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Sample records for chromosome losses

  1. Loss of Y Chromosome in Men Tied to Alzheimer's Risk

    Science.gov (United States)

    ... Loss of Y Chromosome in Men Tied to Alzheimer's Risk Study raises provocative questions, expert says To ... age may have an increased risk of developing Alzheimer's disease, a new study suggests. The study of ...

  2. Estimating Tempo and Mode of Y Chromosome Turnover: Explaining Y Chromosome Loss With the Fragile Y Hypothesis

    OpenAIRE

    Blackmon, Heath; Demuth, Jeffery P.

    2014-01-01

    Chromosomal sex determination is phylogenetically widespread, having arisen independently in many lineages. Decades of theoretical work provide predictions about sex chromosome differentiation that are well supported by observations in both XY and ZW systems. However, the phylogenetic scope of previous work gives us a limited understanding of the pace of sex chromosome gain and loss and why Y or W chromosomes are more often lost in some lineages than others, creating XO or ZO systems. To gain...

  3. Estimating tempo and mode of Y chromosome turnover: explaining Y chromosome loss with the fragile Y hypothesis.

    Science.gov (United States)

    Blackmon, Heath; Demuth, Jeffery P

    2014-06-01

    Chromosomal sex determination is phylogenetically widespread, having arisen independently in many lineages. Decades of theoretical work provide predictions about sex chromosome differentiation that are well supported by observations in both XY and ZW systems. However, the phylogenetic scope of previous work gives us a limited understanding of the pace of sex chromosome gain and loss and why Y or W chromosomes are more often lost in some lineages than others, creating XO or ZO systems. To gain phylogenetic breadth we therefore assembled a database of 4724 beetle species' karyotypes and found substantial variation in sex chromosome systems. We used the data to estimate rates of Y chromosome gain and loss across a phylogeny of 1126 taxa estimated from seven genes. Contrary to our initial expectations, we find that highly degenerated Y chromosomes of many members of the suborder Polyphaga are rarely lost, and that cases of Y chromosome loss are strongly associated with chiasmatic segregation during male meiosis. We propose the "fragile Y" hypothesis, that recurrent selection to reduce recombination between the X and Y chromosome leads to the evolution of a small pseudoautosomal region (PAR), which, in taxa that require XY chiasmata for proper segregation during meiosis, increases the probability of aneuploid gamete production, with Y chromosome loss. This hypothesis predicts that taxa that evolve achiasmatic segregation during male meiosis will rarely lose the Y chromosome. We discuss data from mammals, which are consistent with our prediction. PMID:24939995

  4. An Assay to Detect In Vivo Y Chromosome Loss in Drosophila Wing Disc Cells

    OpenAIRE

    Szabad, Janos; Bellen, Hugo J.; Venken, Koen J. T.

    2012-01-01

    Loss of the Y chromosome in Drosophila has no impact on cell viability and therefore allows us to assay the impact of environmental agents and genetic alterations on chromosomal loss. To detect in vivo chromosome loss in cells of the developing Drosophila wing primordia, we first engineered a Y chromosome with an attP docking site. By making use of the ΦC31 integrase system, we site-specifically integrated a genomic transgene encompassing the multiple wing hair ( mwh ) locus into this attP si...

  5. SUMO-targeted ubiquitin ligase RNF4 plays a critical role in preventing chromosome loss.

    Science.gov (United States)

    Hirota, Kouji; Tsuda, Masataka; Murai, Junko; Takagi, Tokiyo; Keka, Islam Shamima; Narita, Takeo; Fujita, Mari; Sasanuma, Hiroyuki; Kobayashi, Junya; Takeda, Shunichi

    2014-10-01

    RING finger protein 4 (RNF4) represents a subclass of ubiquitin ligases that target proteins modified by the small ubiquitin-like modifier (SUMO) for ubiquitin-mediated degradation. We disrupted the RNF4 gene in chicken DT40 cells and found that the resulting RNF4(-/-) cells gradually lost proliferation capability. Strikingly, this compromised proliferation was associated with an unprecedented cellular effect: the gradual decrease in the number of intact chromosomes. In the 6 weeks after gene targeting, there was a 25% reduction in the DNA content of the RNF4(-/-) cells. Regarding trisomic chromosome 2, 60% of the RNF4(-/-) cells lost one homologue, suggesting that DNA loss was mediated by whole chromosome loss. To determine the cause of this chromosome loss, we examined cell-cycle checkpoint pathways. RNF4(-/-) cells showed a partial defect in the spindle assembly checkpoint, premature dissociation of sister chromatids, and a marked increase in the number of lagging chromosomes at anaphase. Thus, combined defects in SAC and sister chromatid cohesion may result in increased lagging chromosomes, leading to chromosome loss without accompanying chromosome gain in RNF4(-/-) cells. We therefore propose that RNF4 plays a novel role in preventing the loss of intact chromosomes and ensures the maintenance of chromosome integrity. PMID:25205350

  6. The Relationship Between Spontaneous Telomere Loss and Chromosome Instability in a Human Tumor Cell Line

    Directory of Open Access Journals (Sweden)

    Bijan Fouladi

    2000-01-01

    Full Text Available Chromosome instability plays an important role in cancer by promoting the alterations in the genome required for tumor cell progression. The loss of telomeres that protect the ends of chromosomes and prevent chromosome fusion has been proposed as one mechanism for chromosome instability in cancer cells, however, there is little direct evidence to support this hypothesis. To investigate the relationship between spontaneous telomere loss and chromosome instability in human cancer cells, clones of the EJ-30 tumor cell line were isolated in which a herpes simplex virus thymidine kinase (HSV-tk gene was integrated immediately adjacent to a telomere. Selection for HSV-tkdeficient cells with ganciclovir demonstrated a high rate of loss of the end these "marked" chromosomes (10-4 events/cell per generation. DNA sequence and cytogenetic analysis suggests that the loss of function of the HSV-tk gene most often involves telomere loss, sister chromatid fusion, and prolonged periods of chromosome instability. In some HSV-tk-deficient cells, telomeric repeat sequences were added on to the end of the truncated HSV-tk gene at a new location, whereas in others, no telomere was detected on the end of the marked chromosome. These results suggest that spontaneous telomere loss is a mechanism for chromosome instability in human cancer cells.

  7. Duplication and loss of chromosome 21 in two children with Down syndrome and acute leukemia

    Energy Technology Data Exchange (ETDEWEB)

    Rogan, P.K.; Close, P.; Gannutz, L. [Pennsylvania State Univ., Hershey, PA (United States)] [and others

    1995-11-06

    Acute leukemia in Down syndrome (DS) is often associated with additional changes in the number of structure of chromosome 21. We present two DS patients whose leukemic karyotypes were associated with changes in chromosome 21 ploidy. Patient 1 developed acute lymphocytic leukemia (type L1); disomy for chromosome 21 was evident in all blast cells examined. Loss of the paternal chromosome in the leukemic clone produced maternal uniparental disomy with isodisomy over a 25-cM interval. The second patient had acute monoblastic leukemia (type M5) with tetrasomy 21 in all leukemic cells. DNA polymorphism analysis showed duplicate paternal chromosomes in the constitutional genotype. The maternal chromosome was subsequently duplicated in the leukemic clone. The distinct inheritance patterns of chromosome 21 in the blast cells of these patients would appear to indicate that leukemogenesis occurred by different genetic mechanisms in each individual. 57 refs., 2 figs., 3 tabs.

  8. Imprinted survival genes preclude loss of heterozygosity of chromosome 7 in cancer cells.

    Science.gov (United States)

    Boot, Arnoud; Oosting, Jan; de Miranda, Noel Fcc; Zhang, Yinghui; Corver, Willem E; van de Water, Bob; Morreau, Hans; van Wezel, Tom

    2016-09-01

    The genomes of a wide range of cancers, including colon, breast, and thyroid cancers, frequently show copy number gains of chromosome 7 and rarely show loss of heterozygosity. The molecular basis for this phenomenon is unknown. Strikingly, oncocytic follicular thyroid carcinomas can display an extreme genomic profile, with homozygosity of all chromosomes except for chromosome 7. The observation that homozygosity of chromosome 7 is never observed suggests that retention of heterozygosity is essential for cells. We hypothesized that cell survival genes are genetically imprinted on either of two copies of chromosome 7, which thwarts loss of heterozygosity at this chromosome in cancer cells. By employing a DNA methylation screen and gene expression analysis, we identified six imprinted genes that force retention of heterozygosity on chromosome 7. Subsequent knockdown of gene expression showed that CALCR, COPG2, GRB10, KLF14, MEST, and PEG10 were essential for cancer cell survival, resulting in reduced cell proliferation, G1 -phase arrest, and increased apoptosis. We propose that imprinted cell survival genes provide a genetic basis for retention of chromosome 7 heterozygosity in cancer cells. The monoallelically expressed cell survival genes identified in this study, and the cellular pathways that they are involved in, offer new therapeutic targets for the treatment of tumours showing retention of heterozygosity on chromosome 7. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. PMID:27265324

  9. Mitotic chromosome loss in a radiation-sensitive strain of the yeast Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Cells of Saccharomyces cerevisiae with mutations in the RAD52 gene have previously been shown to be defective in meiotic and mitotic recombination, in sporulation, and in repair of radiation-induced damage to DNA. In this study we show that diploid cells homozygous for rad52 lose chromosomes at high frequencies and that these frequencies of loss can be increased dramatically by exposure of these cells to x-rays. Genetic analyses of survivors of x-ray treatment demonstrate that chromosome loss events result in the conversion of diploid cells to cells with near haploid chromosome numbers

  10. Loss of the Y-chromosome in the primary metastasis of a male sex cord stromal tumor : Pathogenetic implications

    NARCIS (Netherlands)

    de Graaff, WE; van Echten, J; van der Veen, AY; Sleijfer, DT; Timmer, A; de Jong, B; Schraffordt Koops, H.

    1999-01-01

    The first published chromosomal pattern of the retroperitoneal lymph node metastasis of a malignant gonadal stroma cell tumor of the adult testis is presented. Karyotyping showed structural chromosomal abnormalities and loss of the Y-chromosome. This loss was confirmed in primary tumor and metastasi

  11. Chromosomal abnormalities in couples with repeated fetal loss: An Indian retrospective study

    Directory of Open Access Journals (Sweden)

    Frenny J Sheth

    2013-01-01

    Full Text Available Background: Recurrent pregnancy loss is a common occurrence and a matter of concern for couples planning the pregnancy. Chromosomal abnormalities, mainly balanced rearrangements, are common in couples with repeated miscarriages. Purpose: The purpose of this study is to evaluate the contribution of chromosomal anomalies causing repeated spontaneous miscarriages and provide detailed characterization of a few structurally altered chromosomes. Materials and Methods: A retrospective cytogenetic study was carried out on 4859 individuals having a history of recurrent miscarriages. The cases were analyzed using G-banding and fluorescence in situ hybridization wherever necessary. Results: Chromosomal rearrangements were found in 170 individuals (3.5%. Translocations were seen in 72 (42.35% cases. Of these, reciprocal translocations constituted 42 (24.70% cases while Robertsonian translocations were detected in 30 (17.64% cases. 7 (4.11% cases were mosaic, 8 (4.70% had small supernumerary marker chromosomes and 1 (0.6% had an interstitial microdeletion. Nearly, 78 (1.61% cases with heteromorphic variants were seen of which inversion of Y chromosome (57.70% and chromosome 9 pericentromeric variants (32.05% were predominantly involved. Conclusions: Chromosomal analysis is an important etiological investigation in couples with repeated miscarriages. Characterization of variants/marker chromosome enable calculation of a more precise recurrent risk in a subsequent pregnancy thereby facilitating genetic counseling and deciding further reproductive options.

  12. Molecular genetic approach to human meningioma: loss of genes on chromosome 22

    Energy Technology Data Exchange (ETDEWEB)

    Seizinger, B.R.; De La Monte, S.; Atkins, L.; Gusella, J.F.; Martuza, R.L.

    1987-08-01

    A molecular genetic approach employing polymorphic DNA markers has been used to investigate the role of chromosomal aberrations in meningioma, one of the most common tumors of the human nervous system. Comparison of the alleles detected by DNA markers in tumor DNA versus DNA from normal tissue revealed chromosomal alterations present in primary surgical specimens. In agreement with cytogenetic studies of cultured meningiomas, the most frequent alteration detected was loss of heterozygosity on chromosome 22. Forty of 51 patients were constitutionally heterozygous for at least one chromosome 22 DNA marker. Seventeen of the 40 constitutionally heterozygotic patients (43%) displayed hemizygosity for the corresponding marker in their meningioma tumor tissues. Loss of heterozygosity was also detected at a significantly lower frequency for markers on several other autosomes. In view of the striking association between acoustic neuroma and meningioma in bilateral acoustic neurofibromatosis and the discovery that acoustic neuromas display specific loss of genes on chromosome 22, the authors propose that a common mechanism involving chromosome 22 is operative in the development of both tumor types. Fine-structure mapping to reveal partial deletions in meningiomas may provide the means to clone and characterize a gene (or genes) of importance for tumorigenesis in this and possibly other clinically associated tumors of the human nervous system.

  13. Loss of heterozygosity on chromosome 3, bands q24----qter, in a diploid meningioma.

    Science.gov (United States)

    Färber, U; Schneider, G; Schrell, U M; Fahlbusch, P; Adams, E F; Blin, N; Henn, W

    1991-01-01

    Cytogenetic analysis of a meningioma from a 46-year-old female patient exhibited as the sole cytogenetic aberration a deletion on the long arm of one chromosome 3 involving bands 3q24----qter. To verify this finding, RFLP analysis was performed with two polymorphic probes, MOX2 and D3S5. The patient was informative for both single copy probes and demonstrated loss of heterozygosity in the region above whereas chromosome 22 displayed no loss of heterozygosity as judged by a proximal and a distal probe. PMID:1680607

  14. LOSS OF HETEROZYGOSITY ON CHROMOSOME 13 IN SQUAMOUS CELL CARCINOMAS OF THE LARYNX

    Institute of Scientific and Technical Information of China (English)

    Bai Sujuan; Zhang Xue; Wang Jun; Sun Kailai; Fei Shengzhong

    1998-01-01

    Objective: To locate lost region of tumor suppressor gene on chromosome 13q in squamous cell carcinoma of the larynx (LSCC) and to provide clues and evidence for discovering and locating new suppressor gene.Methods: Loss of heterozygosity (LOH) on chromosome 13q was analyzed in 58 LSCC patients by microsatellite polymorphic sequences in loci D13S765 (13q13), RB1.20(13q14.2), D13S133 (13q14.3) and D13S318 (13q21) on chromosome 13 by PCR. Results: There weren't any LOH on chromosome 13q in 3 cases with preinvasive LSCC. Forty-five percentage (24/53) of the 53 invasive LSCC cases showed LOH at one or more loci on chromosome 13q region. The highest percentage of LOH on chromosome 13q was 52% (22/53) at D13S765locus. Conclusion: The deletion region on chromosome 13q was located near by D13S765 locus which is centromeric to RB1. In this region there is suppressor gene, which is related to the genesis and development of LSCC, possibly including RB1. The inactivation of these suppressor genes may be related to the genesis and development of invasive LSCC.

  15. Restriction enzyme buffers and 5-azacytidine induce loss of protein and banding in plant metaphase chromosomes

    Energy Technology Data Exchange (ETDEWEB)

    Olszewska, M.J.; Gernand, D.; Luchniak, P.; Sakowicz, T. [Lodz Univ. (Poland)

    1995-12-31

    The incubation of root meristem of `Vicia faba` L. with 5-azacytidine for 72 h (5 cell cycles) resulted in shorter DNA fragments after digestion with a restriction enzyme Sau3A. under the same condition `in situ` digestion of metaphase chromosomes with Sau3A revealed a stronger banding (C-banding-like) pattern in 5-azacytidine-treated chromosomes than in the control. This difference could hardly be attributed to the euchromatin demethylation as 5-azacytidine caused a loss of chromosomal proteins; similar effect was found as a result of incubation with some restriction endonuclease buffers which did not diminish the labelling with {sup 3}H-thymidine. After 5-azacytidine administration the entrance of cells into mitosis was delayed, the metaphase chromosomes were under condensed and the pattern of DNA replication remained unchanged. (author). 27 refs, 4 figs, 2 tabs.

  16. Restriction enzyme buffers and 5-azacytidine induce loss of protein and banding in plant metaphase chromosomes

    International Nuclear Information System (INIS)

    The incubation of root meristem of 'Vicia faba' L. with 5-azacytidine for 72 h (5 cell cycles) resulted in shorter DNA fragments after digestion with a restriction enzyme Sau3A. under the same condition 'in situ' digestion of metaphase chromosomes with Sau3A revealed a stronger banding (C-banding-like) pattern in 5-azacytidine-treated chromosomes than in the control. This difference could hardly be attributed to the euchromatin demethylation as 5-azacytidine caused a loss of chromosomal proteins; similar effect was found as a result of incubation with some restriction endonuclease buffers which did not diminish the labelling with 3H-thymidine. After 5-azacytidine administration the entrance of cells into mitosis was delayed, the metaphase chromosomes were under condensed and the pattern of DNA replication remained unchanged. (author). 27 refs, 4 figs, 2 tabs

  17. Duplication and loss of chromosome 21 in two children with Down Syndrome and acute leukemia

    Energy Technology Data Exchange (ETDEWEB)

    Rogan, P.K.; Close, P.; Seip, J.R. [Pennsylvania State Univ. College of Medicine, Hershey, PA (United States)] [and others

    1994-09-01

    Acute leukemia in patients with Trisomy 21 (Down Syndrome; DS) may often result in additional karyotypic changes in the number or structure of chromosome 21. We present two DS patients whose immunoblast karyotypes were associated with changes in chromosome 21 ploidy. Patient L.E. developed acute lymphocytic leukemia concomitant with the loss of a single copy of chromosome 21. Trisomy 21 in this individual was due to maternal meiosis I nondisjunction. A recombination event resulted in reduction of maternal alleles to homozygosity distal to D21S167. Loss of the paternal chromosomes in the leukemia clone produced uniparental maternal disomy with isodisomy over a 25cM interval. This could, in theory, permit the unopposed expression of one or more homozygous recessive maternal tumor-associated genes, thus providing an explanation for leukemogenesis in this patient. Patient E.H. was diagnosed with acute monoblastic leukemia and consistently displayed tetrasomy 21 in the blast cell population. The DS karyotype probably arose from a mitotic error in which the paternal chromosome was duplicated. DNA polymorphism analysis indicated that the additional chromosome in the leukemia clone was of maternal origin. The presence of equal numbers of maternal and paternal chromosomes in the tetraploid blast clone would not appear to be consistent with the expression of a mutant tumor suppressor gene in this patient. Although tetrasomy 21 could be a non-specific karyotypic abnormality unrelated to leukemogenesis, it is possible that monoblastic leukemia may be a consequence of increased expression of one or more genes on this chromosome.

  18. Cytogenetic and genetic studies of radiation-induced chromosome damage in mouse oocytes. Part 2. Induced chromosome loss and dominant visible mutations

    International Nuclear Information System (INIS)

    The rates of X-ray induced loss of chromosome 19 in mouse oocytes were investigated in 2 experiments using a genetic complementation test. After 1 Gy of acute X-rays to immediately preovulatory stage oocytes, chromosome 19 loss was estimated to have occurred in 1.68% of cells. In comparison, after 4 Gy of acute X-rays to dictyate stage oocytes, the rate was estimated at 1.18%. The slightly higher rate of chromosome loss in the former cell stage after a smaller dose of radiation reflects the known increased radiosensitivity of mouse oocytes in the period shortly before ovulation. Comparison of the observations here for chromosome 19 with published data for chromosome 1 suggests that chromosome length is one of the principal factors in determining the initial rate of induced loss in mouse oocytes. Ten dominant visible mutations were recovered among 1674 offspring following irradiation of preovulatory oocytes, and 8 in 2025 offspring after treatment of dictyate cells. Nine dominant mutations were karyotyped, 5 of these were found to be associated with a visible chromosome rearrangement. The data obtained in the present study show that radiation-induced chromosome anomalies in female germ cells are not all filtered out by prenatal embryonic death but that a proportion has the potential to contribute to the genetic burden of the next generation

  19. The gene-reduction effect of chromosomal losses detected in gastric cancers

    Directory of Open Access Journals (Sweden)

    Choi Sang-Wook

    2010-11-01

    Full Text Available Abstract Background The level of loss of heterozygosity (LOH that reduces a gene dose and exerts a cell-adverse effect is known to be a parameter for the genetic staging of gastric cancers. This study investigated if the cell-adverse effect induced with the gene reduction was a rate-limiting factor for the LOH events in two distinct histologic types of gastric cancers, the diffuse- and intestinal-types. Methods The pathologic specimens obtained from 145 gastric cancer patients were examined for the level of LOH using 40 microsatellite markers on eight cancer-associated chromosomes (3p, 4p, 5q, 8p, 9p, 13q, 17p and 18q. Results Most of the cancer-associated chromosomes were found to belong to the gene-poor chromosomes and to contain a few stomach-specific genes that were highly expressed. A baseline-level LOH involving one or no chromosome was frequent in diffuse-type gastric cancers. The chromosome 17 containing a relatively high density of genes was commonly lost in intestinal-type cancers but not in diffuse-type cancers. A high-level LOH involving four or more chromosomes tended to be frequent in the gastric cancers with intestinal and mixed differentiation. Disease relapse was common for gastric cancers with high-level LOH through both the hematogenous (38% and non-hematogenous (36% routes, and for the baseline-level LOH cases through the non-hematogenous route (67%. Conclusions The cell-adverse effect of gene reduction is more tolerated in intestinal-type gastric cancers than in diffuse-type cancers, and the loss of high-dose genes is associated with hematogenous metastasis.

  20. Specific loss of chromosomes 1, 2, 6, 10, 13, 17, and 21 in chromophobe renal cell carcinomas revealed by comparative genomic hybridization.

    OpenAIRE

    Speicher, M. R.; Schoell, B; du Manoir, S.; Schröck, E; Ried, T; Cremer, T.; Störkel, S.; Kovacs, A.; Kovacs, G

    1994-01-01

    We analyzed 19 chromophobe renal cell carcinomas by means of comparative genomic hybridization. Two tumors revealed no numerical abnormalities. In the remaining 17 cases we found loss of entire chromosomes with underrepresentation of chromosome 1 occurring in all 17 cases; loss of chromosomes 2, 10, and 13 in 16 cases; loss of chromosomes 6 and 21 in 15 tumors; and loss of chromosome 17 in 13 cases. The loss of the Y chromosome was observed in 6 of 13 tumors from male patients, whereas 1 X ch...

  1. Specific loss of chromosomes 1, 2, 6, 10, 13, 17, and 21 in chromophobe renal cell carcinomas revealed by comparative genomic hybridization

    OpenAIRE

    Speicher, Michael R.; Schoell, B; Manoir, Stanislas du; Schröck, Evelin; Ried, Thomas; Cremer, Thomas; Störkel, S.; Kovacs, Gyula

    1994-01-01

    We analyzed 19 chromophobe renal cell carcinomas by means of comparative genomic hybridization. Two tumors revealed no numerical abnormalities. In the remaining 17 cases we found loss of entire chromosomes with underrepresentation of chromosome 1 occurring in all 17 cases; loss of chromosomes 2, 10, and 13 in 16 cases; loss of chromosomes 6 and 21 in 15 tumors; and loss of chromosome 17 in 13 cases. The loss of the Y chromosome was observed in 6 of 13 tumors from male patients, whereas 1 X ch...

  2. Contribution of chromosomal abnormalities and genes of the major histocompatibility complex to early pregnancy losses

    OpenAIRE

    Tkach I. R.; Sosnina K. O.; Huleyuk N. L.; Terpylyak O. I.; Zastavna D. V.; Weise A.; Kosyakova N.; Liehr T.

    2015-01-01

    Aim. The determination of chromosomal abnormalities in samples from early pregnancy losses and allelic polymorphism of HLA–DRB1 and DQA1 genes in couples with recurrent miscarriage. Methods. Banding cytogenetic and interphase mFISH analysis, DNA extraction by salting method, PCR, agarose gel electrophoresis. Results. Cytogenetic and molecular-cytogenetic investigations of SA material identified karyotype anomalies in 32.4 % of cases with prevalence of autosomal trisomy – 42.65 %, triploidy – ...

  3. Specific loss of chromosomes 1, 2, 6, 10, 13, 17, and 21 in chromophobe renal cell carcinomas revealed by comparative genomic hybridization.

    Science.gov (United States)

    Speicher, M R; Schoell, B; du Manoir, S; Schröck, E; Ried, T; Cremer, T; Störkel, S; Kovacs, A; Kovacs, G

    1994-08-01

    We analyzed 19 chromophobe renal cell carcinomas by means of comparative genomic hybridization. Two tumors revealed no numerical abnormalities. In the remaining 17 cases we found loss of entire chromosomes with underrepresentation of chromosome 1 occurring in all 17 cases; loss of chromosomes 2, 10, and 13 in 16 cases; loss of chromosomes 6 and 21 in 15 tumors; and loss of chromosome 17 in 13 cases. The loss of the Y chromosome was observed in 6 of 13 tumors from male patients, whereas 1 X chromosome was lost in 3 of 4 tumors obtained from females. Comparative genomic hybridization results were verified by interphase cytogenetics. We conclude that a specific combination of multiple chromosomal losses characterizes chromophobe renal cell carcinomas and may help to differentiate them unequivocally from other types of kidney cancer. PMID:7519827

  4. Specific loss of chromosomes 1, 2, 6, 10, 13, 17, and 21 in chromophobe renal cell carcinomas revealed by comparative genomic hybridization.

    Science.gov (United States)

    Speicher, M. R.; Schoell, B.; du Manoir, S.; Schröck, E.; Ried, T.; Cremer, T.; Störkel, S.; Kovacs, A.; Kovacs, G.

    1994-01-01

    We analyzed 19 chromophobe renal cell carcinomas by means of comparative genomic hybridization. Two tumors revealed no numerical abnormalities. In the remaining 17 cases we found loss of entire chromosomes with underrepresentation of chromosome 1 occurring in all 17 cases; loss of chromosomes 2, 10, and 13 in 16 cases; loss of chromosomes 6 and 21 in 15 tumors; and loss of chromosome 17 in 13 cases. The loss of the Y chromosome was observed in 6 of 13 tumors from male patients, whereas 1 X chromosome was lost in 3 of 4 tumors obtained from females. Comparative genomic hybridization results were verified by interphase cytogenetics. We conclude that a specific combination of multiple chromosomal losses characterizes chromophobe renal cell carcinomas and may help to differentiate them unequivocally from other types of kidney cancer. Images Figure 1 Figure 2 PMID:7519827

  5. LOSS OF HETEROZYGOSITY ON CHROMOSOME 17p13.3 IN OVARIAN CANCER AND CERVICAL CANCER

    Institute of Scientific and Technical Information of China (English)

    Zhang Guoling; Yang Huijian; Xu Kaili; Zhou Jin; Qin Ruidi; Lu Minghua

    1998-01-01

    Objective:To identify the loss of heterozygosity (LOH) on chromosome 17p13.3 in ovarian cancer and cervical cancer. Methods: The frequency of LOH on chromosome 17p13.3 in DNA samples from 24 ovarian cancers, 9 cervical cancers, and 13 non-malignant gynecological diseases were determined respectively, using Southern blot method with probe PYNZ.22. Results:LOH on 17p13.3 was found in 12 of 24 (50.0%) ovarian cancers (including a borderline mucinous cystadenoma), 4of 9 (44.4%) cervical carcinomas, and 1 of 13 (7.7%) nonmalignant gynecological diseases, which was cervical intraepithelial neoplasm HI (CIN Ⅲ) (P<0.01).Conclusion: These results show that LOH on 17p13.3 is associated with ovarian cancer and cervical cancer,suggesting that detection of LOH on 17p13.3 may be helpful to understand the molecular pathogenesis of ovarian cancer and cervical cancer.

  6. Clinical significance of chromosome 1p/19q loss of heterozygosity and Sox17 expression in oligodendrogliomas

    OpenAIRE

    Li, Junzhi; Miao, Na; Liu, Ming; Cui, Wenli; Liu, Xia; Li, Xinxia; Xiaoli SHI; Qing, Song; Ma, Yuqing; Zhang, Wei; Biekemituofu, Hadeti

    2014-01-01

    Objective: To study chromosome 1p/19q loss of heterozygosity (LOH) and Sox17 protein expression in oligodendrogliomas and correlate this loss with clinicopathological features. Methods: This study included 100 cases of oligodendrogliomas at the First Affiliated Hospital of Xinjiang Medical University from 2003 to 2014. The cases included paraffin-embedded tissues from 50 low-grade oligodendrogliomas and 50 anaplastic oligodendrogliomas. Chromosome 1p/19q LOH was detected by fluorescence in si...

  7. Contribution of chromosomal abnormalities and genes of the major histocompatibility complex to early pregnancy losses

    Directory of Open Access Journals (Sweden)

    Tkach I. R.

