBV among healthy humans, mirroring known relationships between subcortical volume and TBV among species. Traditional TBV correction methods assume linear scaling and can therefore invert or exaggerate sex and SCA effects on subcortical anatomy. Allometric analysis restricts sex-differences to: (1) greater pallidal volume (PV) in males, and (2) relative caudate head expansion and ventral striatum contraction in females. Allometric analysis of SCA reveals that supernumerary X- and Y-chromosomes both cause disproportionate reductions in PV, and coordinated deformations of striatopallidal shape. Our study provides a novel understanding of sex and sex-chromosome dosage effects on subcortical organization, using an allometric approach that can be generalized to other basic and clinical structural neuroimaging settings.

  16. Dosage compensation and sex-specific epigenetic landscape of the X chromosome in the pea aphid.

    Science.gov (United States)

    Richard, Gautier; Legeai, Fabrice; Prunier-Leterme, Nathalie; Bretaudeau, Anthony; Tagu, Denis; Jaquiéry, Julie; Le Trionnaire, Gaël

    2017-01-01

    Heterogametic species display a differential number of sex chromosomes resulting in imbalanced transcription levels for these chromosomes between males and females. To correct this disequilibrium, dosage compensation mechanisms involving gene expression and chromatin accessibility regulations have emerged throughout evolution. In insects, these mechanisms have been extensively characterized only in Drosophila but not in insects of agronomical importance. Aphids are indeed major pests of a wide range of crops. Their remarkable ability to switch from asexual to sexual reproduction during their life cycle largely explains the economic losses they can cause. As heterogametic insects, male aphids are X0, while females (asexual and sexual) are XX. Here, we analyzed transcriptomic and open chromatin data obtained from whole male and female individuals to evaluate the putative existence of a dosage compensation mechanism involving differential chromatin accessibility of the pea aphid's X chromosome. Transcriptomic analyses first showed X/AA and XX/AA expression ratios for expressed genes close to 1 in males and females, respectively, suggesting dosage compensation in the pea aphid. Analyses of open chromatin data obtained by Formaldehyde-Assisted Isolation of Regulatory Elements (FAIRE-seq) revealed a X chromosome chromatin accessibility globally and significantly higher in males than in females, while autosomes' chromatin accessibility is similar between sexes. Moreover, chromatin environment of X-linked genes displaying similar expression levels in males and females-and thus likely to be compensated-is significantly more accessible in males. Our results suggest the existence of an underlying epigenetic mechanism enhancing the X chromosome chromatin accessibility in males to allow X-linked gene dose correction between sexes in the pea aphid, similar to Drosophila. Our study gives new evidence into the comprehension of dosage compensation in link with chromatin biology in

  17. Small supernumerary marker chromosomes (sSMC in humans; are there B chromosomes hidden among them

    Directory of Open Access Journals (Sweden)

    Ogilvie Caroline

    2008-06-01

    Full Text Available Abstract Background Small supernumerary marker chromosomes (sSMC and B-chromosomes represent a heterogeneous collection of chromosomes added to the typical karyotype, and which are both small in size. They may consist of heterochromatic and/or euchromatic material. Also a predominance of maternal transmission was reported for both groups. Even though sSMC and B-chromosomes show some similarity it is still an open question if B-chromosomes are present among the heterogeneous group of sSMC. According to current theories, sSMC would need drive, drift or beneficial effects to increase in frequency in order to become B chromosome. However, up to now no B-chromosomes were described in human. Results Here we provide first evidence and discuss, that among sSMC B-chromosomes might be hidden. We present two potential candidates which may already be, or may in future evolve into B chromosomes in human: (i sSMC cases where the marker is stainable only by DNA derived from itself; and (ii acrocentric-derived inverted duplication sSMC without associated clinical phenotype. Here we report on the second sSMC stainable exclusively by its own DNA and show that for acrocentric derived sSMC 3.9× more are familial cases than reported for other sSMC. Conclusion The majority of sSMC are not to be considered as B-chromosomes. Nonetheless, a minority of sSMC show similarities to B-chromosomes. Further studies are necessary to come to final conclusions for that problem.

  18. Use of chromosome microdissection in fish molecular cytogenetics

    OpenAIRE

    2008-01-01

    Chromosome microdissection is a technique in which whole chromosomes or chromosomal segments are dissected under an inverted microscope yielding chromosome-specific sequences. Several protocol modifications introduced during the past 15 years reduced the number of chromosomes required for most applications. This is of particular interest to fish molecular cytogenetics, since most species present highly uniform karyotypes which make impossible the collection of multiple copies of the same chro...

  19. Healing of Broken Linear Dicentric Chromosomes in Yeast

    OpenAIRE

    Haber, James E; Thorburn, Patricia C.

    1984-01-01

    In yeast, meiotic recombination between a linear chromosome III and a haploid-viable circular chromosome will yield a dicentric, tandemly duplicated chromosome. Spores containing apparently intact dicentric chromosomes were recovered from tetrads with three viable spores. The spore containing the dicentric inherited URA3 (part of the recombinant DNA used to join regions near the ends of the chromosome into a circle) as well as HML, HMR and MAL2 (located near the two ends of a linear but dele...

  20. Analysis of repetitive DNA in chromosomes by flow cytometry.

    Science.gov (United States)

    Brind'Amour, Julie; Lansdorp, Peter M

    2011-06-01

    We developed a flow cytometry method, chromosome flow fluorescence in situ hybridization (FISH), called CFF, to analyze repetitive DNA in chromosomes using FISH with directly labeled peptide nucleic acid (PNA) probes. We used CFF to measure the abundance of interstitial telomeric sequences in Chinese hamster chromosomes and major satellite sequences in mouse chromosomes. Using CFF we also identified parental homologs of human chromosome 18 with different amounts of repetitive DNA.

  1. Correcting Reflux Laparoscopically

    Directory of Open Access Journals (Sweden)

    Eric C Poulin

    1998-01-01

    Full Text Available Most operations in the abdominal cavity and chest can be performed using minimally invasive techniques. As yet it has not been determined which laparoscopic procedures are preferable to the same operations done through conventional laparotomy. However, most surgeons who have completed the learning curves of these procedures believe that most minimally invasive techniques will be scientifically recognized soon. The evolution, validation and justification of advanced laparoscopic surgical methods seem inevitable. Most believe that the trend towards procedures that minimize or eliminate the trauma of surgery while adhering to accepted surgical principles is irreversible. The functional results of laparoscopic antireflux surgery in the seven years since its inception have been virtually identical to the success curves generated with open fundoplication in past years. Furthermore, overall patient outcomes with laparoscopic procedures have been superior to outcomes with the traditional approach. Success is determined by patient selection and operative technique. Patient evaluation should include esophagogastroduodenoscopy, barium swallow, 24 h pH study and esophageal motility study. Gastric emptying also should be evaluated. Patients who have abnormal propulsion in the esophagus should not receive a complete fundoplication (Nissen because it adds a factor of obstruction. Dor or Toupet procedures are adequate alternatives. Prokinetic agents, dilation or pyloroplasty are used for pyloric obstruction ranging from little to more severe. Correcting reflux laparoscopically is more difficult in patients with obesity, peptic strictures, paraesophageal hernias, short esophagus, or a history of previous upper abdominal or antireflux surgery.

  2. Klinefelter syndrome and other sex chromosomal aneuploidies

    Directory of Open Access Journals (Sweden)

    Graham John M

    2006-10-01

    Full Text Available Abstract The term Klinefelter syndrome (KS describes a group of chromosomal disorder in which there is at least one extra X chromosome to a normal male karyotype, 46,XY. XXY aneuploidy is the most common disorder of sex chromosomes in humans, with prevalence of one in 500 males. Other sex chromosomal aneuploidies have also been described, although they are much less frequent, with 48,XXYY and 48,XXXY being present in 1 per 17,000 to 1 per 50,000 male births. The incidence of 49,XXXXY is 1 per 85,000 to 100,000 male births. In addition, 46,XX males also exist and it is caused by translocation of Y material including sex determining region (SRY to the X chromosome during paternal meiosis. Formal cytogenetic analysis is necessary to make a definite diagnosis, and more obvious differences in physical features tend to be associated with increasing numbers of sex chromosomes. If the diagnosis is not made prenatally, 47,XXY males may present with a variety of subtle clinical signs that are age-related. In infancy, males with 47,XXY may have chromosomal evaluations done for hypospadias, small phallus or cryptorchidism, developmental delay. The school-aged child may present with language delay, learning disabilities, or behavioral problems. The older child or adolescent may be discovered during an endocrine evaluation for delayed or incomplete pubertal development with eunuchoid body habitus, gynecomastia, and small testes. Adults are often evaluated for infertility or breast malignancy. Androgen replacement therapy should begin at puberty, around age 12 years, in increasing dosage sufficient to maintain age appropriate serum concentrations of testosterone, estradiol, follicle stimulating hormone (FSH, and luteinizing hormone (LH. The effects on physical and cognitive development increase with the number of extra Xs, and each extra X is associated with an intelligence quotient (IQ decrease of approximately 15–16 points, with language most affected

  3. Molecular mapping of chromosomes 17 and X

    Energy Technology Data Exchange (ETDEWEB)

    Barker, D.F.

    1991-01-15

    Progress toward the construction of high density genetic maps of chromosomes 17 and X has been made by isolating and characterizing a relatively large set of polymorphic probes for each chromosome and using these probes to construct genetic maps. We have mapped the same polymorphic probes against a series of chromosome breakpoints on X and 17. The probes could be assigned to over 30 physical intervals on the X chromosome and 7 intervals on 17. In many cases, this process resulted in improved characterization of the relative locations of the breakpoints with respect to each other and the definition of new physical intervals. The strategy for isolation of the polymorphic clones utilized chromosome specific libraries of 1--15 kb segments from each of the two chromosomes. From these libraries, clones were screened for those detecting restriction fragment length polymorphisms. The markers were further characterized, the chromosomal assignments confirmed and in most cases segments of the original probes were subcloned into plasmids to produce probes with improved signal to noise ratios for use in the genetic marker studies. The linkage studies utilize the CEPH reference families and other well-characterized families in our collection which have been used for genetic disease linkage work. Preliminary maps and maps of portions of specific regions of 17 and X are provided. We have nearly completed a map of the 1 megabase Mycoplasma arthritidis genome by applying these techniques to a lambda phage library of its genome. We have found bit mapping to be an efficient means to organize a contiguous set of overlapping clones from a larger genome.

  4. Comparative analysis of clastogen-induced chromosome aberrations observed with light microscopy and by means of atomic force microscopy.

    Science.gov (United States)

    Koleva, Vanya Petrova; Dragoeva, Asya Pencheva; Andreeva, Andreana Ivanova; Burova, Marina Todorova; Georgiev, Sevdalin; Enchev, Dobromir Dimitrov

    2013-04-30

    Different types of chromosome aberration were observed in mouse bone-marrow cells after treatment with 4-bromo-N,N-diethyl-5,5-dimethyl-2,5-dihydro-1,2-oxaphosphol-2-amine 2-oxide (Br-oxaphosphole, Br-oxph) in a previous study. The aim of the present study is to perform a comparative analysis of these chromosomal damages observed with light microscopy (LM) and by means of atomic force microscopy (AFM). The kinds of aberrations scored by LM were substantially corrected by images at the ultrastructural level. The AFM analysis excluded 29.0% of gaps and 33.3% of fusion-type aberrations. On the other hand, AFM revealed the presence of aberrations that were not visible under the LM. This indicates that only AFM images would provide precise information about the real nature of chromosomal damages. The results of our study revealed that the 'real gaps' represented about 50% of all the gaps visible under LM. Excluded 'false gaps' were detected via AFM as breaks or decondensed chromosome regions. These results would support the statement that gaps must be included when testing genotoxicity. The ultrastructural analysis also confirmed the validity of using LM in the mouse bone-marrow chromosome aberration test, as a tool for detecting genotoxicity of chemicals in routine studies. When there is a need for precise evaluation of chromosome damage, only AFM images can provide information on specific genotoxic effects.

  5. Meiotic chromosomes and stages of sex chromosome evolution in fish: zebrafish, platyfish and guppy.

    Science.gov (United States)

    Traut, W; Winking, H

    2001-01-01

    We describe SC complements and results from comparative genomic hybridization (CGH) on mitotic and meiotic chromosomes of the zebrafish Danio rerio, the platyfish Xiphophorus maculatus and the guppy Poecilia reticulata. The three fish species represent basic steps of sex chromosome differentiation: (1) the zebrafish with an all-autosome karyotype; (2) the platyfish with genetically defined sex chromosomes but no differentiation between X and Y visible in the SC or with CGH in meiotic and mitotic chromosomes; (3) the guppy with genetically and cytogenetically differentiated sex chromosomes. The acrocentric Y chromosomes of the guppy consists of a proximal homologous and a distal differential segment. The proximal segment pairs in early pachytene with the respective X chromosome segment. The differential segment is unpaired in early pachytene but synapses later in an 'adjustment' or 'equalization' process. The segment includes a postulated sex determining region and a conspicuous variable heterochromatic region whose structure depends on the particular Y chromosome line. CGH differentiates a large block of predominantly male-specific repetitive DNA and a block of common repetitive DNA in that region.

  6. Microsatellite Organization in the B Chromosome and A Chromosome Complement in Astyanax (Characiformes, Characidae) Species.

    Science.gov (United States)

    Piscor, Diovani; Parise-Maltempi, Patricia P

    2016-01-01

    The organization of microsatellites in B and sex chromosomes has been linked to chromosomal evolution in a number of animal groups. Here, the chromosomal organizations of (CA)15, (GA)15, (CG)15, (GACA)4, and (GATA)8 microsatellites were examined in several Astyanax species with different diploid numbers: Astyanax mexicanus (2n = 50 + 1 B chromosome), A. altiparanae (2n = 50), A. marionae (2n = 48), A. fasciatus (2n = 46), and A. schubarti (2n = 36). The (CA)15 and (GA)15 microsatellites were dispersed across the chromosomes of A. altiparanae and A. fasciatus but were also observed as clusters (CA and GA for A. altiparanae, and CA for A. fasciatus). In A. marionae and A. schubarti, the (CA)15 and (GA)15 microsatellites were dispersed but were also observed as clustered signals and coincident with heterochromatic regions. In all 4 of these species, the (CG)15 and (GACA)4 microsatellites were dispersed across chromosomes, and the (GATA)8 microsatellite was co-localized with 5S rDNA. In A. mexicanus, the (CA)15, (GA)15, (CG)15, (GATA)8, and (GACA)4 microsatellites were weakly detected and dispersed across the chromosomes of the A complement. On the B chromosome, signals for the different microsatellites were weak, strong, absent, weak, and absent, respectively. The distribution of microsatellites and the locational relationship between microsatellites and 5S rDNA are discussed, and a possible evolutionary pathway is proposed for microsatellites in Astyanax. © 2016 S. Karger AG, Basel.

  7. MDC1 directs chromosome-wide silencing of the sex chromosomes in male germ cells.

    Science.gov (United States)

    Ichijima, Yosuke; Ichijima, Misako; Lou, Zhenkun; Nussenzweig, André; Camerini-Otero, R Daniel; Chen, Junjie; Andreassen, Paul R; Namekawa, Satoshi H

    2011-05-01

    Chromosome-wide inactivation is an epigenetic signature of sex chromosomes. The mechanism by which the chromosome-wide domain is recognized and gene silencing is induced remains unclear. Here we identify an essential mechanism underlying the recognition of the chromosome-wide domain in the male germline. We show that mediator of DNA damage checkpoint 1 (MDC1), a binding partner of phosphorylated histone H2AX (γH2AX), defines the chromosome-wide domain, initiates meiotic sex chromosome inactivation (MSCI), and leads to XY body formation. Importantly, MSCI consists of two genetically separable steps. The first step is the MDC1-independent recognition of the unsynapsed axis by DNA damage response (DDR) factors such as ataxia telangiectasia and Rad3-related (ATR), TOPBP1, and γH2AX. The second step is the MDC1-dependent chromosome-wide spreading of DDR factors to the entire chromatin. Furthermore, we demonstrate that, in somatic cells, MDC1-dependent amplification of the γH2AX signal occurs following replicative stress and is associated with transcriptional silencing. We propose that a common DDR pathway underlies both MSCI and the response of somatic cells to replicative stress. These results establish that the DDR pathway centered on MDC1 triggers epigenetic silencing of sex chromosomes in germ cells.

  8. Increased sex chromosome expression and epigenetic abnormalities in spermatids from male mice with Y chromosome deletions.

    Science.gov (United States)

    Reynard, Louise N; Turner, James M A

    2009-11-15

    During male meiosis, the X and Y chromosomes are transcriptionally silenced, a process termed meiotic sex chromosome inactivation (MSCI). Recent studies have shown that the sex chromosomes remain substantially transcriptionally repressed after meiosis in round spermatids, but the mechanisms involved in this later repression are poorly understood. Mice with deletions of the Y chromosome long arm (MSYq-) have increased spermatid expression of multicopy X and Y genes, and so represent a model for studying post-meiotic sex chromosome repression. Here, we show that the increase in sex chromosome transcription in spermatids from MSYq- mice affects not only multicopy but also single-copy XY genes, as well as an X-linked reporter gene. This increase in transcription is accompanied by specific changes in the sex chromosome histone code, including almost complete loss of H4K8Ac and reduction of H3K9me3 and CBX1. Together, these data show that an MSYq gene regulates sex chromosome gene expression as well as chromatin remodelling in spermatids.

  9. Tracking of chromosome dynamics in live Streptococcus pneumoniae reveals that transcription promotes chromosome segregation.

    Science.gov (United States)

    Kjos, Morten; Veening, Jan-Willem

    2014-03-01

    Chromosome segregation is an essential part of the bacterial cell cycle but is poorly characterized in oval-shaped streptococci. Using time-lapse fluorescence microscopy and total internal reflection fluorescence microscopy, we have tracked the dynamics of chromosome segregation in live cells of the human pathogen Streptococcus pneumoniae. Our observations show that the chromosome segregation process last for two-thirds of the total cell cycle; the origin region segregates rapidly in the early stages of the cell cycle while nucleoid segregation finishes just before cell division. Previously we have demonstrated that the DNA-binding protein ParB and the condensin SMC promote efficient chromosome segregation, likely by an active mechanism. We now show that in the absence of SMC, cell division can occur over the unsegregated chromosomes. However, neither smc nor parB are essential in S. pneumoniae, suggesting the importance of additional mechanisms. Here we have identified the process of transcription as one of these mechanisms important for chromosome segregation in S. pneumoniae. Transcription inhibitors rifampicin and streptolydigin as well as mutants affected in transcription elongation cause chromosome segregation defects. Together, our results highlight the importance of passive (or indirect) processes such as transcription for chromosome segregation in oval-shaped bacteria.

  10. Tracking of chromosome dynamics in live Streptococcus pneumoniae reveals that transcription promotes chromosome segregation

    NARCIS (Netherlands)

    Kjos, Morten; Veening, Jan-Willem

    2014-01-01

    Chromosome segregation is an essential part of the bacterial cell cycle but is poorly characterized in oval-shaped streptococci. Using time-lapse fluorescence microscopy and total internal reflection fluorescence microscopy, we have tracked the dynamics of chromosome segregation in live cells of the

  11. Sequencing papaya X and Yh chromosomes reveals molecular basis of incipient sex chromosome evolution.

    Science.gov (United States)

    Wang, Jianping; Na, Jong-Kuk; Yu, Qingyi; Gschwend, Andrea R; Han, Jennifer; Zeng, Fanchang; Aryal, Rishi; VanBuren, Robert; Murray, Jan E; Zhang, Wenli; Navajas-Pérez, Rafael; Feltus, F Alex; Lemke, Cornelia; Tong, Eric J; Chen, Cuixia; Wai, Ching Man; Singh, Ratnesh; Wang, Ming-Li; Min, Xiang Jia; Alam, Maqsudul; Charlesworth, Deborah; Moore, Paul H; Jiang, Jiming; Paterson, Andrew H; Ming, Ray

    2012-08-21

    Sex determination in papaya is controlled by a recently evolved XY chromosome pair, with two slightly different Y chromosomes controlling the development of males (Y) and hermaphrodites (Y(h)). To study the events of early sex chromosome evolution, we sequenced the hermaphrodite-specific region of the Y(h) chromosome (HSY) and its X counterpart, yielding an 8.1-megabase (Mb) HSY pseudomolecule, and a 3.5-Mb sequence for the corresponding X region. The HSY is larger than the X region, mostly due to retrotransposon insertions. The papaya HSY differs from the X region by two large-scale inversions, the first of which likely caused the recombination suppression between the X and Y(h) chromosomes, followed by numerous additional chromosomal rearrangements. Altogether, including the X and/or HSY regions, 124 transcription units were annotated, including 50 functional pairs present in both the X and HSY. Ten HSY genes had functional homologs elsewhere in the papaya autosomal regions, suggesting movement of genes onto the HSY, whereas the X region had none. Sequence divergence between 70 transcripts shared by the X and HSY revealed two evolutionary strata in the X chromosome, corresponding to the two inversions on the HSY, the older of which evolved about 7.0 million years ago. Gene content differences between the HSY and X are greatest in the older stratum, whereas the gene content and order of the collinear regions are identical. Our findings support theoretical models of early sex chromosome evolution.

  12. Mechanisms of ring chromosome formation in 11 cases of human ring chromosome 21

    DEFF Research Database (Denmark)

    McGinniss, M J; Kazazian, H H; Stetten, G

    1992-01-01

    We studied the mechanism of ring chromosome 21 (r(21)) formation in 13 patients (11 unique r(21)s), consisting of 7 from five families with familial r(21) and 6 with de novo r(21). The copy number of chromosome 21 sequences in the rings of these patients was determined by quantitative dosage anal...

  13. Unique sex chromosome systems in Ellobius: How do male XX chromosomes recombine and undergo pachytene chromatin inactivation?

    OpenAIRE

    Sergey Matveevsky; Irina Bakloushinskaya; Oxana Kolomiets

    2016-01-01

    Most mammalian species have heteromorphic sex chromosomes in males, except for a few enigmatic groups such as the mole voles Ellobius, which do not have the Y chromosome and Sry gene. The Ellobius (XX ♀♂ ) system of sex chromosomes has no analogues among other animals. The structure and meiotic behaviour of the two X chromosomes were investigated for males of the sibling species Ellobius talpinus and Ellobius tancrei. Their sex chromosomes, despite their identical G-structure, demonstrate sho...

  14. Unpacking Corrections in Mobile Instruction

    DEFF Research Database (Denmark)

    Levin, Lena; Cromdal, Jakob; Broth, Mathias

    2017-01-01

    This article deals with the organisation of correction in mobile instructional settings. Five sets of video data (>250 h) documenting how learners were instructed to fly aeroplanes, drive cars and ride bicycles in real life traffic were examined to reveal some common features of correction...... exchanges. Through detailed multimodal analysis of participants’ actions, it is shown how instructors systematically elaborate their corrective instructions to include relevant information about the trouble and remedial action – a practice we refer to as unpacking corrections. It is proposed...... that the practice of unpacking the local particulars of corrections (i) provides for the instructional character of the interaction, and (ii) is highly sensitive to the relevant physical and mobile contingencies. These findings contribute to the existing literature on the interactional organisation of correction...

  15. Gravitational Correction to Vacuum Polarization

    CERN Document Server

    Jentschura, U D

    2015-01-01

    We consider the gravitational correction to (electronic) vacuum polarization in the presence of a gravitational background field. The Dirac propagators for the virtual fermions are modified to include the leading gravitational correction (potential term) which corresponds to a coordinate-dependent fermion mass. The mass term is assumed to be uniform over a length scale commensurate with the virtual electron-positron pair. The on-mass shell renormalization condition ensures that the gravitational correction vanishes on the mass shell of the photon, i.e., the speed of light is unaffected by the quantum field theoretical loop correction, in full agreement with the equivalence principle. Nontrivial corrections are obtained for off-shell, virtual photons. We compare our findings to other works on generalized Lorentz transformations and combined quantum-electrodynamic gravitational corrections to the speed of light which have recently appeared in the literature.