    2015-02-01

    Full Text Available Aim. The determination of chromosomal abnormalities in samples from early pregnancy losses and allelic polymorphism of HLA–DRB1 and DQA1 genes in couples with recurrent miscarriage. Methods. Banding cytogenetic and interphase mFISH analysis, DNA extraction by salting method, PCR, agarose gel electrophoresis. Results. Cytogenetic and molecular-cytogenetic investigations of SA material identified karyotype anomalies in 32.4 % of cases with prevalence of autosomal trisomy – 42.65 %, triploidy – 30.38 % and monosomy X – 19.11 %. Complex analysis of frequency and distribution of allelic variants of genes HLA-DRB1 and HLA-DQA1 allowed establishing the alleles DRB1*0301, DRB1*1101-1104 and DQA1*0501 to be aggressor alleles in women with recurrent pregnancy loss (RPL. The cumulative homology of allelic polymorphism of more than 50 % of HLA-DRB1 and HLA-DQA1 loci between partners increases the risk of RPL by almost four times. Conclusion. The detected chromosome aneuploidies in the samples from products of conception and the changes in the major histocompatibility complex genes can cause the failure of a couples reproductive function and can lead to an early fetal loss.

  8. Chromosome 22q a frequent site of allele loss in head and neck carcinoma

    DEFF Research Database (Denmark)

    Poli-Frederico, R C; Bergamo, N A; Reis, P P;

    2000-01-01

    to evaluate the presence of LOH on chromosome 22q11.2-13 and determine whether there was a relationship between loss in this genomic region and tumor histologic parameters, anatomic site, and survival in patients with squamous cell carcinoma of the head and neck (HNSCC). METHODS: Fifty matched blood...... tumor suppressor gene (TSG) and involved in upper aerodigestive tract carcinogenesis. In particular, laryngeal tumors may harbor another putative TSG on 22q11.2-q12.3 that may play a role in aggressive stage III/IV disease....

  9. Cancer of the ampulla of Vater: chromosome 17p allelic loss is associated with poor prognosis

    OpenAIRE

    Scarpa, A.; Di, P; Talamini, G; Falconi, M; Lemoine, N; Iacono, C.; Achille, A.; Baron, A; Zamboni, G

    2000-01-01

    BACKGROUND—Cancer of the ampulla of Vater kills 60% of affected patients. Local spread of the tumour (T stage) is the only reliable prognostic factor. Nevertheless, any cancer stage includes long term survivors and patients dying from the disease. The molecular anomalies involved in this process have the potential to serve as additional prognostic markers.
AIM—To evaluate if allelic losses (LOH) of chromosomes 17p and 18q may be of prognostic value in multivariate survival analysis.
METHODS—W...

  10. LOSS OF HETEROZYGOSITY FOR MARKERS ON 22CHROMOSOME IN SPORADIC SCHWANNOMA

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Objective To analyze the loss of heterozygosity ( LOH) for markers on chromosome 22 ( CHR 22 ) and its significance with their clinical behaviors. Methods The frequency of CHR22 LOH in 36 schwannomas was observed by dena tured polyacrylamide gels and silver staining, and the proliferative index of schwannoma was calculated by Ki-67 and PCNA im munohistochemistry. Results 15 schwannomas (41.6%) showed allele loss. The proliferative index of schwannomas with LOH were significantly higher than those without LOH (P<0.05). In acoustic neuromas, patients with LOH were younger at the age of diagnosis, larger size of tumor, shorter history and higher growth rate than those without LOH, but with no signifi cance. Conclusion CHR22 LOH was the frequent event in the tumorigenesis of sporadic schwannoma. There were some links between CHR22 LOH and clinical behavior.

  11. Loss of heterozigosity in the short arm of human chromosome 3 in sporadic lung cancer

    Directory of Open Access Journals (Sweden)

    Lina Marcela Barrera

    2010-12-01

    Full Text Available Introduction: Loss of Heterozygocity (LOH in the short arm of human chromosome 3 (3p is a frequent event in different types of sporadic tumors, including lung cancer (LC.Aim: To determine 3p LOH in LC samples using 17 microsatellite markers.Methodology: In a pilot study on volunteers, thirteen LC biopsies (tumor tissue and 4 ml of blood (normal tissue from the same patient were collected. DNA extraction and Polymerase Chain Reaction (PCR were performed with 17 microsatellite markers to analyze LOH. Amplified fragments were run on 6% denaturalizing polyacrilamide gels and were visualized by using silver stain. Descriptive analysis was performed for each region on the 3p chromosome.Results: All tumors were informative for one or more of the analyzed markers. LOH was found in one or more loci in eleven samples (84.6%. The markers with major LOH were UBE1L (23.1%, D3S1317, D3S1300, D3S1284, D3S1274, D3S3049, and D3S1577 (15.4%. Three samples showed microsatellite instability (changes in the length of the microsatellite in different loci. The percentages of LOH for the regions of 3p were: 17.6 % for 3p24-25, 11.62% for 3p21-22, 20% for 3p13-14, and 18.42% for the 3p12 region.Conclusions: Chromosomal regions with allelic loss were identified where probably other GSTs involved in the development of the LC are localized. It should increases sample size and marker number in order to narrow a minimal region and to identify a unknown gene involved in LC.

  12. Effects of arsenic upon the no-disyuntion and X chromosome loss mechanisms in Drosophila melanogaster

    International Nuclear Information System (INIS)

    In the present investigation we make the analysis of the effect of the sodium arsenite chemistry in concentration 0.2 m M over the events of no-disyuntion and chromosome loss X in germinal cells of Drosophila melanogaster. The Drosophila lineages used for this assay were: females (y2 wa / y2 wa ; e/e) and males (XC2 yf bb- / Bs Y y+). Those lineages were propagated and isolated for to be used after in the assays. Subsequently these, we make some links types with these individuals with the object to observed the effects of the oral administration of sodium arsenite in the adult individuals, in each one, we induce a damage in the sperm of the male with gamma radiation (25 Gy) and was observed immediately the results of the different assay applied in the first generation (F1). Finally, we analyze and compare the results in contrast with and other investigation we find that the chemistry cause a significant increment in the chromosome loss X either the No-disyuntion was not significative. Also, the arsenite sodium increment the male descendant productivity, so, we deduced that the sodium arsenite do not cause an inhibition of the reparation mechanisms present in the Drosophila melanogaster female ovocites, but the chemistry operated like a modulator of this mechanisms, and prevent an increment of the damage provoked for the gamma radiation over the Drosophila melanogaster male sperm. (Author)

  13. Deregulated sex chromosome gene expression with male germ cell-specific loss of Dicer1.

    Directory of Open Access Journals (Sweden)

    Anne R Greenlee

    Full Text Available MicroRNAs (miRNAs are a class of endogenous, non-coding RNAs that mediate post-transcriptional gene silencing by inhibiting mRNA translation and promoting mRNA decay. DICER1, an RNase III endonuclease encoded by Dicer1, is required for processing short 21-22 nucleotide miRNAs from longer double-stranded RNA precursors. Here, we investigate the loss of Dicer1 in mouse postnatal male germ cells to determine how disruptions in the miRNA biogenesis pathway may contribute to infertility. Reduced levels of Dicer1 transcripts and DICER1 were confirmed in germ cell knock-out (GCKO testes by postnatal day 18 (P18. Compared to wild-type (WT at 8 weeks, GCKO males had no change in body weight; yet showed significant reductions in testis mass and sperm number. Histology and fertility tests confirmed spermatogenic failure in GCKO males. Array analyses at P18 showed that in comparison to WT testes, 75% of miRNA genes and 37% of protein coding genes were differentially expressed in GCKO testes. Among these, 96% of miRNA genes were significantly down-regulated, while 4% miRNA genes were overexpressed. Interestingly, we observed preferential overexpression of genes encoded on the sex chromosomes in GCKO testes, including more than 80% of previously identified targets of meiotic sex chromosome inactivation (MSCI. Compared to WT, GCKO mice showed higher percentages of germ cells at early meiotic stages (leptotene and zygotene but lower percentages at later stages (pachytene, diplotene and metaphase I providing evidence that deletion of Dicer1 leads to disruptions in meiotic progression. Therefore, deleting Dicer1 in early postnatal germ cells resulted in deregulation of transcripts encoded by genes on the sex chromosomes, impaired meiotic progression and led to spermatogenic failure and infertility.

  14. Effect of the Major Repeat Sequence on Chromosome Loss in Candida albicans

    OpenAIRE

    Lephart, Paul R.; Chibana, Hiroji; Magee, Paul T.

    2005-01-01

    The major repeat sequence (MRS) is found at least once on all but one chromosome in Candida albicans, but as yet it has no known relation to the phenotype. The MRS affects karyotypic variation by serving as a hot spot for chromosome translocation and by expanding and contracting internal repeats, thereby changing chromosome length. Thus, MRSs on different chromosomes and those on chromosome homologues can differ in size. We proposed that the MRS's unique repeat structure and, more specificall...

  15. Mechanisms involved in the induction of aneuploidy: the significance of chromosome loss

    Directory of Open Access Journals (Sweden)

    A.I. Seoane

    2000-12-01

    Full Text Available The induction of aneuploidy by physical and chemical agents using different test systems was evaluated. The effect of X-rays, caffeine, acetaldehyde, ethanol, diethylstilbestrol, propionaldehyde, and chloral hydrate was studied by chromosome counting in Chinese hamster embryonic diploid cells. Aneugenic ability of cadmium chloride, cadmium sulfate, potassium dichromate, chromium chloride, nickel chloride, and nickel sulfate was assessed by means of anaphase-telophase analysis in Chinese hamster ovary cells. Chromosome counting in human fibroblasts (MRC-5 cell line was employed to evaluate the effect of cacodilic acid, cadmium chloride, cadmium sulfate, and potassium dichromate. Finally, the induction of kinetochore-positive and kinetochore negative micronuclei by cadmium chloride, cadmium sulfate, potassium dichromate, chromium chloride, and nickel chloride was studied using CREST antibodies. When the effect of different agents was determined by chromosome counting, an increase of hypoploid but not of hyperploid cells was observed. Anaphase-telophase analysis showed that metal salts increased the frequency of lagging chromosomes. This finding has been confirmed by the increment of kinetochore-positive micronuclei using CREST antibodies. Therefore, chromosome loss could be considered as the main cause of induced aneuploidy.A indução de aneuploidia por agentes físicos e químicos usando diferentes sistemas de teste foi avaliada. O efeito de raios-X, cafeína, acetaldeído, etanol, dietilestilbestrol, propionaldeído e hidrato de cloral foi estudado por contagem cromossômica em células diplóides embriônicas de hamster chinês. A habilidade aneugênica de cloreto de cádmio, sulfato de cádmio, dicromato de potássio, cloreto de crômio, cloreto de níquel e sulfato de níquel foi avaliada por meio de análise de anáfase-telófase em células de ovário de hamster chinês. A contagem cromossômica em fibroblastos humanos (linhagem celular

  16. Chromosomal mutations and chromosome loss measured in a new human-hamster hybrid cell line, ALC: studies with colcemid, ultraviolet irradiation, and 137Cs gamma-rays

    Science.gov (United States)

    Kraemer, S. M.; Waldren, C. A.; Chatterjee, A. (Principal Investigator)

    1997-01-01

    Small mutations, megabase deletions, and aneuploidy are involved in carcinogenesis and genetic defects, so it is important to be able to quantify these mutations and understand mechanisms of their creation. We have previously quantified a spectrum of mutations, including megabase deletions, in human chromosome 11, the sole human chromosome in a hamster-human hybrid cell line AL. S1- mutants have lost expression of a human cell surface antigen, S1, which is encoded by the M1C1 gene at 11p13 so that mutants can be detected via a complement-mediated cytotoxicity assay in which S1+ cells are killed and S1- cells survive. But loss of genes located on the tip of the short arm of 11 (11p15.5) is lethal to the AL hybrid, so that mutants that have lost the entire chromosome 11 die and escape detection. To circumvent this, we fused AL with Chinese hamster ovary (CHO) cells to produce a new hybrid, ALC, in which the requirement for maintaining 11p15.5 is relieved, allowing us to detect mutations events involving loss of 11p15.5. We evaluated the usefulness of this hybrid by conducting mutagenesis studies with colcemid, 137Cs gamma-radiation and UV 254 nm light. Colcemid induced 1000 more S1- mutants per unit dose in ALC than in AL; the increase for UV 254 nm light was only two-fold; and the increase for 137Cs gamma-rays was 12-fold. The increase in S1- mutant fraction in ALC cells treated with colcemid and 137Cs gamma-rays were largely due to chromosome loss and 11p deletions often containing a breakpoint within the centromeric region.

  17. Loss of heterozygosity on chromosome 10q23 and mutation of the phosphatase and tensin homolog deleted from chromosome 10 tumor suppressor gene in Korean hepatocellular carcinoma patients.

    Science.gov (United States)

    Bae, Jei-Jun; Rho, Jin-Woo; Lee, Tae-Jin; Yun, Sung-Su; Kim, Hong-Jin; Choi, Joon-Hyuk; Jeong, Daewon; Jang, Byeong-Churl; Lee, Tae-Yoon

    2007-10-01

    Loss of heterozygosity (LOH) in the 10q23 chromosomal region was analyzed in 18 tissue samples from Korean hepatocellular carcinoma (HCC) patients. LOH at the phosphatase and tensin homolog deleted from chromosome 10 (PTEN) region (D10S215, AFMa086wg9 and D10S541) was found in 8 of the 18 (44.4%) HCCs. LOH (20%) and microsatellite instability (26.7%) were also frequently found at the D10S2177 locus, which is located on the telomere side of the PTEN region. LOH was found in other loci, such as AFM280we1 and D10S2281. The presence of LOH in regions other than the PTEN region on chromosome 10q23 suggested the presence of additional tumor suppressor gene(s). PTEN mutation was found in only a subset of HCCs: A single base insertion at the end of the 5'-end splice signal (AG-GUAAGUU) in intron 5 and a silent mutation in exon 6 (codon 188, CTG-Val to CTA). Our data collectively suggest that the genetic alterations of chromosome 10q23, including the PTEN gene, could be important in hepatocarcinogenesis in the Korean population. PMID:17786367

  18. Mosaic Loss of Chromosome Y in Blood Is Associated with Alzheimer Disease.

    Science.gov (United States)

    Dumanski, Jan P; Lambert, Jean-Charles; Rasi, Chiara; Giedraitis, Vilmantas; Davies, Hanna; Grenier-Boley, Benjamin; Lindgren, Cecilia M; Campion, Dominique; Dufouil, Carole; Pasquier, Florence; Amouyel, Philippe; Lannfelt, Lars; Ingelsson, Martin; Kilander, Lena; Lind, Lars; Forsberg, Lars A

    2016-06-01

    Men have a shorter life expectancy compared with women but the underlying factor(s) are not clear. Late-onset, sporadic Alzheimer disease (AD) is a common and lethal neurodegenerative disorder and many germline inherited variants have been found to influence the risk of developing AD. Our previous results show that a fundamentally different genetic variant, i.e., lifetime-acquired loss of chromosome Y (LOY) in blood cells, is associated with all-cause mortality and an increased risk of non-hematological tumors and that LOY could be induced by tobacco smoking. We tested here a hypothesis that men with LOY are more susceptible to AD and show that LOY is associated with AD in three independent studies of different types. In a case-control study, males with AD diagnosis had higher degree of LOY mosaicism (adjusted odds ratio = 2.80, p = 0.0184, AD events = 606). Furthermore, in two prospective studies, men with LOY at blood sampling had greater risk for incident AD diagnosis during follow-up time (hazard ratio [HR] = 6.80, 95% confidence interval [95% CI] = 2.16-21.43, AD events = 140, p = 0.0011). Thus, LOY in blood is associated with risks of both AD and cancer, suggesting a role of LOY in blood cells on disease processes in other tissues, possibly via defective immunosurveillance. As a male-specific risk factor, LOY might explain why males on average live shorter lives than females. PMID:27231129

  19. A mutation in the centriole-associated protein centrin causes genomic instability via increased chromosome loss in Chlamydomonas reinhardtii

    Directory of Open Access Journals (Sweden)

    Marshall Wallace F

    2005-05-01

    Full Text Available Abstract Background The role of centrioles in mitotic spindle function remains unclear. One approach to investigate mitotic centriole function is to ask whether mutation of centriole-associated proteins can cause genomic instability. Results We addressed the role of the centriole-associated EF-hand protein centrin in genomic stability using a Chlamydomonas reinhardtii centrin mutant that forms acentriolar bipolar spindles and lacks the centrin-based rhizoplast structures that join centrioles to the nucleus. Using a genetic assay for loss of heterozygosity, we found that this centrin mutant showed increased genomic instability compared to wild-type cells, and we determined that the increase in genomic instability was due to a 100-fold increase in chromosome loss rates compared to wild type. Live cell imaging reveals an increased rate in cell death during G1 in haploid cells that is consistent with an elevated rate of chromosome loss, and analysis of cell death versus centriole copy number argues against a role for multipolar spindles in this process. Conclusion The increased chromosome loss rates observed in a centrin mutant that forms acentriolar spindles suggests a role for centrin protein, and possibly centrioles, in mitotic fidelity.

  20. HHV-8-unrelated primary effusion-like lymphoma associated with clonal loss of inherited chromosomally-integrated human herpesvirus-6A from the telomere of chromosome 19q.

    Science.gov (United States)

    Zhang, Enjie; Cotton, Victoria E; Hidalgo-Bravo, Alberto; Huang, Yan; Bell, Adam J; Jarrett, Ruth F; Wilkie, Gavin S; Davison, Andrew J; Nacheva, Ellie P; Siebert, Reiner; Majid, Aneela; Kelpanides, Inga; Jayne, Sandrine; Dyer, Martin J; Royle, Nicola J

    2016-01-01

    Primary effusion lymphomas (PEL) are associated with human herpesvirus-8 (HHV-8) and usually occur in immunocompromised individuals. However, there are numerous reports of HHV-8-unrelated PEL-like lymphomas with unknown aetiology. Here we characterize an HHV-8-unrelated PEL-like lymphoma in an elderly woman who was negative for human immunodeficiency viruses 1 and 2, and hepatitis B and C. The woman was, however, a carrier of an inherited-chromosomally-integrated human herpesvirus-6A (iciHHV-6A) genome in one 19q telomere. The iciHHV-6A genome was complete in blood DNA, encoding a full set of protein-coding genes. Interestingly, the entire iciHHV-6A genome was absent from the HHV-8-unrelated-PEL-like lymphoma cells despite retention of both copies of chromosome 19. The somatic loss of the 19q-iciHHV-6A genome occurred very early during lymphoma development and we propose it occurred via telomere-loop formation and excision to release a circular viral genome that was subsequently lost. Whether release of the HHV-6A genome from the telomere contributed to lymphomagenesis, or was coincidental, remains unclear but this event may have deregulated the expression of HHV-6A or 19q genes or else disrupted telomere function. To establish the frequency and importance of iciHHV-6 loss from telomeres, the HHV-6 copy number should be assessed in tumours that arise in iciHHV-6 carriers. PMID:26947392

  1. Loss of chromosome 1p/19q in oligodendroglial tumors: refinement of chromosomal critical regions and evaluation of internexin immunostaining as a surrogate marker.

    LENUS (Irish Health Repository)

    Buckley, Patrick G

    2011-03-01

    Loss of chromosome 1p\\/19q in oligodendrogliomas represents a powerful predictor of good prognosis. Expression of internexin (INA), a neuronal specific intermediate filament protein, has recently been proposed as a surrogate marker for 1p\\/19q deletion based on the high degree of correlation between both parameters in oligodendrogliomas. The aim of this study was to assess further the diagnostic utility of INA expression in a set of genetically well-characterized oligodendrogliomas. On the basis of a conservative approach for copy number determination, using both comparative genomic hybridization and fluorescent in situ hybridization, INA expression as a surrogate marker for 1p\\/19q loss had both reduced specificity (80%) and sensitivity (79%) compared with respective values of 86% and 96% reported in the previous report. The histologic interpretation and diagnostic value of INA expression in oligodendrogliomas should therefore be assessed with greater caution when compared with 1p\\/19q DNA copy number analysis. In addition, DNA copy number aberrations of chromosomes 10, 16, and 17 were detected exclusively in 1p\\/19q codeleted samples, suggesting that other regions of the genome may contribute to the 1p\\/19q-deleted tumor phenotype inthese samples.

  2. Loss-of-heterozygosity on chromosome 19q in early-stage serous ovarian cancer is associated with recurrent disease

    International Nuclear Information System (INIS)

    Ovarian cancer is a heterogeneous disease and prognosis for apparently similar cases of ovarian cancer varies. Recurrence of the disease in early stage (FIGO-stages I-II) serous ovarian cancer results in survival that is comparable to those with recurrent advanced-stage disease. The aim of this study was to investigate if there are specific genomic aberrations that may explain recurrence and clinical outcome. Fifty-one women with early stage serous ovarian cancer were included in the study. DNA was extracted from formalin fixed samples containing tumor cells from ovarian tumors. Tumor samples from thirty-seven patients were analysed for allele-specific copy numbers using OncoScan single nucleotide polymorphism arrays from Affymetrix and the bioinformatic tool Tumor Aberration Prediction Suite. Genomic gains, losses, and loss-of-heterozygosity that associated with recurrent disease were identified. The most significant differences (p < 0.01) in Loss-of-heterozygosity (LOH) were identified in two relatively small regions of chromosome 19; 8.0-8,8 Mbp (19 genes) and 51.5-53.0 Mbp (37 genes). Thus, 56 genes on chromosome 19 were potential candidate genes associated with clinical outcome. LOH at 19q (51-56 Mbp) was associated with shorter disease-free survival and was an independent prognostic factor for survival in a multivariate Cox regression analysis. In particular LOH on chromosome 19q (51-56 Mbp) was significantly (p < 0.01) associated with loss of TP53 function. The results of our study indicate that presence of two aberrations in TP53 on 17p and LOH on 19q in early stage serous ovarian cancer is associated with recurrent disease. Further studies related to the findings of chromosomes 17 and 19 are needed to elucidate the molecular mechanism behind the recurring genomic aberrations and the poor clinical outcome

  3. Functional loss of E-cadherin and cadherin-11 alleles on chromosome 16q22 in colonic cancer.

    Science.gov (United States)

    Braungart, E; Schumacher, C; Hartmann, E; Nekarda, H; Becker, K F; Höfler, H; Atkinson, M J

    1999-04-01

    Proteins of the cadherin family regulate cellular adhesion and motility and are believed to act as tumour suppressors. Previous studies have identified frequent mutation and allelic inactivation of the E-cadherin (cadherin-1) locus in diffuse gastric cancer. At least two other cadherin genes, P-cadherin (cadherin-3) and OB-cadherin (cadherin-11), have been mapped close to the E-cadherin gene on chromosome 16q22. As this region of the genome is frequently deleted in malignancy, multiple cadherin loci may be affected by losses of chromosome 16q22. The expression of mRNA transcripts from polymorphic alleles of the E-cadherin and cadherin-11 genes was examined in 30 cases of colonic, gastric, and renal carcinoma. In gastric cancer, loss of expression of one allele was restricted to the E-cadherin locus, whilst in renal carcinoma neither locus was affected. In colonic cancers, loss of expression of one E-cadherin allele was detected in 5 of 22 cases, whilst loss of a cadherin-11 allele was seen in 5 of 23 cases. This functional loss of cadherin gene expression may be due to gene deletion, inactivation or recombination. As no evidence of cadherin gene mutation was observed in the remaining transcripts, we can conclude that these two genes are only indirectly involved in the pathogenesis of colorectal cancer. PMID:10398117

  4. Detection of complete and partial chromosome gains and losses by comparative genomic in situ hybridization

    OpenAIRE

    Manoir, Stanislas du; Speicher, Michael R.; Joos, Stefan; Schröck, Evelin; Popp, Susanne, 1983-; Döhner, Hartmut; Kovacs, Gyula; Robert-Nicoud, Michel; Lichter, Peter; Cremer, Thomas

    1993-01-01

    Comparative genomic in situ hybridization (CGH) provides a new possibility for searching genomes for imbalanced genetic material. Labeled genomic test DNA, prepared from clinical or tumor specimens, is mixed with differently labeled control DNA prepared from cells with normal chromosome complements. The mixed probe is used for chromosomal in situ suppression (CISS) hybridization to normal metaphase spreads (CGH-metaphase spreads). Hybridized test and control DNA sequences are detected via dif...

  5. Acquired cystic disease-associated renal cell carcinoma with gain of chromosomes 3, 7, and 16, gain of chromosome X, and loss of chromosome Y.

    Science.gov (United States)

    Kuroda, Naoto; Shiotsu, Tomoyuki; Hes, Ondrej; Michal, Michal; Shuin, Taro; Lee, Gang-Hong

    2010-12-01

    Acquired cystic disease (ACD)-associated renal cell carcinoma (RCC) has been recently described. To date, there are no reports on genetic findings of G-band karyotype of ACD-associated RCC. In this article, we report the first report of G-band karyotype of ACD-associated RCC. A 66-year-old Japanese man was found to have a left renal tumor during the follow-up of hemodialysis consequent to chronic renal failure. Left nephrectomy was performed. Histological examination of three tumors in the left kidney showed the cribriform or microcystic growth pattern of neoplastic cells with eosinophilic cytoplasm, and many oxalate crystals were observed. The G-band karyotype of ACD-associated RCC showed 49, X, +X, -Y, +3, +7, +16. These chromosomal abnormalities resemble those of sporadic papillary RCC that has been previously reported. Finally, we suggest that this tumor may show a close relationship between ACD-associated RCC and papillary RCC, but a large-scale study will be needed to clarify the relationship between ACD-associated RCC and papillary RCC. PMID:21267700

  6. Biclonal myelodysplastic syndrome involving six chromosomes and monoallelic loss of RB1 - A rare case

    Directory of Open Access Journals (Sweden)

    Klein Elisabeth

    2011-08-01

    Full Text Available Abstract Background Myelodysplastic syndrome (MDS represents a group of clonal hematological disorders characterized by progressive cytopenia, and reflects to defects in erythroid, myeloid and megakaryocytic maturation. MDS is more frequently observed in older aged patients with cytogenetic abnormalities like monosomy of chromosome(s 5 and/or 7. In 50% of de novo MDS cases, chromosomal aberrations are found and rearrangements involving the retinoblastoma (RB1 gene in 13q14 are found. Results Here, we are presenting a case report of a rare biclonal MDS with a karyotype of 45, XY,-4, der(6t(4;6(p15.1;p21.3, der(8t(4;8(q31.2;q22, t(13;16(q21.3;p11.211/45, XY, der(7t(7;13(p22.2~22.3;q21.3,-13 9. The patient was diagnosed according to WHO classification as refractory anemia with excess of blasts (RAEB-II. Immunophenotyping was positive for CD11b, CD11c, CD10, CD13, CD15, CD16 and CD33. Conclusion We report, a novel and cytogenetically rare case of a biclonal MDS with complex chromosomal aberrations and deletion of RB1-gene in both clones. These findings are associated with a poor prognosis as the patient died 3 months after diagnosis.

  7. Screening for CPG Methylation and Allele Loss on Chromosome 14q

    Science.gov (United States)

    A study to follow-up on chromosomal regions identified from a genome-wide linkage analysis of nasopharyngeal carcinoma (NPC) families in Taiwan and an independent gene expression analysis of sporadic NPC tumors collected from a case-control study

  8. Loss of chromosome 9p21 and decreased p16 expression correlate with malignant gastrointestinal stromal tumor

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    AIM: To investigate loss of heterozygosity (LOH) of chromosome 9p21 and the prognostic relevance of p16 expression in gastrointestinal stromal tumor (GIST). METHODS: Fifty-one GIST patients (30 men and 21 women; median age 59 years; range 29-80 years) treated surgically within a 10-year period were grouped by aggressive behavior risk (17 with very low and low, 14 intermediate, and 20 high risk). GISTs were characterized immunohistochemically and evaluated for LOH of 9p21 by microsatellite analysis at D9S175...

  9. Mechanisms involved in the induction of aneuploidy: the significance of chromosome loss

    OpenAIRE

    A.I. Seoane; Güerci, A.M; F.N. Dulout

    2000-01-01

    The induction of aneuploidy by physical and chemical agents using different test systems was evaluated. The effect of X-rays, caffeine, acetaldehyde, ethanol, diethylstilbestrol, propionaldehyde, and chloral hydrate was studied by chromosome counting in Chinese hamster embryonic diploid cells. Aneugenic ability of cadmium chloride, cadmium sulfate, potassium dichromate, chromium chloride, nickel chloride, and nickel sulfate was assessed by means of anaphase-telophase analysis in Chinese hamst...

  10. The Effects of X Chromosome Loss on Neuroanatomical and Cognitive Phenotypes During Adolescence: a Multi-modal Structural MRI and Diffusion Tensor Imaging Study.

    Science.gov (United States)

    Xie, Sheng; Zhang, Zhixin; Zhao, Qiuling; Zhang, Jiaying; Zhong, Suyu; Bi, Yanchao; He, Yong; Pan, Hui; Gong, Gaolang

    2015-09-01

    The absence of all or part of one X chromosome in female humans causes Turner's syndrome (TS), providing a unique "knockout model" to investigate the role of the X chromosome in neuroanatomy and cognition. Previous studies have demonstrated TS-associated brain differences; however, it remains largely unknown 1) how the brain structures are affected by the type of X chromosome loss and 2) how X chromosome loss influences the brain-cognition relationship. Here, we addressed these by investigating gray matter morphology and white matter connectivity using a multimodal MRI dataset from 34 adolescent TS patients (13 mosaic and 21 nonmosaic) and 21 controls. Intriguingly, the 2 TS groups exhibited significant differences in surface area in the right angular gyrus and in white matter integrity of the left tapetum of corpus callosum; these data support a link between these brain phenotypes and the type of X chromosome loss in TS. We further showed that the X chromosome modulates specific brain-cognition relationships: thickness and surface area in multiple cortical regions are positively correlated with working-memory performance in controls but negatively in TS. These findings provide novel insights into the X chromosome effect on neuroanatomical and cognitive phenotypes and highlight the role of genetic factors in brain-cognition relationships. PMID:24770708

  11. LOSS OF HETEROZYGOSITY FOR MARKERS ON 22 CHROMOSOME IN SPORADIC SCHWANNOMA

    Institute of Scientific and Technical Information of China (English)

    卞留贯; 沈建康; 孙青芳; 邱永明; 徐纪文; 罗其中

    2000-01-01

    ffeSUnt6 Objectif Analyser la carte d' hetdrozgritd(LOH, lass of heterozgrity) pour marqueurs sur chromosome22 (CHR22 ) et son rapest avec scs manifeStations cliniques. afl~ In frdquence de LOH CHR22 a ate obServde chez 36sehwennomes per gel an poly-acrylamide denature et coloration an sel d' argent. L' indice de Proliferation de schndnnome etaitcolculd per immunohistochimie Ki-67, PCNA. haultats 15 SChwennomes (41. 6% ) out ~id une d' alldle. L' indian de ~if betion cab ieS fornd~ awe ~ etait significoti~t...