  16. Food systems in correctional settings

    DEFF Research Database (Denmark)

    Smoyer, Amy; Kjær Minke, Linda

    Food is a central component of life in correctional institutions and plays a critical role in the physical and mental health of incarcerated people and the construction of prisoners' identities and relationships. An understanding of the role of food in correctional settings and the effective...... management of food systems may improve outcomes for incarcerated people and help correctional administrators to maximize their health and safety. This report summarizes existing research on food systems in correctional settings and provides examples of food programmes in prison and remand facilities......, including a case study of food-related innovation in the Danish correctional system. It offers specific conclusions for policy-makers, administrators of correctional institutions and prison-food-service professionals, and makes proposals for future research....

  17. Nested Quantum Error Correction Codes

    CERN Document Server

    Wang, Zhuo; Fan, Hen; Vedral, Vlatko

    2009-01-01

    The theory of quantum error correction was established more than a decade ago as the primary tool for fighting decoherence in quantum information processing. Although great progress has already been made in this field, limited methods are available in constructing new quantum error correction codes from old codes. Here we exhibit a simple and general method to construct new quantum error correction codes by nesting certain quantum codes together. The problem of finding long quantum error correction codes is reduced to that of searching several short length quantum codes with certain properties. Our method works for all length and all distance codes, and is quite efficient to construct optimal or near optimal codes. Two main known methods in constructing new codes from old codes in quantum error-correction theory, the concatenating and pasting, can be understood in the framework of nested quantum error correction codes.

  18. Processor register error correction management

    Science.gov (United States)

    Bose, Pradip; Cher, Chen-Yong; Gupta, Meeta S.

    2016-12-27

    Processor register protection management is disclosed. In embodiments, a method of processor register protection management can include determining a sensitive logical register for executable code generated by a compiler, generating an error-correction table identifying the sensitive logical register, and storing the error-correction table in a memory accessible by a processor. The processor can be configured to generate a duplicate register of the sensitive logical register identified by the error-correction table.

  19. Comparison of Topographic Correction Methods

    Directory of Open Access Journals (Sweden)

    Rudolf Richter

    2009-07-01

    Full Text Available A comparison of topographic correction methods is conducted for Landsat-5 TM, Landsat-7 ETM+, and SPOT-5 imagery from different geographic areas and seasons. Three successful and known methods are compared: the semi-empirical C correction, the Gamma correction depending on the incidence and exitance angles, and a modified Minnaert approach. In the majority of cases the modified Minnaert approach performed best, but no method is superior in all cases.

  20. Selection and fine mapping of chromosome-specific cDNAs: application to human chromosome 1.

    Science.gov (United States)

    Mancini, M; Sala, C; Rivella, S; Toniolo, D

    1996-12-01

    We have developed a methodology for identification and fine mapping of chromosome-specific transcripts. Combining digestion of DNA with different restriction enzymes, ligation to "bubble" linkers, and PCR amplification from Alu and "bubble" primers, we have synthesized human chromosome 1-specific sequences from DNA of a somatic cell hybrid, A9Neol. After hybridization to human fetal brain cDNA, we could efficiently capture chromosome 1-specific cDNAs. The cDNAs were sequenced and used as probes in hybridizations to high-density filters containing the arrayed CEPH Mega-YAC library and to the arrayed cDNA library from infant brain made by B. Soares, which has been extensively sequenced. By this approach we have been able to select chromosome 1-specific cDNAs, to map them to chromosome 1 YAC contigs, and to identify and map corresponding longer cDNAs and ESTs.

  1. Female chromosome X mosaicism is age-related and preferentially affects the inactivated X chromosome

    DEFF Research Database (Denmark)

    Machiela, Mitchell J; Zhou, Weiyin; Karlins, Eric

    2016-01-01

    To investigate large structural clonal mosaicism of chromosome X, we analysed the SNP microarray intensity data of 38,303 women from cancer genome-wide association studies (20,878 cases and 17,425 controls) and detected 124 mosaic X events >2 Mb in 97 (0.25%) women. Here we show rates for X......-chromosome mosaicism are four times higher than mean autosomal rates; X mosaic events more often include the entire chromosome and participants with X events more likely harbour autosomal mosaic events. X mosaicism frequency increases with age (0.11% in 50-year olds; 0.45% in 75-year olds), as reported for Y...... and autosomes. Methylation array analyses of 33 women with X mosaicism indicate events preferentially involve the inactive X chromosome. Our results provide further evidence that the sex chromosomes undergo mosaic events more frequently than autosomes, which could have implications for understanding...

  2. Neo-sex chromosomes in the black muntjac recapitulate incipient evolution of mammalian sex chromosomes

    DEFF Research Database (Denmark)

    Zhou, Qi; Wang, Jun; Huang, Ling

    2008-01-01

    SNX22 abolished a microRNA target site. Finally, expression analyses revealed complex patterns of expression divergence between neo-Y and neo-X alleles. CONCLUSION: The nascent neo-sex chromosome system of black muntjacs is a valuable model in which to study the evolution of sex chromosomes in mammals......BACKGROUND: The regular mammalian X and Y chromosomes diverged from each other at least 166 to 148 million years ago, leaving few traces of their early evolution, including degeneration of the Y chromosome and evolution of dosage compensation. RESULTS: We studied the intriguing case of black...... muntjac, in which a recent X-autosome fusion and a subsequent large autosomal inversion within just the past 0.5 million years have led to inheritance patterns identical to the traditional X-Y (neo-sex chromosomes). We compared patterns of genome evolution in 35-kilobase noncoding regions and 23 gene...

  3. Chromosome 10q tetrasomy: First reported case

    Energy Technology Data Exchange (ETDEWEB)

    Blackston, R.D.; May, K.M.; Jones, F.D. [Emory Univ., Atlanta, GA (United States)] [and others

    1994-09-01

    While there are several reports of trisomy 10q (at least 35), we are not aware of previous cases of 10q tetrasomy. We present what we believe to be the initial report of such a case. R.J. is a 6 1/2 year old white male who presented with multiple dysmorphic features, marked articulation problems, hyperactivity, and developmental delays. He is the product of a term uncomplicated pregnancy. There was a normal spontaneous vaginal delivery with a birth weight of 6 lbs. 4oz. and length was 19 1/2 inch. Dysmorphic features include small size, an asymmetrically small head, low set ears with overfolded helixes, bilateral ptosis, downslanting eyes, right eye esotropia, prominent nose, asymmetric facies, high palate, mild pectus excavatum deformity of chest, and hyperextensible elbow joints. The patient is in special needs classes for mildly mentally handicapped students. Chromosome analysis at a resolution of 800 bands revealed a complex rearrangement of chromosomes 10 and 11. The segment 10q25.3 to q16.3 appears to be inverted and duplicated within the long arm of chromosome 10 at band q25.3 and the same segment of chromosome 10 is present on the terminal end of the short arm of chromosome 11. There is no visible loss of material from chromosome 11. Fluorescence in situ hybridization was performed with a chromosome 10 specific {open_quotes}paint{close_quotes} to confirm that all of the material on the abnormal 10 and the material on the terminal short arm of 11 was from chromosome 10. Thus, it appears that the segment 10q25.3 to q26.3 is present in four copies. Parental chromosome studies are normal. We compared findings which differ in that the case of 10q tetrasomy did not have prenatal growth deficiency, microphthalmia, cleft palate, digital anomalies, heart, or renal defects. Whereas most cases of 10q trisomy are said to have severe mental deficiency, our case of 10q tetrasomy was only mildly delayed. We report this first apparent cited case of 10q tetrasomy.

  4. Food systems in correctional settings

    DEFF Research Database (Denmark)

    Smoyer, Amy; Kjær Minke, Linda

    Food is a central component of life in correctional institutions and plays a critical role in the physical and mental health of incarcerated people and the construction of prisoners' identities and relationships. An understanding of the role of food in correctional settings and the effective mana......, including a case study of food-related innovation in the Danish correctional system. It offers specific conclusions for policy-makers, administrators of correctional institutions and prison-food-service professionals, and makes proposals for future research....

  5. Origin of B chromosomes in the genus Astyanax (Characiformes, Characidae) and the limits of chromosome painting.

    Science.gov (United States)

    de A Silva, Duílio M Z; Daniel, Sandro Natal; Camacho, Juan Pedro M; Utsunomia, Ricardo; Ruiz-Ruano, Francisco J; Penitente, Manolo; Pansonato-Alves, José Carlos; Hashimoto, Diogo Teruo; Oliveira, Claudio; Porto-Foresti, Fábio; Foresti, Fausto

    2016-06-01

    Eukaryote genomes are frequently burdened with the presence of supernumerary (B) chromosomes. Their origin is frequently investigated by chromosome painting, under the hypothesis that sharing the repetitive DNA sequences contained in the painting probes is a sign of common descent. However, the intragenomic mobility of many anonymous DNA sequences contained in these probes (e.g., transposable elements) adds high uncertainty to this conclusion. Here we test the validity of chromosome painting to investigate B chromosome origin by comparing its results for seven B chromosome types in two fish species genus Astyanax, with those obtained (1) by means of the physical mapping of 18S ribosomal DNA (rDNA), H1 histone genes, the As51 satellite DNA and the (AC)15 microsatellite, and (2) by comparing the nucleotide sequence of one of these families (ITS regions from ribosomal DNA) between genomic DNA from B-lacking individuals in both species and the microdissected DNA from two metacentric B chromosomes found in these same species. Intra- and inter-specific painting suggested that all B chromosomes that were assayed shared homologous DNA sequences among them, as well as with a variable number of A chromosomes in each species. This finding would be consistent with a common origin for all seven B chromosomes analyzed. By contrast, the physical mapping of repetitive DNA sequences failed to give support to this hypothesis, as no more than two B-types shared a given repetitive DNA. Finally, sequence analysis of the ITS regions suggested that at least some of the B chromosomes could have had a common origin.

  6. Quantified effects of chromosome-nuclear envelope attachments on 3D organization of chromosomes.

    Science.gov (United States)

    Kinney, Nicholas Allen; Onufriev, Alexey V; Sharakhov, Igor V

    2015-01-01

    We use a combined experimental and computational approach to study the effects of chromosome-nuclear envelope (Chr-NE) attachments on the 3D genome organization of Drosophila melanogaster (fruit fly) salivary gland nuclei. We consider 3 distinct models: a Null model - without specific Chr-NE attachments, a 15-attachment model - with 15 previously known Chr-NE attachments, and a 48-attachment model - with 15 original and 33 recently identified Chr-NE attachments. The radial densities of chromosomes in the models are compared to the densities observed in 100 experimental images of optically sectioned salivary gland nuclei forming "z-stacks." Most of the experimental z-stacks support the Chr-NE 48-attachment model suggesting that as many as 48 chromosome loci with appreciable affinity for the NE are necessary to reproduce the experimentally observed distribution of chromosome density in fruit fly nuclei. Next, we investigate if and how the presence and the number of Chr-NE attachments affect several key characteristics of 3D genome organization: chromosome territories and gene-gene contacts. This analysis leads to novel insight about the possible role of Chr-NE attachments in regulating the genome architecture. Specifically, we find that model nuclei with more numerous Chr-NE attachments form more distinct chromosome territories and their chromosomes intertwine less frequently. Intra-chromosome and intra-arm contacts are more common in model nuclei with Chr-NE attachments compared to the Null model (no specific attachments), while inter-chromosome and inter-arm contacts are less common in nuclei with Chr-NE attachments. We demonstrate that Chr-NE attachments increase the specificity of long-range inter-chromosome and inter-arm contacts. The predicted effects of Chr-NE attachments are rationalized by intuitive volume vs. surface accessibility arguments.