  12. Loss of Y-chromosome does not correlate with age at onset of head and neck carcinoma: a case-control study

    Energy Technology Data Exchange (ETDEWEB)

    Silva Veiga, L.C. [Departamento de Genética, Instituto de Biociências, Universidade Estadual Paulista, Botucatu, SP (Brazil); Departamento de Clínica Médica, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Bérgamo, N.A. [Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, GO (Brazil); Reis, P.P. [Departamento de Cirurgia e Ortopedia, Faculdade de Medicina de Botucatu, Universidade Estadual Paulista, Botucatu, SP (Brazil); Kowalski, L.P. [Departamento de Cirurgia de Cabeça e Pescoço e Otorrinolaringologia, Hospital A.C. Camargo, São Paulo, SP (Brazil); Rogatto, S.R. [Laboratório NeoGene, Departamento de Urologia, Faculdade de Medicina de Botucatu, Universidade Estadual Paulista, Botucatu, SP (Brazil); Departamento de Pesquisa, Hospital A.C. Camargo,Fundação Antônio Prudente, São Paulo, SP (Brazil)

    2012-01-20

    Loss of Y-chromosome has been correlated with older age in males. Furthermore, current evidence indicates that Y-chromosome loss also occurs in several human tumors, including head and neck carcinomas. However, the association between Y nullisomy and the occurrence of neoplasias in elderly men has not been well established. In the present study, the association between Y-chromosome loss and head and neck carcinomas was evaluated by comparison to cells from peripheral blood lymphocytes and normal mucosa of cancer-free individuals matched for age using dual-color fluorescence in situ hybridization. Twenty-one patients ranging in age from 28 to 68 years were divided into five-year groups for comparison with 16 cancer-free individuals matched for age. The medical records of all patients were examined to obtain clinical and histopathological data. None of the patients had undergone radiotherapy or chemotherapy before surgery. In all groups, the frequency of Y-chromosome loss was higher among patients than among normal reference subjects (P < 0.0001) and was not age-dependent. These data suggest that Y-chromosome loss is a tumor-specific alteration not associated with advanced age in head and neck carcinomas.

  13. Loss of Y-chromosome does not correlate with age at onset of head and neck carcinoma: a case-control study

    International Nuclear Information System (INIS)

    Loss of Y-chromosome has been correlated with older age in males. Furthermore, current evidence indicates that Y-chromosome loss also occurs in several human tumors, including head and neck carcinomas. However, the association between Y nullisomy and the occurrence of neoplasias in elderly men has not been well established. In the present study, the association between Y-chromosome loss and head and neck carcinomas was evaluated by comparison to cells from peripheral blood lymphocytes and normal mucosa of cancer-free individuals matched for age using dual-color fluorescence in situ hybridization. Twenty-one patients ranging in age from 28 to 68 years were divided into five-year groups for comparison with 16 cancer-free individuals matched for age. The medical records of all patients were examined to obtain clinical and histopathological data. None of the patients had undergone radiotherapy or chemotherapy before surgery. In all groups, the frequency of Y-chromosome loss was higher among patients than among normal reference subjects (P < 0.0001) and was not age-dependent. These data suggest that Y-chromosome loss is a tumor-specific alteration not associated with advanced age in head and neck carcinomas

  14. Genotoxic profile of inhibitors of topoisomerases I (camptothecin) and II (etoposide) in a mitotic recombination and sex-chromosome loss somatic eye assay of Drosophila melanogaster.

    Science.gov (United States)

    Sortibrán, América Nitxin Castañeda; Téllez, María Guadalupe Ordaz; Rodríguez-Arnaiz, Rosario

    2006-04-30

    Genotoxic carcinogens which interact with DNA may produce double-strand breaks as normal intermediates of homologous mitotic recombination, and may give rise to structural chromosome aberrations and inter-chromosomal deletion-recombination. The genotoxic profile of two inhibitors of DNA topoisomerases were evaluated using an in vivo somatic w/w+ eye assay of Drosophila melanogaster for the detection of loss of heterozygosity (LOH) by homologous mitotic recombination, intra-chromosomal recombination and structural chromosomal aberrations. We studied camptothecin (CPT) as a topoisomerase-I-interactive agent and etoposide (ETOP) as a topoisomerase II inhibitor. These drugs act by stabilizing a ternary complex consisting of topoisomerases covalently linked to DNA at single-strand or at double-strand breaks, thereby preventing the relegation step of the breakage/rejoining reaction mediated by the enzyme. The genotoxic profiles were determined from the appearance of eye tissue in adult flies, in which LOH and expression of the reporter gene white produced light clones. The results demonstrated that both compounds were significantly genotoxic, with CPT being more effective than ETOP. Inter-chromosomal mitotic recombination was the major mechanism responsible for the induction of light spots by both compounds in XX females. Loss of the ring X chromosome (rX), was significantly enhanced by CPT, and this topoisomerase blocker also produced intra-chromosomal recombination (XY males). PMID:16529987

  15. Frequent loss of heterozygosity at 8p22 chromosomal region in diffuse type of gastric cancer

    Institute of Scientific and Technical Information of China (English)

    Hedayat Allah Hosseini; Ali Ahani; Hamid Galehdari; Ali Mohammad Froughmand; Masoud Hosseini; Abdolrahim Masjedizadeh; Mohammad Reza Zali

    2007-01-01

    AIM: To study the loss of heterozygosity (LOH) at 8p21-23 locus in diffuse gastric cancer.METHODS: To evaluate the involvement of this region in gastric cancer, we used eight microsatellite markers covering two Mb of mentioned region, to perform a high-resolution analysis of allele loss in 42 cases of late diffuse gastric adenocarcinoma.RESULTS: Six of these STS makers: D8S1149, D8S1645,D8S1643, D8S1508, D8S1591, and D8S1145 showed 36%, 28%, 37%, 41%, 44% and 53% LOH, respectively.CONCLUSION: A critical region of loss, close to the NAT2 locus and relatively far from FEZ1 gene currently postulated as tumor suppressor gene in this region.

  16. Molecular subtypes in head and neck cancer exhibit distinct patterns of chromosomal gain and loss of canonical cancer genes.

    Directory of Open Access Journals (Sweden)

    Vonn Walter

    Full Text Available Head and neck squamous cell carcinoma (HNSCC is a frequently fatal heterogeneous disease. Beyond the role of human papilloma virus (HPV, no validated molecular characterization of the disease has been established. Using an integrated genomic analysis and validation methodology we confirm four molecular classes of HNSCC (basal, mesenchymal, atypical, and classical consistent with signatures established for squamous carcinoma of the lung, including deregulation of the KEAP1/NFE2L2 oxidative stress pathway, differential utilization of the lineage markers SOX2 and TP63, and preference for the oncogenes PIK3CA and EGFR. For potential clinical use the signatures are complimentary to classification by HPV infection status as well as the putative high risk marker CCND1 copy number gain. A molecular etiology for the subtypes is suggested by statistically significant chromosomal gains and losses and differential cell of origin expression patterns. Model systems representative of each of the four subtypes are also presented.

  17. Maternal uniparental disomy for human chromosome 14, due to loss of a chromosome 14 from somatic cells with t(13; 14) trisomy 14

    Energy Technology Data Exchange (ETDEWEB)

    Antonarakis, S.E.; Blouin, J.L.; Maher, J.; Avramopoulos, D.; Thomas, G.; Talbot, C.C. Jr. (Johns Hopkins Univ., Baltimore (United States))

    1993-06-01

    Uniparental disomy (UPD) for particular chromosomes is increasingly recognized as a cause of abnormal phenotypes in humans. The authors recently studied a 9-year-old female with a de novo Robertsonian translocation t(13;14), short stature, mild developmental delay, scoliosis, hyperextensible joints, hydrocephalus that resolved spontaneously during the first year of life, and hyperchloesterolemia. To determine the parental origin of chromosomes 13 and 14 in the proband, they have studied the genotypes of DNA polymorphic markers due to (GT)n repeats in the patient and her parents' blood DNA. The genotypes of markers D14S43, D14S45, D14S49, and D14S54 indicated maternal UPD for chromosome 14. There was isodisomy for proximal markers and heterodisomy for distal markers, suggesting a recombination event on maternal chromosomes 14. In addition, DNA analysis first revealed -- and subsequent cytogenetic analysis confirmed -- that there was mosaic trisomy 14 in 5% of blood lymphocytes. There was normal (biparental) inheritance for chromosome 13, and there was no evidence of false paternity in genotypes of 11 highly polymorphic markers on human chromosome 21. Two cases of maternal UPD for chromosome 14 have previously been reported, one with a familial rob t(13;14) and the other with a t(14;14). There are several similarities among these patients, and a [open quotes]maternal UPD chromosome 14 syndrome[close quotes] is emerging; however, the contribution of the mosaic trisomy 14 to the phenotype cannot be evaluated. The study of de novo Robertsonian translocations of the type reported here should reveal both the extent of UPD in these events and the contribution of particular chromosomes involved in certain phenotypes. 33 refs., 3 figs., 1 tab.

  18. Loss-of-heterozygosity on chromosome 19q in early-stage serous ovarian cancer is associated with recurrent disease

    Directory of Open Access Journals (Sweden)

    Skirnisdottir Ingiridur

    2012-09-01

    Full Text Available Abstract Background Ovarian cancer is a heterogeneous disease and prognosis for apparently similar cases of ovarian cancer varies. Recurrence of the disease in early stage (FIGO-stages I-II serous ovarian cancer results in survival that is comparable to those with recurrent advanced-stage disease. The aim of this study was to investigate if there are specific genomic aberrations that may explain recurrence and clinical outcome. Methods Fifty-one women with early stage serous ovarian cancer were included in the study. DNA was extracted from formalin fixed samples containing tumor cells from ovarian tumors. Tumor samples from thirty-seven patients were analysed for allele-specific copy numbers using OncoScan single nucleotide polymorphism arrays from Affymetrix and the bioinformatic tool Tumor Aberration Prediction Suite. Genomic gains, losses, and loss-of-heterozygosity that associated with recurrent disease were identified. Results The most significant differences (p  Conclusions The results of our study indicate that presence of two aberrations in TP53 on 17p and LOH on 19q in early stage serous ovarian cancer is associated with recurrent disease. Further studies related to the findings of chromosomes 17 and 19 are needed to elucidate the molecular mechanism behind the recurring genomic aberrations and the poor clinical outcome.

  19. A map of nuclear matrix attachment regions within the breast cancer loss-of-heterozygosity region on human chromosome 16q22.1

    DEFF Research Database (Denmark)

    Shaposhnikov, Sergey A.; Akopov, Sergey B.; Chernov, Igor P.;

    2007-01-01

    There is abundant evidence that the DNA in eukaryotic cells is organized into loop domains that represent basic structural and functional units of chromatin packaging. To explore the DNA domain organization of the breast cancer loss-of-heterozygosity region on human chromosome 16q22.1, we have id...

  20. E-cadherin and loss of heterozygosity at chromosome 16 in breast carcinogenesis: different genetic pathways in ductal and lobular breast cancer?

    International Nuclear Information System (INIS)

    Loss of heterozygosity at the long arm of chromosome 16 is one of the most frequent genetic events in breast cancer. In the search for tumour suppressor genes that are the target of loss of heterozygosity at 16q, the E-cadherin gene CDH1 was unveiled by the identification of truncating mutations in the retained copy. However, only lobular tumours showed E-cadherin mutations. Whereas investigations are still devoted to finding the target genes in the more frequent ductal breast cancers, other studies suspect the E-cadherin gene to also be the target in this tumour type. The present article discusses the plausibility of those two lines of thought

  1. Loss of Ubr2, an E3 ubiquitin ligase, leads to chromosome fragility and impaired homologous recombinational repair

    Energy Technology Data Exchange (ETDEWEB)

    Ouyang, Yan [Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095 (United States); Kwon, Yong Tae [Center for Pharmacogenetics and Department of Pharmaceutical Sciences, University of Pittsburgh, Pittsburgh, PA 15261 (United States); An, Jee Young [Center for Pharmacogenetics and Department of Pharmaceutical Sciences, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Eller, Danny [Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095 (United States); Tsai, S.-C. [Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095 (United States); Diaz-Perez, Silvia [Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095 (United States); Troke, Joshua J. [Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095 (United States); Teitell, Michael A. [Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095 (United States); Marahrens, York [Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095 (United States)]. E-mail: ymarahrens@mednet.ucla.edu

    2006-04-11

    The N-end rule pathway of protein degradation targets proteins with destabilizing N-terminal residues. Ubr2 is one of the E3 ubiquitin ligases of the mouse N-end rule pathway. We have previously shown that Ubr2{sup -/-} male mice are infertile, owing to the arrest of spermatocytes between the leptotene/zygotene and pachytene of meiosis I, the failure of chromosome pairing, and subsequent apoptosis. Here, we report that mouse fibroblast cells derived from Ubr2{sup -/-} embryos display genome instability. The frequency of chromosomal bridges and micronuclei were much higher in Ubr2{sup -/-} fibroblasts than in +/+ controls. Metaphase chromosome spreads from Ubr2{sup -/-} cells revealed a high incidence of spontaneous chromosomal gaps, indicating chromosomal fragility. These fragile sites were generally replicated late in S phase. Ubr2{sup -/-} cells were hypersensitive to mitomycin C, a DNA cross-linking agent, but displayed normal sensitivity to gamma-irradiation. A reporter assay showed that Ubr2{sup -/-} cells are significantly impaired in the homologous recombination repair of a double strand break. In contrast, Ubr2{sup -/-} cells appeared normal in an assay for non-homologous end joining. Our results therefore unveil the role of the ubiquitin ligase Ubr2 in maintaining genome integrity and in homologous recombination repair.

  2. Further study of genetic interactions: Loss of short arm material in patients with ring chromosome 4 changes developmental pattern of del(4) (q33)

    Energy Technology Data Exchange (ETDEWEB)

    Lurie, I.W. [Univ. of Maryland, Baltimore, MD (United States)

    1995-04-10

    Segment 4q33 is not considered a probable location of a gene related with limb deficiency by Roberts and Tabin; however, the occurrence of ectrodactyly or its equivalents in at least 9 published cases of monosomy 4q33 suggests probable location of one of these genes in that region. Ulnar ray defects and/or ectrodactyly were the prevailing forms. An additional loss of the tip of 4p in patients with ring chromosome 4 leads to a change of limb deficiency type: 8 of 9 patients with r(4) and limb deficiency had radial ray defects. Therefore, interactions between a proposed {1/2} dose {open_quotes}ectrodactyly{close_quotes} gene on 4q33 and some {1/2} dosage genes on distal 4p (or disturbed cellular homeostasis due to a ring chromosome 4) can change the development pattern of limb deficiency. Possible mechanisms and significance of the phenomenon are discussed. 36 refs., 1 tab.

  3. Loss of the N-myc oncogene in a patient with a small interstitial deletion of the short arm of chromosome 2

    Energy Technology Data Exchange (ETDEWEB)

    Saal, H.M. [Children`s Hospital Medical Center, Cincinnati, OH (United States); Johnson, R.C.; Carr, A.G.; Samango-Sprouse, C. [George Washington Univ. School of Medicine, Washington, DC (United States)] [and others

    1996-12-30

    To our knowledge, only four previous cases of distal chromosome 2p deletions exist in the literature. We present a patient with minor facial anomalies who had a distal interstitial deletion of the short arm of chromosome 2, del(2)(p24.2p25.1). This patient had many features seen in other patients with distal 2p deletion including short stature, {open_quotes}rectangular{close_quotes} facies, microcephaly, hypotonia, and mental retardation. This patient also has sensorineural hearing loss which has been described in one other patient with a similar deletion. The N-myc oncogene has been mapped to 2p24. By fluorescence in situ hybridization using a cDNA probe for the N-myc oncogene, this patient was found to have a deletion of the N-myc oncogene. This confirms the previous map location for N-myc. 17 refs., 3 figs., 1 tab.

  4. Chromosomal gains and genomic loss of p53 and p16 genes in Barrett's esophagus detected by fluorescence in situ hybridization of cytology specimens.

    Science.gov (United States)

    Fahmy, Mona; Skacel, Marek; Gramlich, Terry L; Brainard, Jennifer A; Rice, Thomas W; Goldblum, John R; Connor, Jason T; Casey, Graham; Legator, Mona S; Tubbs, Raymond R; Falk, Gary W

    2004-05-01

    Endoscopic brush cytology is a promising surveillance technique for Barrett's esophagus. Ancillary markers are sought to increase the sensitivity of cytology and allow identification of patients at increased risk for disease progression. To determine if there are specific genetic changes in Barrett's esophagus with associated high-grade dysplasia/intramucosal adenocarcinoma compared to those without dysplasia, we performed fluorescence in situ hybridization (FISH) on cytologic specimens using probes to chromosomes and genomic regions previously described as altered in this disease. We studied archival brush cytology slides from 40 Barrett's esophagus patients: 21 with biopsy-proven high-grade dysplasia/carcinoma and 19 with no dysplasia and a minimum 5 years of negative follow-up. Centromeric enumeration probes (CEP) for chromosomes 6, 7, 11, and 12, and locus-specific probes (LSI) for 9p21 (p16 gene), and 17p13.1 (p53 gene) loci along with their corresponding CEP (9 and 17, respectively) were used in this study. A positive FISH result was defined as the presence of cells with >2 CEP signals or with a loss of the LSI signals relative to their corresponding CEP. p53 locus loss and/or aneusomy of chromosomes 6, 7, 11, and 12 abnormalities could be detected by FISH in routinely processed endoscopic brush cytology specimens from 95% of biopsy-positive cases with a specificity of 100%. Interestingly, all five cases with cytologic changes classified as indefinite for dysplasia from patients with a positive biopsy showed changes by FISH. Loss of the p16 locus was seen commonly in patients both with and without dysplasia/carcinoma. Selected biomarkers from this study merit further investigation to determine their potential to detect genetic changes in patients with Barrett's esophagus prior to the development of high-grade dysplasia. PMID:15017433

  5. Gain of Chromosome 4qter and Loss of 5pter: An Unusual Case with Features of Cri du Chat Syndrome

    Directory of Open Access Journals (Sweden)

    Frenny Sheth

    2012-01-01

    Full Text Available Here, we present a case with an unusual chromosomal rearrangement in a child with a predominant phenotype of high-pitched crying showing deletion encompassing CTNND2 due to an unbalanced translocation of chromosomes 4 and 5. This rearrangement led to a duplication of ~35 Mb in 4qter which replaced 18 Mb genetic materials in 5pter. Even though, in this patient, there was no clinically obvious modification to the classical phenotypes of CdCS, and the influence of the 4q-duplication cannot be completely excluded in this case. However, the region 4q34.1–34.3 was previously reported as a region not leading to phenotypic changes if present in three copies, an observation which could possibly be supported by this case. Conclusion. This study showed that in a patient with an unbalanced translocation resulting in 5p deletion, the presence of partial trisomy of chromosome 4q could be clinically insignificant.

  6. Loss of centromeric histone H2AT120 phosphorylation accompanies somatic chromosomes inactivation in the aberrant spermatocytes of Acricotopus lucidus (Diptera, Chironomidae).

    Science.gov (United States)

    Staiber, Wolfgang

    2016-01-01

    In the germ line of the chironomid Acricotopus lucidus, two cells with quite different chromosome constitutions result from the last unequal gonial mitosis. In the male, the future primary spermatocyte receives all the germ line-limited chromosomes (=Ks) together with somatic chromosomes (=Ss), and later on undergoes meiotic divisions, while the connected aberrant spermatocyte gets only Ss and remains undivided with chromosomes inactivated in a metaphase-like condensed state. This raises the question whether the centromeres of the permanently condensed Ss of the aberrant spermatocyte remain active during meiosis of the connected regular spermatocyte. Active centromeres exhibit an epigenetic phosphorylation mark at threonine 120 of histone H2A. To visualise the centromeric H2A phosphorylation of the Ss in the aberrant spermatocyte, meiotic stages were immunostained with different anti-phospho histone H2AT120 antibodies. Clear H2AT120ph signals appear at the centromeres of the Ss during prophase, persist on the metaphase-like condensed Ss during meiosis I of the connected primary spermatocyte and disappear during transition to meiosis II. The centromeres of the Ss and Ks of the regular spermatocytes display H2AT120ph signals from prophase I to anaphase II. The loss of the H2AT120 phosphorylation detected on the centromeres of the Ss of the aberrant spermatocyte indicating their deactivation supports the idea of a programmed inactivation of the Ss to block the entry of the germ line-derived aberrant spermatocyte, lacking Ks, into meiosis, and thus to prevent the generation of sperms possessing only Ss. This mechanism would ensure the presence of the Ks in the germ line. PMID:25820679

  7. Loss of chromosome 13 is the most frequent genomic imbalance in malignant fibrous histiocytomas. A comparative genomic hybridization analysis of a series of 30 cases.

    Science.gov (United States)

    Mairal, A; Terrier, P; Chibon, F; Sastre, X; Lecesne, A; Aurias, A

    1999-06-01

    Regional chromosome localizations of DNA copy number imbalances were studied by comparative genomic hybridization in 30 malignant fibrous histiocytomas: 13 primary tumors (2 myxoid, 9 storiform pleomorphic, and 2 with more undifferentiated phenotype) and 17 local recurrences (2 myxoid, 11 storiform pleomorphic, and 4 with more undifferentiated phenotype). Abnormal comparative genomic hybridization (CGH) profiles were observed in 25 tumors (83%). The most frequent gains (ratio > 1.2) corresponded, by order of frequency, to entire Xp, and bands 1q21, 19q13.1, 19p13, 5p13-p14, 1p31, 17p, 18p, 20q, 1p35, 17q23, and 22q12. High levels of gains (ratio > 1.5) were recurrently detected for Xp (10 cases), and in bands 1q21-q22 (8 cases), 3q27 (4 cases), 5p13-p14 (3 cases), 13q32-q34 (3 cases), 15q22-q26 (3 cases), and 17p11-p12 (3 cases). Losses of 13q12-q14 or 13q21 were observed in a large proportion of tumors (17 cases), suggesting that a gene localized in this region could act as a tumor suppressor gene. Losses of 11q23, 2q32, 11p13, 10p, 1q4, 9p2, 16q12, 4q3, 10q25, 3p23, 2p24, and 12p were also recurrently observed. Taken together, these results provide an overview of chromosome imbalances present in MFH, which could be of use for diagnostic purposes. They point to various chromosome regions which may harbor genes important for malignant fibrous histiocytomas (MFH) oncogenesis and progression. PMID:10347550

  8. Loss of sequences on the short arm of chromosome 17 is a late event in squamous carcinoma of the cervix

    OpenAIRE

    Herrington, C S; Worsham, M; Southern, S A; Mackowiak, P; Wolman, S R

    2001-01-01

    Aims—To determine by fluorescence in situ hybridisation (FISH) whether deletion of D17S34, a subtelomeric probe for 17p, occurs in invasive squamous carcinoma of the cervix, and to determine the extent of such loss by analysis of the p53 and HER2/NEU genes.

  9. 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

  10. A genetic study of the effects of the repair-deficient mei-9sup(a) mutation in Drosophila on spontaneous and X-ray-induced paternal sex chromosome loss

    International Nuclear Information System (INIS)

    The repair-deficient mutant, mei-9sup(a) in Drosophila melanogaster was investigated regarding its effect on spontaneous and X-ray induced chromosome loss in male postmeiotic cells. From matings of males carrying a mei-9sup(a) or an ordinary ring-X and a doubly marked Y chromosome (Bsup(s)Yy+) with mei-9sup(a) or ordinary females, the spontaneous frequencies of complete loss, partial loss, and inferred ring-X loss (based on shifts in sex ratio female:male) were significantly higher with mei-9sup(a) than with non-mei-9sup(a). When males were given 3000 rad X-irradiation, frequencies of induced partial loss, inferred ring-X loss and the reduction in the number of progeny per femal were significantly greater with mei-9sup(a) than with non-mei-9sup(a). The result provide evidence that the mei-9sup(a) is a potentiator of both spontaneous and X-ray-induced chromosome lesions in sperm of the Drosophila male. Evidence is presented which implicates the presence of mei-9sup(a) in the P1 female and not the male as (at least) largely responsible for the characteristic mei-9sup(a) effects. (orig.)

  11. Clinical significance of chromosome karyotyping of couple in women with pregnancy loss%妊娠丢失夫妇染色体核型分析的临床意义

    Institute of Scientific and Technical Information of China (English)

    侯兴华; 王君; 王亚君

    2014-01-01

    目的 探讨染色体异常与妊娠丢失的关系.方法 收集260对妊娠丢失夫妇的临床资料,采用传统的细胞遗传学方法进行外周血淋巴细胞培养和染色体核型分析.结果 48例标本染色体异常,发生率为18.5%(48/260),包括28例(58.3%)结构异常、18例(37.5%)多态性改变、2例(4.2%)数目异常.染色体结构异常主要是平衡易位(71.4%,20/28).偶发性与复发性妊娠丢失(RPL)夫妇之间的染色体异常发生率差异无统计学意义(P>0.05).结论 染色体异常可导致妊娠丢失,平衡易位是其主要原因,夫妇双方孕前进行染色体检查有助于优生指导.%Objective To evaluate the correlation between parental chromosomal abnormalities and pregnancy loss.Methods Clinical data were collected from 260 couples who experienced pregnancy loss in the outpatient of our hospital.Chromosomes from cultured peripheral blood lymphocytes were analyzed using conventional cytogenetic analysis.Results Parental chromosomal abnormality was detected in 48 cases (18.5%),which were structural abnormality (28 cases,58.3%),chromosome polymorphism (18 cases,37.5%)and numeric abnormality (2 cases,4.2%).Most of the structural abnormalities were balanced chromosomal translocations (71.4%,20/28).There was no significant difference in positive rate of chromosomal abnormality between sporadic and recurrent pregnancy loss (P > 0.05).Conclusion Pregnancy loss can be caused by chromosomal abnormalities in couples,most of which are balanced translocations.It is very necessary for the clinicians to provide chromosome examination for the couples who experienced pregnancy loss in order to obtain a better pregnancy outcome.

  12. A map of nuclear matrix attachment regions within the breast cancer loss-of-heterozygosity region on human chromosome 16q22.1.

    Science.gov (United States)

    Shaposhnikov, Sergey A; Akopov, Sergey B; Chernov, Igor P; Thomsen, Preben D; Joergensen, Claus; Collins, Andrew R; Frengen, Eirik; Nikolaev, Lev G

    2007-03-01

    There is abundant evidence that the DNA in eukaryotic cells is organized into loop domains that represent basic structural and functional units of chromatin packaging. To explore the DNA domain organization of the breast cancer loss-of-heterozygosity region on human chromosome 16q22.1, we have identified a significant portion of the scaffold/matrix attachment regions (S/MARs) within this region. Forty independent putative S/MAR elements were assigned within the 16q22.1 locus. More than 90% of these S/MARs are AT rich, with GC contents as low as 27% in 2 cases. Thirty-nine (98%) of the S/MARs are located within genes and 36 (90%) in gene introns, of which 15 are in first introns of different genes. The clear tendency of S/MARs from this region to be located within the introns suggests their regulatory role. The S/MAR resource constructed may contribute to an understanding of how the genes in the region are regulated and of how the structural architecture and functional organization of the DNA are related. PMID:17188460

  13. Clonal evolution and clinical significance of copy number neutral loss of heterozygosity of chromosome arm 6p in acquired aplastic anemia.

    Science.gov (United States)

    Betensky, Marisol; Babushok, Daria; Roth, Jacquelyn J; Mason, Philip J; Biegel, Jaclyn A; Busse, Tracy M; Li, Yimei; Lind, Curt; Papazoglou, Anna; Monos, Dimitri; Podsakoff, Gregory; Bessler, Monica; Olson, Timothy S

    2016-01-01

    Acquired aplastic anemia (aAA) results from the T cell-mediated autoimmune destruction of hematopoietic stem cells. Factors predicting response to immune suppression therapy (IST) or development of myelodysplastic syndrome (MDS) are beginning to be elucidated. Our recent data suggest most patients with aAA treated with IST develop clonal somatic genetic alterations in hematopoietic cells. One frequent acquired abnormality is copy-number neutral loss of heterozygosity on chromosome 6p (6p CN-LOH) involving the human leukocyte antigen (HLA) locus. We hypothesized that because 6p CN-LOH clones may arise from selective pressure to escape immune surveillance through deletion of HLA alleles, the development of 6p CN-LOH may affect response to IST. We used single nucleotide polymorphism array genotyping and targeted next-generation sequencing of HLA alleles to assess frequency of 6p CN-LOH, identity of HLA alleles lost through 6p CN-LOH, and impact of 6p CN-LOH on response to IST. 6p CN-LOH clones were present in 11.3% of patients, remained stable over time, and were not associated with development of MDS-defining cytogenetic abnormalities. Notably, no patient with 6p CN-LOH treated with IST achieved a complete response. In summary, clonal 6p CN-LOH in aAA defines a unique subgroup of patients that may provide insights into hematopoietic clonal evolution. PMID:26702937

  14. Observations of radiation-induced chromosome fragment loss in live mammalian cells in culture, and its effect on colony-forming ability

    International Nuclear Information System (INIS)

    A preceding paper (Grote, Joshi, Revell and Shaw 1981) describe a method for the direct scrutiny of live cultured mammalian cells with a microscope, and reported that all diploid Syrian hamster cells (BHK 21 C13) of a sample given 1.4 Gy of 220 kV X-rays in G1 reached post-radiation mitosis without discernible abnormality, but then diverged in observed behaviour: descendant cells from some first mitoses continued to proliferate normally while cells from other first mitoses behaved abnormally and produced either slow-growth or stop-growth colonies. This paper completes the study of the same irradiated cell sample, and shows that these post-mitotic differences in clonogenic ability were related to acentric chromosome fragment losses at post-radiation mitosis, which were detected in live daughter-cell pairs as micronuclei. The proportion of live daughter-cell pairs scored as deficient was at least 80 per cent of the proportion of comparable fixed-and-stained mitoses with detected acentric fragments. (author)

  15. Chromosome 5 allelic losses are early events in tumours of the papilla of Vater and occur at sites similar to those of gastric cancer.

    OpenAIRE

    Achille, A.; Baron, A; Zamboni, G; Di Pace, C.; Orlandini, S.; Scarpa, A.

    1998-01-01

    During our studies of DNA fingerprinting of tumours of the pancreas and papilla (ampulla) of Vater, using arbitrarily primed polymerase chain reaction (AP-PCR), we noticed two bands showing a decreased intensity in six of ten ampullary tumours with respect to matched normal tissues. Those bands were both assigned to chromosome 5. Such a finding was somewhat in contrast with the reportedly low frequency of APC gene mutations in ampullary cancers, located at chromosome 5q21, and suggested that ...

  16. Combined array-comparative genomic hybridization and single-nucleotide polymorphism-loss of heterozygosity analysis reveals complex changes and multiple forms of chromosomal instability in colorectal cancers

    DEFF Research Database (Denmark)

    Gaasenbeek, Michelle; Howarth, Kimberley; Rowan, Andrew J;

    2006-01-01

    Cancers with chromosomal instability (CIN) are held to be aneuploid/polyploid with multiple large-scale gains/deletions, but the processes underlying CIN are unclear and different types of CIN might exist. We investigated colorectal cancer cell lines using array-comparative genomic hybridization ...

  17. Chromosomal aberration

    International Nuclear Information System (INIS)

    Chromosomal aberrations are classified into two types, chromosome-type and chromatid-type. Chromosom-type aberrations include terminal deletion, dicentric, ring and interstitial deletion, and chromatid-type aberrations include achromatic lesion, chromatid deletion, isochromatid deletion and chromatid exchange. Clastogens which induce chromosomal aberration are divided into ''S-dependent'' agents and ''S-independent''. It might mean whether they can induce double strand breaks independent of the S phase or not. Double strand breaks may be the ultimate lesions to induce chromosomal aberrations. Caffeine added even in the G2 phase appeared to modify the frequency of chromatid aberrations induced by X-rays and mitomycin C. Those might suggest that the G2 phase involves in the chromatid aberration formation. The double strand breaks might be repaired by ''G2 repair system'', the error of which might yield breakage types of chromatid aberrations and the by-pass of which might yield chromatid exchanges. Chromosome-type aberrations might be formed in the G1 phase. (author)

  18. Temporal genomic evolution of bird sex chromosomes

    DEFF Research Database (Denmark)

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

    2014-01-01

    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...... evolved very recently. CONCLUSIONS: In conclusion, we uncover that the sequence and expression patterns of Z chromosome genes covary with their ages of becoming Z-linked. In contrast to the mammalian X chromosomes, such patterns are mainly driven by mutational bias and genetic drift in birds, due...... to the opposite sex-biased inheritance of Z vs. X....

  19. 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. PMID:26111960

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

    Directory of Open Access Journals (Sweden)

    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.

  1. Chromosomal Conditions

    Science.gov (United States)

    ... labor & premature birth The newborn intensive care unit (NICU) Birth defects & other health conditions Loss & grief Tools & ... labor & premature birth The newborn intensive care unit (NICU) Birth defects & other health conditions Loss & grief Ask ...

  2. 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.

  3. 甲状腺肿瘤3号染色体短臂杂合性缺失的研究%Loss of heterozygosity on chromosome 3p in thyroid tumors

    Institute of Scientific and Technical Information of China (English)

    胡孟钧; 徐航娣; 周韧; 郦秀芳; 张海勇

    2008-01-01

    目的 探讨甲状腺肿瘤中3号染色体短臂(3p)杂合性缺失(LOH)状态及其临床意义.方法 收集74例甲状腺肿瘤标本,包括20例甲状腺腺瘤(FA)、24例滤泡性甲状腺癌(FTC)和30例乳头状甲状腺癌(Prc).通过PCR扩增和银染分析其3p上11个微卫星位点的杂合性缺失状态.结果 FFC的LOH频率达到71%(17/24),PTC中30%(9/30),FA中10%(2/20).FFC的3p LOH频率显著高于FA和PTC(P<0.01).FTC中存在两个最小共同缺失区,分别位于3p26-pter和3p14.2-3p22.PTC上存在一个最小共同缺失区,位于3p 25.2-26.1.结论 FTC的3p LOH频率显著高于FA和PTC.3p的3个最小缺失区上可能存在着与FTC和PTC发生发展相关的肿瘤抑制基因.%Objective To study the loss of heterozygosity(LOH)on chromosome 3p in thyroid tumors. Methods LOH at 11 microsatellite loci Wag analyzed in 74 cases of thyroid tumors(including 20 follicular adenomas, 24 follicular thyroid carcinomas and 30 papillary thyroid carcinomas)by polymerase chain reaction and silver stain. Results LOH on chromosome 3p Wag detected in 71% of follicular thyroid carcinoma(17/24), 30%of the papillary thyroid carcinoma(9/30) and 10%of the follicular adenoma (2/20)case. Two minimal common deleted regions(CDR)(3p26-pter and 3p14. 2-3p22)involving significant sites of LOH has identified in follicular thyroid carcinoma. There Was also one CDR(3p25. 2-26. 1)in papilhry thyroid careinoma. Conclusions LOH is more frequently identified in follicular thyroid careinoma than in papillary thyroid carcinoma and follicular adenoma. The 3 CDR on chromosome 3p may harbor tumor suppressor genes involved in the pathogenesis of follicular thyroid carcinoma and papillary thyroid carcinoma.

  4. CHROMOSOMAL ABNORMALITIES IN PATIENTS WITH RECURRENT MISCARRIAGE

    OpenAIRE

    Daniela Mierla; Viorica Radoi; Veronica Stoian

    2012-01-01

    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, ka...

  5. Chromosome Microarray.

    Science.gov (United States)

    Anderson, Sharon

    2016-01-01

    Over the last half century, knowledge about genetics, genetic testing, and its complexity has flourished. Completion of the Human Genome Project provided a foundation upon which the accuracy of genetics, genomics, and integration of bioinformatics knowledge and testing has grown exponentially. What is lagging, however, are efforts to reach and engage nurses about this rapidly changing field. The purpose of this article is to familiarize nurses with several frequently ordered genetic tests including chromosomes and fluorescence in situ hybridization followed by a comprehensive review of chromosome microarray. It shares the complexity of microarray including how testing is performed and results analyzed. A case report demonstrates how this technology is applied in clinical practice and reveals benefits and limitations of this scientific and bioinformatics genetic technology. Clinical implications for maternal-child nurses across practice levels are discussed. PMID:27276104

  6. MRPS18CP2 alleles and DEFA3 absence as putative chromosome 8p23.1 modifiers of hearing loss due to mtDNA mutation A1555G in the 12S rRNA gene

    Directory of Open Access Journals (Sweden)

    Fischel-Ghodsian Nathan

    2007-12-01

    Full Text Available Abstract Background Mitochondrial DNA (mtDNA mutations account for at least 5% of cases of postlingual, nonsyndromic hearing impairment. Among them, mutation A1555G is frequently found associated with aminoglycoside-induced and/or nonsyndromic hearing loss in families presenting with extremely variable clinical phenotypes. Biochemical and genetic data have suggested that nuclear background is the main factor involved in modulating the phenotypic expression of mutation A1555G. However, although a major nuclear modifying locus was located on chromosome 8p23.1 and regardless intensive screening of the region, the gene involved has not been identified. Methods With the aim to gain insights into the factors that determine the phenotypic expression of A1555G mutation, we have analysed in detail different genetic and genomic elements on 8p23.1 region (DEFA3 gene absence, CLDN23 gene and MRPS18CP2 pseudogene in a group of 213 A1555G carriers. Results Family based association studies identified a positive association for a polymorphism on MRPS18CP2 and an overrepresentation of DEFA3 gene absence in the deaf group of A1555G carriers. Conclusion Although none of the factors analysed seem to have a major contribution to the phenotype, our findings provide further evidences of the involvement of 8p23.1 region as a modifying locus for A1555G 12S rRNA gene mutation.

  7. Radiation induced chromosome instability in human fibroblasts

    International Nuclear Information System (INIS)

    Evidence has been arising that some biological effects can manifest many cell divisions after irradiation. We have demonstrated that de novo chromosome instability can be detected 10- 15 mean population doubling after heavy ion irradiations. This chromosome instability is characterized by end to end fusions between specific chromosomes. The specificity of the instability may differ from one donor to another but for the same donor, the same instability should be observed after irradiation, during the senescence process and after SV40 transfection (before crisis). In irradiated primary culture fibroblasts, the expression of the delayed chromosomal instability lasts for several cell divisions without inducing cell death. Several rounds of fusions- breakage-fusions can be performed and unbalanced clones emerge (gain or loss of chromosomes with the shorter telomeres would become unstable first.. The difference in the chromosomal instability among donors could be due to a polymorphism in telomere lengths. This could induce large variation in long term response to irradiation among individuals. (author)

  8. 小鼠卵母细胞染色体三维双光子荧光图像的轴向衰减%Intensity Loss of Two-Photon Excitation Fluorescence Microscopy Images of Mouse Oocyte Chromosomes

    Institute of Scientific and Technical Information of China (English)

    赵凤英; 吴宏新; 陈瓞延; 马万云

    2014-01-01

    severe axial inten-sity loss in two-photon microscopic images of mouse oocytes due to the absorption and scattering effects .It is necessary to make compensation for these images of mouse oocyte chromosomes obtained from two-photon microscopic system .It will be specially needed in studying the quantitative three-dimensional information of mouse oocytes .

  9. Mechanisms of Chromosome Number Evolution in Yeast

    Science.gov (United States)

    Gordon, Jonathan L.; Byrne, Kevin P.; Wolfe, Kenneth H.

    2011-01-01

    The whole-genome duplication (WGD) that occurred during yeast evolution changed the basal number of chromosomes from 8 to 16. However, the number of chromosomes in post-WGD species now ranges between 10 and 16, and the number in non-WGD species (Zygosaccharomyces, Kluyveromyces, Lachancea, and Ashbya) ranges between 6 and 8. To study the mechanism by which chromosome number changes, we traced the ancestry of centromeres and telomeres in each species. We observe only two mechanisms by which the number of chromosomes has decreased, as indicated by the loss of a centromere. The most frequent mechanism, seen 8 times, is telomere-to-telomere fusion between two chromosomes with the concomitant death of one centromere. The other mechanism, seen once, involves the breakage of a chromosome at its centromere, followed by the fusion of the two arms to the telomeres of two other chromosomes. The only mechanism by which chromosome number has increased in these species is WGD. Translocations and inversions have cycled telomere locations, internalizing some previously telomeric genes and creating novel telomeric locations. Comparison of centromere structures shows that the length of the CDEII region is variable between species but uniform within species. We trace the complete rearrangement history of the Lachancea kluyveri genome since its common ancestor with Saccharomyces and propose that its exceptionally low level of rearrangement is a consequence of the loss of the non-homologous end joining (NHEJ) DNA repair pathway in this species. PMID:21811419

  10. Mitotic chromosome structure

    International Nuclear Information System (INIS)

    Mounting evidence is compiling linking the physical organizational structure of chromosomes and the nuclear structure to biological function. At the base of the physical organizational structure of both is the concept of loop formation. This implies that physical proximity within chromosomes is provided for otherwise distal genomic regions and thus hierarchically organizing the chromosomes. Together with entropy many experimental observations can be explained with these two concepts. Among the observations that can be explained are the measured physical extent of the chromosomes, their shape, mechanical behavior, the segregation into territories (chromosomal and territories within chromosomes), the results from chromosome conformation capture experiments, as well as linking gene expression to structural organization.

  11. Fetal chromosome analysis: screening for chromosome disease?

    DEFF Research Database (Denmark)

    Philip, J; Tabor, Ann; Bang, J;

    1983-01-01

    A + B). Pregnant women 35 years of age, women who previously had a chromosomally abnormal child, families with translocation carriers or other heritable chromosomal disease, families where the father was 50 years or more and women in families with a history of Down's syndrome (group A), were...... unbalanced chromosome abnormality in group A (women with elevated risk) is significantly higher than in group B + C (women without elevated risk) (relative risk 2.4). Women with a known familial translocation and women 40 years or more have a relative risk of 5.7 of having an unbalanced chromosome......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...

  12. ASOCIACIÓN ENTRE LA PÉRDIDA DEL CROMOSOMA X EN MUJERES DE EDAD AVANZADA Y EL POLIMORFISMO DE LA APOLIPOPROTEÍNA A-IV: 360 GLN/HIS ASSOCIATION OF CHROMOSOME X LOSS IN ELDERLY WOMEN WITH APOLIPOPROTEIN A-IV: 360 POLYMORPHISM

    Directory of Open Access Journals (Sweden)

    Tatiana Flank Ejchel

    2004-01-01

    Full Text Available La pérdida del cromosoma X en mujeres, asociada a la edad avanzada, es un fenómeno ya reconocido hace décadas. Los factores genéticos que llevan a esta pérdida o a la no-disyunción cromosómica, son poco conocidos. Polimorfismos de apolipoproteínas fueron asociados a la ocurrencia de síndromes cromosómicos como las trisomías del 18 y 21 y fue sugerida su participación en la segregación cromosómica. Polimorfismos de la apolipoproteína AIV:360 fueron asociados a molestias cardiovasculares en la población brasileña.Veinticuatro mujeres entre 72 a 87 años, fueron seleccionadas para estudiar la presencia o ausencia del alelo 2 (HIS y analizar la pérdida del cromosoma X. El análisis citogenético fue realizado en núcleos interfásicos de cultivos de linfocitos por técnica de hibridación in situ con sonda fluorescente centromérica del cromosoma X. El análisis genotípico fue realizado a partir de ADN extraído de la sangre, amplificado por PCR y digerido por la enzima de restricción Fnu4HI. Se observó una proporción significantemente mayor de células con la pérdida del cromosoma X, en mujeres con alelo 2 (HIS. Estos resultados indican la participación del gen de la ApoA-IV en la no-disyunción cromosómica. Los mecanismos de su actuación pueden estar relacionados a daños oxidativos producto de alteraciones en la microcirculación e inducción de muerte celular. La comprensión de este mecanismo todavía necesita de mayor investigaciónChromosome X loss associated with advancing age in women is well stablished in cytogenetics. However, genetic factors involved in this chromosome loss or no disjunction are poorly understood. Apolipoproteins have been associated with chromosome syndromes, such as Trisomy 21 and 18 and their participation in chromosome segregation have been suggested. Apolipoprotein A-IV:360 polymorphism has been associated with cardiovascular diseases, in our population. Twenty four old women, aged 72 to 87

  13. Sex determining mechanisms in insects based on imprinting and elimination of chromosomes

    OpenAIRE

    Sánchez Rodríguez, Lucas

    2014-01-01

    As a rule, the sex of an individual is fixed at fertilisation, being the chromosomal constitution of the zygote a direct consequence of the chromosomal constitution of the gametes. However, there are cases in which the chromosomal differences determining sex are brought about by elimination or inactivation of chromosomes in the embryo. In Sciaridae insects, all zygotes start with the XXX constitution; the loss of either one or two X chromosomes determines whether the zygote becomes XX (fem...

  14. 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

  15. Haploidization via Chromosome Elimination: Means and Mechanisms.

    Science.gov (United States)

    Ishii, Takayoshi; Karimi-Ashtiyani, Raheleh; Houben, Andreas

    2016-04-29

    The ability to generate haploids and subsequently induce chromosome doubling significantly accelerates the crop breeding process. Haploids have been induced through the generation of plants from haploid tissues (in situ gynogenesis and androgenesis) and through the selective loss of a parental chromosome set via inter- or intraspecific hybridization. Here, we focus on the mechanisms responsible for this selective chromosome elimination. CENH3, a variant of the centromere-specific histone H3, has been exploited to create an efficient method of haploid induction, and we discuss this approach in some detail. Parallels have been drawn with chromosome-specific elimination, which occurs as a normal part of differentiation and sex determination in many plant and animal systems. PMID:26772657

  16. Pathogenesis of vestibular schwannoma in ring chromosome 22

    Directory of Open Access Journals (Sweden)

    Debiec-Rychter Maria

    2009-09-01

    Full Text Available Abstract Background Ring chromosome 22 is a rare human constitutional cytogenetic abnormality. Clinical features of neurofibromatosis type 1 and 2 as well as different tumour types have been reported in patients with ring chromosome 22. The pathogenesis of these tumours is not always clear yet. Methods We report on a female patient with a ring chromosome 22 presenting with severe mental retardation, autistic behaviour, café-au-lait macules and facial dysmorphism. Peripheral blood lymphocytes were karyotyped and array CGH was performed on extracted DNA. At the age of 20 years she was diagnosed with a unilateral vestibular schwannoma. Tumour cells were analyzed by karyotyping, array CGH and NF2 mutation analysis. Results Karyotype on peripheral blood lymphocytes revealed a ring chromosome 22 in all analyzed cells. A 1 Mb array CGH experiment on peripheral blood DNA showed a deletion of 5 terminal clones on the long arm of chromosome 22. Genetic analysis of vestibular schwannoma tissue revealed loss of the ring chromosome 22 and a somatic second hit in the NF2 gene on the remaining chromosome 22. Conclusion We conclude that tumours can arise by the combination of loss of the ring chromosome and a pathogenic NF2 mutation on the remaining chromosome 22 in patients with ring chromosome 22. Our findings indicate that patients with a ring 22 should be monitored for NF2-related tumours starting in adolescence.

  17. A high number of losses in 13q14 chromosome band is associated with a worse outcome and biological differences in patients with B-cell chronic lymphoid leukemia

    OpenAIRE

    Hernández, José Ángel; Rodríguez, Ana Eugenia; González, Marcos; Benito, Rocío; Fontanillo, Celia; Sandoval, Virgilio; Romero, Mercedes; Martín-Núñez, Guillermo; de Coca, Alfonso García; Fisac, Rosa; Galende, Josefina; Recio, Isabel; Ortuño, Francisco; García, Juan Luis; De Las Rivas, Javier

    2009-01-01

    In B-cell chronic lymphoid leukemia, patients with 13q14 deletion generally have a favorable outcome. The findings of this study suggest that the number of malignant cells with 13q14 deletion may influence the outcome of patients with this cytogenetic abnormality as a single chromosomal aberration. A high number of malignant cells carrying the 13q14 deletion, as assessed by FISH, appears to be associated with short overall survival and time to progression.

  18. Chimpanzee chromosome 12 is homologous to human chromosome 2q

    Energy Technology Data Exchange (ETDEWEB)

    Sun, N. C.; Sun, C. R.Y.; Ho, T.

    1977-01-01

    Most of the 46 human chromosomes find their counterparts in the 48 chimpanzee chromosomes except for chromosome 2 which has been hypothesized to have been derived from a centric fusion of two chimpanzee acrocentric chromosomes. These two chromosomes correspond to the human chromosomes 2p and 2g. This conclusion is based primarily on chromosome banding techniques, and the somatic cell hybridization technique has also been used. (HLW)

  19. Meiotic chromosomal variation resulting from irradiation of pollen in maize

    International Nuclear Information System (INIS)

    The objective of this study was to standardize an induction strategy of chromosome aberrations in maize inbred line L-869. Pollen grains irradiated with 0, 36 and 72 Gy were used for fertilization. Resulting seeds were planted in a greenhouse to assess the number of abnormal meiotic cells. Germination, height, sterility and mortality were verified. Cells with delayed separation of chromosomes, translocation, deficiency, abnormal pairing, later condensation and anaphase bridges were observed. The number of abnormalities increased as the dosage increased but chromosome aberration types were the same regardless of the dosages used. Various chromosome-altered plants were obtained without viability loss. (author)

  20. Cloning of the Epstein-Barr Virus-Related Rhesus Lymphocryptovirus as a Bacterial Artificial Chromosome: a Loss-of-Function Mutation of the rhBARF1 Immune Evasion Gene ▿ †

    OpenAIRE

    Ohashi, Makoto; Orlova, Nina; Quink, Carol; Wang, Fred

    2010-01-01

    Rhesus macaques are naturally infected with a gammaherpesvirus which is in the same lymphocryptovirus (LCV) genus as and closely related to Epstein-Barr virus (EBV). The rhesus macaque LCV (rhLCV) contains a repertoire of genes identical to that of EBV, and experimental rhLCV infection of naive rhesus macaques accurately models acute and persistent EBV infection of humans. We cloned the LCL8664 rhLCV strain as a bacterial artificial chromosome to create recombinant rhLCV for investigation in ...

  1. Origin and evolution of X chromosome inactivation.

    Science.gov (United States)

    Gribnau, Joost; Grootegoed, J Anton

    2012-06-01

    Evolution of the mammalian sex chromosomes heavily impacts on the expression of X-encoded genes, both in marsupials and placental mammals. The loss of genes from the Y chromosome forced a two-fold upregulation of dose sensitive X-linked homologues. As a corollary, female cells would experience a lethal dose of X-linked genes, if this upregulation was not counteracted by evolution of X chromosome inactivation (XCI) that allows for only one active X chromosome per diploid genome. Marsupials rely on imprinted XCI, which inactivates always the paternally inherited X chromosome. In placental mammals, random XCI (rXCI) is the predominant form, inactivating either the maternal or paternal X. In this review, we discuss recent new insights in the regulation of XCI. Based on these findings, we propose an X inactivation center (Xic), composed of a cis-Xic and trans-Xic that encompass all elements and factors acting to control rXCI either in cis or in trans. We also highlight that XCI may have evolved from a very small nucleation site on the X chromosome in the vicinity of the Sox3 gene. Finally, we discuss the possible evolutionary road maps that resulted in imprinted XCI and rXCI as observed in present day mammals. PMID:22425180

  2. Demasculinization of the Anopheles gambiae X chromosome

    Directory of Open Access Journals (Sweden)

    Magnusson Kalle

    2012-05-01

    Full Text Available Abstract Background In a number of organisms sex-biased genes are non-randomly distributed between autosomes and the shared sex chromosome X (or Z. Studies on Anopheles gambiae have produced conflicting results regarding the underrepresentation of male-biased genes on the X chromosome and it is unclear to what extent sexual antagonism, dosage compensation or X-inactivation in the male germline, the evolutionary forces that have been suggested to affect the chromosomal distribution of sex-biased genes, are operational in Anopheles. Results We performed a meta-analysis of sex-biased gene expression in Anopheles gambiae which provides evidence for a general underrepresentation of male-biased genes on the X-chromosome that increased in significance with the observed degree of sex-bias. A phylogenomic comparison between Drosophila melanogaster, Aedes aegypti and Culex quinquefasciatus also indicates that the Anopheles X chromosome strongly disfavours the evolutionary conservation of male-biased expression and that novel male-biased genes are more likely to arise on autosomes. Finally, we demonstrate experimentally that transgenes situated on the Anopheles gambiae X chromosome are transcriptionally silenced in the male germline. Conclusion The data presented here support the hypothesis that the observed demasculinization of the Anopheles X chromosome is driven by X-chromosome inactivation in the male germline and by sexual antagonism. The demasculinization appears to be the consequence of a loss of male-biased expression, rather than a failure in the establishment or the extinction of male-biased genes.

  3. Roles of the Y chromosome genes in human cancers

    Directory of Open Access Journals (Sweden)

    Tatsuo Kido

    2015-06-01

    Full Text Available Male and female differ genetically by their respective sex chromosome composition, that is, XY as male and XX as female. Although both X and Y chromosomes evolved from the same ancestor pair of autosomes, the Y chromosome harbors male-specific genes, which play pivotal roles in male sex determination, germ cell differentiation, and masculinization of various tissues. Deletions or translocation of the sex-determining gene, SRY, from the Y chromosome causes disorders of sex development (previously termed as an intersex condition with dysgenic gonads. Failure of gonadal development results not only in infertility, but also in increased risks of germ cell tumor (GCT, such as gonadoblastoma and various types of testicular GCT. Recent studies demonstrate that either loss of Y chromosome or ectopic expression of Y chromosome genes is closely associated with various male-biased diseases, including selected somatic cancers. These observations suggest that the Y-linked genes are involved in male health and diseases in more frequently than expected. Although only a small number of protein-coding genes are present in the male-specific region of Y chromosome, the impacts of Y chromosome genes on human diseases are still largely unknown, due to lack of in vivo models and differences between the Y chromosomes of human and rodents. In this review, we highlight the involvement of selected Y chromosome genes in cancer development in men.

  4. The fragile Y hypothesis: Y chromosome aneuploidy as a selective pressure in sex chromosome and meiotic mechanism evolution.

    Science.gov (United States)

    Blackmon, Heath; Demuth, Jeffery P

    2015-09-01

    Loss of the Y-chromosome is a common feature of species with chromosomal sex determination. However, our understanding of why some lineages frequently lose Y-chromosomes while others do not is limited. The fragile Y hypothesis proposes that in species with chiasmatic meiosis the rate of Y-chromosome aneuploidy and the size of the recombining region have a negative correlation. The fragile Y hypothesis provides a number of novel insights not possible under traditional models. Specifically, increased rates of Y aneuploidy may impose positive selection for (i) gene movement off the Y; (ii) translocations and fusions which expand the recombining region; and (iii) alternative meiotic segregation mechanisms (achiasmatic or asynaptic). These insights as well as existing evidence for the frequency of Y-chromosome aneuploidy raise doubt about the prospects for long-term retention of the human Y-chromosome despite recent evidence for stable gene content in older non-recombining regions. PMID:26200104

  5. Cancer chromosomal instability: therapeutic and diagnostic challenges.

    Science.gov (United States)

    McGranahan, Nicholas; Burrell, Rebecca A; Endesfelder, David; Novelli, Marco R; Swanton, Charles

    2012-06-01

    Chromosomal instability (CIN)-which is a high rate of loss or gain of whole or parts of chromosomes-is a characteristic of most human cancers and a cause of tumour aneuploidy and intra-tumour heterogeneity. CIN is associated with poor patient outcome and drug resistance, which could be mediated by evolutionary adaptation fostered by intra-tumour heterogeneity. In this review, we discuss the clinical consequences of CIN and the challenges inherent to its measurement in tumour specimens. The relationship between CIN and prognosis supports assessment of CIN status in the clinical setting and suggests that stratifying tumours according to levels of CIN could facilitate clinical risk assessment. PMID:22595889

  6. ATM Modulates the Loading of Recombination Proteins onto a Chromosomal Translocation Breakpoint Hotspot

    OpenAIRE

    Jiying Sun; Yukako Oma; Masahiko Harata; Kazuteru Kono; Hiroki Shima; Aiko Kinomura; Tsuyoshi Ikura; Hidekazu Suzuki; Shuki Mizutani; Roland Kanaar; Satoshi Tashiro

    2010-01-01

    textabstractChromosome translocations induced by DNA damaging agents, such as ionizing radiation and certain chemotherapies, alter genetic information resulting in malignant transformation. Abrogation or loss of the ataxia-telangiectasia mutated (ATM) protein, a DNA damage signaling regulator, increases the incidence of chromosome translocations. However, how ATM protects cells from chromosome translocations is still unclear. Chromosome translocations involving the MLL gene on 11q23 are the m...

  7. Plant sex chromosome evolution.

    Science.gov (United States)

    Charlesworth, Deborah

    2013-01-01

    It is now well established that plants have an important place in studies of sex chromosome evolution because of the repeated independent evolution of separate sexes and sex chromosomes. There has been considerable recent progress in studying plant sex chromosomes. In this review, I focus on how these recent studies have helped clarify or answer several important questions about sex chromosome evolution, and I shall also try to clarify some common misconceptions. I also outline future work that will be needed to make further progress, including testing some important ideas by genetic, molecular, and developmental approaches. Systems with different ages can clearly help show the time course of events during changes from an ancestral co-sexual state (hermaphroditism or monoecy), and I will also explain how different questions can be studied in lineages whose dioecy or sex chromosomes evolved at different times in the past. PMID:23125359

  8. Vibrio chromosomes share common history

    OpenAIRE

    Gevers Dirk; Chang Sarah; Chang LeeAnn; Kirkup Benjamin C; Polz Martin F

    2010-01-01

    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 ...