  7. Deficit of mitonuclear genes on the human X chromosome predates sex chromosome formation.

    Science.gov (United States)

    Dean, Rebecca; Zimmer, Fabian; Mank, Judith E

    2015-01-29

    Two taxa studied to date, the therian mammals and Caenorhabditis elegans, display underrepresentations of mitonuclear genes (mt-N genes, nuclear genes whose products are imported to and act within the mitochondria) on their X chromosomes. This pattern has been interpreted as the result of sexual conflict driving mt-N genes off of the X chromosome. However, studies in several other species have failed to detect a convergent biased distribution of sex-linked mt-N genes, leading to questions over the generality of the role of sexual conflict in shaping the distribution of mt-N genes. Here we tested whether mt-N genes moved off of the therian X chromosome following sex chromosome formation, consistent with the role of sexual conflict, or whether the paucity of mt-N genes on the therian X is a chance result of an underrepresentation on the ancestral regions that formed the X chromosome. We used a synteny-based approach to identify the ancestral regions in the platypus and chicken genomes that later formed the therian X chromosome. We then quantified the movement of mt-N genes on and off of the X chromosome and the distribution of mt-N genes on the human X and ancestral X regions. We failed to find an excess of mt-N gene movement off of the X. The bias of mt-N genes on ancestral therian X chromosomes was also not significantly different from the biases on the human X. Together our results suggest that, rather than conflict driving mt-N genes off of the mammalian X, random biases on chromosomes that formed the X chromosome could explain the paucity of mt-N genes in the therian lineage.

  8. Chromosome analysis and sorting using flow cytometry.

    Science.gov (United States)

    Doležel, Jaroslav; Kubaláková, Marie; Cíhalíková, Jarmila; Suchánková, Pavla; Simková, Hana

    2011-01-01

    Chromosome analysis and sorting using flow cytometry (flow cytogenetics) is an attractive tool for fractionating plant genomes to small parts. The reduction of complexity greatly simplifies genetics and genomics in plant species with large genomes. However, as flow cytometry requires liquid suspensions of particles, the lack of suitable protocols for preparation of solutions of intact chromosomes delayed the application of flow cytogenetics in plants. This chapter outlines a high-yielding procedure for preparation of solutions of intact mitotic chromosomes from root tips of young seedlings and for their analysis using flow cytometry and sorting. Root tips accumulated at metaphase are mildly fixed with formaldehyde, and solutions of intact chromosomes are prepared by mechanical homogenization. The advantages of the present approach include the use of seedlings, which are easy to handle, and the karyological stability of root meristems, which can be induced to high degree of metaphase synchrony. Chromosomes isolated according to this protocol have well-preserved morphology, withstand shearing forces during sorting, and their DNA is intact and suitable for a range of applications.

  9. Chromosomal polymorphism in the Sporothrix schenckii complex.

    Science.gov (United States)

    Sasaki, Alexandre A; Fernandes, Geisa F; Rodrigues, Anderson M; Lima, Fábio M; Marini, Marjorie M; Dos S Feitosa, Luciano; de Melo Teixeira, Marcus; Felipe, Maria Sueli Soares; da Silveira, José Franco; de Camargo, Zoilo P

    2014-01-01

    Sporotrichosis is a polymorphic disease caused by a complex of thermodimorphic fungi including S. brasiliensis, S. schenckii sensu stricto (s. str.), S. globosa and S. luriei. Humans and animals can acquire the disease through traumatic inoculation of propagules into the subcutaneous tissue. Despite the importance of sporotrichosis as a disease that can take epidemic proportions there are just a few studies dealing with genetic polymorphisms and genomic architecture of these pathogens. The main objective of this study was to investigate chromosomal polymorphisms and genomic organization among different isolates in the S. schenckii complex. We used pulsed field gel electrophoresis (PFGE) to separate chromosomal fragments of isolated DNA, followed by probe hybridization. Nine loci (β-tubulin, calmodulin, catalase, chitin synthase 1, Internal Transcribed Spacer, Pho85 cyclin-dependent kinase, protein kinase C Ss-2, G protein α subunit and topoisomerase II) were mapped onto chromosomal bands of Brazilian isolates of S. schenckii s. str. and S. brasiliensis. Our results revealed the presence of intra and interspecies polymorphisms in chromosome number and size. The gene hybridization analysis showed that closely related species in phylogenetic analysis had similar genetic organizations, mostly due to identification of synteny groups in chromosomal bands of similar sizes. Our results bring new insights into the genetic diversity and genome organization among pathogenic species in the Sporothrix schenckii complex.

  10. Evolution and survival on eutherian sex chromosomes.

    Directory of Open Access Journals (Sweden)

    Melissa A Wilson

    2009-07-01

    Full Text Available Since the two eutherian sex chromosomes diverged from an ancestral autosomal pair, the X has remained relatively gene-rich, while the Y has lost most of its genes through the accumulation of deleterious mutations in nonrecombining regions. Presently, it is unclear what is distinctive about genes that remain on the Y chromosome, when the sex chromosomes acquired their unique evolutionary rates, and whether X-Y gene divergence paralleled that of paralogs located on autosomes. To tackle these questions, here we juxtaposed the evolution of X and Y homologous genes (gametologs in eutherian mammals with their autosomal orthologs in marsupial and monotreme mammals. We discovered that genes on the X and Y acquired distinct evolutionary rates immediately following the suppression of recombination between the two sex chromosomes. The Y-linked genes evolved at higher rates, while the X-linked genes maintained the lower evolutionary rates of the ancestral autosomal genes. These distinct rates have been maintained throughout the evolution of X and Y. Specifically, in humans, most X gametologs and, curiously, also most Y gametologs evolved under stronger purifying selection than similarly aged autosomal paralogs. Finally, after evaluating the current experimental data from the literature, we concluded that unique mRNA/protein expression patterns and functions acquired by Y (versus X gametologs likely contributed to their retention. Our results also suggest that either the boundary between sex chromosome strata 3 and 4 should be shifted or that stratum 3 should be divided into two strata.

  11. Assembly and disassembly of mammalian chromosome pellicle

    Institute of Scientific and Technical Information of China (English)

    NIZUMEI; JELITTLE; 等

    1992-01-01

    By means of indirect double immunofluorescent staining,the coordination of PI antigen and perichromonucleolin(PCN),the constituent of nuclear periphery and nucleolus respectively,in the assembly and disassembly of chromosome pellicle during mitosis was studied.It was found that in 3T3 cells,during mitosis PI antigen began to coat the condensing chromosome surface earlier than PCN did.However,both of them completed their coating on chromosome at approximately the same stage of mitosis,prometaphase metaphase,The dissociation of mitosis,Prometaphase metaphase.The dissociation of PI antigen from chromosome pellicle to participate the formation of nuclear periphery took place also ahead of that of PCN,At early telophase PI antigen had been extensively involved in the formation of nuclear periphery,while PCN remained in association with the surface of decondensing chromosomes.At late telophase,when PI antigen was localized in an fairly well formed nuclear periphery,PCN was in a stage of forming prenucleolar bodies.

  12. Chromosomal Abnormality in Men with Impaired Spermatogenesis

    Directory of Open Access Journals (Sweden)

    Dana Mierla

    2014-03-01

    Full Text Available Background: Chromosomal abnormalities and Y chromosome microdeletions are regarded as two most frequent genetic causes associated with failure of spermatogenesis in the Caucasian population. Materials and Methods: To investigate the distribution of genetic defects in the Romanian population with azoospermia or severe oligozoospermia, karyotype analysis by G-banding was carried out in 850 idiopathic infertile men and in 49 fertile men with one or more children. Screening for microdeletions in the azoospermia factor (AZF region of Y chromosome was performed by multiplex polymerase chain reaction (PCR on a group of 67 patients with no detectable chromosomal abnormality. The results of the two groups were compared by a two-tailed Fisher’s exact test. Results: In our study chromosomal abnormalities were observed in 12.70% and 8.16% of infertile and fertile individuals respectively. Conclusion: Our data suggests that infertile men with severe azoospermia have higher incidences of genetic defects than fertile men and also patients from any other group. Infertile men with normal sperm present a higher rate of polymorphic variants. It is important to know whether there is a genetic cause of male infertility before patients are subjected to intracytoplasmic sperm injection (ICSI or testicular sperm extraction (TESE/ICSI treatment.

  13. Chromosome-specific DNA Repeat Probes

    Energy Technology Data Exchange (ETDEWEB)

    Baumgartner, Adolf; Weier, Jingly Fung; Weier, Heinz-Ulrich G.

    2006-03-16

    In research as well as in clinical applications, fluorescence in situ hybridization (FISH) has gained increasing popularity as a highly sensitive technique to study cytogenetic changes. Today, hundreds of commercially available DNA probes serve the basic needs of the biomedical research community. Widespread applications, however, are often limited by the lack of appropriately labeled, specific nucleic acid probes. We describe two approaches for an expeditious preparation of chromosome-specific DNAs and the subsequent probe labeling with reporter molecules of choice. The described techniques allow the preparation of highly specific DNA repeat probes suitable for enumeration of chromosomes in interphase cell nuclei or tissue sections. In addition, there is no need for chromosome enrichment by flow cytometry and sorting or molecular cloning. Our PCR-based method uses either bacterial artificial chromosomes or human genomic DNA as templates with {alpha}-satellite-specific primers. Here we demonstrate the production of fluorochrome-labeled DNA repeat probes specific for human chromosomes 17 and 18 in just a few days without the need for highly specialized equipment and without the limitation to only a few fluorochrome labels.

  14. New orbit correction method uniting global and local orbit corrections

    Science.gov (United States)

    Nakamura, N.; Takaki, H.; Sakai, H.; Satoh, M.; Harada, K.; Kamiya, Y.

    2006-01-01

    A new orbit correction method, called the eigenvector method with constraints (EVC), is proposed and formulated to unite global and local orbit corrections for ring accelerators, especially synchrotron radiation(SR) sources. The EVC can exactly correct the beam positions at arbitrarily selected ring positions such as light source points, simultaneously reducing closed orbit distortion (COD) around the whole ring. Computer simulations clearly demonstrate these features of the EVC for both cases of the Super-SOR light source and the Advanced Light Source (ALS) that have typical structures of high-brilliance SR sources. In addition, the effects of errors in beam position monitor (BPM) reading and steering magnet setting on the orbit correction are analytically expressed and also compared with the computer simulations. Simulation results show that the EVC is very effective and useful for orbit correction and beam position stabilization in SR sources.

  15. The Physical Genome Mapping of Anopheles albimanus Corrected Scaffold Misassemblies and Identified Interarm Rearrangements in Genus Anopheles

    Directory of Open Access Journals (Sweden)

    Gleb N. Artemov

    2017-01-01

    Full Text Available The genome of the Neotropical malaria vector Anopheles albimanus was sequenced as part of the 16 Anopheles Genomes Project published in 2015. The draft assembly of this species consisted of 204 scaffolds with an N50 scaffold size of 18.1 Mb and a total assembly size of 170.5 Mb. It was among the smallest genomes with the longest scaffolds in the 16 Anopheles species cluster, making An. albimanus the logical choice for anchoring the genome assembly to chromosomes. In this study, we developed a high-resolution cytogenetic photomap with completely straightened polytene chromosomes from the salivary glands of the mosquito larvae. Based on this photomap, we constructed a chromosome-based genome assembly using fluorescent in situ hybridization of PCR-amplified DNA probes. Our physical mapping, assisted by an ortholog-based bioinformatics approach, identified and corrected nine misassemblies in five large genomic scaffolds. Misassemblies mostly occurred in junctions between contigs. Our comparative analysis of scaffolds with the An. gambiae genome detected multiple genetic exchanges between pericentromeric regions of chromosomal arms caused by partial-arm translocations. The final map consists of 40 ordered genomic scaffolds and corrected fragments of misassembled scaffolds. The An. albimanus physical map comprises 98.2% of the total genome assembly and represents the most complete genome map among mosquito species. This study demonstrates that physical mapping is a powerful tool for correcting errors in draft genome assemblies and for creating chromosome-anchored reference genomes.

  16. [DNA image-fluorimetry of individual human chromosomes].

    Science.gov (United States)

    Agafonova, N A; Sakuta, G A; Rozanov, Iu M; Shteĭn, G I; Kudriavtsev, B N

    2013-01-01

    Mucrofluorimetric method for the determination of DNA content in individual human chromosomes has been developed. The method is based on a preliminary identification of chromosomes with Hoechst 33258, followed by staining of the chromosomes with Feulgen reaction using Schiffs reagent type ethidium bromide-SO2, then measuring the fluorescence intensity of the chromosomes using an image analyzer. The method allows to determine the DNA content of individual chromosomes with accuracy up to 4.5 fg. DNA content of individual human chromosomes, their p-and q-arms as well as homologous chromosomes were measured using the developed method. It has been shown that the DNA content in the chromosomes of normal human karyotype is unstable. Fluctuations in the DNA content in some chromosomes can vary 35-40 fg.

  17. Function of the sex chromosomes in mammalian fertility.

    Science.gov (United States)

    Heard, Edith; Turner, James

    2011-10-01

    The sex chromosomes play a highly specialized role in germ cell development in mammals, being enriched in genes expressed in the testis and ovary. Sex chromosome abnormalities (e.g., Klinefelter [XXY] and Turner [XO] syndrome) constitute the largest class of chromosome abnormalities and the commonest genetic cause of infertility in humans. Understanding how sex-gene expression is regulated is therefore critical to our understanding of human reproduction. Here, we describe how the expression of sex-linked genes varies during germ cell development; in females, the inactive X chromosome is reactivated before meiosis, whereas in males the X and Y chromosomes are inactivated at this stage. We discuss the epigenetics of sex chromosome inactivation and how this process has influenced the gene content of the mammalian X and Y chromosomes. We also present working models for how perturbations in sex chromosome inactivation or reactivation result in subfertility in the major classes of sex chromosome abnormalities.

  18. Spindle checkpoint-independent inhibition of mitotic chromosome segregation by Drosophila Mps1.

    Science.gov (United States)

    Althoff, Friederike; Karess, Roger E; Lehner, Christian F

    2012-06-01

    Monopolar spindle 1 (Mps1) is essential for the spindle assembly checkpoint (SAC), which prevents anaphase onset in the presence of misaligned chromosomes. Moreover, Mps1 kinase contributes in a SAC-independent manner to the correction of erroneous initial attachments of chromosomes to the spindle. Our characterization of the Drosophila homologue reveals yet another SAC-independent role. As in yeast, modest overexpression of Drosophila Mps1 is sufficient to delay progression through mitosis during metaphase, even though chromosome congression and metaphase alignment do not appear to be affected. This delay in metaphase depends on the SAC component Mad2. Although Mps1 overexpression in mad2 mutants no longer causes a metaphase delay, it perturbs anaphase. Sister kinetochores barely move apart toward spindle poles. However, kinetochore movements can be restored experimentally by separase-independent resolution of sister chromatid cohesion. We propose therefore that Mps1 inhibits sister chromatid separation in a SAC-independent manner. Moreover, we report unexpected results concerning the requirement of Mps1 dimerization and kinase activity for its kinetochore localization in Drosophila. These findings further expand Mps1's significance for faithful mitotic chromosome segregation and emphasize the importance of its careful regulation.

  19. Strategies for sequencing human chromosome 16

    Energy Technology Data Exchange (ETDEWEB)

    Sutherland, G.R.

    1996-06-01

    This project funded for four years (02.92 to 01.96) was a renewal of a project funded for 2.5 years (07.89 to 01.92). This report covers the period 07.89 to 07.94. The original project was entitled {open_quotes}Correlation of physical and genetic maps of Human Chromosome 16{close_quotes}. The aim over this period was to construct a cytogenetic-based physical map of chromosome 16, to enable integration of its physical and genetic maps. This was achieved by collaboration and isolation of new markers until each bin on the physical map contained a polymorphic marker on the linkage map. A further aim was to integrate all mapping data for this chromosome and to achieve contig closure over band q24.

  20. Chromosomal Instability Confers Intrinsic Multidrug Resistance

    DEFF Research Database (Denmark)

    Lee, Alvin J. X.; Endesfelder, David; Rowan, Andrew J.

    2011-01-01

    their diploid parental cells only with increasing chromosomal heterogeneity and isogenic cell line models of CIN+ displayed multidrug resistance relative to their CIN- parental cancer cell line derivatives. In a meta-analysis of CRC outcome following cytotoxic treatment, CIN+ predicted worse progression......-free or disease-free survival relative to patients with CIN- disease. Our results suggest that stratifying tumor responses according to CIN status should be considered within the context of clinical trials to minimize the confounding effects of tumor CIN status on drug sensitivity. Cancer Res; 71(5); 1858-70. (c......Aneuploidy is associated with poor prognosis in solid tumors. Spontaneous chromosome missegregation events in aneuploid cells promote chromosomal instability (CIN) that may contribute to the acquisition of multidrug resistance in vitro and heighten risk for tumor relapse in animal models...

  1. The complete sequence of human chromosome 5

    Energy Technology Data Exchange (ETDEWEB)

    Schmutz, Jeremy; Martin, Joel; Terry, Astrid; Couronne, Olivier; Grimwood, Jane; Lowry, State; Gordon, Laurie A.; Scott, Duncan; Xie, Gary; Huang, Wayne; Hellsten, Uffe; Tran-Gyamfi, Mary; She, Xinwei; Prabhakar, Shyam; Aerts, Andrea; Altherr, Michael; Bajorek, Eva; Black, Stacey; Branscomb, Elbert; Caoile, Chenier; Challacombe, Jean F.; Chan, Yee Man; Denys, Mirian; Detter, Chris; Escobar, Julio; Flowers, Dave; Fotopulos, Dea; Glavina, Tijana; Gomez, Maria; Gonzales, Eidelyn; Goodstenin, David; Grigoriev, Igor; Groza, Matthew; Hammon, Nancy; Hawkins, Trevor; Haydu, Lauren; Israni, Sanjay; Jett, Jamie; Kadner, Kristen; Kimbal, Heather; Kobayashi, Arthur; Lopez, Frederick; Lou, Yunian; Martinez, Diego; Medina, Catherine; Morgan, Jenna; Nandkeshwar, Richard; Noonan, James P.; Pitluck, Sam; Pollard, Martin; Predki, Paul; Priest, James; Ramirez, Lucia; Rash, Sam; Retterer, James; Rodriguez, Alex; Rogers, Stephanie; Salamov, Asaf; Salazar, Angelica; Thayer, Nina; Tice, Hope; Tsai, Ming; Ustaszewska, Anna; Vo, Nu; Wheeler, Jeremy; Wu, Kevin; Yang, Joan; Dickson, Mark; Cheng, Jan-Fang; Eichler, Evan E.; Olsen, Anne; Pennacchio, Len A.; Rokhsar, Daniel S.; Richardson, Paul; Lucas, Susan M.; Myers, Richard M.; Rubin, Edward M.

    2004-04-15

    Chromosome 5 is one of the largest human chromosomes yet has one of the lowest gene densities. This is partially explained by numerous gene-poor regions that display a remarkable degree of noncoding and syntenic conservation with non-mammalian vertebrates, suggesting they are functionally constrained. In total, we compiled 177.7 million base pairs of highly accurate finished sequence containing 923 manually curated protein-encoding genes including the protocadherin and interleukin gene families and the first complete versions of each of the large chromosome 5 specific internal duplications. These duplications are very recent evolutionary events and play a likely mechanistic role, since deletions of these regions are the cause of debilitating disorders including spinal muscular atrophy (SMA).

  2. Chromosomal abnormalities in a psychiatric population

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, K.E.; Lubetsky, M.J.; Wenger, S.L.; Steele, M.W. [Univ. of Pittsburgh Medical Center, PA (United States)

    1995-02-27

    Over a 3.5 year period of time, 345 patients hospitalized for psychiatric problems were evaluated cytogenetically. The patient population included 76% males and 94% children with a mean age of 12 years. The criteria for testing was an undiagnosed etiology for mental retardation and/or autism. Cytogenetic studies identified 11, or 3%, with abnormal karyotypes, including 4 fragile X positive individuals (2 males, 2 females), and 8 with chromosomal aneuploidy, rearrangements, or deletions. While individuals with chromosomal abnormalities do not demonstrate specific behavioral, psychiatric, or developmental problems relative to other psychiatric patients, our results demonstrate the need for an increased awareness to order chromosomal analysis and fragile X testing in those individuals who have combinations of behavioral/psychiatric, learning, communication, or cognitive disturbance. 5 refs., 1 fig., 2 tabs.

  3. Are chromosomal imbalances important in cancer?

    Science.gov (United States)

    Stallings, Raymond L

    2007-06-01

    Tumor-specific patterns of large-scale chromosomal imbalances characterize most forms of cancer. Based on evidence primarily from neuroblastomas, it can be argued that large-scale chromosomal imbalances are crucial for tumor pathogenesis and have an impact on the global transcriptional profile of cancer cells, and that some imbalances even initiate cancer. The genes and genetic pathways that have been dysregulated by such imbalances remain surprisingly elusive. Many genes are affected by the regions of gain and loss, and there are complex interactions and relationships that occur between these genes, hindering their identification. The study of untranslated RNA sequences, such as microRNAs, is in its infancy, and it is likely that such sequences are also dysregulated by chromosomal imbalance, contributing to pathogenesis.

  4. Origin of extra chromosome in Patau syndrome.

    Science.gov (United States)

    Ishikiriyama, S; Niikawa, N

    1984-01-01

    Five live-born infants with Patau syndrome were studied for the nondisjunctional origin of the extra chromosome. Transmission modes of chromosomes 13 from parents to a child were determined using both QFQ- and RFA-heteromorphisms as markers, and the origin was ascertained in all of the patients. The extra chromosome had originated in nondisjunction at the maternal first meiotic division in two patients, at the maternal second meiosis in other two, and at the paternal first meiosis in the remaining one. Summarizing the results of the present study, together with those of the previous studies on a liveborn and abortuses with trisomy 13, nondisjunction at the maternal and the paternal meiosis occurred in this trisomy in the ratio of 14:3. This ratio is not statistically different from that inferred from the previous studies for Down syndrome. These findings suggest that there may be a fundamental mechanism common to the occurrence of nondisjunction in the acrocentric trisomies.

  5. Origin and domestication of papaya Yh chromosome.

    Science.gov (United States)

    VanBuren, Robert; Zeng, Fanchang; Chen, Cuixia; Zhang, Jisen; Wai, Ching Man; Han, Jennifer; Aryal, Rishi; Gschwend, Andrea R; Wang, Jianping; Na, Jong-Kuk; Huang, Lixian; Zhang, Lingmao; Miao, Wenjing; Gou, Jiqing; Arro, Jie; Guyot, Romain; Moore, Richard C; Wang, Ming-Li; Zee, Francis; Charlesworth, Deborah; Moore, Paul H; Yu, Qingyi; Ming, Ray

    2015-04-01

    Sex in papaya is controlled by a pair of nascent sex chromosomes. Females are XX, and two slightly different Y chromosomes distinguish males (XY) and hermaphrodites (XY(h)). The hermaphrodite-specific region of the Y(h) chromosome (HSY) and its X chromosome counterpart were sequenced and analyzed previously. We now report the sequence of the entire male-specific region of the Y (MSY). We used a BAC-by-BAC approach to sequence the MSY and resequence the Y regions of 24 wild males and the Y(h) regions of 12 cultivated hermaphrodites. The MSY and HSY regions have highly similar gene content and structure, and only 0.4% sequence divergence. The MSY sequences from wild males include three distinct haplotypes, associated with the populations' geographic locations, but gene flow is detected for other genomic regions. The Y(h) sequence is highly similar to one Y haplotype (MSY3) found only in wild dioecious populations from the north Pacific region of Costa Rica. The low MSY3-Y(h) divergence supports the hypothesis that hermaphrodite papaya is a product of human domestication. We estimate that Y(h) arose only ∼ 4000 yr ago, well after crop plant domestication in Mesoamerica >6200 yr ago but coinciding with the rise of the Maya civilization. The Y(h) chromosome has lower nucleotide diversity than the Y, or the genome regions that are not fully sex-linked, consistent with a domestication bottleneck. The identification of the ancestral MSY3 haplotype will expedite investigation of the mutation leading to the domestication of the hermaphrodite Y(h) chromosome. In turn, this mutation should identify the gene that was affected by the carpel-suppressing mutation that was involved in the evolution of males.