  9. Formation of new chromosomes as a virulence mechanism in yeast Candida glabrata

    DEFF Research Database (Denmark)

    Poláková, S.; Blume, C.; Zárate, J. A.;

    2009-01-01

    chromosomes were translocations of chromosomal arms. However, also larger segmental duplications were frequent and occasionally we observed novel chromosomes. Apparently, this yeast can generate a new chromosome by duplication of chromosome segments carrying a centromere and subsequently adding novel......In eukaryotes, the number and rough organization of chromosomes is well preserved within isolates of the same species. Novel chromosomes and loss of chromosomes are infrequent and usually associated with pathological events. Here, we analyzed 40 pathogenic isolates of a haploid and asexual yeast......, Candida glabrata, for their genome structure and stability. This organism has recently become the second most prevalent yeast pathogen in humans. Although the gene sequences were well conserved among different strains, their chromosome structures differed drastically. The most frequent events reshaping...

  10. Sex-biased gene expression at homomorphic sex chromosomes in emus and its implication for sex chromosome evolution.

    Science.gov (United States)

    Vicoso, Beatriz; Kaiser, Vera B; Bachtrog, Doris

    2013-04-16

    Sex chromosomes originate from autosomes. The accumulation of sexually antagonistic mutations on protosex chromosomes selects for a loss of recombination and sets in motion the evolutionary processes generating heteromorphic sex chromosomes. Recombination suppression and differentiation are generally viewed as the default path of sex chromosome evolution, and the occurrence of old, homomorphic sex chromosomes, such as those of ratite birds, has remained a mystery. Here, we analyze the genome and transcriptome of emu (Dromaius novaehollandiae) and confirm that most genes on the sex chromosome are shared between the Z and W. Surprisingly, however, levels of gene expression are generally sex-biased for all sex-linked genes relative to autosomes, including those in the pseudoautosomal region, and the male-bias increases after gonad formation. This expression bias suggests that the emu sex chromosomes have become masculinized, even in the absence of ZW differentiation. Thus, birds may have taken different evolutionary solutions to minimize the deleterious effects imposed by sexually antagonistic mutations: some lineages eliminate recombination along the protosex chromosomes to physically restrict sexually antagonistic alleles to one sex, whereas ratites evolved sex-biased expression to confine the product of a sexually antagonistic allele to the sex it benefits. This difference in conflict resolution may explain the preservation of recombining, homomorphic sex chromosomes in other lineages and illustrates the importance of sexually antagonistic mutations driving the evolution of sex chromosomes. PMID:23547111

  11. Chromosomal Abnormalities Subdivide Ependymal Tumors into Clinically Relevant Groups

    Science.gov (United States)

    Hirose, Yuichi; Aldape, Kenneth; Bollen, Andrew; James, C. David; Brat, Daniel; Lamborn, Kathleen; Berger, Mitchel; Feuerstein, Burt G.

    2001-01-01

    Ependymoma occurs most frequently within the central nervous system of children and young adults. We determined relative chromosomal copy-number aberrations in 44 ependymomas using comparative genomic hybridization. The study included 24 intracranial and 20 spinal cord tumors from pediatric and adult patients. Frequent chromosomal aberrations in intracranial tumors were gain of 1q and losses on 6q, 9, and 13. Gain of 1q and loss on 9 were preferentially associated with histological grade 3 tumors. On the other hand, gain on chromosome 7 was recognized almost exclusively in spinal cord tumors, and was associated with various other chromosomal aberrations including frequent loss of 22q. We conclude that cytogenetic analysis of ependymomas may help to classify these tumors and provide leads concerning their initiation and progression. The relationship of these aberrations to patient outcome needs to be addressed. PMID:11238062

  12. 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.

  13. A new chromosome was born: comparative chromosome painting in Boechera.

    Science.gov (United States)

    Koch, Marcus A

    2015-09-01

    Comparative chromosome painting is a powerful tool to study the evolution of chromosomes and genomes. Analyzing karyotype evolution in cruciferous plants highlights the origin of aberrant chromosomes in apomictic Boechera and further establishes the cruciferous plants as important model system for our understanding of plant chromosome and genome evolution. PMID:26228436

  14. Chimpanzee chromosome 13 is homologous to human chromosome 2p

    Energy Technology Data Exchange (ETDEWEB)

    Sun, N. C.; Sun, C. R.Y.; Ho, T.

    1977-01-01

    Similarities between human and chimpanzee chromosomes are shown by chromosome banding techniques and somatic cell hybridization techniques. Cell hybrids were obtained from the chimpanzee lymphocyte LE-7, and the Chinese hamster mutant cell, Gal-2. Experiments showed that the ACPL, MDHs, and Gal-Act genes could be assigned to chimpanzee chromosome 13, and since these genes have been assigned to human chromosme 2p, it is suggested that chimpanzee chromosome 13 is homologous to human chromosome 2p. (HLW)

  15. Chromosome condensation and segmentation

    International Nuclear Information System (INIS)

    Some aspects of chromosome condensation in mammalians -humans especially- were studied by means of cytogenetic techniques of chromosome banding. Two further approaches were adopted: a study of normal condensation as early as prophase, and an analysis of chromosome segmentation induced by physical (temperature and γ-rays) or chemical agents (base analogues, antibiotics, ...) in order to show out the factors liable to affect condensation. Here 'segmentation' means an abnormal chromosome condensation appearing systematically and being reproducible. The study of normal condensation was made possible by the development of a technique based on cell synchronization by thymidine and giving prophasic and prometaphasic cells. Besides, the possibility of inducing R-banding segmentations on these cells by BrdU (5-bromodeoxyuridine) allowed a much finer analysis of karyotypes. Another technique was developed using 5-ACR (5-azacytidine), it allowed to induce a segmentation similar to the one obtained using BrdU and identify heterochromatic areas rich in G-C bases pairs

  16. 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.

  17. Chromosome numbers in Bromeliaceae

    OpenAIRE

    2000-01-01

    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. u...

  18. Chromosomal imbalances revealed in primary rhabdomyosarcomas by comparative genomic hybridization

    Institute of Scientific and Technical Information of China (English)

    LI Qiao-xin; LIU Chun-xia; CHUN Cai-pu; QI Yan; CHANG Bin; LI Xin-xia; CHEN Yun-zhao; NONG Wei-xia; LI Hong-an; LI Feng

    2009-01-01

    Background Previous cytogenetic studies revealed aberrations varied among the throe subtypes of rhabdomyosarcoma. We profiled chromosomal imbalances in the different subtypes and investigated the relationships between clinical parameters and genomic aberrations.Methods Comparative genomic hybridization was used to investigate genomic imbalances in 25 cases of primary rhabdomyosarcomas and two rhabdomyosarcoma cell lines. Specimens were reviewed to determine histological type, pathological grading and clinical staging.Results Changes involving one or more regions of the genome were seen in all rhabdomyosarcomal patients. For rhabdomyosarcoma, DNA sequence gains were most frequently (>30%) seen in chromosomes 2p, 12q, 6p, 9q, 10q, 1p,2q, 6q, 8q, 15q and 18q; losses from 3p, 11p and 6p. In aggressive alveolar rhabdomyosarcoma, frequent gains were seen on chromosomes 12q, 2p, 6p, 2q, 4q, 10q and 15q; losses from 3p, 6p, 1q and 5q. For embryonic rhabdomyosarcoma, frequent gains were on 7p, 9q, 2p, 18q, 1p and 8q; losses only from 11p. Frequently gained chromosome arms of translocation associated with rhabdomyosarcoma were 12q, 2, 6, 10q, 4q and 15q; losses from 3p,6p and 5q. The frequently gained chromosome arms of nontranslocation associated with rhabdomyosarcoma were 2p,9q and 18q, while 11p and 14q were the frequently lost chromosome arms. Gains on chromosome 12q were significantly correlated with translocation type. Gains on chromosome 9q were significantly correlated with clinical staging. Conclusions Gains on chromosomes 2p, 12q, 6p, 9q, 10q, 1p, 2q, 6q, 8q, 15q and 18q and losses on chromosomes 3p, 11p and 6p may be related to rhabdomyosarcomal carcinogenesis. Furthermore, gains on chromosome 12q may be correlated with translocation and gains on chromosome 9q with the early stages of rhabdomyosarcoma.

  19. Micromechanics of human mitotic chromosomes

    International Nuclear Information System (INIS)

    Eukaryote cells dramatically reorganize their long chromosomal DNAs to facilitate their physical segregation during mitosis. The internal organization of folded mitotic chromosomes remains a basic mystery of cell biology; its understanding would likely shed light on how chromosomes are separated from one another as well as into chromosome structure between cell divisions. We report biophysical experiments on single mitotic chromosomes from human cells, where we combine micromanipulation, nano-Newton-scale force measurement and biochemical treatments to study chromosome connectivity and topology. Results are in accord with previous experiments on amphibian chromosomes and support the 'chromatin network' model of mitotic chromosome structure. Prospects for studies of chromosome-organizing proteins using siRNA expression knockdowns, as well as for differential studies of chromosomes with and without mutations associated with genetic diseases, are also discussed

  20. 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.

  1. Computer aided analysis of additional chromosome aberrations in Philadelphia chromosome positive acute lymphoblastic leukaemia using a simplified computer readable cytogenetic notation

    Directory of Open Access Journals (Sweden)

    Mohr Brigitte

    2003-01-01

    Full Text Available Abstract Background The analysis of complex cytogenetic databases of distinct leukaemia entities may help to detect rare recurring chromosome aberrations, minimal common regions of gains and losses, and also hot spots of genomic rearrangements. The patterns of the karyotype alterations may provide insights into the genetic pathways of disease progression. Results We developed a simplified computer readable cytogenetic notation (SCCN by which chromosome findings are normalised at a resolution of 400 bands. Lost or gained chromosomes or chromosome segments are specified in detail, and ranges of chromosome breakpoint assignments are recorded. Software modules were written to summarise the recorded chromosome changes with regard to the respective chromosome involvement. To assess the degree of karyotype alterations the ploidy levels and numbers of numerical and structural changes were recorded separately, and summarised in a complex karyotype aberration score (CKAS. The SCCN and CKAS were used to analyse the extend and the spectrum of additional chromosome aberrations in 94 patients with Philadelphia chromosome positive (Ph-positive acute lymphoblastic leukemia (ALL and secondary chromosome anomalies. Dosage changes of chromosomal material represented 92.1% of all additional events. Recurring regions of chromosome losses were identified. Structural rearrangements affecting (pericentromeric chromosome regions were recorded in 24.6% of the cases. Conclusions SCCN and CKAS provide unifying elements between karyotypes and computer processable data formats. They proved to be useful in the investigation of additional chromosome aberrations in Ph-positive ALL, and may represent a step towards full automation of the analysis of large and complex karyotype databases.

  2. 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.

  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. 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.

  5. The prevalence of chromosomal aberrations associated with myelodysplastic syndromes in China.

    Science.gov (United States)

    Hu, Qinyong; Chu, Yuxin; Song, Qibin; Yao, Yi; Yang, Weihong; Huang, Shiang

    2016-08-01

    This study aims to investigate the prevalence and distribution of diverse chromosomal aberrations associated with myelodysplastic syndromes (MDS) in China. Bone marrow samples were collected from multiple cities in China. Metaphase cytogenetic (MC) analysis and fluorescence in situ hybridization (FISH) were initially used to test chromosomal lesions. Affymetrix CytoScan 750 K genechip platform performed a genome-wide detection of chromosomal aberrations. Chromosomal gain was identified in 76 patients; the most prevalent was trisomy 8(17.9 %). New chromosomal gain was detected on chromosome 9, 19p, and X. Chromosomal loss was detected in 101 patients. The most frequent was loss 5q (21.0 %). Some loss and gain were not identified by MC or FISH but identified by genechip. UPD was solely identified by genechip in 51 patients; the most prevalent were UPD 7q (4.94 %) and UPD 17p (4.32 %). Furthermore, complex chromosomal aberrations were detected in 56 patients. In conclusion, Affymetrix CytoScan 750 K genechip was more precise than MC and FISH in detection of cryptic chromosomal aberrations relevant to MDS. Analysis of the prevalence and distribution of diverse chromosomal aberrations in China may improve strategies for MDS diagnosis and therapies. PMID:27225263

  6. Ring chromosome 13

    DEFF Research Database (Denmark)

    Brandt, C A; Hertz, Jens Michael; Petersen, M B; Vogel, F; Noer, H; Mikkelsen, M

    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 with...

  7. 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…

  8. 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.

  9. Chromosomes, cancer and radiosensitivity

    International Nuclear Information System (INIS)

    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

  10. Chromosome Morphology in Kniphofia.

    Directory of Open Access Journals (Sweden)

    J. M. J de Wet

    1960-12-01

    Full Text Available A number of species and varieties of the genus  Kniphofia (Liliaceae were studied cytologically. The somatic chromosome number is  2n = 12 in all the species. This is also true in  Notosceptrum natalense Baker.

  11. Structural organization of the inactive X chromosome in the mouse.

    Science.gov (United States)

    Giorgetti, Luca; Lajoie, Bryan R; Carter, Ava C; Attia, Mikael; Zhan, Ye; Xu, Jin; Chen, Chong Jian; Kaplan, Noam; Chang, Howard Y; Heard, Edith; Dekker, Job

    2016-07-28

    X-chromosome inactivation (XCI) involves major reorganization of the X chromosome as it becomes silent and heterochromatic. During female mammalian development, XCI is triggered by upregulation of the non-coding Xist RNA from one of the two X chromosomes. Xist coats the chromosome in cis and induces silencing of almost all genes via its A-repeat region, although some genes (constitutive escapees) avoid silencing in most cell types, and others (facultative escapees) escape XCI only in specific contexts. A role for Xist in organizing the inactive X (Xi) chromosome has been proposed. Recent chromosome conformation capture approaches have revealed global loss of local structure on the Xi chromosome and formation of large mega-domains, separated by a region containing the DXZ4 macrosatellite. However, the molecular architecture of the Xi chromosome, in both the silent and expressed regions,remains unclear. Here we investigate the structure, chromatin accessibility and expression status of the mouse Xi chromosome in highly polymorphic clonal neural progenitors (NPCs) and embryonic stem cells. We demonstrate a crucial role for Xist and the DXZ4-containing boundary in shaping Xi chromosome structure using allele-specific genome-wide chromosome conformation capture (Hi-C) analysis, an assay for transposase-accessible chromatin with high throughput sequencing (ATAC-seq) and RNA sequencing. Deletion of the boundary disrupts mega-domain formation, and induction of Xist RNA initiates formation of the boundary and the loss of DNA accessibility. We also show that in NPCs, the Xi chromosome lacks active/inactive compartments and topologically associating domains (TADs), except around genes that escape XCI. Escapee gene clusters display TAD-like structures and retain DNA accessibility at promoter-proximal and CTCF-binding sites. Furthermore, altered patterns of facultative escape genes indifferent neural progenitor clones are associated with the presence of different TAD

  12. Organization of the bacterial chromosome.

    OpenAIRE

    Krawiec, S.; Riley, M

    1990-01-01

    Recent progress in studies on the bacterial chromosome is summarized. Although the greatest amount of information comes from studies on Escherichia coli, reports on studies of many other bacteria are also included. A compilation of the sizes of chromosomal DNAs as determined by pulsed-field electrophoresis is given, as well as a discussion of factors that affect gene dosage, including redundancy of chromosomes on the one hand and inactivation of chromosomes on the other hand. The distinction ...

  13. Derivative chromosome 11 in a child resulting from a complex rearrangement involving chromosomes 3, 6 and 11 in father: Significance of parental karyotyping

    Directory of Open Access Journals (Sweden)

    Prabhat Ranjan

    2013-01-01

    Full Text Available The presence of derivative chromosome in a child with phenotypic features necessitates the need of parental karyotyping to ascertain the exact amount of loss or gain of the genetic material. The aim of this study was to emphasize the importance of parental karyotyping. Cytogenetic evaluation of the proband and his father were carried out at Laboratory. Cytogenetic analysis was performed on phytohemagglutinin stimulated cultures. The derivative chromosome 11 in proband was ascertained to have additional material from chromosome 6p arising from complex chromosomal rearrangement in the father. Karyotyping is the basic, cost-effective preliminary investigation in a child with mental subnormality or congenital anomalies.

  14. Loss of heterozygosity of chromosome 1p/19q and p53 protein expression in oligodendroglioma%少突胶质细胞瘤染色体1p/19 q杂合性缺失与p53蛋白表达的相关性研究

    Institute of Scientific and Technical Information of China (English)

    熊佶; 刘颖; 李超; 朱静静; 叶诸榕; 毛颖; 汪寅

    2009-01-01

    Objective To study the status of loss of heterozygosity ( LOH) of chromosome lp/19q and p53 protein expression in oligodendroglioma,as compared to astrocytoma.Methods One hundred and ninety-one cases of glioma of different histologic types and grades,including 116 cases of low-grade of oligodendroglioma ( 86 paraffin-embedded and 30 fresh tissues) ,45 cases of anaplastic oligodendroglioma (all paraffin-embedded tissues) and 30 cases of astrocytoma of various grades ( all paraffin-embedded tissues),were enrolled into the study.The LOH of chromosome lp/19q was investigated by polymerase chain reaction ( PCR) -based microsatellite analysis.The p53 protein expression was demonstrated by immunohistochemical staining.Results The rates of lp loss, 19q loss and lp/19q loss were 69.8% ,64%,and 57.0% respectively in the 86 paraffin-embedded low-grade oligodendroglioma samples,as compared to 71.1%,60.0% and 55.6% respectively in the 45 paraffin-embedded anaplastic oligodendroglioma samples.There was no difference of LOH of lp/19q between low-grade oligodendroglioma and anaplastic oligodendroglioma (P > 0.05).In the 30 cases of low-grade oligodendroglioma with fresh tissues available,the rates of lp loss,19q loss and lp/19q loss were 70.0%,63.3% and 60.0% respectively.The LOH of lp/19q between paraffin-embedded and fresh samples was not statistically significant (P >0.05).In the 30 cases of astrocytoma,the rates of lp loss,19q loss and lp/19q loss were 23.3%,33.3% and 20.0% respectively,which were significantly less than those in oligodendroglioma (P 0.05).30例WHO Ⅱ级少突胶质细胞瘤新鲜标本染色体1p缺失率为70.0%(21/30)、19q缺失率为63.3%(19/30)、1p/19q联合缺失率为60.0%(18/30),与石蜡标本的缺失率比较差异无统计学意义(P>0.05).30例星形细胞起源的肿瘤染色体对应三种缺失率分别为23.3%(7/30)、33.3%(10/30)及20.0%(6/30),与少突胶质细胞瘤差异有统计学意义(P<0.05).86例WHO Ⅱ

  15. Sequencing of rhesus macaque Y chromosome clarifies origins and evolution of the DAZ (Deleted in AZoospermia) genes

    OpenAIRE

    Hughes, Jennifer F.; Skaletsky, Helen; Page, David C.

    2012-01-01

    Studies of Y chromosome evolution often emphasize gene loss, but this loss has been counterbalanced by addition of new genes. The DAZ genes, which are critical to human spermatogenesis, were acquired by the Y chromosome in the ancestor of Old World monkeys and apes. We and our colleagues recently sequenced the rhesus macaque Y chromosome, and comparison of this sequence to human and chimpanzee enables us to reconstruct much of the evolutionary history of DAZ. We report that DAZ arrived on the...

  16. Development of a novel HAC-based "gain of signal" quantitative assay for measuring chromosome instability (CIN) in cancer cells

    OpenAIRE

    Kim, Jung Hyun; Lee, Hee Sheung; Lee, Nicholas C.O.; Goncharov, Nikolay V.; Kumeiko, Vadim; Masumoto, Hiroshi; Earnshaw, William C.; Kouprina, Natalay; Larionov, Vladimir

    2016-01-01

    Accumulating data indicates that chromosome instability (CIN) common to cancer cells can be used as a target for cancer therapy. At present the rate of chromosome mis-segregation is quantified by laborious techniques such as coupling clonal cell analysis with karyotyping or fluorescence in situ hybridization (FISH). Recently, a novel assay was developed based on the loss of a non-essential human artificial chromosome (HAC) carrying a constitutively expressed EGFP transgene ("loss of signal" a...

  17. Hearing Loss

    Science.gov (United States)

    ... labor & premature birth The newborn intensive care unit (NICU) Birth defects & other health conditions Loss & grief Tools & ... labor & premature birth The newborn intensive care unit (NICU) Birth defects & other health conditions Loss & grief Ask ...

  18. [Chromosomal organization of the genomes of small-chromosome plants].

    Science.gov (United States)

    Muravenko, O V; Zelenin, A V

    2009-11-01

    An effective approach to study the chromosome organization in genomes of plants with small chromosomes and/or with low-informative C-banding patterns was developed in the course of investigation of the karyotypes of cotton plant, camomile, flax, and pea. To increase the resolving power of chromosome analysis, methods were worked out for revealing early replication patterns on chromosomes and for artificial impairment of mitotic chromosome condensation with the use of a DNA intercalator, 9-aminoacridine (9-AMA). To estimate polymorphism of the patterns of C-banding of small chromosomes on preparations obtained with the use of 9-AMA, it is necessary to choose a length interval that must not exceed three average sizes of metaphase chromosomes without the intercalator. The use of 9-AMA increases the resolution of differential C- and OR-banding and the precision of physical chromosome mapping by the FISH method. Of particular importance in studying small chromosomes is optimization of the computer-aided methods used to obtain and process chromosome images. The complex approach developed for analysis of the chromosome organization in plant genomes was used to study the karyotypes of 24 species of the genus Linum L. It permitted their chromosomes to be identified for the first time, and, in addition, B chromosomes were discovered and studied in the karyotypes of the species of the section Syllinum. By similarity of the karyotypes, the studied flax species were distributed in eight groups in agreement with the clusterization of these species according to the results of RAPD analysis performed in parallel. Systematic positions and phylogenetic relationships of the studied flax species were verified. Out results can serve as an important argument in favour of the proposal to develop a special program for sequencing the genome of cultivated flax (L. usitatissimum L.), which is a major representative of small-chromosome species. PMID:20058798

  19. Persistent Increase in Chromosome Instability in Lung Cancer : Possible Indirect Involvement of p53 Inactivation

    OpenAIRE

    Haruki, Nobuhiro; Harano, Tomoko; Masuda, Akira; Kiyono, Tohru; TAKAHASHI, TAKAO; Tatematsu, Yoshio; Shimizu, Shigeki; Mitsudomi, Tetsuya; Konishi, Hiroyuki; Osada, Hirotaka; Fujii, Yoshitaka; Takahashi, Takashi

    2001-01-01

    Karyotype and fluorescence in situ hybridization analyses have demonstrated the frequent presence of an altered static state of the number of chromosomes (ie, aneuploidy) in lung cancer, but it has not been directly established whether aneuploidy is in fact associated with a persistent increase in the rate of chromosomal losses and gains (ie, chromosome instability, or CIN). The study presented here used a panel of 10 lung cancer cell lines to provide for the first time direct evidence that C...

  20. Dicentric chromosome in the bone marrow of a child with megakaryoblastic leukaemia and Down's syndrome.

    OpenAIRE

    Wilkie, A O; Kitchen, C.; Oakhill, A; Howell, R T; Berry, P J

    1988-01-01

    A two year old girl with Down's syndrome (constitutional karyotype: 47 + 21), presenting with pancytopenia, developed acute megakaryoblastic leukaemia (AMKL). Her bone marrow contained an abnormal clone with a novel dicentric chromosome derived from chromosomes 5 and 7 (karyotype 46, XX, -5, -7, +dic (5;7) (p 13; p 11.2), +21. This case provides further evidence for a connection between chromosome 21 and this unusual form of childhood leukaemia, and raises questions about the loss of short ar...

  1. Rapid mapping of chromosomal breakpoints: from blood to BAC in 20 days

    OpenAIRE

    Mei Wang; Adolf Baumgartner; Weier, Jingly F.; Johnson Kwan; Chun-Mei Lu; Tomas Escudero; Santiago MunnĂŠ; Weier, Heinz-Ulrich G.

    2009-01-01

    Structural chromosome aberrations and associated segmental or chromosomal aneusomies are major causes of reproductive failure in humans. Despite the fact that carriers of reciprocal balanced translocation often have no other clinical symptoms or disease, impaired chromosome homologue pairing in meiosis and karyokinesis errors lead to over-representation of translocations carriers in the infertile population and in recurrent pregnancy loss patients. At present, clinicians have no means to sele...

  2. Chromosome Structural Alteration an Unusual Abnormality Characterizing Human Neoplasia

    Directory of Open Access Journals (Sweden)

    Abolfazl Movafagh

    2016-04-01

    Full Text Available Background and Aim: Ring chromosomes are rare cytogenetic abnormalities that occur in less than 10% of hematopoietic malignancies. They are rare in blood disorder. The present review has focused on the ring chromosome associated with oncology malignancies. Materials and Methods: By reviewing the web-based search for all English scientific peer review articles published, was initiated using Medline/PubMed, Mitelman database (http://cgap.nci.nih.gov/Chromosomes/Mitelman, and other pertinent references on websites about ring chromosomes in Oncology. The software program as End Note was used to handle the proper references for instruction to author. Karyotype descriptions were cited according to ISCN.Conclusion: Ring chromosomes are rare chromosomal aberrations, almost many times are of de novo origin, presenting a different phenotype regarding the loss of genetic material. The karyotype represents the main analysis for detection of ring chromosomes, but other molecular technics are necessary for complete characterization. The information of this review article adds to the spectrum of both morphology and genetic rearrangements in the field of oncology malignancies.

  3. 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.

  4. The one-cell mouse embryo: cell cycle-dependent radiosensitivity and development of chromosomal anomalies in postradiation cell cycles

    International Nuclear Information System (INIS)

    One-cell mouse embryos were irradiated with X-rays at different cell cycle stages. Examination of structural chromosomal anomalies and micronucleus formation in postradiation mitoses and interphases demonstrated cell cycle-dependent radiosensitivities in the order: late G2 phase > G1 phase > S phase > early G2 phase > stage of decondensing nuclei. Comparison of the quality and quantity of chromosomal aberrations from the first to third mitosis led to the conclusion that new chromosomal anomalies were formed in the course of postirradiation cell cycles. This hypothesis was supported by an increasing number of micronuclei from 24 to 48 h post-conception. In addition to structural chromosomal aberrations, radiation-induced chromosome loss was observed with a frequency that was obviously independent of the exposed cell cycle phase. Loss of acentric chromosome fragments and of single chromosomes contributed to the micronucleus formation. (author)

  5. Mapping of metastasis suppressor genes for prostate cancer by microcell-mediated chromosome transfer

    Institute of Scientific and Technical Information of China (English)

    TomohikoICHIKAWA; ShigeruHOSOKI; HiroyoshiSUZUKI; KoichiroAKAKURA; TatsuoIGARASHI; YuzoFURUYA; MitsuoOSHIMURA; CarrieW.RINKER-SCHAEFFER; NaokiNIHEI; JohnT.ISAACS; HaruoITO

    2000-01-01

    Aim: To identify the metastasis suppressor genes for prostate cancer. Methods: A copy of human chromosomes was introduced into the highly metastatic Dunning R-3327 rat prostate cancer cells by the use of microcell-mediated chromosome transfer. Relationships between the size of human chromosomes introduced into microcell hybrid clones and the number of lung metastases produced by the clones were analyzed to determine which part of human chromosomes contained the metastasis suppressor gene (s) for prostate cancer. To determine portions of human chromosomes introduced, G-banding chromosomal analysis, fluorescence in situ hybridization analysis, and polymerase chain reaction analysis were performed. Results: Each of microcell hybrid clones containing human chromosomes 7, 8, 10, 11, 12, or 17 showed decreased ability to metastasize to the lung without any loss of ttmaorigenicity. This demonstrates that these human chromosomes contain metastasis suppressor genes for prostate cancer. Spontaneous deletion of portions of human chromosomes was observed in the human chromosome 7, 10, 11, 12, and 17 studies. In the human chromosome 8 study, irradiated microcell-mediated chromosome transfer was performed to enrich chromosomal ann deletions of human chromosome 8. Molecular and cytogenetic analyses of microcell hybrid clones demonstrated that metastasis suppressor genes on human chromosomes were located on 7q21-22, 7q31.2-32, 8p21-12, 10q11-22, 11p13-11.2, 12p11-q13, 12q24-ter, and 17pter-q23. KAI1 and MKK4/SEKI were identified as metastasis suppressor genes from 11p11.2 and 17p12, respectively. Conclusion: This assay system is useful to identify metastasis suppressor gene (s) for prostate cancer.

  6. Haploinsufficiency and the sex chromosomes from yeasts to humans

    Directory of Open Access Journals (Sweden)

    Oliver Stephen G

    2011-02-01

    Full Text Available Abstract Background Haploinsufficient (HI genes are those for which a reduction in copy number in a diploid from two to one results in significantly reduced fitness. Haploinsufficiency is increasingly implicated in human disease, and so predicting this phenotype could provide insights into the genetic mechanisms behind many human diseases, including some cancers. Results In the present work we show that orthologues of Saccharomyces cerevisiae HI genes are preferentially retained across the kingdom Fungi, and that the HI genes of S. cerevisiae can be used to predict haploinsufficiency in humans. Our HI gene predictions confirm known associations between haploinsufficiency and genetic disease, and predict several further disorders in which the phenotype may be relevant. Haploinsufficiency is also clearly relevant to the gene-dosage imbalances inherent in eukaryotic sex-determination systems. In S. cerevisiae, HI genes are over-represented on chromosome III, the chromosome that determines yeast's mating type. This may be a device to select against the loss of one copy of chromosome III from a diploid. We found that orthologues of S. cerevisiae HI genes are also over-represented on the mating-type chromosomes of other yeasts and filamentous fungi. In animals with heterogametic sex determination, accumulation of HI genes on the sex chromosomes would compromise fitness in both sexes, given X chromosome inactivation in females. We found that orthologues of S. cerevisiae HI genes are significantly under-represented on the X chromosomes of mammals and of Caenorhabditis elegans. There is no X inactivation in Drosophila melanogaster (increased expression of X in the male is used instead and, in this species, we found no depletion of orthologues to yeast HI genes on the sex chromosomes. Conclusion A special relationship between HI genes and the sex/mating-type chromosome extends from S. cerevisiae to Homo sapiens, with the microbe being a useful model for

  7. Effects of heavy-ion beams on chromosomes of common wheat, Triticum aestivum

    Energy Technology Data Exchange (ETDEWEB)

    Kikuchi, Shinji; Saito, Yoshinaka [Laboratory of Plant Genetics and Breeding Science, Faculty of Agriculture, Tottori University, 4-101 Koyama-Minami, Tottori 680-8553 (Japan); Ryuto, Hiromichi; Fukunishi, Nobuhisa; Abe, Tomoko [RIKEN Nishina Center, RIKEN, Hirosawa, Wako 351-0198 (Japan); Tanaka, Hiroyuki [Laboratory of Plant Genetics and Breeding Science, Faculty of Agriculture, Tottori University, 4-101 Koyama-Minami, Tottori 680-8553 (Japan); Tsujimoto, Hisashi, E-mail: tsujim@muses.tottori-u.ac.jp [Laboratory of Plant Genetics and Breeding Science, Faculty of Agriculture, Tottori University, 4-101 Koyama-Minami, Tottori 680-8553 (Japan)

    2009-10-02

    To investigate the nature of plant chromosomes irradiated by heavy-ion beams, the effects of nitrogen (N) and neon (Ne) ion beams on hexaploid wheat chromosomes were compared with those of X-ray. Chromosome aberrations, such as short, ring and dicentric chromosomes appeared in high frequency. The average numbers of chromosome breaks at LD-50 by irradiation with X-ray, N and Ne ion beams were 32, 20 and 20, respectively. These values may be underestimated because chromosome rearrangement without change in chromosome morphology was not counted. Thus, we subsequently used a wheat line with a pair of extra chromosomes from an alien species (Leymus racemosus) and observed the fate of the irradiated marker chromosomes by genomic in situ hybridization. This analysis revealed that 50 Gy of neon beam induced about eight times more breaks than those induced by X-ray. This result suggests that heavy-ion beams induce chromosome rearrangement in high frequency rather than loss of gene function. This suggests further that most of the novel mutations produced by ion beam irradiation, which have been used in plant breeding, may not be caused by ordinary gene disruption but by chromosome rearrangements.

  8. 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.

  9. ATM modulates the loading of recombination proteins onto a chromosomal translocation breakpoint hotspot

    NARCIS (Netherlands)

    J. Sun (Jiying); Y. Oma (Yukako); M. Harata (Masahiko); K. Kono (Kazuteru); H. Shima (Hiroki); A. Kinomura (Aiko); T. Ikura (Tsuyoshi); H. Suzuki (Hidekazu); S. Mizutani (Shuki); R. Kanaar (Roland); S. Tashiro (Satoshi)

    2010-01-01

    textabstractChromosome translocations induced by DNA damaging agents, such as ionizing radiation and certain chemotherapies, alter genetic information resulting in malignant transformation. Abrogation or loss of the ataxia-telangiectasia mutated (ATM) protein, a DNA damage signaling regulator, incre

  10. Resumption of mitosis in frozen-thawed embryos is not related to the chromosomal constitution

    DEFF Research Database (Denmark)

    Agerholm, Inge E; Kølvrå, Steen; Crüger, Dorthe G;

    2007-01-01

    OBJECTIVE: To study the relation between the resumption of mitosis after thaw and chromosomal constitution in frozen-thawed embryos. In addition, to evaluate the correlation among the three parameters of resumption of mitosis after thaw, postthaw blastomere loss, and multinucleation. DESIGN: Frozen......(S): Forty IVF and/or intracytoplasmic sperm injection patients. INTERVENTION(S): Embryo thawing, morphological evaluation, and fluorescence in situ hybridization analysis for aneuploidy screening. MAIN OUTCOME MEASURE(S): Resumption of mitosis, blastomere loss, multinucleation, and chromosome enumeration....... RESULT(S): No difference was observed in the chromosomal constitution of embryos with and without resumption of mitosis. Neither was the postthaw blastomere loss connected to the chromosomal constitution. The resumption of mitosis was not associated with postthaw loss of blastomeres or with...

  11. Molecular fundamentals of chromosomal mutagenesis

    International Nuclear Information System (INIS)

    Precise quantitative correlation between the yield of chromosome structure damages and the yield of DNA damages is shown when comparing data on molecular and cytogenetic investigations carried out in cultural Mammalia cells. As the chromosome structure damage is to be connected with the damage of its carcass structure, then it is natural that DNA damage in loop regions is not to affect considerably the structure, while DNA damage lying on the loop base and connected with the chromosome carcass is to play a determining role in chromosomal mutagenesis. This DNA constitutes 1-2% from the total quantity of nuclear DNA. If one accepts that damages of these regions of DNA are ''hot'' points of chromosomal mutagenesis, then it becomes clear why 1-2% of preparation damages in a cell are realized in chromosome structural damages

  12. 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...... hybridization approach developed for label-free detection of the chromosome translocations. For specific translocation detection it is necessary to determine that the two DNA sequences forming a derivative chromosome are connected, which is achieved by two subsequent hybridization steps. The electrochemical...... impedance spectroscopy was selected as the sensing method on a microfabricated chip with array of 12 electrode sets. Two independent chips (Chip1 and Chip2) were used for targeting the chromosomal fragments involved in the translocation. Each chip was differentially functionalized with DNA probes matching...

  13. Frequent meiotic recombination between the ends of truncated chromosome fragments of Saccharomyces cerevisiae.

    OpenAIRE

    Arbel, T; Shemesh, R; Simchen, G.

    1999-01-01

    A single truncated chromosome fragment (TCF) in diploid cells undergoes frequent ectopic recombination during meiosis between markers located near the ends of the fragment. Tetrads produced by diploids with a single TCF show frequent loss of one of the two markers. This marker loss could result either from recombination of the TCF with one of the two copies of the chromosome from which it was derived or from ectopic recombination between the ends of the TCF. The former would result in shorten...

  14. 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.

  15. Reference-assisted chromosome assembly

    OpenAIRE

    Kim, Jaebum; Larkin, Denis M; Cai, Qingle; Asan,; Zhang, Yongfen; Ge, Ri-Li; Auvil, Loretta; Capitanu, Boris; Zhang, Guojie; Lewin, Harris A.; Ma, Jian

    2013-01-01

    One of the most difficult problems in modern genomics is the assembly of full-length chromosomes using next generation sequencing (NGS) data. To address this problem, we developed “reference-assisted chromosome assembly” (RACA), an algorithm to reliably order and orient sequence scaffolds generated by NGS and assemblers into longer chromosomal fragments using comparative genome information and paired-end reads. Evaluation of results using simulated and real genome assemblies indicates that ou...

  16. Sex determination by chromosome manipulation in fish

    International Nuclear Information System (INIS)

    Since it is impossible to artificially remove only sex chromosomes in sperm, gamma- or UV-irradiation has been used in destroying all chromosomes without loss of abilities of sperm movement and egg activation. It has been shown that a dose of gamma rays required for this purpose is 105 rad in any species of fish. For UV-irradiation, a 15 W lamp is used and irradiation for 60 to 120 seconds is required. With such an irradiation technique, gynogenetic haploid embryogenesis is induced. In developing normal diploid embryos of eggs inseminated with irradiated sperm (gynogenetic diploid embryogenesis with XX type), it is furthermore necessary to use physical procedures, such as low or high temperature and hydrostatic pressure. Irradiated sperm of different species of fish has also been used in inducing gynogenesis. As the most desirable technique, it is proposed to physiologically convert the sex of gynogenetic diploid embryos into males and to use sperm from those physiological males with XX chromosomes. Theoretical possibility of developing androgenetic haploid embryogenesis has been suggested. (Namekawa, K.)

  17. Hidden loss

    DEFF Research Database (Denmark)

    Kieffer-Kristensen, Rikke; Johansen, Karen Lise Gaardsvig

    2013-01-01

    finding indicates that the children experienced numerous losses, many of which were often suppressed or neglected by the children to protect the ill parents. CONCLUSIONS: The findings indicated that the children seemed to make a special effort to hide their feelings of loss and grief in order to protect...

  18. 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…

  19. X-chromosome workshop.

    Science.gov (United States)

    Paterson, A D

    1998-01-01

    Researchers presented results of ongoing research to the X-chromosome workshop of the Fifth World Congress on Psychiatric Genetics, covering a wide range of disorders: X-linked infantile spasms; a complex phenotype associated with deletions of Xp11; male homosexuality; degree of handedness; bipolar affective disorder; schizophrenia; childhood onset psychosis; and autism. This report summarizes the presentations, as well as reviewing previous studies. The focus of this report is on linkage findings for schizophrenia and bipolar disorder from a number of groups. For schizophrenia, low positive lod scores were obtained for markers DXS991 and DXS993 from two studies, although the sharing of alleles was greatest from brother-brother pairs in one study, and sister-sister in the other. Data from the Irish schizophrenia study was also submitted, with no strong evidence for linkage on the X chromosome. For bipolar disease, following the report of a Finnish family linked to Xq24-q27, the Columbia group reported some positive results for this region from 57 families, however, another group found no evidence for linkage to this region. Of interest, is the clustering of low positive linkage results that point to regions for possible further study. PMID:9686435

  20. Chromosome analysis and sorting

    Czech Academy of Sciences Publication Activity Database

    Doležel, Jaroslav; Kubaláková, Marie; Suchánková, Pavla; Kovářová, Pavlína; Bartoš, Jan; Šimková, Hana

    Weinheim : Wiley-VCH, 2007 - (Doležel, J.; Greilhuber, J.; Suda, J.), s. 373-403 ISBN 978-3-527-31487-4 R&D Projects: GA ČR GA521/04/0607; GA ČR GP521/05/P257; GA ČR GD521/05/H013; GA MŠk(CZ) LC06004 Grant ostatní: Mendelova zemědělská a lesnická univerzita v Brně / Agronomická fakulta(CZ) ME 844 Institutional research plan: CEZ:AV0Z5038910 Source of funding: V - iné verejné zdroje ; V - iné verejné zdroje ; V - iné verejné zdroje ; V - iné verejné zdroje ; V - iné verejné zdroje Keywords : Plant flow cytometry * chromosome sorting * flow cytogenetics Subject RIV: EB - Genetics ; Molecular Biology http://books. google .com/books?id=3cwakORieqUC&pg=PA373&lpg=PA373&dq=Chromosome+analysis+and+sorting&source=web&ots=8IyvJlBQyq&sig=_NlXyQQgBCwpj1pTC9YITvvVZqU

  1. The chromosome passenger complex is required for fidelity of chromosome transmission and cytokinesis in meiosis of mouse oocytes.

    Science.gov (United States)

    Sharif, Bedra; Na, Jie; Lykke-Hartmann, Karin; McLaughlin, Stephen H; Laue, Ernest; Glover, David M; Zernicka-Goetz, Magdalena

    2010-12-15

    The existence of two forms of the chromosome passenger complex (CPC) in the mammalian oocyte has meant that its role in female meiosis has remained unclear. Here we use loss- and gain-of function approaches to assess the meiotic functions of one of the shared components of these complexes, INCENP, and of the variable kinase subunits, Aurora B or Aurora C. We show that either the depletion of INCENP or the combined inhibition of Aurora kinases B and C activates the anaphase-promoting complex or cyclosome (APC/C) before chromosomes have properly congressed in meiosis I and also prevents cytokinesis and hence extrusion of the first polar body. Overexpression of Aurora C also advances APC/C activation and results in cytokinesis failure in a high proportion of oocytes, indicative of a dominant effect on CPC function. Together, this points to roles for the meiotic CPC in functions similar to the mitotic roles of the complex: correcting chromosome attachment to microtubules, facilitating the spindle-assembly checkpoint (SAC) function and enabling cytokinesis. Surprisingly, overexpression of Aurora B leads to a failure of APC/C activation, stabilization of securin and consequently a failure of chiasmate chromosomes to resolve - a dominant phenotype that is completely suppressed by depletion of INCENP. Taken together with the differential distribution of Aurora proteins B and C on chiasmate chromosomes, this points to differential functions of the two forms of CPC in regulating the separation of homologous chromosomes in meiosis I. PMID:21123620

  2. Complementation of a DNA repair defect in xeroderma pigmentosum cells by transfer of human chromosome 9

    International Nuclear Information System (INIS)

    Complementation of the repair defect in xeroderma pigmentosum cells of complementation group A was achieved by the transfer of human chromosome 9. A set of mouse-human hybrid cell lines, each containing a single Ecogpt-marked human chromosome, was used as a source of donor chromosomes. Chromosome transfer to XPTG-1 cells, a hypoxanthine/guanine phosphoribosyltransferase-deficient mutant of simian virus 40-transformed complementation group A cells, was achieved by microcell fusion and selection for Ecogpt. Chromosome-transfer clones of XPTG-1 cells, each containing a different human donor chromosome, were analyzed for complementation of sensitivity to UV irradiation. Among all the clones, increased levels of resistance to UV was observed only in clones containing chromosome 9. Since our recipient cell line XPTG-1 is hypoxanthine/guanine phosphoribosyltransferase deficient, cultivation of Ecogpt+ clones in medium containing 6-thioguanine permits selection of cells for loss of the marker and, by inference, transferred chromosome 9. Clones isolated for growth in 6-thioguanine, which have lost the Ecogpt-marked chromosome, exhibited a UV-sensitive phenotype, confirming the presence of the repair gene(s) for complementation group A on chromosome 9

  3. Identification and description of distinct B chromosomes in Cyphocharax modestus (Characiformes, Curimatidae

    Directory of Open Access Journals (Sweden)

    Lessandra Viviane De Rosa Santos

    2008-01-01

    Full Text Available Cytogenetic analyses were performed in Cyphocharax modestus, collected at Paranapanema River and Tietê River (São Paulo State, Brazil. A karyotype with 2n = 54 chromosomes was observed in the animals from both Brazilian freshwater river systems. One to four B chromosomes were also detected in individuals from the Paranapanema River, which represents the probable first report of more than a single supernumerary element in a species of the Curimatidae group. C-banding revealed centromeric and telomeric heterochromatin blocks in several chromosomes of the normal karyotype complement of C. modestus. Moreover, while some B chromosomes were characterized by the complete absence of C-bands, others were totally heterochromatic. Although there was a prevalence of B chromosomes in males of C. modestus, at least one supernumerary element was found in males and/or females of several other populations of the species, which suggests that the presence of these chromosomes seems to represent a general trait of C. modestus. A possible origin of the described B chromosomes may be related to the occurrence of a chromosome non-disjunction followed by the loss of euchromatic segments, an event that should have occurred in chromosomes that present conspicuous centromeric heterochromatic blocks and even in chromosomes that lack C-bands in this region, resulting in small supernumerary elements.

  4. Chromosomal mosaicism in mouse two-cell embryos after paternal exposure to acrylamide

    Energy Technology Data Exchange (ETDEWEB)

    Marchetti, Francesco; Bishop, Jack; Lowe, Xiu; Wyrobek, Andrew J

    2008-10-14

    Chromosomal mosaicism in human preimplantation embryos is a common cause ofspontaneous abortions, however, our knowledge of its etiology is limited. We used multicolor fluorescence in situ hybridization (FISH) painting to investigate whether paternally-transmitted chromosomal aberrations result in mosaicism in mouse 2-cell embryos. Paternal exposure to acrylamide, an important industrial chemical also found in tobacco smoke and generated during the cooking process of starchy foods, produced significant increases in chromosomally defective 2-cell embryos, however, the effects were transient primarily affecting the postmeiotic stages of spermatogenesis. Comparisons with our previous study of zygotes demonstrated similar frequencies of chromosomally abnormal zygotes and 2-cell embryos suggesting that there was no apparent selection against numerical or structural chromosomal aberrations. However, the majority of affected 2-cell embryos were mosaics showing different chromosomal abnormalities in the two blastomeric metaphases. Analyses of chromosomal aberrations in zygotes and 2-cell embryos showed a tendency for loss of acentric fragments during the first mitotic division ofembryogenesis, while both dicentrics and translocations apparently underwent propersegregation. These results suggest that embryonic development can proceed up to the end of the second cell cycle of development in the presence of abnormal paternal chromosomes and that even dicentrics can persist through cell division. The high incidence of chromosomally mosaic 2-cell embryos suggests that the first mitotic division of embryogenesis is prone to missegregation errors and that paternally-transmitted chromosomal abnromalities increase the risk of missegregation leading to embryonic mosaicism.

  5. Memory loss

    Science.gov (United States)

    A person with memory loss needs a lot of support. It helps to show the person familiar objects, music, or and photos or play familiar music. Write down when the person should take any medicine or do other ...

  6. 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.

  7. Causes of oncogenic chromosomal translocation

    OpenAIRE

    Aplan, Peter D.

    2005-01-01

    Non-random chromosomal translocations are frequently associated with a variety of cancers, especially hematologic malignancies and childhood sarcomas In addition to their diagnostic utility, chromosomal translocations are increasingly being used in the clinic to guide therapeutic decisions. However, the mechanisms which cause these translocations remain poorly understood. Illegit...

  8. Genetics Home Reference: ring chromosome 20 syndrome

    Science.gov (United States)

    ... 3 links) Encyclopedia: Chromosome Encyclopedia: Epilepsy Health Topic: Epilepsy Genetic and Rare Diseases Information Center (1 link) Ring chromosome 20 Additional NIH Resources (2 links) National Human Genome Research Institute: Chromosome Abnormalities National Institute of ...

  9. Genetics Home Reference: ring chromosome 14 syndrome

    Science.gov (United States)

    ... Encyclopedia: Chromosome Health Topic: Developmental Disabilities Health Topic: Epilepsy Genetic and Rare Diseases Information Center (1 link) Ring chromosome 14 Additional NIH Resources (2 links) National Human Genome Research Institute: Chromosome Abnormalities National Institute of ...

  10. 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. PMID:26566111

  11. Selection-Driven Gene Loss in Bacteria

    OpenAIRE

    Koskiniemi, Sanna; Sun, Song; Berg, Otto; Andersson, Dan I.

    2012-01-01

    Gene loss by deletion is a common evolutionary process in bacteria, as exemplified by bacteria with small genomes that have evolved from bacteria with larger genomes by reductive processes. The driving force(s) for genome reduction remains unclear, and here we examined the hypothesis that gene loss is selected because carriage of superfluous genes confers a fitness cost to the bacterium. In the bacterium Salmonella enterica, we measured deletion rates at 11 chromosomal positions and the fitne...

  12. ADN et chromosomes

    OpenAIRE

    Hayes, Hélène

    2000-01-01

    Chaque chromosome contient une seule molécule d’ADN. L’ADN déroulé d’un noyau de cellule humaine mesurerait environ 1,8 m : chaque molécule d’ADN est enroulée et compactée en plusieurs étapes, grâce à l’association de différentes protéines, et loge dans le noyau de 6 µm de diamètre. Le degré de condensation de l’ADN est variable selon les régions chromosomiques et les régions les moins condensées sont les plus riches en gènes. L’ADN est composé d’une variété de séquences codantes ou non et ré...

  13. X-Chromosome dosage compensation.

    Science.gov (United States)

    Meyer, Barbara J

    2005-01-01

    In mammals, flies, and worms, sex is determined by distinctive regulatory mechanisms that cause males (XO or XY) and females (XX) to differ in their dose of X chromosomes. In each species, an essential X chromosome-wide process called dosage compensation ensures that somatic cells of either sex express equal levels of X-linked gene products. The strategies used to achieve dosage compensation are diverse, but in all cases, specialized complexes are targeted specifically to the X chromosome(s) of only one sex to regulate transcript levels. In C. elegans, this sex-specific targeting of the dosage compensation complex (DCC) is controlled by the same developmental signal that establishes sex, the ratio of X chromosomes to sets of autosomes (X:A signal). Molecular components of this chromosome counting process have been defined. Following a common step of regulation, sex determination and dosage compensation are controlled by distinct genetic pathways. C. elegans dosage compensation is implemented by a protein complex that binds both X chromosomes of hermaphrodites to reduce transcript levels by one-half. The dosage compensation complex resembles the conserved 13S condensin complex required for both mitotic and meiotic chromosome resolution and condensation, implying the recruitment of ancient proteins to the new task of regulating gene expression. Within each C. elegans somatic cell, one of the DCC components also participates in the separate mitotic/meiotic condensin complex. Other DCC components play pivotal roles in regulating the number and distribution of crossovers during meiosis. The strategy by which C. elegans X chromosomes attract the condensin-like DCC is known. Small, well-dispersed X-recognition elements act as entry sites to recruit the dosage compensation complex and to nucleate spreading of the complex to X regions that lack recruitment sites. In this manner, a repressed chromatin state is spread in cis over short or long distances, thus establishing the

  14. 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...

  15. 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...

  16. 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

  17. Mitotic chromosome condensation in vertebrates

    International Nuclear Information System (INIS)

    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

  18. 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

    2013-01-01

    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. PMID:23884766

  19. Computer aided analysis of additional chromosome aberrations in Philadelphia chromosome positive acute lymphoblastic leukaemia using a simplified computer readable cytogenetic notation

    OpenAIRE

    Mohr Brigitte; Jauch Anna; Heinze Barbara; Fonatsch Christa; Balz Harald; Bradtke Jutta; Schoch Claudia; Rieder Harald

    2003-01-01

    Abstract Background The analysis of complex cytogenetic databases of distinct leukaemia entities may help to detect rare recurring chromosome aberrations, minimal common regions of gains and losses, and also hot spots of genomic rearrangements. The patterns of the karyotype alterations may provide insights into the genetic pathways of disease progression. Results We developed a simplified computer readable cytogenetic notation (SCCN) by which chromosome findings are normalised at a resolution...

  20. Derivative chromosome 11 in a child resulting from a complex rearrangement involving chromosomes 3, 6 and 11 in father: Significance of parental karyotyping

    OpenAIRE

    Prabhat Ranjan; Kundanbala Desai; Shailaja Gada Saxena

    2013-01-01

    The presence of derivative chromosome in a child with phenotypic features necessitates the need of parental karyotyping to ascertain the exact amount of loss or gain of the genetic material. The aim of this study was to emphasize the importance of parental karyotyping. Cytogenetic evaluation of the proband and his father were carried out at Laboratory. Cytogenetic analysis was performed on phytohemagglutinin stimulated cultures. The derivative chromosome 11 in proband was ascertained to have ...

  1. Chromosome conservation in squamate reptiles revealed by comparative chromosome painting

    Czech Academy of Sciences Publication Activity Database

    Giovannotti, M.; Pokorná, Martina; Kratochvíl, L.; Caputo, V.; Olmo, E.; Ferguson-Smith, M. A.; Rens, W.

    Manchester : ICCS, 2011. 78-78. [Intarnational Chromosome Conference /18./. 29.08.2011-02.09.2011, Manchester] Institutional research plan: CEZ:AV0Z50450515 Keywords : squamate reptiles Subject RIV: EG - Zoology

  2. 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.

  3. Mechanisms of ring chromosome formation, ring instability and clinical consequences

    Directory of Open Access Journals (Sweden)

    Guilherme Roberta S

    2011-12-01

    Full Text Available Abstract Background The breakpoints and mechanisms of ring chromosome formation were studied and mapped in 14 patients. Methods Several techniques were performed such as genome-wide array, MLPA (Multiplex Ligation-Dependent Probe Amplification and FISH (Fluorescent in situ Hybridization. Results The ring chromosomes of patients I to XIV were determined to be, respectively: r(3(p26.1q29, r(4(p16.3q35.2, r(10(p15.3q26.2, r(10(p15.3q26.13, r(13(p13q31.1, r(13(p13q34, r(14(p13q32.33, r(15(p13q26.2, r(18(p11.32q22.2, r(18(p11.32q21.33, r(18(p11.21q23, r(22(p13q13.33, r(22(p13q13.2, and r(22(p13q13.2. These rings were found to have been formed by different mechanisms, such as: breaks in both chromosome arms followed by end-to-end reunion (patients IV, VIII, IX, XI, XIII and XIV; a break in one chromosome arm followed by fusion with the subtelomeric region of the other (patients I and II; a break in one chromosome arm followed by fusion with the opposite telomeric region (patients III and X; fusion of two subtelomeric regions (patient VII; and telomere-telomere fusion (patient XII. Thus, the r(14 and one r(22 can be considered complete rings, since there was no loss of relevant genetic material. Two patients (V and VI with r(13 showed duplication along with terminal deletion of 13q, one of them proved to be inverted, a mechanism known as inv-dup-del. Ring instability was detected by ring loss and secondary aberrations in all but three patients, who presented stable ring chromosomes (II, XIII and XIV. Conclusions We concluded that the clinical phenotype of patients with ring chromosomes may be related with different factors, including gene haploinsufficiency, gene duplications and ring instability. Epigenetic factors due to the circular architecture of ring chromosomes must also be considered, since even complete ring chromosomes can result in phenotypic alterations, as observed in our patients with complete r(14 and r(22.

  4. Targeted Chromosomal Translocations and Essential Gene Knockout Using CRISPR/Cas9 Technology in Caenorhabditis elegans.

    Science.gov (United States)

    Chen, Xiangyang; Li, Mu; Feng, Xuezhu; Guang, Shouhong

    2015-12-01

    Many genes play essential roles in development and fertility; their disruption leads to growth arrest or sterility. Genetic balancers have been widely used to study essential genes in many organisms. However, it is technically challenging and laborious to generate and maintain the loss-of-function mutations of essential genes. The CRISPR/Cas9 technology has been successfully applied for gene editing and chromosome engineering. Here, we have developed a method to induce chromosomal translocations and produce genetic balancers using the CRISPR/Cas9 technology and have applied this approach to edit essential genes in Caenorhabditis elegans. The co-injection of dual small guide RNA targeting genes on different chromosomes resulted in reciprocal translocation between nonhomologous chromosomes. These animals with chromosomal translocations were subsequently crossed with animals that contain normal sets of chromosomes. The F1 progeny were subjected to a second round of Cas9-mediated gene editing. Through this method, we successfully produced nematode strains with specified chromosomal translocations and generated a number of loss-of-function alleles of two essential genes (csr-1 and mes-6). Therefore, our method provides an easy and efficient approach to generate and maintain loss-of-function alleles of essential genes with detailed genetic background information. PMID:26482793

  5. Familial transmission of a deletion of chromosome 21 derived from a translocation between chromosome 21 and an inverted chromosome 22.

    Science.gov (United States)

    Aviv, H; Lieber, C; Yenamandra, A; Desposito, F

    1997-06-27

    Chromosome analysis of a newborn boy with Down syndrome resulted in the identification of a family with an unusual derivative chromosome 22. The child has 46 chromosomes, including two chromosomes 21, one normal chromosome 22, and a derivative chromosome 22. Giemsa banding and fluorescent in situ hybridization (FISH) studies show that the derivative chromosome is chromosome 22 with evidence of both paracentric and pericentric inversions, joined to the long arm of chromosome 21 from 21q21.2 to qter. The rearrangement results in partial trisomy 21 extending from 21q21.2 to 21q terminus in the patient. The child's mother, brother, maternal aunt, and maternal grandmother are all carriers of the derivative chromosome. All have 45 chromosomes, with one normal chromosome 21, one normal chromosome 22, and the derivative chromosome 22. The rearrangement results in the absence of the short arm, the centromere, and the proximal long arm of chromosome 21 (del 21pter-21q21.2) in carriers. Carriers of the derivative chromosome in this family have normal physical appearance, mild learning disabilities and poor social adjustment. PMID:9182781

  6. Meiosis and chromosome painting of sex chromosome systems in Ceboidea.

    Science.gov (United States)

    Mudry, M D; Rahn, I M; Solari, A J

    2001-06-01

    The identity of the chromosomes involved in the multiple sex system of Alouatta caraya (Aca) and the possible distribution of this system among other Ceboidea were investigated by chromosome painting of mitotic cells from five species and by analysis of meiosis at pachytene in two species. The identity of the autosome #7 (X2) involved in the multiple system of Aca and its breakage points were demonstrated by both meiosis and chromosome painting. These features are identical to those described by Consigliere et al. [1996] in Alouatta seniculus sara (Assa) and Alouatta seniculus arctoidea (Asar). This multiple system was absent in the other four Ceboidea species studied here. However, data from the literature strongly suggest the presence of this multiple in other members of this genus. The presence of this multiple system among several species and subspecies that show high levels of chromosome rearrangements may suggest a special selective value of this multiple. The meiotic features of the sex systems of Aca and Cebus apella paraguayanus (Cap) are strikingly different at pachytene, as the latter system is similar to the sex pair of man and other primates. The relatively large genetic distances between species presently showing this multiple system suggest that its origin is not recent. Other members of the same genus should be investigated at meiosis and by chromosome painting in order to know the extent and distribution of this complex sex-chromosome system. PMID:11376445

  7. The microcell mediated transfer of human chromosome 8 into highly metastatic rat liver cancer cell line C5F

    Institute of Scientific and Technical Information of China (English)

    Hu Liu; Sheng-Long Ye; Jiong Yang; Zhao-You Tang; Yin-Kun Liu; Lun-Xiu Qin; Shuang-Jian Qiu; Rui-Xia Sun

    2003-01-01

    AIM: Our previous research on the surgical samples of primary liver cancer with CGH showed that the loss of human chromosome 8p had correlation with the metastatic phenotype of liver cancer. In order to seek the functional evidence that there could be a metastatsis suppressor gene (s) for liver cancer on human chromosome 8, we tried to transfer normal human chromosome 8 into rat liver cancer cell line C5F, which had high metastatic potential to lung.METHODS: Human chromosome 8 randomly marked with neo gene was introduced into C5F cell line by MMCT and positive microcell hybrids were screened by double selections of G418 and HAT. Single cell isolation cloning was applied to clone microcell hybrids. Finally, STS-PCR and WCP-FISH were used to confirm the introduction.RESULTS: Microcell hybrids resistant to HAT and G418 were obtained and 15 clones were obtained by single-cell isolation cloning. STS-PCR and WCP-FISH proved that human chromosome 8 had been successfully introduced into rat liver cancer cell line C5F. STS-PCR detected a random loss in the chromosome introduced and WCP-FISH found a consistent recombination of the introduced human chromosome with the rat chromosome.CONCLUSION: The successful introduction of human chromosome 8 into highly metastatic rat liver cancer cell line builds the basis for seeking functional evidence of a metastasis suppressor gene for liver cancer harboring on human chromosome 8 and its subsequent cloning.