  6. Microchimeric Cells, Sex Chromosome Aneuploidies and Cancer.

    Science.gov (United States)

    Korkmaz, Deniz Taştemir; Demirhan, Osman; Abat, Deniz; Demirberk, Bülent; Tunç, Erdal; Kuleci, Sedat

    2015-09-01

    The phenomenon of feta-maternal microchimerisms inspires numerous questions. Many questions remain to be answered regarding this new avenue of genetics. The X and Y chromosomes have been associated with malignancy in different types of human tumors. We aimed to investigate the numerical aberrations of chromosomes X and Y in lung cancer (LC) and bladder cancer (BC) and review recent evidence for possible roles of microchimeric cells (McCs) in these cancers. We carried out cytogenetic analysis of the tumor and blood sampling in 52 cases of people with BC and LC, and also with 30 healthy people. A total of 48 (92.3 %) of the patients revealed sex chromosome aneuploidies (SCAs). A total SCAs was found in 9.8 % of 2282 cells that were analyzed as one or more cells in each case. The 68 and 95 SCAs were found in the 1952 (8.4 %) cells in peripheral blood, and 41 and 19 SCAs in the 330 (18.2 %) cells in the tumoral tissues respectively. There was a significant difference in the frequencies of SCAs between the patients and the control groups determined by the Fischer's Exact Test (p chromosome monosomies. Largely a Y chromosome loss was present in 77.8 % of the men, and the 47, XXY karyotype was found in 33.3 % of them. The second most common SCA was monosomy X, and was found in 71.4 % of the women. McCs were observed in 26.9 % of the 52 patients, and the frequencies of McCs were higher in the blood than in the tissues (p aneuploidies of X and Y chromosomes play a role in the pathogenesis of cancers.

  7. Molecular mapping of chromosomes 17 and X

    Energy Technology Data Exchange (ETDEWEB)

    Barker, D.F.

    1989-01-01

    The basic aims of this project are the construction of high density genetic maps of chromosomes 17 and X and the utilization of these maps for the subsequent isolation of a set of physically overlapping DNA segment clones. The strategy depends on the utilization of chromosome specific libraries of small (1--15 kb) segments from each of the two chromosomes. Since the time of submission of our previous progress report, we have refined the genetic map of markers which we had previously isolated for chromosome 17. We have completed our genetic mapping in CEPH reference and NF1 families of 15 markers in the pericentric region of chromosome 17. Physical mapping results with three probes, were shown be in very close genetic proximity to the NF1 gene, with respect to two translocation breakpoints which disrupt the activity of the gene. All three of the probes were found to lie between the centromere and the most proximal translocation breakpoint, providing important genetic markers proximal to the NF1 gene. Our primary focus has shifted to the X chromosome. We have isolated an additional 30 polymorphic markers, bringing the total number we have isolated to over 80. We have invested substantial effort in characterizing the polymorphisms at each of these loci and constructed plasmid subclones which reveal the polymorphisms for nearly all of the loci. These subclones are of practical value in that they produce simpler and stronger patterns on human genomic Southern blots, thus improving the efficiency of the genetic mapping experiments. These subclones may also be of value for deriving DNA sequence information at each locus, necessary for establishing polymerase chain reaction primers specific for each locus. Such information would allow the use of each locus as a sequence tagged site.

  8. Human male meiotic sex chromosome inactivation.

    Science.gov (United States)

    de Vries, Marieke; Vosters, Sanne; Merkx, Gerard; D'Hauwers, Kathleen; Wansink, Derick G; Ramos, Liliana; de Boer, Peter

    2012-01-01

    In mammalian male gametogenesis the sex chromosomes are distinctive in both gene activity and epigenetic strategy. At first meiotic prophase the heteromorphic X and Y chromosomes are placed in a separate chromatin domain called the XY body. In this process, X,Y chromatin becomes highly phosphorylated at S139 of H2AX leading to the repression of gonosomal genes, a process known as meiotic sex chromosome inactivation (MSCI), which has been studied best in mice. Post-meiotically this repression is largely maintained. Disturbance of MSCI in mice leads to harmful X,Y gene expression, eventuating in spermatocyte death and sperm heterogeneity. Sperm heterogeneity is a characteristic of the human male. For this reason we were interested in the efficiency of MSCI in human primary spermatocytes. We investigated MSCI in pachytene spermatocytes of seven probands: four infertile men and three fertile controls, using direct and indirect in situ methods. A considerable degree of variation in the degree of MSCI was detected, both between and within probands. Moreover, in post-meiotic stages this variation was observed as well, indicating survival of spermatocytes with incompletely inactivated sex chromosomes. Furthermore, we investigated the presence of H3K9me3 posttranslational modifications on the X and Y chromatin. Contrary to constitutive centromeric heterochromatin, this heterochromatin marker did not specifically accumulate on the XY body, with the exception of the heterochromatic part of the Y chromosome. This may reflect the lower degree of MSCI in man compared to mouse. These results point at relaxation of MSCI, which can be explained by genetic changes in sex chromosome composition during evolution and candidates as a mechanism behind human sperm heterogeneity.

  9. Human male meiotic sex chromosome inactivation.

    Directory of Open Access Journals (Sweden)

    Marieke de Vries

    Full Text Available In mammalian male gametogenesis the sex chromosomes are distinctive in both gene activity and epigenetic strategy. At first meiotic prophase the heteromorphic X and Y chromosomes are placed in a separate chromatin domain called the XY body. In this process, X,Y chromatin becomes highly phosphorylated at S139 of H2AX leading to the repression of gonosomal genes, a process known as meiotic sex chromosome inactivation (MSCI, which has been studied best in mice. Post-meiotically this repression is largely maintained. Disturbance of MSCI in mice leads to harmful X,Y gene expression, eventuating in spermatocyte death and sperm heterogeneity. Sperm heterogeneity is a characteristic of the human male. For this reason we were interested in the efficiency of MSCI in human primary spermatocytes. We investigated MSCI in pachytene spermatocytes of seven probands: four infertile men and three fertile controls, using direct and indirect in situ methods. A considerable degree of variation in the degree of MSCI was detected, both between and within probands. Moreover, in post-meiotic stages this variation was observed as well, indicating survival of spermatocytes with incompletely inactivated sex chromosomes. Furthermore, we investigated the presence of H3K9me3 posttranslational modifications on the X and Y chromatin. Contrary to constitutive centromeric heterochromatin, this heterochromatin marker did not specifically accumulate on the XY body, with the exception of the heterochromatic part of the Y chromosome. This may reflect the lower degree of MSCI in man compared to mouse. These results point at relaxation of MSCI, which can be explained by genetic changes in sex chromosome composition during evolution and candidates as a mechanism behind human sperm heterogeneity.

  10. Chromosomes of Protists: The crucible of evolution.

    Science.gov (United States)

    Soyer-Gobillard, Marie-Odile; Dolan, Michael F

    2015-12-01

    As early as 1925, the great protozoologist Edouard Chatton classified microorganisms into two categories, the prokaryotic and the eukaryotic microbes, based on light microscopical observation of their nuclear organization. Now, by means of transmission electron microscopy, we know that prokaryotic microbes are characterized by the absence of nuclear envelope surrounding the bacterial chromosome, which is more or less condensed and whose chromatin is deprived of histone proteins but presents specific basic proteins. Eukaryotic microbes, the protists, have nuclei surrounded by a nuclear envelope and have chromosomes more or less condensed, with chromatin-containing histone proteins organized into nucleosomes. The extraordinary diversity of mitotic systems presented by the 36 phyla of protists (according to Margulis et al., Handbook of Protoctista, 1990) is in contrast to the relative homogeneity of their chromosome structure and chromatin components. Dinoflagellates are the exception to this pattern. The phylum is composed of around 2000 species, and characterized by unique features including their nucleus (dinokaryon), dinomitosis, chromosome organization and chromatin composition. Although their DNA synthesis is typically eukaryotic, dinoflagellates are the only eukaryotes in which the chromatin, organized into quasi-permanently condensed chromosomes, is in some species devoid of histones and nucleosomes. In these cases, their chromatin contains specific DNA-binding basic proteins. The permanent compaction of their chromosomes throughout the cell cycle raises the question of the modalities of their division and their transcription. Successful in vitro reconstitution of nucleosomes using dinoflagellate DNA and heterologous corn histones raises questions about dinoflagellate evolution and phylogeny. [Int Microbiol 18(4):209-216 (2015)].

  11. Unpacking Corrections in Mobile Instruction

    DEFF Research Database (Denmark)

    Levin, Lene; Broth, Mathias; Cromdal, Jakob

    2017-01-01

    This article deals with the organisation of correction in mobile instructional settings. Five sets of video data (>250 h) documenting how learners were instructed to fly aeroplanes, drive cars and ride bicycles in real life traffic were examined to reveal some common features of correction exchan...

  12. Feature Referenced Error Correction Apparatus.

    Science.gov (United States)

    A feature referenced error correction apparatus utilizing the multiple images of the interstage level image format to compensate for positional...images and by the generation of an error correction signal in response to the sub-frame registration errors. (Author)

  13. [Familial, structural aberration of the Y chromosome with fertility disorders].

    Science.gov (United States)

    Gall, H; Schmid, M; Schmidtke, J; Schempp, W; Weber, L

    1985-11-01

    Cytogenetic studies on a patient with Klinefelter's syndrome revealed an inherited, structural aberration of the Y-chromosome which has not been described before. The aberrant Y-chromosome was characterized by eight different banding methods. The value of individual staining techniques in studies on Y-heterochromatin aberrations is emphasized. Analysis of the cytogenetic studies (banding methods, restriction endonuclease of DNA, and measurement of the length of the Y-chromosome) permits an interpretation to be made on how the aberrant Y-chromosome originated. The functions of the Y-chromosome are discussed. The decrease in fertility (cryptozoospermia) in the two brothers with the same aberrant Y-chromosome was striking.

  14. From equator to pole: splitting chromosomes in mitosis and meiosis

    Science.gov (United States)

    Duro, Eris

    2015-01-01

    During eukaryotic cell division, chromosomes must be precisely partitioned to daughter cells. This relies on a mechanism to move chromosomes in defined directions within the parental cell. While sister chromatids are segregated from one another in mitosis and meiosis II, specific adaptations enable the segregation of homologous chromosomes during meiosis I to reduce ploidy for gamete production. Many of the factors that drive these directed chromosome movements are known, and their molecular mechanism has started to be uncovered. Here we review the mechanisms of eukaryotic chromosome segregation, with a particular emphasis on the modifications that ensure the segregation of homologous chromosomes during meiosis I. PMID:25593304

  15. Chromosome studies in the genus Pterotricha (Gnaphosidae from Turkey

    Directory of Open Access Journals (Sweden)

    Kumbiçak Zübeyde

    2014-01-01

    Full Text Available The diploid chromosome set and male meiosis of two spider species belonging to the family Gnaphosidae from Turkey are described. Both Pterotricha kochi and Pterotricha lesserti exhibited the diploid chromosome number as 2n♂=22 and X1X20 sex chromosome type. All chromosomes were acrocentric. During the first meiotic division, both species had ten autosomal bivalents and two sex chromosomes that were positively heteropycnotic. At the second meiotic division, two kinds of nuclei were determined, with or without sex chromosome. These data will contribute to our knowledge of the evolution of the genus Pterotricha.

  16. The DNA sequence of the human X chromosome

    OpenAIRE

    Ross, Mark T.; Grafham, Darren V.; Coffey, Alison J; Scherer, Steven; McLay, Kirsten; Muzny, Donna; Platzer, Matthias; Howell, Gareth R.; Burrows, Christine; Bird, Christine P.; Frankish, Adam; Lovell, Frances L.; Howe, Kevin L; Jennifer L Ashurst; Fulton, Robert S.

    2005-01-01

    The human X chromosome has a unique biology that was shaped by its evolution as the sex chromosome shared by males and females. We have determined 99.3% of the euchromatic sequence of the X chromosome. Our analysis illustrates the autosomal origin of the mammalian sex chromosomes, the stepwise process that led to the progressive loss of recombination between X and Y, and the extent of subsequent degradation of the Y chromosome. LINE1 repeat elements cover one-third of the X chromosome, with a...