  8. [Role of transposons in origin and evolution of plant XY sex chromosomes].

    Science.gov (United States)

    Shufen, Li; Sha, Li; Chuanliang, Deng; Longdou, Lu; Wujun, Gao

    2015-02-01

    The XY sex-determination system is crucial for plant reproduction. However, little is known about the mechanism of the origin and evolution of the XY sex chromosomes. It has been believed that a pair of autosomes is evolved to produce young sex chromosomes (neo-X chromosome and neo-Y chromosome) by loss of function or gain of function mutation, which influences the development of pistil or stamen. With the aggravation of the recombination suppression between neo-X and neo-Y and consequent expanding of the non-recombination region, the proto-sex chromosomes were finally developed to heteromorphic sex chromosomes. Accumulation of repetitive sequences and DNA methylation were probably involved in this process. Transposons, as the most abundant repetitive sequences in the genome, might be the initial motivation factors for the evolution of sex chromosome. Moreover, transposons may also increase heterochromatin expansion and recombination suppression of sex chromosome by local epigenetics modification. In this review, we summarize the function of transposon accumulation and the relationship between transposon and heterochromatization in the evolution of plant sex chromosome. PMID:25665642

  9. Distribution of Telomeric Sequences (TTAGGG)n in Rearranged Chromosomes of Phyllotine Rodents (Cricetidae, Sigmodontinae).

    Science.gov (United States)

    Lanzone, Cecilia; Labaroni, Carolina; Suárez, Natalia; Rodríguez, Daniela; Herrera, Macarena L; Bolzán, Alejandro D

    2015-01-01

    Phyllotines are sigmodontine rodents endemic to South America with broad genetic variability, Robertsonian polymorphisms being the most frequent. Moreover, this taxon includes a species with multiple sex chromosomes, which is infrequent in mammals. However, molecular cytogenetic techniques have never been applied to phyllotines to elucidate their karyotypic evolution. We studied the chromosomes of 4 phyllotine species using FISH with a pantelomeric probe (TTAGGG)n. Graomys griseoflavus, Eligmodontia puerulus, and E. morgani are polymorphic for Robertsonian translocations, whereas Salinomys delicatus possesses XX/ XY1Y2 sex chromosomes. Telomeric signals were detected at both ends of all chromosomes of the studied species. In S. delicatus interstitial telomeric sequences (ITS) were observed in the 3 major chromosome pairs, which are equidistant from one of the telomeres in these chromosomes. These results suggest that ITS are important in the reshuffling of the highly derived karyotype of S. delicatus. Considering the phylogeny of phyllotines, the Robertsonian rearrangements of G. griseoflavus, E. puerulus, and E. morgani possibly represent chromosome fusions which have occurred independently. The pericentromeric regions of the biarmed chromosomes of these species do not contain telomeric sequences characteristic for strict fusions of recent origin, suggesting a common pattern of telomeric repeat loss during chromosomal evolution of these rodents. PMID:27035350

  10. Patterns of molecular evolution of an avian neo-sex chromosome.

    Science.gov (United States)

    Pala, Irene; Hasselquist, Dennis; Bensch, Staffan; Hansson, Bengt

    2012-12-01

    Newer parts of sex chromosomes, neo-sex chromosomes, offer unique possibilities for studying gene degeneration and sequence evolution in response to loss of recombination and population size decrease. We have recently described a neo-sex chromosome system in Sylvioidea passerines that has resulted from a fusion between the first half (10 Mb) of chromosome 4a and the ancestral sex chromosomes. In this study, we report the results of molecular analyses of neo-Z and neo-W gametologs and intronic parts of neo-Z and autosomal genes on the second half of chromosome 4a in three species within different Sylvioidea lineages (Acrocephalidea, Timaliidae, and Alaudidae). In line with hypotheses of neo-sex chromosome evolution, we observe 1) lower genetic diversity of neo-Z genes compared with autosomal genes, 2) moderate synonymous and weak nonsynonymous sequence divergence between neo-Z and neo-W gametologs, and 3) lower GC content on neo-W than neo-Z gametologs. Phylogenetic reconstruction of eight neo-Z and neo-W gametologs suggests that recombination continued after the split of Alaudidae from the rest of the Sylvioidea lineages (i.e., after ~42.2 Ma) and with some exceptions also after the split of Acrocephalidea and Timaliidae (i.e., after ~39.4 Ma). The Sylvioidea neo-sex chromosome shares classical evolutionary features with the ancestral sex chromosomes but, as expected from its more recent origin, shows weaker divergence between gametologs. PMID:22826461

  11. Radiation-induced chromosomal instability in human mammary epithelial cells

    Science.gov (United States)

    Durante, M.; Grossi, G. F.; Yang, T. C.

    1996-01-01

    Karyotypes of human cells surviving X- and alpha-irradiation have been studied. Human mammary epithelial cells of the immortal, non-tumorigenic cell line H184B5 F5-1 M/10 were irradiated and surviving clones isolated and expanded in culture. Cytogenetic analysis was performed using dedicated software with an image analyzer. We have found that both high- and low-LET radiation induced chromosomal instability in long-term cultures, but with different characteristics. Complex chromosomal rearrangements were observed after X-rays, while chromosome loss predominated after alpha-particles. Deletions were observed in both cases. In clones derived from cells exposed to alpha-particles, some cells showed extensive chromosome breaking and double minutes. Genomic instability was correlated to delayed reproductive death and neoplastic transformation. These results indicate that chromosomal instability is a radiation-quality-dependent effect which could determine late genetic effects, and should therefore be carefully considered in the evaluation of risk for space missions.

  12. 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.

  13. Methods for chromosome-specific staining

    Science.gov (United States)

    Gray, Joe W.; Pinkel, Daniel

    1995-01-01

    Methods and compositions for chromosome-specific staining are provided. Compositions comprise heterogenous mixtures of labeled nucleic acid fragments having substantially complementary base sequences to unique sequence regions of the chromosomal DNA for which their associated staining reagent is specific. Methods include methods for making the chromosome-specific staining compositions of the invention, and methods for applying the staining compositions to chromosomes.

  14. Chromosome Architecture and Genome Organization

    OpenAIRE

    Giorgio Bernardi

    2015-01-01

    How the same DNA sequences can function in the three-dimensional architecture of interphase nucleus, fold in the very compact structure of metaphase chromosomes and go precisely back to the original interphase architecture in the following cell cycle remains an unresolved question to this day. The strategy used to address this issue was to analyze the correlations between chromosome architecture and the compositional patterns of DNA sequences spanning a size range from a few hundreds to a few...

  15. Chromosome evolution in Neotropical butterflies

    OpenAIRE

    Saura, Anssi; Von Schoultz, Barbara; Saura, Anja O.; Brown, Keith S., Jr.

    2013-01-01

    We list the chromosome numbers for 65 species of Neotropical Hesperiidae and 104 species or subspecies of Pieridae. In Hesperiidae the tribe Pyrrhopygini have a modal n = 28, Eudaminae and Pyrgini a modal n = 31, while Hesperiinae have n = around 29. Among Pieridae, Coliadinae have a strong modal n = 31 and among Pierinae Anthocharidini are almost fixed for n = 15 while Pierini vary with n = 26 as the most common chromosome number. Dismorphiinae show wide variation. We discuss these results i...

  16. Chromosome 3p microsatellite allelotyping in neuroblastoma: a report on the technical hurdles.

    Science.gov (United States)

    Hoebeeck, Jasmien; De Wilde, Bram; Michels, Evi; Combaret, Valérie; Yigit, Nurten; De Smet, Els; Van Roy, Nadine; Stanbridge, Eric; Ru, Ning; Laureys, Geneviève; De Paepe, Anne; Speleman, Frank; Vandesompele, Jo

    2009-10-01

    Pinpointing critical regions of recurrent loss may help localize tumor suppressor genes. To determine the regions of loss on chromosome 3p in neuroblastoma, we performed loss of heterozygosity analysis using 16 microsatellite markers in a series of 65 primary tumors and 29 neuroblastoma cell lines. In this study, we report the results and discuss the technical hurdles that we encountered during data generation and interpretation that are of relevance for current studies or tests employing microsatellites. To provide functional support for the implication of 3p tumor suppressor genes in this childhood malignancy, we performed a microcell-mediated chromosome 3 transfer in neuroblastoma cells. PMID:19544108

  17. 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.

  18. Chromosome evolution in Neotropical butterflies.

    Science.gov (United States)

    Saura, Anssi; Von Schoultz, Barbara; Saura, Anja O; Brown, Keith S

    2013-06-01

    We list the chromosome numbers for 65 species of Neotropical Hesperiidae and 104 species or subspecies of Pieridae. In Hesperiidae the tribe Pyrrhopygini have a modal n = 28, Eudaminae and Pyrgini a modal n = 31, while Hesperiinae have n = around 29. Among Pieridae, Coliadinae have a strong modal n = 31 and among Pierinae Anthocharidini are almost fixed for n = 15 while Pierini vary with n = 26 as the most common chromosome number. Dismorphiinae show wide variation. We discuss these results in the context of chromosome numbers of over 1400 Neotropical butterfly species and subspecies derived from about 3000 populations published here and in earlier papers of a series. The overall results show that many Neotropical groups are characterized by karyotype instability with several derived modal numbers or none at all, while almost all taxa of Lepidoptera studied from the other parts of the world have one of n = 29-31 as modal numbers. Possibly chromosome number changes become fixed in the course of speciation driven by biotic interactions. Population subdivision and structuring facilitate karyotype change. Factors that stabilize chromosome numbers include hybridization among species sharing the same number, migration, sexual selection and possibly the distribution of chromosomes within the nucleus. PMID:23865963

  19. Chromosome Architecture and Genome Organization

    Science.gov (United States)

    Bernardi, Giorgio

    2015-01-01

    How the same DNA sequences can function in the three-dimensional architecture of interphase nucleus, fold in the very compact structure of metaphase chromosomes and go precisely back to the original interphase architecture in the following cell cycle remains an unresolved question to this day. The strategy used to address this issue was to analyze the correlations between chromosome architecture and the compositional patterns of DNA sequences spanning a size range from a few hundreds to a few thousands Kilobases. This is a critical range that encompasses isochores, interphase chromatin domains and boundaries, and chromosomal bands. The solution rests on the following key points: 1) the transition from the looped domains and sub-domains of interphase chromatin to the 30-nm fiber loops of early prophase chromosomes goes through the unfolding into an extended chromatin structure (probably a 10-nm “beads-on-a-string” structure); 2) the architectural proteins of interphase chromatin, such as CTCF and cohesin sub-units, are retained in mitosis and are part of the discontinuous protein scaffold of mitotic chromosomes; 3) the conservation of the link between architectural proteins and their binding sites on DNA through the cell cycle explains the “mitotic memory” of interphase architecture and the reversibility of the interphase to mitosis process. The results presented here also lead to a general conclusion which concerns the existence of correlations between the isochore organization of the genome and the architecture of chromosomes from interphase to metaphase. PMID:26619076

  20. Evolution of Sex Chromosomes in Insects

    OpenAIRE

    Kaiser, Vera B; Bachtrog, Doris

    2010-01-01

    Sex chromosomes have many unusual features relative to autosomes. Y (or W) chromosomes lack genetic recombination, are male- (female-) limited, and show an abundance of genetically inert heterochromatic DNA but contain few functional genes. X (or Z) chromosomes also show sex-biased transmission (i.e., X chromosomes show female-biased and Z-chromosomes show male-biased inheritance) and are hemizygous in the heterogametic sex. Their unusual ploidy level and pattern of inheritance imply that sex...

  1. Seventy Million Years of Concerted Evolution of a Homoeologous Chromosome Pair, in Parallel, in Major Poaceae Lineages[W

    Science.gov (United States)

    Wang, Xiyin; Tang, Haibao; Paterson, Andrew H.

    2011-01-01

    Whole genome duplication ~70 million years ago provided raw material for Poaceae (grass) diversification. Comparison of rice (Oryza sativa), sorghum (Sorghum bicolor), maize (Zea mays), and Brachypodium distachyon genomes revealed that one paleo-duplicated chromosome pair has experienced very different evolution than all the others. For tens of millions of years, the two chromosomes have experienced illegitimate recombination that has been temporally restricted in a stepwise manner, producing structural stratification in the chromosomes. These strata formed independently in different grass lineages, with their similarities (low sequence divergence between paleo-duplicated genes) preserved in parallel for millions of years since the divergence of these lineages. The pericentromeric region of this homeologous chromosome pair accounts for two-thirds of the gene content differences between the modern chromosomes. Both intriguing and perplexing is a distal chromosomal region with the greatest DNA similarity between surviving duplicated genes but also with the highest concentration of lineage-specific gene pairs found anywhere in these genomes and with a significantly elevated gene evolutionary rate. Intragenomic similarity near this chromosomal terminus may be important in hom(e)ologous chromosome pairing. Chromosome structural stratification, together with enrichment of autoimmune response–related (nucleotide binding site–leucine-rich repeat) genes and accelerated DNA rearrangement and gene loss, confer a striking resemblance of this grass chromosome pair to the sex chromosomes of other taxa. PMID:21266659

  2. Chromosome 3p alterations in pancreatic endocrine neoplasia

    Science.gov (United States)

    Amato, Eliana; Barbi, Stefano; Malpeli, Giorgio; Bersani, Samantha; Pelosi, Giuseppe; Capelli, Paola

    2010-01-01

    Pancreatic endocrine tumors (PET) are rare neoplasms classified as functioning (F-PET) or non-functioning (NF-PET) according to the presence of a clinical syndrome due to hormonal hypersecretion. PETs show variable degrees of clinical aggressiveness and loss of chromosome 3p has been suggested to be associated with an advanced stage of disease. We assessed chromosome 3p copy number in 113 primary PETs and 32 metastases by fluorescence in situ hybridization (FISH) using tissue microarrays. The series included 56 well-differentiated endocrine tumors (WDET), 62 well-differentiated endocrine carcinomas (WDEC), and 6 poorly differentiated endocrine carcinomas (PDEC). Chromosome 3p alterations were found in 23/113 (20%) primary tumors, with losses being predominant over gains (14% vs. 6%). Loss of 3p was found in 5/55 (9%) WDET, 11/52 (21%) WDEC, and never in PDEC. Gains of 3p were detected in 4/55 (7%) WDET, no WDEC, but notably in 3/6 (50%) PDEC (OR 23.6; P = 0.003). Metastases were more frequently monosomic for 3p compared to primary tumors (OR 3.6; P = 0.005). Monosomy was significantly associated with larger tumor size, more advanced tumor stage, and metastasis. No association was found with survival. Chromosome 3p copy number alterations are frequent events in advanced stage PET, with gains prevailing in PDEC while losses are more frequent in WDEC, supporting the view that a specific pattern of alterations are involved in these diverse disease subtypes. PMID:20981439

  3. Positional and functional mapping of a neuroblastoma differentiation gene on chromosome 11

    Directory of Open Access Journals (Sweden)

    Bader Scott

    2005-07-01

    Full Text Available Abstract Background Loss of chromosome 11q defines a subset of high-stage aggressive neuroblastomas. Deletions are typically large and mapping efforts have thus far not lead to a well defined consensus region, which hampers the identification of positional candidate tumour suppressor genes. In a previous study, functional evidence for a neuroblastoma suppressor gene on chromosome 11 was obtained through microcell mediated chromosome transfer, indicated by differentiation of neuroblastoma cells with loss of distal 11q upon introduction of chromosome 11. Interestingly, some of these microcell hybrid clones were shown to harbour deletions in the transferred chromosome 11. We decided to further exploit this model system as a means to identify candidate tumour suppressor or differentiation genes located on chromosome 11. Results In a first step, we performed high-resolution arrayCGH DNA copy-number analysis in order to evaluate the chromosome 11 status in the hybrids. Several deletions in both parental and transferred chromosomes in the investigated microcell hybrids were observed. Subsequent correlation of these deletion events with the observed morphological changes lead to the delineation of three putative regions on chromosome 11: 11q25, 11p13->11p15.1 and 11p15.3, that may harbour the responsible differentiation gene. Conclusion Using an available model system, we were able to put forward some candidate regions that may be involved in neuroblastoma. Additional studies will be required to clarify the putative role of the genes located in these chromosomal segments in the observed differentiation phenotype specifically or in neuroblastoma pathogenesis in general.

  4. Chromosome painting in the manatee supports Afrotheria and Paenungulata

    Directory of Open Access Journals (Sweden)

    Zori Roberto T

    2007-01-01

    Full Text Available Abstract Background Sirenia (manatees, dugongs and Stellar's sea cow have no evolutionary relationship with other marine mammals, despite similarities in adaptations and body shape. Recent phylogenomic results place Sirenia in Afrotheria and with elephants and rock hyraxes in Paenungulata. Sirenia and Hyracoidea are the two afrotherian orders as yet unstudied by comparative molecular cytogenetics. Here we report on the chromosome painting of the Florida manatee. Results The human autosomal and X chromosome paints delimited a total of 44 homologous segments in the manatee genome. The synteny of nine of the 22 human autosomal chromosomes (4, 5, 6, 9, 11, 14, 17, 18 and 20 and the X chromosome were found intact in the manatee. The syntenies of other human chromosomes were disrupted in the manatee genome into two to five segments. The hybridization pattern revealed that 20 (15 unique associations of human chromosome segments are found in the manatee genome: 1/15, 1/19, 2/3 (twice, 3/7 (twice, 3/13, 3/21, 5/21, 7/16, 8/22, 10/12 (twice, 11/20, 12/22 (three times, 14/15, 16/19 and 18/19. Conclusion There are five derived chromosome traits that strongly link elephants with manatees in Tethytheria and give implicit support to Paenungulata: the associations 2/3, 3/13, 8/22, 18/19 and the loss of the ancestral eutherian 4/8 association. It would be useful to test these conclusions with chromosome painting in hyraxes. The manatee chromosome painting data confirm that the associations 1/19 and 5/21 phylogenetically link afrotherian species and show that Afrotheria is a natural clade. The association 10/12/22 is also ubiquitous in Afrotheria (clade I, present in Laurasiatheria (clade IV, only partially present in Xenarthra (10/12, clade II and absent in Euarchontoglires (clade III. If Afrotheria is basal to eutherians, this association could be part of the ancestral eutherian karyotype. If afrotherians are not at the root of the eutherian tree, then the 10

  5. Retrospective dosimetry using chromosome painting

    International Nuclear Information System (INIS)

    Chromosome aberration frequency measured in peripheral lymphocytes of persons exposed to ionizing radiation has been used since 1960s for dose assessment. Suspected overexposure is usually evaluated by the frequency of dicentrics and centric rings using an appropriate in vitro calibration curve. However, these chromosome aberrations are unstable with time after exposure and dose reconstruction may encounter uncertainties when the time between the exposure and the analysis is considerable or even unknown. It appears that translocations persist with time after exposure and may be used as an indication of acute past overexposures. Moreover, they appear to accumulate the cytogenetical information, which correlates with the dose received under fractionated, chronic or even occupational exposure conditions. Translocations may be detected using G-banding, which allows to score the total amount of radiation induced translocations but it is a time consuming method, or by Chromosome Painting, a method base on the Fluorescence in situ Hybridization (FISH) technique, painting only some chromosome pairs with specific whole chromosome probes and then extrapolating the observed translocation frequencies to the full genome. The latter method allows a faster aberration scoring than G-banding and appears to be the most promissory tool for biodosimetry, particularly when it is necessary to assess low doses and consequently to score a large number of metaphases, e.g. radiation workers exposed within dose limits. As with the unstable chromosome aberration, it is necessary an in vitro calibration curve based on the frequency of stable chromosome aberrations to assess doses. Our laboratory performed calibration curves for Co60 γ-rays based on the frequencies of unstable (dicentrics and centric rings detected by conventional Giemsa staining) and stable chromosome aberrations (translocations and inversions, detected by G-banding). In order to minimize the interlaboratory variability, we

  6. Molecular cytogenetic and phenotypic characterization of ring chromosome 13 in three unrelated patients

    Science.gov (United States)

    Abdallah-Bouhjar, Inesse B.; Mougou-Zerelli, Soumaya; Hannachi, Hanene; Gmidène, Abir; Labalme, Audrey; Soyah, Najla; Sanlaville, Damien; Saad, Ali; Elghezal, Hatem

    2013-01-01

    We report on the cytogenetic and molecular investigations of constitutional de-novo ring chromosome 13s in three unrelated patients for better understanding and delineation of the phenotypic variability characterizing this genomic rearrangement. The patient’s karyotypes were as follows: 46,XY,r(13)(p11q34) dn for patients 1 and 2 and 46,XY,r(13)(p11q14) dn for patient 3, as a result of the deletion in the telomeric regions of chromosome 13. The patients were, therefore, monosomic for the segment 13q34 → 13qter; in addition, for patient 3, the deletion was larger, encompassing the segment 13q14 → 13qter. Fluorescence in situ hybridization confirmed these rearrangement and array CGH technique showed the loss of at least 2.9 Mb on the short arm and 4.7 Mb on the long arm of the chromosome 13 in patient 2. Ring chromosome 13 (r(13)) is associated with several phenotypic features like intellectual disability, marked short stature, brain and heart defects, microcephaly and genital malformations in males, including undescended testes and hypospadias. However, the hearing loss and speech delay that were found in our three patients have rarely been reported with ring chromosome 13. Although little is known about its etiology, there is interesting evidence for a genetic cause for the ring chromosome 13. We thus performed a genotype-phenotype correlation analysis to ascertain the contribution of ring chromosome 13 to the clinical features of our three cases.

  7. 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 ...

  8. 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.

  9. Radiation-induced chromosomal instability

    Energy Technology Data Exchange (ETDEWEB)

    Ritter, S. [GSI, Biophysics, Darmstadt (Germany)

    1999-03-01

    Recent studies on radiation-induced chromosomal instability in the progeny of exposed mammalian cells were briefly described as well as other related studies. For the analysis of chromosomal damage in clones, cells were seeded directly after exposure in cell well-dish to form single cell clones and post-irradiation chromosome aberrations were scored. Both exposure to isoeffective doses of X-ray or 270 MeV/u C-ions (13 keV/{mu}m) increased the number of clones with abnormal karyotype and the increase was similar for X-ray and for C-ions. Meanwhile, in the progeny of cells for mass cultures, there was no indication of a delayed expression of chromosomal damage up to 40 population doublings after the exposure. A high number of aberrant cells were only observed directly after exposure to 10.7 MeV/u O-ions, i.e. in the first cycle cells and decreased with subsequent cell divisions. The reason for these differences in the radiation-induced chromosomal instability between clonal isolates and mass culture has not been clarified. Recent studies indicated that genomic instability occurs at a high frequency in the progeny of cells irradiated with both sparsely and densely ionizing radiation. Such genomic instability is thought likely to increase the risk of carcinogenesis, but more data are required for a well understanding of the health risks resulting from radiation-induced delayed instability. (M.N.)

  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. Chromosomal rearrangement interferes with meiotic X chromosome inactivation

    Czech Academy of Sciences Publication Activity Database

    Homolka, David; Ivánek, Robert; Čapková, Jana; Jansa, Petr; Forejt, Jiří

    2007-01-01

    Roč. 17, č. 10 (2007), s. 1431-1437. ISSN 1088-9051 R&D Projects: GA MŠk(CZ) 1M0520; GA ČR GA301/06/1334; GA ČR GA301/07/1383 Grant ostatní: Howard Hughes Medical Institute(US) HHMI 55000306 Institutional research plan: CEZ:AV0Z50520514 Keywords : chromosomal translocations * meiotic X chromosome inactivation * spermatogenesis Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 11.224, year: 2007

  12. Increased low-level chromosome 21 mosaicism in older individuals with Down syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Jenkins, E.C.; Genovese, M.; Ye, Ling Ling [New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY (United States)] [and others

    1997-01-20

    During a study of the familial aggregation of Down syndrome (DS) and Alzheimer disease (AD), we observed an increase in mosaicism for disomy 21 in older individuals with DS. In a total of 213 DS subjects who were studied cytogenetically, only 1 of 121 (0.8%) under age 45 exhibited mosaicism, while 14 of 92 (15.2%) who were age 45 or older had mosaicism. Mosaicism in this report connotes {open_quotes}low-level{close_quotes} mosaicism, where all 15 individuals exhibited a modal chromosome number of 47 (i.e., trisomy 21), and at least two cells lacked one of the three chromosomes 21. The occurrence of aneuploidy for chromosomes 15, 17, and X increased with age, and an inverse correlation between chromosome loss and size was also observed. Because older individuals had not been karyotyped at birth, it was not possible to determine whether our observations were due to either increased survival of mosaic individuals or accumulation of disomy 21 cells via increased chromosome loss with aging of the trisomy 21 individual. Using a modeling approach involving life table methods, we obtained results that suggested acquired mosaicism as the predominant mechanism to explain our findings. These results support the hypothesis that as individuals with DS age, there is an increased loss of chromosome 21. 30 refs., 5 tabs.

  13. Two complementary recombinant chromosomes 5 in a healthy woman.

    Science.gov (United States)

    Bartsch, O; Ergun, M A; Balci, S; Kan, D; Eggermann, T; Kotzot, D

    2006-01-01

    We report a healthy woman with two abortions who is a carrier for a rare heterozygous double recombinant of an inv(5) chromosome, karyotype 46,XX,rec(5)dup(5p) inv(5)(p13q22),rec(5)dup(5q)inv(5)(p13q22). Her father had a 46,XY,inv(5)(p13q22) karyotype; his consanguineous wife had died. Molecular investigation of 11 highly polymorphic markers spanning chromosome 5 revealed biparental inheritance for two markers (D5S406, D5S681) on 5p15.3 and 5q13.1, and an allele constellation not compatible with paternal heterodisomy for marker D5S623 on 5q11.2. Eight markers were not informative. Three mechanisms of formation are proposed: First, fertilization of a normal oocyte by a sperm carrying the two recombinant chromosomes 5, followed by postzygotic recombination between the normal maternal homologue and the rec(5)dup(5p), and by loss of the mitotically recombined maternal homologue, leading to segmental paternal heterodisomy 5q13-->qter (trisomic rescue). Second, postzygotic recombination in a 46,XX,inv(5)(p13q22) zygote resulting in the 46,XX,rec(5)dup(5p)inv(5)(p13q22),rec(5) dup(5q)inv(5)(p13q22) karyotype, followed by absence of the original cell line in lymphocytes. Third and most likely, both parents were inv(5) carriers and complementary recombinations in maternal and paternal meiosis resulted in a zygote with two recombinant chromosomes 5. Our patient refused any further studies but later reported the birth of a phenotypically normal child. This is the first report known to us of complementation by two non-homologous recombinant chromosomes in a phenotypically normal woman, and the first example of a child born to a carrier of complementary recombinant chromosomes. PMID:16825772

  14. Alternative Lengthening of Telomeres: Recurrent Cytogenetic Aberrations and Chromosome Stability under Extreme Telomere Dysfunction

    Directory of Open Access Journals (Sweden)

    Despoina Sakellariou

    2013-11-01

    Full Text Available Human tumors using the alternative lengthening of telomeres (ALT exert high rates of telomere dysfunction. Numerical chromosomal aberrations are very frequent, and structural rearrangements are widely scattered among the genome. This challenging context allows the study of telomere dysfunction-driven chromosomal instability in neoplasia (CIN in a massive scale. We used molecular cytogenetics to achieve detailed karyotyping in 10 human ALT neoplastic cell lines.We identified 518 clonal recombinant chromosomes affected by 649 structural rearrangements. While all human chromosomes were involved in random or clonal, terminal, or pericentromeric rearrangements and were capable to undergo telomere healing at broken ends, a differential recombinatorial propensity of specific genomic regions was noted.We show that ALT cells undergo epigenetic modifications rendering polycentric chromosomes functionally monocentric, and because of increased terminal recombinogenicity, they generate clonal recombinant chromosomes with interstitial telomeric repeats. Losses of chromosomes 13, X, and 22, gains of 2, 3, 5, and 20, and translocation/deletion events involving several common chromosomal fragile sites (CFSs were recurrent. Long-term reconstitution of telomerase activity in ALT cells reduced significantly the rates of random ongoing telomeric and pericentromeric CIN. However, the contribution of CFS in overall CIN remained unaffected, suggesting that in ALT cells whole-genome replication stress is not suppressed by telomerase activation. Our results provide novel insights into ALT-driven CIN, unveiling in parallel specific genomic sites that may harbor genes critical for ALT cancerous cell growth.