  17. From equator to pole: splitting chromosomes in mitosis and meiosis.

    Science.gov (United States)

    Duro, Eris; Marston, Adèle L

    2015-01-15

    During eukaryotic cell division, chromosomes must be precisely partitioned to daughter cells. This relies on a mechanism to move chromosomes in defined directions within the parental cell. While sister chromatids are segregated from one another in mitosis and meiosis II, specific adaptations enable the segregation of homologous chromosomes during meiosis I to reduce ploidy for gamete production. Many of the factors that drive these directed chromosome movements are known, and their molecular mechanism has started to be uncovered. Here we review the mechanisms of eukaryotic chromosome segregation, with a particular emphasis on the modifications that ensure the segregation of homologous chromosomes during meiosis I.

  18. Physical mapping of human chromosome 16

    Energy Technology Data Exchange (ETDEWEB)

    Sutherland, G.R.

    1992-01-01

    Project aims for the past year have been to refine the cytogenetic based physical map of human chromosome 16. This has been achieved by extending the panel of mouse/human hybrids of chromosome 16 to over sixty hybrids and mapping approximately 250 DNA makers. The high resolution of this physical map, with an average distance between breakpoints of less than 1.6 Mb, and the availability of at least one STS in the majority of these intervals, will be the basis for constructing extensive contigs of cloned DNA.

  19. Non-disjunction of chromosome 18

    DEFF Research Database (Denmark)

    Bugge, M; Collins, A; Petersen, M B

    1998-01-01

    A sample of 100 trisomy 18 conceptuses analysed separately and together with a published sample of 61 conceptuses confirms that an error in maternal meiosis II (MII) is the most frequent cause of non-disjunction for chromosome 18. This is unlike all other human trisomies that have been studied......, which show a higher frequency in maternal meiosis I (MI). Maternal MI trisomy 18 shows a low frequency of recombination in proximal p and medial q, but not the reduction in proximal q observed in chromosome 21 MI non-disjunction. Maternal MII non-disjunction does not fit the entanglement model...

  20. X-chromosome inactivation and escape

    Indian Academy of Sciences (India)

    Christine M. Disteche; Joel B. Berletch

    2015-12-01

    X-chromosome inactivation, which was discovered by Mary Lyon in 1961 results in random silencing of one X chromosome in female mammals. This review is dedicated to Mary Lyon, who passed away last year. She predicted many of the features of X inactivation, for e.g., the existence of an X inactivation center, the role of L1 elements in spreading of silencing and the existence of genes that escape X inactivation. Starting from her published work here we summarize advances in the field.

  1. Conserved synteny between pig chromosome 8 and human chromosome 4 but rearranged and distorted linkage maps

    Energy Technology Data Exchange (ETDEWEB)

    Ellegren, H.; Edfors-Lilja, I.; Anderson, L. (Swedish Univ. of Agricultural Sciences, Uppsala (Sweden)); Wintero, A.K. (Royal Veterinary and Agricultural Univ., Fredriksberg (Denmark))

    1993-09-01

    The porcine genes encoding interleukin 2, alcohol dehydrogenase (class I) gamma polypeptide, and osteopontin were mapped to chromosome 8 by linkage analysis. Together with previous assignments to this chromosome (the albumin, platelet-derived growth factor receptor A, and fibrinogen genes), an extensive syntenic homology with human chromosome 4 was discovered. Loci from about three-quarters of the q arm of human chromosome 4 are on pig chromosome 8. However, the linear order of the markers is not identical in the two species, and there are several examples of interspecific differences in the recombination fractions between adjacent markers. The conserved synteny between man and the pig gives strong support to a previous suggestion that a synteny group present in the ancestor of mammalian species has been retained on human chromosome 4q. Since loci from this synteny group are found on two cattle chromosomes, the bovine rearrangement must have occurred after the split of Suidae and Bovidae within Artiodactyla. 29 refs., 3 figs., 1 tab.

  2. Microdissection and chromosome painting of X and B chromosomes in the grasshopper Eyprepocnemis plorans.

    Science.gov (United States)

    Teruel, M; Cabrero, J; Perfectti, F; Acosta, M J; Sánchez, A; Camacho, J P M

    2009-01-01

    The relative location of 2 repetitive DNAs, i.e. ribosomal (rDNA) and a tandemly repeated satellite DNA (satDNA), with respect to the centromere, suggested that B chromosomes in the grasshopper Eyprepocnemis plorans derived intraspecifically from the X chromosome. To test this hypothesis, we microdissected X and B chromosomes and amplified the obtained DNA by 2 different procedures, the conventional DOP-PCR method and the single-cell whole-genome amplification GenomePlex method. We then generated DNA probes to perform chromosome painting. Our results have confirmed that X and B chromosomes share many DNA sequences between them and with most of the autosomes, especially at locations where the satDNA and rDNA reside, in consistency with previous information. This supports the hypothesis of an intraspecific origin of B chromosomes in E. plorans. Nevertheless, the present results did not help to clarify whether Bs were derived from the X chromosome or else from 1 or more autosomes.

  3. mars and tousled-like kinase act in parallel to ensure chromosome fidelity in Drosophila

    Directory of Open Access Journals (Sweden)

    Huang Hsiao-Yu

    2009-06-01

    Chromosome fidelity in progeny from parents with reduced mars and/or tlk activity was impaired. The results from cytological studies revealed that mars and tlk function in parallel and that a balance between mars activity and tlk activity is required for cells to progress through mitosis correctly, thus ensuring chromosome fidelity.

  4. Origin of amphibian and avian chromosomes by fission, fusion, and retention of ancestral chromosomes

    Science.gov (United States)

    Voss, Stephen R.; Kump, D. Kevin; Putta, Srikrishna; Pauly, Nathan; Reynolds, Anna; Henry, Rema J.; Basa, Saritha; Walker, John A.; Smith, Jeramiah J.

    2011-01-01

    Amphibian genomes differ greatly in DNA content and chromosome size, morphology, and number. Investigations of this diversity are needed to identify mechanisms that have shaped the evolution of vertebrate genomes. We used comparative mapping to investigate the organization of genes in the Mexican axolotl (Ambystoma mexicanum), a species that presents relatively few chromosomes (n = 14) and a gigantic genome (>20 pg/N). We show extensive conservation of synteny between Ambystoma, chicken, and human, and a positive correlation between the length of conserved segments and genome size. Ambystoma segments are estimated to be four to 51 times longer than homologous human and chicken segments. Strikingly, genes demarking the structures of 28 chicken chromosomes are ordered among linkage groups defining the Ambystoma genome, and we show that these same chromosomal segments are also conserved in a distantly related anuran amphibian (Xenopus tropicalis). Using linkage relationships from the amphibian maps, we predict that three chicken chromosomes originated by fusion, nine to 14 originated by fission, and 12–17 evolved directly from ancestral tetrapod chromosomes. We further show that some ancestral segments were fused prior to the divergence of salamanders and anurans, while others fused independently and randomly as chromosome numbers were reduced in lineages leading to Ambystoma and Xenopus. The maintenance of gene order relationships between chromosomal segments that have greatly expanded and contracted in salamander and chicken genomes, respectively, suggests selection to maintain synteny relationships and/or extremely low rates of chromosomal rearrangement. Overall, the results demonstrate the value of data from diverse, amphibian genomes in studies of vertebrate genome evolution. PMID:21482624

  5. Telomere dysfunction and chromosome structure modulate the contribution of individual chromosomes in abnormal nuclear morphologies

    Energy Technology Data Exchange (ETDEWEB)

    Pampalona, J.; Soler, D.; Genesca, A. [Department of Cell Biology, Physiology and Immunology, Universitat Autonoma de Barcelona, Bellaterra E-08193 (Spain); Tusell, L., E-mail: laura.tusell@uab.es [Department of Cell Biology, Physiology and Immunology, Universitat Autonoma de Barcelona, Bellaterra E-08193 (Spain)

    2010-01-05

    The cytokinesis-block micronucleus assay has emerged as a biomarker of chromosome damage relevant to cancer. Although it was initially developed to measure micronuclei, it is also useful for measuring nucleoplasmic bridges and nuclear buds. Abnormal nuclear morphologies are frequently observed in malignant tissues and short-term tumour cell cultures. Changes in chromosome structure and number resulting from chromosome instability are important factors in oncogenesis. Telomeres have become key players in the initiation of chromosome instability related to carcinogenesis by means of breakage-fusion-bridge cycles. To better understand the connection between telomere dysfunction and the appearance of abnormal nuclear morphologies, we have characterised the presence of micronuclei, nucleoplasmic bridges and nuclear buds in human mammary primary epithelial cells. These cells can proliferate beyond the Hayflick limit by spontaneously losing expression of the p16{sup INK4a} protein. Progressive telomere shortening leads to the loss of the capping function, and the appearance of end-to-end chromosome fusions that can enter into breakage-fusion-bridge cycles generating massive chromosomal instability. In human mammary epithelial cells, different types of abnormal nuclear morphologies were observed, however only nucleoplasmatic bridges and buds increased significantly with population doublings. Fluorescent in situ hybridisation using centromeric and painting specific probes for chromosomes with eroded telomeres has revealed that these chromosomes are preferentially included in the different types of abnormal nuclear morphologies observed, thus reflecting their common origin. Accordingly, real-time imaging of cell divisions enabled us to determine that anaphase bridge resolution was mainly through chromatin breakage and the formation of symmetric buds in daughter nuclei. Few micronuclei emerged in this cell system thus validating the scoring of nucleoplasmic bridges and

  6. Newborn with Supernumerary Marker Chromosome Derived from Chromosomes 11 And 22- A Case Report.

    Science.gov (United States)

    Vahidi Mehrjardi, Mohammad Yahya; Dehghan Tezerjani, Masoud; Nori-Shadkam, Mahmoud; Kalantar, Seyed Mehdi; Dehghani, Mohammadreza

    2016-03-01

    The interpretation of supernumerary chromosome is important for genetic counseling and prognosis. Here, we used SNP array and conventional karyotyping method to identify a denovo marker chromosome originated from chromosome 22 and 11 in a newborn transferred to the Neonatal Intensive Care Unit of Shahid Sadoughi Hospital in 2015. Clinical abnormalities identified in the newborn were dysmorphic face, intrauterine growth retardation, atrial septal defect (ASD), the hypoplasia of corpus callosum and septum pellucidum. These clinical abnormalities can be related to this marker, and it may help genetic counselor for predicting abnormality risk in susceptible individuals as well as prenatal diagnosis.

  7. Dispensable chromosomes in Fusarium oxysporum f. sp. lycopersici.

    Science.gov (United States)

    Vlaardingerbroek, Ido; Beerens, Bas; Schmidt, Sarah M; Cornelissen, Ben J C; Rep, Martijn

    2016-12-01

    The genomes of many filamentous fungi consist of a 'core' part containing conserved genes essential for normal development as well as conditionally dispensable (CD) or lineage-specific (LS) chromosomes. In the plant-pathogenic fungus Fusarium oxysporum f. sp. lycopersici, one LS chromosome harbours effector genes that contribute to pathogenicity. We employed flow cytometry to select for events of spontaneous (partial) loss of either the two smallest LS chromosomes or two different core chromosomes. We determined the rate of spontaneous loss of the 'effector' LS chromosome in vitro at around 1 in 35 000 spores. In addition, a viable strain was obtained lacking chromosome 12, which is considered to be a part of the core genome. We also isolated strains carrying approximately 1-Mb deletions in the LS chromosomes and in the dispensable core chromosome. The large core chromosome 1 was never observed to sustain deletions over 200 kb. Whole-genome sequencing revealed that some of the sites at which the deletions occurred were the same in several independent strains obtained for the two chromosomes tested, indicating the existence of deletion hotspots. For the core chromosome, this deletion hotspot was the site of insertion of the marker used to select for loss events. Loss of the core chromosome did not affect pathogenicity, whereas loss of the effector chromosome led to a complete loss of pathogenicity. © 2016 THE AUTHORS. MOLECULAR PLANT PATHOLOGY PUBLISHED BY BRITISH SOCIETY FOR PLANT PATHOLOGY AND JOHN WILEY & SONS LTD.

  8. Occurrence of aneuploidy for the X chromosome in over 1,300 unrelated specimens screened for the fragile X chromosome

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1994-07-15

    An apparent association between the occurrence of the fragile X syndrome and Klinefelter and Down syndromes has been reported over the past few years. We reported 3 cells with extra X chromosomes [XXY (one cell), XXXY (2 cells)] in a fragile X male who exhibited 37 fragile X chromosomes in 200 cells studied. After making this observation, we decided to determine the number of X chromosomes in all fragile X chromosome analyses to see if there was any increased mitotic nondisjunction for the X chromosome. We conclude that there was no association between the fragile X syndrome and X chromosome mitotic nondisjunction/aneuploidy in this group of individuals. 9 refs., 1 tab.

  9. The Escherichia coli chromosome is organized with the left and right chromosome arms in separate cell halves

    DEFF Research Database (Denmark)

    Nielsen, Henrik Jørck; Ottesen, Jesper R.; Youngren, Brenda

    2006-01-01

    We have developed a system for the simultaneous labelling of two specific chromosomal sites using two different fluorescent ParB/parS systems. Using this, we demonstrate that the two chromosome arms are spatially arranged in newborn cells such that markers on the left arm of the chromosome lie...... in one half of the cell and markers on the right arm of the chromosome lie in the opposite half. This is achieved by reorganizing the chromosome arms of the two nucleoids in pre-division cells relative to the cell quarters. The spatial reorganization of the chromosome arms ensures that the two...

  10. Persistence of Breakage in Specific Chromosome Bands 6 Years after Acute Exposure to Oil

    Science.gov (United States)

    Francés, Alexandra; Hildur, Kristin; Barberà, Joan Albert; Rodríguez-Trigo, Gema; Zock, Jan-Paul; Giraldo, Jesús; Monyarch, Gemma; Rodriguez-Rodriguez, Emma; de Castro Reis, Fernanda; Souto, Ana; Gómez, Federico P.; Pozo-Rodríguez, Francisco; Templado, Cristina; Fuster, Carme

    2016-01-01

    Background The identification of breakpoints involved in chromosomal damage could help to detect genes involved in genetic disorders, most notably cancer. Until now, only one published study, carried out by our group, has identified chromosome bands affected by exposure to oil from an oil spill. In that study, which was performed two years after the initial oil exposure in individuals who had participated in clean-up tasks following the wreck of the Prestige, three chromosomal bands (2q21, 3q27, 5q31) were found to be especially prone to breakage. A recent follow-up study, performed on the same individuals, revealed that the genotoxic damage had persisted six years after oil exposure. Objectives To determine whether there exist chromosome bands which are especially prone to breakages and to know if there is some correlation with those detected in the previous study. In addition, to investigate if the DNA repair problems detected previously persist in the present study. Design Follow-up study performed six years after the Prestige oil spill. Setting Fishermen cooperatives in coastal villages. Participants Fishermen highly exposed to oil spill who participated in previous genotoxic study six years after the oil. Measurements Chromosome damage in peripheral lymphocytes. For accurate identification of the breakpoints involved in chromosome damage of circulating lymphocytes, a sequential stain/G-banding technique was employed. To determine the most break-prone chromosome bands, two statistical methods, the Fragile Site Multinomial and the chi-square tests (where the bands were corrected by their length) were used. To compare the chromosome lesions, structural chromosome alterations and gaps/breaks between two groups of individuals we used the GEE test which takes into account a possible within-individual correlation. Dysfunctions in DNA repair mechanisms, expressed as chromosome damage, were assessed in cultures with aphidicolin by the GEE test. Results Cytogenetic

  11. Rapid detection of chromosome 18 aneuploidies in amniocytes by using primed in situ labeling (PRINS) technique

    Institute of Scientific and Technical Information of China (English)

    杨建滨; 郑树

    2002-01-01

    This paper presents a feasible method for rapid detection of the interphase nuclei of uncultured amniocytes for chromosomes 18 by using our modified primed in situ labeling (PRINS) technique. A total of 262 independent, uncultured amniotic fluid samples were analysed in a blind fashion before the karyotype was available. In addition, 62 samples were examined by fluorescence in situ hybridization (FISH) for comparison. In more than 95% of the samples PRINS reactions with primer 18cen were successfully induced. Two samples were properly identified and correctly scored as trisomic 18. PRINS reaction could be performed automatically in less than one hour with a programmable thermocycler. Our studies showed that the PRINS technique is simple, rapid and cost-effective. It is as sensitive and specific as FISH; can enhance the accuracy of standard cytogenetic analysis; and allows identification of chromosomes 18 aneuploidies in uncultured amniocytes in significantly less time.

  12. Updating quasar bolometric luminosity corrections

    CERN Document Server

    Runnoe, Jessie C; Shang, Zhaohui

    2012-01-01

    Bolometric corrections are used in quasar studies to quantify total energy output based on a measurement of a monochromatic luminosity. First, we enumerate and discuss the practical difficulties of determining such corrections, then we present bolometric luminosities between 1 \\mu m and 8 keV rest frame and corrections derived from the detailed spectral energy distributions of 63 bright quasars of low to moderate redshift (z = 0.03-1.4). Exploring several mathematical fittings, we provide practical bolometric corrections of the forms L_iso=\\zeta \\lambda L_{\\lambda} and log(L_iso)=A+B log(\\lambda L_{\\lambda}) for \\lambda= 1450, 3000, and 5100 \\AA, where L_iso is the bolometric luminosity calculated under the assumption of isotropy. The significant scatter in the 5100 \\AA\\ bolometric correction can be reduced by adding a first order correction using the optical slope, \\alpha_\\lambda,opt. We recommend an adjustment to the bolometric correction to account for viewing angle and the anisotropic emission expected fr...

  13. PARTIAL TRISOMY CHROMOSOME 5 COSEGREGATING WITH SCHIZOPHRENIA

    OpenAIRE

    Bassett, Anne S.; McGillivray, Barbara C.; Jones, Barry D.; Pantzar, J. Tapio

    1988-01-01

    Schizophrenia was associated with a distinct autosomal abnormality in two related mildly dysmorphic individuals. The finding of cosegregation of schizophrenia and a partial trisomy of chromosome 5 in the family suggests a potential location of a gene or genes linked to schizophrenia.

  14. Regulation of chromosomal replication in Caulobacter crescentus.

    Science.gov (United States)

    Collier, Justine

    2012-03-01

    The alpha-proteobacterium Caulobacter crescentus is characterized by its asymmetric cell division, which gives rise to a replicating stalked cell and a non-replicating swarmer cell. Thus, the initiation of chromosomal replication is tightly regulated, temporally and spatially, to ensure that it is coordinated with cell differentiation and cell cycle progression. Waves of DnaA and CtrA activities control when and where the initiation of DNA replication will take place in C. crescentus cells. The conserved DnaA protein initiates chromosomal replication by directly binding to sites within the chromosomal origin (Cori), ensuring that DNA replication starts once and only once per cell cycle. The CtrA response regulator represses the initiation of DNA replication in swarmer cells and in the swarmer compartment of pre-divisional cells, probably by competing with DnaA for binding to Cori. CtrA and DnaA are controlled by multiple redundant regulatory pathways that include DNA methylation-dependent transcriptional regulation, temporally regulated proteolysis and the targeting of regulators to specific locations within the cell. Besides being critical regulators of chromosomal replication, CtrA and DnaA are also master transcriptional regulators that control the expression of many genes, thus connecting DNA replication with other events of the C. crescentus cell cycle. Copyright © 2012 Elsevier Inc. All rights reserved.

  15. Nondisjunction of chromosome 15: Origin and recombination

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, W.P.; Bernasconi, F.; Schinzel, A.A.; Mutirangura, A.; Ledbetter, D.H. (Baylor College of Medicine, Houston, TX (United States)); Langlois, S. (Univ. of Britisch Columbia, Vancouver (Canada)); Morris, M.A.; Malcolm, S.

    1993-09-01

    Thirty-two cases of uniparental disomy (UPD), ascertained from Prader-Willi syndrome patients (N=27) and Angelman syndrome patients (N-5), are used to investigate the pattern of recombination associated with nondisjunction of chromosome 15. In addition, the meiotic stage of nondisjunction is inferred by using markers mapping near the centromere. Two basic approaches to the analysis of recombination in specific pairwise intervals along the chromosome. This method shows a significant reduction in recombination for two of five intervals examined. Second, the observed frequency of each recombinant class (i.e., zero, one, two, three, or more observable crossovers) is compared with expected values. This is useful for testing whether the reduction in recombination can be attributed solely to a proportion of cases with no recombination at all (because of asynapsis), with the remaining groups showing normal recombination (or even excess recombination), or whether recombination is uniformly reduced. Analysis of maternal UPD(15) data shows a slight reduction in the multiple-recombinant classes, with a corresponding increase in both the zero- and one-recombinant classes over expected values. The majority, more than 82%, of the extra chromosomes in maternal UPD(15) cases are due to meiotic I nondisjunction events. In contrast, more paternal UPD(15) cases so far examined appear to have a postzygotic origin of the extra paternal chromosome. 33 refs., 1 fig., 7 tabs.

  16. Plasmid and chromosome partitioning: surprises from phylogeny

    DEFF Research Database (Denmark)

    Gerdes, Kenn; Møller-Jensen, Jakob; Bugge Jensen, Rasmus

    2000-01-01

    Plasmids encode partitioning genes (par) that are required for faithful plasmid segregation at cell division. Initially, par loci were identified on plasmids, but more recently they were also found on bacterial chromosomes. We present here a phylogenetic analysis of par loci from plasmids and chr...

  17. Chromosomes with a life of their own.

    Science.gov (United States)

    Jones, R N; González-Sánchez, M; González-García, M; Vega, J M; Puertas, M J

    2008-01-01

    B chromosomes (Bs) can be described as 'passengers in the genome', a term that has been used for the repetitive DNA which comprises the bulk of the genome in large genome species, except that Bs have a life of their own as independent chromosomes. As with retrotransposons they can accumulate in number, but in this case by various processes of mitotic or meiotic drive, based on their own autonomous ways of using spindles, especially in the gametophyte phase of the life cycle of flowering plants. This selfish property of drive ensures their survival and spread in natural populations, even against a gradient of harmful effects on the host plant phenotype. Bs are inhabitants of the nucleus and they are subject to control by 'genes' in the A chromosome (As) complement. This interaction with the As, together with the balance between drive and harmful effects makes a dynamic system in the life of a B chromosome, notwithstanding the fact that we are only now beginning to unravel the story in a few favoured species. In this review we concentrate mainly on recent developments in the Bs of rye and maize, two of the species currently receiving most attention. We focus on their population dynamics and on the molecular basis of their structural organisation and mechanisms of drive, as well as on their mode of origin and potential applications in plant biotechnology.

  18. Psychoeducational Implications of Sex Chromosome Anomalies

    Science.gov (United States)

    Wodrich, David L.; Tarbox, Jennifer

    2008-01-01

    Numerous anomalies involving the sex chromosomes (X or Y) have been documented and their impact on development, learning, and behavior studied. This article reviews three of these disorders, Turner syndrome, Klinefelter syndrome, and Lesch-Nyhan disease. Each of these three is associated with one or more selective impairments or behavioral…

  19. Progressive segregation of the Escherichia coli chromosome

    DEFF Research Database (Denmark)

    Nielsen, Henrik Jørck; Youngren, Brenda; Hansen, Flemming G.

    2006-01-01

    We have followed the fate of 14 different loci around the Escherichia coli chromosome in living cells at slow growth rate using a highly efficient labelling system and automated measurements. Loci are segregated as they are replicated, but with a marked delay. Most markers segregate in a smooth...

  20. Chromosomes and plant cell division in space

    Science.gov (United States)

    Krikorian, A. D.

    1988-01-01

    The objectives were: examination of chromosomal aberrations; development of an experimental system; and engineering design units (EDUs) evaluation. Evaluation criteria are presented. Procedures were developed for shuttle-based investigations which result in the procurement of plant root tips for subsequent cytological examination.