  15. Experimental approach to prezygotic chromosome screening using only a single pair of gametes in mice.

    Science.gov (United States)

    Watanabe, Hiroyuki; Kohda, Atsushi; Tateno, Hiroyuki

    2015-01-01

    During in vitro embryo production, chromosome screening is essential to prevent pregnancy losses caused by embryonic chromosome aberrations. When the chromosome screening is completed before fertilization, gametes are effectively utilized as genetic resources. The aim of this study was to investigate whether chromosome screening of gametes accompanied by fertilization would be feasible using a single mouse spermatozoon and oocyte. Metaphase II oocytes were divided into a cytoplast and a karyoplast. For genome cloning of the gametes, androgenic and gynogenic embryos were produced by microinjection of sperm into cytoplasts and parthenogenetic activation of karyoplasts, respectively. Pairs of blastomeres from androgenic and gynogenic embryos were fused electrically to produce diploid embryos, which were transferred into pseudopregnant surrogate mothers to examine fetal development. Blastomeres from androgenic and gynogenic embryos were individually treated with calyculin A-a specific inhibitor of type 1 and 2A protein phosphatases-for 2 h to induce premature chromosome condensation. Thereafter, chromosome analysis of blastomeres, reflecting the genetic constitution of individual spermatozoa and oocytes, was performed, and we confirmed that most of the androgenic and gynogenic 2-cell embryos had a haploid set of chromosomes in their sister blastomeres. The reconstructed embryos from blastomeres of androgenic and gynogenic 2-cell embryos could be implanted and develop into live fetuses, albeit at low efficiency. This study indicates that prezygotic chromosome screening and embryo production using a single pair of gametes may be practicable. PMID:26234555

  16. Alternative lengthening of telomeres: recurrent cytogenetic aberrations and chromosome stability under extreme telomere dysfunction.

    Science.gov (United States)

    Sakellariou, Despoina; Chiourea, Maria; Raftopoulou, Christina; Gagos, Sarantis

    2013-11-01

    Human tumors using the alternative lengthening of telomeres (ALT) exert high rates of telomere dysfunction. Numerical chromosomal aberrations are very frequent, and structural rearrangements are widely scattered among the genome. This challenging context allows the study of telomere dysfunction-driven chromosomal instability in neoplasia (CIN) in a massive scale. We used molecular cytogenetics to achieve detailed karyotyping in 10 human ALT neoplastic cell lines. We identified 518 clonal recombinant chromosomes affected by 649 structural rearrangements. While all human chromosomes were involved in random or clonal, terminal, or pericentromeric rearrangements and were capable to undergo telomere healing at broken ends, a differential recombinatorial propensity of specific genomic regions was noted. We show that ALT cells undergo epigenetic modifications rendering polycentric chromosomes functionally monocentric, and because of increased terminal recombinogenicity, they generate clonal recombinant chromosomes with interstitial telomeric repeats. Losses of chromosomes 13, X, and 22, gains of 2, 3, 5, and 20, and translocation/deletion events involving several common chromosomal fragile sites (CFSs) were recurrent. Long-term reconstitution of telomerase activity in ALT cells reduced significantly the rates of random ongoing telomeric and pericentromeric CIN. However, the contribution of CFS in overall CIN remained unaffected, suggesting that in ALT cells whole-genome replication stress is not suppressed by telomerase activation. Our results provide novel insights into ALT-driven CIN, unveiling in parallel specific genomic sites that may harbor genes critical for ALT cancerous cell growth. PMID:24339742

  17. Escape Artists of the X Chromosome.

    Science.gov (United States)

    Balaton, Bradley P; Brown, Carolyn J

    2016-06-01

    Inactivation of one X chromosome in mammalian females achieves dosage compensation between XX females and XY males; however, over 15% of human X-linked genes continue to be expressed from the inactive X chromosome. New genomic methodologies have improved our identification and characterization of these escape genes, revealing the importance of DNA sequence, chromatin structure, and chromosome ultrastructure in regulating expression from an otherwise inactive chromosome. Study of these exceptions to the rule of silencing highlights the interconnectedness of chromatin and chromosome structure in X-chromosome inactivation (XCI). Recent advances also demonstrate the importance of these genes in sexually dimorphic disease risk, particularly cancer. PMID:27103486

  18. Adults with Chromosome 18 Abnormalities.

    Science.gov (United States)

    Soileau, Bridgette; Hasi, Minire; Sebold, Courtney; Hill, Annice; O'Donnell, Louise; Hale, Daniel E; Cody, Jannine D

    2015-08-01

    The identification of an underlying chromosome abnormality frequently marks the endpoint of a diagnostic odyssey. However, families are frequently left with more questions than answers as they consider their child's future. In the case of rare chromosome conditions, a lack of longitudinal data often makes it difficult to provide anticipatory guidance to these families. The objective of this study is to describe the lifespan, educational attainment, living situation, and behavioral phenotype of adults with chromosome 18 abnormalities. The Chromosome 18 Clinical Research Center has enrolled 483 individuals with one of the following conditions: 18q-, 18p-, Tetrasomy 18p, and Ring 18. As a part of the ongoing longitudinal study, we collect data on living arrangements, educational level attained, and employment status as well as data on executive functioning and behavioral skills on an annual basis. Within our cohort, 28 of the 483 participants have died, the majority of whom have deletions encompassing the TCF4 gene or who have unbalanced rearrangement involving other chromosomes. Data regarding the cause of and age at death are presented. We also report on the living situation, educational attainment, and behavioral phenotype of the 151 participants over the age of 18. In general, educational level is higher for people with all these conditions than implied by the early literature, including some that received post-high school education. In addition, some individuals are able to live independently, though at this point they represent a minority of patients. Data on executive function and behavioral phenotype are also presented. Taken together, these data provide insight into the long-term outcome for individuals with a chromosome 18 condition. This information is critical in counseling families on the range of potential outcomes for their child. PMID:25403900

  19. Making chromosome abnormalities treatable conditions.

    Science.gov (United States)

    Cody, Jannine DeMars; Hale, Daniel Esten

    2015-09-01

    Individuals affected by the classic chromosome deletion syndromes which were first identified at the beginning of the genetic age, are now positioned to benefit from genomic advances. This issue highlights five of these conditions (4p-, 5p-, 11q-, 18p-, and 18q-). It focuses on the increased in understanding of the molecular underpinnings and envisions how these can be transformed into effective treatments. While it is scientifically exciting to see the phenotypic manifestations of hemizygosity being increasingly understood at the molecular and cellular level, it is even more amazing to consider that we are now on the road to making chromosome abnormalities treatable conditions. PMID:26351122

  20. Using Chromosomes to Teach Evolution: Chromosomal Rearrangements in Speciation Events.

    Science.gov (United States)

    Offner, Susan

    1994-01-01

    Uses diagrams to aid in discussing how the English map of the human chromosomes, published by Offner in 1993, can be used to illustrate some important questions in evolution, as well as give students a glimpse into some of the mechanisms underlying evolutionary change. (ZWH)

  1. Characterization of chromosome structures of Falconinae (Falconidae, Falconiformes, Aves) by chromosome painting and delineation of chromosome rearrangements during their differentiation

    OpenAIRE

    Nishida, Chizuko; Ishijima, Junko; KOSAKA, Ayumi; Tanabe, Hideyuki; Habermann, Felix A.; Griffin, Darren K.; MATSHUDA, Yoichi; 秀之, 田辺

    2008-01-01

    Karyotypes of most bird species are characterized by around 2n = 80 chromosomes, comprising 7–10 pairs of large- and medium-sized macrochromosomes including sex chromosomes and numerous morphologically indistinguishable microchromosomes. The Falconinae of the Falconiformes has a different karyotype from the typical avian karyotype in low chromosome numbers, little size difference between macrochromosomes and a smaller number of microchromosomes. To characterize chromosome structures of Falcon...

  2. Characterization of chromosome structures of Falconinae (Falconidae, Falconiformes, Aves) by chromosome painting and delineation of chromosome rearrangements during their differentiation

    OpenAIRE

    Nishida, Chizuko; Ishijima, Junko; KOSAKA, Ayumi; Tanabe, Hideyuki; Habermann, Felix A.; Griffin, Darren K.; Matsuda, Yoichi

    2008-01-01

    Karyotypes of most bird species are characterized by around 2n = 80 chromosomes, comprising 7Y10 pairs of large- and medium-sized macrochromosomes including sex chromosomes and numerous morphologically indistinguishable microchromosomes. The Falconinae of the Falconiformes has a different karyotype from the typical avian karyotype in low chromosome numbers, little size difference between macrochromosomes and a smaller number of microchromosomes. To characterize chromosome structures of Falcon...

  3. Mean expression of the X chromosome is associated with neuronal density

    Directory of Open Access Journals (Sweden)

    James Thomas Swingland

    2012-11-01

    Full Text Available Neurodegenerative diseases are characterised by neuronal loss. Neuronal loss causes a varying density of neurons across samples which confounds results from gene expression studies. Chromosome X is known to be specifically important in brain. We hypothesised the existence of a chromosomal signature of gene expression associated with the X-chromosome for neurological conditions not normally associated with that chromosome. The hypothesis was investigated using microarray datasets from studies on Parkinson's disease, Alzheimer's disease and Huntington's disease. Data were analysed using Chromowave, an analytical tool for detecting spatially extended expression changes across chromosomes. To examine associations with neuronal density, expressions from a set of neuron specific genes were extracted. The association between these genes and the expression patterns extracted by Chromowave was then analyzed. We observed an extended pattern of low expression of ChrX consistent in all the neurodegenerative disease brain datasets. There was a strong correlation between mean ChrX expression and the pattern extracted from the autosomal neuronal specific genes, but no correlation with mean autosomal expression. No chromosomal patterns associated with the neuron specific genes were found on other chromosomes. The chromosomal expression pattern was not present in datasets from blood cells. The ChrX:Autosome expression ratio was also higher in neuronal cells than in tissues with a mix of cell types.The results suggest that a loss of neurons manifests in gene expression experiments primarily as a reduction in mean expression of genes along ChrX. The most likely explanation for this finding relates to the documented general up-regulation of ChrX in brain tissue which, this work suggests, occurs primarily in neurons. The purpose and mechanisms behind this cell specific higher expression warrant further research, which may also help elucidate connectio

  4. Uniparental disomy of chromosome 16 in offsprings of Familial Mediterranean Fever (FMF) patients treated with colchicine

    Energy Technology Data Exchange (ETDEWEB)

    Korenstein, A.; Avivi, L. [Tel-Avivi University (Israel); Ravia, Y. [Sheba Medical Center, Tel-Hashomer (Israel)

    1994-09-01

    Uniparental disomy (UPD), an altered mode of Mendelian inheritance, may reveal expression of recessive alleles due to the loss of heterozygosity, as well as imprinted genes. The mechanism causing UPD can be best elucidated in offsprings of individuals at high risk for chromosomal non-disjunction. Such individuals are Familial Mediterranean Fever (FMF) patients, who are routinely treated with the antimitotic agent colchicine, and, therefore, are expected to be at an increased risk for aneuploidy. A dominant mode of inheritance was observed in four FMF offsprings having one parent exhibiting the FMF phenotype (homozygote recessive) while the other was free of the mutant allele (as assumed from his ethnic background). Out of these, two exhibited UPD of chromosome 16, which carries the FMF gene, as judged from four different RFLP markers along this chromosome. Since in both case the UPD was of maternal origin, it is suggested that the colchicine-treated FMF mothers contributed two doses of chromosome 16, presumably due to meiotic non-disjunction, followed by a somatic loss of the paternal chromosome 16 in the embryo. The somatic chromosome loss is also assumed to be caused by the antimitotic drug since the mother continued to receive it during pregnancy. Whether the UPD arises from the colchicine treatment, from the high tendency of chromosome 16 to maternal non-disjunction or from both remains to be elucidated. Our results highlighted the importance of taking UPD into account when counseling individuals who are either treated with antimitotic agents or are carriers of recessive mutant alleles which are mapped to chromosomes prone to aneuploidy.

  5. Mathematical glimpse on the Y chromosome degeneration

    Science.gov (United States)

    Lobo, M. P.

    2006-04-01

    The Y chromosomes are genetically degenerate and do not recombine with their matching partners X. Non-recombination of XY pairs has been pointed out as the key factor for the degeneration of the Y chromosome. The aim here is to show that there is a mathematical asymmetry in sex chromosomes which leads to the degeneration of Y chromosomes even in the absence of XX and XY recombination. A model for sex-chromosome evolution in a stationary regime is proposed. The consequences of their asymmetry are analyzed and lead us to a couple of conclusions. First, Y chromosome degeneration shows up sqrt{2} more often than X chromosome degeneration. Second, if nature prohibits female mortalities from beeing exactly 50%, then Y chromosome degeneration is inevitable.

  6. Chromosomal abnormalities in spontaneous abortion after assisted reproductive treatment

    Directory of Open Access Journals (Sweden)

    Kim You

    2010-11-01

    Full Text Available Abstract Background We evaluated cytogenetic results occurring with first trimester pregnancy loss, and assessed the type and frequency of chromosomal abnormalities after assisted reproductive treatment (ART and compared them with a control group. We also compared the rate of chromosomal abnormalities according to infertility causes in ICSI group. Methods A retrospective cohort analysis was made of all patients who were referred to the Genetics Laboratory of Fertility Center of CHA Gangnam Medical Center from 2005 to 2009 because of clinical abortion with a subsequent dilation and evacuation (D&E performed, and patients were grouped by type of conception as follows: conventional IVF (in vitro fertilization (n = 114, ICSI (intracytoplasmic sperm injection (n = 140, and control (natural conception or intrauterine insemination [IUI] (n = 128. Statistical analysis was performed using SPSS software. Results A total 406 specimens were referred to laboratory, ten abortuses were excluded, and in 14 cases, we did not get any spontaneous metaphase, chromosomal constitutions of 382 specimens were successfully obtained with conventional cytogenetic methods. Overall, 52.62% of the miscarriages were found to be cytogenetically abnormal among all patients, the frequency was 48.4% in the control group, 54.3% of miscarriages after ICSI and 55.3% after conventional IVF (p = 0.503. The most prevalent abnormalities were autosomal trisomy, however, nine (11.69% sex chromosome aneuploidy were noted in the ICSI group vs. four (6.45% and two (3.23% cases in the conventional IVF group and control group. We compared chromosomal abnormalities of miscarriages after ICSI according to infertility factor. 55.71% underwent ICSI due to male factors, 44.29% due to non-male factors. ICSI group having male factors showed significantly higher risk of chromosomal abnormalities than ICSI group having non-male factors (65.8% vs. 34.2%, p = 0.009, odds ratio = 1.529, 95% CI = 1

  7. 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 ...

  8. Vibrio chromosome-specific families

    DEFF Research Database (Denmark)

    Lukjancenko, Oksana; Ussery, David

    2014-01-01

    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...

  9. 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. PMID:27505434

  10. Chromosome Territory Modeller and Viewer

    Science.gov (United States)

    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. PMID:27505434

  11. Multicolor spectral karyotyping of human chromosomes.

    Science.gov (United States)

    Schröck, E; du Manoir, S; Veldman, T; Schoell, B; Wienberg, J; Ferguson-Smith, M A; Ning, Y; Ledbetter, D H; Bar-Am, I; Soenksen, D; Garini, Y; Ried, T

    1996-07-26

    The simultaneous and unequivocal discernment of all human chromosomes in different colors would be of significant clinical and biologic importance. Whole-genome scanning by spectral karyotyping allowed instantaneous visualization of defined emission spectra for each human chromosome after fluorescence in situ hybridization. By means of computer separation (classification) of spectra, spectrally overlapping chromosome-specific DNA probes could be resolved, and all human chromosomes were simultaneously identified. PMID:8662537

  12. CHROMOSOMAL ABNORMALITIES IN PATIENTS WITH SPERM DISORDERS

    OpenAIRE

    L. Y. Pylyp; L. A. Spinenko; V. D. Zukin; N. M. Bilko

    2013-01-01

    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 intrac...

  13. Evolution of sex chromosomes ZW of Schistosoma mansoni inferred from chromosome paint and BAC mapping analyses.

    Science.gov (United States)

    Hirai, Hirohisa; Hirai, Yuriko; LoVerde, Philip T

    2012-12-01

    Chromosomes of schistosome parasites among digenetic flukes have a unique evolution because they exhibit the sex chromosomes ZW, which are not found in the other groups of flukes that are hermaphrodites. We conducted molecular cytogenetic analyses for investigating the sex chromosome evolution using chromosome paint analysis and BAC clones mapping. To carry this out, we developed a technique for making paint probes of genomic DNA from a single scraped chromosome segment using a chromosome microdissection system, and a FISH mapping technique for BAC clones. Paint probes clearly identified each of the 8 pairs of chromosomes by a different fluorochrome color. Combination analysis of chromosome paint analysis with Z/W probes and chromosome mapping with 93 BAC clones revealed that the W chromosome of Schistosoma mansoni has evolved by at least four inversion events and heterochromatinization. Nine of 93 BAC clones hybridized with both the Z and W chromosomes, but the locations were different between Z and W chromosomes. The homologous regions were estimated to have moved from the original Z chromosome to the differentiated W chromosome by three inversions events that occurred before W heterohcromatinization. An inversion that was observed in the heterochromatic region of the W chromosome likely occurred after W heterochromatinization. These inversions and heterochromatinization are hypothesized to be the key factors that promoted the evolution of the W chromosome of S. mansoni. PMID:22831897

  14. Chromosome Aberrations by Heavy Ions

    Science.gov (United States)

    Ballarini, Francesca; Ottolenghi, Andrea

    It is well known that mammalian cells exposed to ionizing radiation can show different types of chromosome aberrations (CAs) including dicentrics, translocations, rings, deletions and complex exchanges. Chromosome aberrations are a particularly relevant endpoint in radiobiology, because they play a fundamental role in the pathways leading either to cell death, or to cell conversion to malignancy. In particular, reciprocal translocations involving pairs of specific genes are strongly correlated (and probably also causally-related) with specific tumour types; a typical example is the BCR-ABL translocation for Chronic Myeloid Leukaemia. Furthermore, aberrations can be used for applications in biodosimetry and more generally as biomarkers of exposure and risk, that is the case for cancer patients monitored during Carbon-ion therapy and astronauts exposed to space radiation. Indeed hadron therapy and astronauts' exposure to space radiation represent two of the few scenarios where human beings can be exposed to heavy ions. After a brief introduction on the main general features of chromosome aberrations, in this work we will address key aspects of the current knowledge on chromosome aberration induction, both from an experimental and from a theoretical point of view. More specifically, in vitro data will be summarized and discussed, outlining important issues such as the role of interphase death/mitotic delay and that of complex-exchange scoring. Some available in vivo data on cancer patients and astronauts will be also reported, together with possible interpretation problems. Finally, two of the few available models of chromosome aberration induction by ionizing radiation (including heavy ions) will be described and compared, focusing on the different assumptions adopted by the authors and on how these models can deal with heavy ions.

  15. A case of trisomy of chromosome 15

    OpenAIRE

    Coldwell, S; Fitzgerald, B.; Semmens, J.M.; Ede, R; Bateman, C

    1981-01-01

    We describe a case of trisomy of chromosome 15 in an infant who presented at birth with numerous abnormalities. As far as we are aware this chromosomal abnormality has not been described before. On the basis of this one case there appear to be no features which are specific to this chromosomal abnormality.

  16. 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

  17. 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 ...

  18. Molecular and cellular pathways associated with chromosome 1p deletions during colon carcinogenesis

    Directory of Open Access Journals (Sweden)

    Payne CM

    2011-05-01

    Full Text Available Claire M Payne, Cheray Crowley-Skillicorn, Carol Bernstein, Hana Holubec, Harris BernsteinDepartment of Cell Biology and Anatomy, College of Medicine, University of Arizona Tucson, AZ, USAAbstract: Chromosomal instability is a major pathway of sporadic colon carcinogenesis. Chromosome arm 1p appears to be one of the “hot spots” in the non-neoplastic mucosa that, when deleted, is associated with the initiation of carcinogenesis. Chromosome arm 1p contains genes associated with DNA repair, spindle checkpoint function, apoptosis, multiple microRNAs, the Wnt signaling pathway, tumor suppression, antioxidant activities, and defense against environmental toxins. Loss of 1p is dangerous since it would likely contribute to genomic instability leading to tumorigenesis. The 1p deletion-associated colon carcinogenesis pathways are reviewed at the molecular and cellular levels. Sporadic colon cancer is strongly linked to a high-fat/low-vegetable/low-micronutrient, Western-style diet. We also consider how selected dietary-related compounds (eg, excess hydrophobic bile acids, and low levels of folic acid, niacin, plant-derived antioxidants, and other modulatory compounds might affect processes leading to chromosomal deletions, and to the molecular and cellular pathways specifically altered by chromosome 1p loss.Keywords: chromosome 1p, colon carcinogenesis, molecular pathways, cellular pathways

  19. Holoprosencephaly due to numeric chromosome abnormalities.

    Science.gov (United States)

    Solomon, Benjamin D; Rosenbaum, Kenneth N; Meck, Jeanne M; Muenke, Maximilian

    2010-02-15

    Holoprosencephaly (HPE) is the most common malformation of the human forebrain. When a clinician identifies a patient with HPE, a routine chromosome analysis is often the first genetic test sent for laboratory analysis in order to assess for a structural or numerical chromosome anomaly. An abnormality of chromosome number is overall the most frequently identified etiology in a patient with HPE. These abnormalities include trisomy 13, trisomy 18, and triploidy, though several others have been reported. Such chromosome number abnormalities are almost universally fatal early in gestation or in infancy. Clinical features of specific chromosome number abnormalities may be recognized by phenotypic manifestations in addition to the HPE. PMID:20104610

  20. Novel insights into mitotic chromosome condensation

    Science.gov (United States)

    Piskadlo, Ewa; Oliveira, Raquel A.

    2016-01-01

    The fidelity of mitosis is essential for life, and successful completion of this process relies on drastic changes in chromosome organization at the onset of nuclear division. The mechanisms that govern chromosome compaction at every cell division cycle are still far from full comprehension, yet recent studies provide novel insights into this problem, challenging classical views on mitotic chromosome assembly. Here, we briefly introduce various models for chromosome assembly and known factors involved in the condensation process (e.g. condensin complexes and topoisomerase II). We will then focus on a few selected studies that have recently brought novel insights into the mysterious way chromosomes are condensed during nuclear division.

  1. Rates of gyrase supercoiling and transcription elongation control supercoil density in a bacterial chromosome.

    Directory of Open Access Journals (Sweden)

    Nikolay Rovinskiy

    Full Text Available Gyrase catalyzes negative supercoiling of DNA in an ATP-dependent reaction that helps condense bacterial chromosomes into a compact interwound "nucleoid." The supercoil density (σ of prokaryotic DNA occurs in two forms. Diffusible supercoil density (σ(D moves freely around the chromosome in 10 kb domains, and constrained supercoil density (σ(C results from binding abundant proteins that bend, loop, or unwind DNA at many sites. Diffusible and constrained supercoils contribute roughly equally to the total in vivo negative supercoil density of WT cells, so σ = σ(C+σ(D. Unexpectedly, Escherichia coli chromosomes have a 15% higher level of σ compared to Salmonella enterica. To decipher critical mechanisms that can change diffusible supercoil density of chromosomes, we analyzed strains of Salmonella using a 9 kb "supercoil sensor" inserted at ten positions around the genome. The sensor contains a complete Lac operon flanked by directly repeated resolvase binding sites, and the sensor can monitor both supercoil density and transcription elongation rates in WT and mutant strains. RNA transcription caused (- supercoiling to increase upstream and decrease downstream of highly expressed genes. Excess upstream supercoiling was relaxed by Topo I, and gyrase replenished downstream supercoil losses to maintain an equilibrium state. Strains with TS gyrase mutations growing at permissive temperature exhibited significant supercoil losses varying from 30% of WT levels to a total loss of σ(D at most chromosome locations. Supercoil losses were influenced by transcription because addition of rifampicin (Rif caused supercoil density to rebound throughout the chromosome. Gyrase mutants that caused dramatic supercoil losses also reduced the transcription elongation rates throughout the genome. The observed link between RNA polymerase elongation speed and gyrase turnover suggests that bacteria with fast growth rates may generate higher supercoil densities

  2. Genetics of dioecy and causal sex chromosomes in plants

    Indian Academy of Sciences (India)

    Sushil Kumar; Renu Kumari; Vishakha Sharma

    2014-04-01

    Dioecy (separate male and female individuals) ensures outcrossing and is more prevalent in animals than in plants. Although it is common in bryophytes and gymnosperms, only 5% of angiosperms are dioecious. In dioecious higher plants, flowers borne on male and female individuals are, respectively deficient in functional gynoecium and androecium. Dioecy is inherited via three sex chromosome systems: XX/XY, XX/X0 and WZ/ZZ, such that XX or WZ is female and XY, X0 or ZZ are males. The XX/XY system generates the rarer XX/X0 andWZ/ZZ systems. An autosome pair begets XY chromosomes. A recessive loss-of-androecium mutation (ana) creates X chromosome and a dominant gynoecium-suppressing (GYS) mutation creates Y chromosome. The ana/ANA and gys/GYS loci are in the sex-determining region (SDR) of the XY pair. Accumulation of inversions, deleterious mutations and repeat elements, especially transposons, in the SDR of Y suppresses recombination between X and Y in SDR, making Y labile and increasingly degenerate and heteromorphic from X. Continued recombination between X and Y in their pseudoautosomal region located at the ends of chromosomal arms allows survival of the degenerated Y and of the species. Dioecy is presumably a component of the evolutionary cycle for the origin of new species. Inbred hermaphrodite species assume dioecy. Later they suffer degenerate-Y-led population regression. Cross-hybridization between such extinguishing species and heterologous species, followed by genome duplication of segregants from hybrids, give rise to new species.

  3. Chromosome territories, X;Y translocation and Premature Ovarian Failure: is there a relationship?

    Directory of Open Access Journals (Sweden)

    Betri Enrico

    2009-09-01

    Full Text Available Abstract Background Premature ovarian failure (POF is a secondary hypergonadotrophic amenorrhea occurring before the age of 40 and affecting 1-3% of females. Chromosome anomalies account for 6-8% of POF cases, but only few cases are associated with translocations involving X and Y chromosomes. This study shows the cytogenetic and molecular analysis of a POF patient came to our attention as she developed a left ovary choriocarcinoma at the age of 10 and at 14 years of age she presented secondary amenorrhea with elevated levels of gonadotropins. Results Breakpoint position on X and Y chromosomes was investigated using Fluorescent In Situ Hybridisation (FISH with a panel of specific BAC probes, microsatellite analysis and evaluation of copy number changes and loss of heterozigosity by Affymetrix® GeneChip platform (Santa Clara, CA, USA. Patient's karyotype resulted 46, X, der(Yt(X;Y(q13.1;q11.223. X inactivation study was assessed by RBA banding and showed preferential inactivation of derivative chromosome. The reciprocal spatial disposition of sexual chromosome territories was investigated using whole chromosome painting and centromeres probes: patient's results didn't show a significant difference in comparison to normal controls. Conclusion The peculiar clinical case come to our attention highlighted the complexity of POF aetiology and of the translocation event, even if our results seem to exclude any effect on nuclear organisation. POF phenotype could be partially explained by skewed X chromosome inactivation that influences gene expression.

  4. Replication asynchrony and differential condensation of X chromosomes in female platypus (Ornithorhynchus anatinus).

    Science.gov (United States)

    Ho, Kristen K K; Deakin, Janine E; Wright, Megan L; Graves, Jennifer A Marshall; Grützner, Frank

    2009-01-01

    A common theme in the evolution of sex chromosomes is the massive loss of genes on the sex-specific chromosome (Y or W), leading to a gene imbalance between males (XY) and females (XX) in a male heterogametic species, or between ZZ and ZW in a female heterogametic species. Different mechanisms have evolved to compensate for this difference in dosage of X-borne genes between sexes. In therian mammals, one of the X chromosomes is inactivated, whereas bird dosage compensation is partial and gene-specific. In therian mammals, hallmarks of the inactive X are monoallelic gene expression, late DNA replication and chromatin condensation. Platypuses have five pairs of X chromosomes in females and five X and five Y chromosomes in males. Gene expression analysis suggests a more bird-like partial and gene-specific dosage compensation mechanism. We investigated replication timing and chromosome condensation of three of the five X chromosomes in female platypus. Our data suggest asynchronous replication of X-specific regions on X(1), X(3) and X(5) but show significantly different condensation between homologues for X(3) only, and not for X(1) or X(5). We discuss these results in relation to recent gene expression analysis of X-linked genes, which together give us insights into possible mechanisms of dosage compensation in platypus. PMID:19874719

  5. Transient Microgeographic Clines during B Chromosome Invasion.

    Science.gov (United States)

    Camacho, Juan Pedro M; Shaw, Michael W; Cabrero, Josefa; Bakkali, Mohammed; Ruíz-Estévez, Mercedes; Ruíz-Ruano, Francisco J; Martín-Blázquez, Rubén; López-León, María Dolores

    2015-11-01

    The near-neutral model of B chromosome evolution predicts that the invasion of a new population should last some tens of generations, but the details on how it proceeds in real populations are mostly unknown. Trying to fill this gap, we analyze here a natural population of the grasshopper Eyprepocnemis plorans at three time points during the last 35 years. Our results show that B chromosome frequency increased significantly during this period and that a cline observed in 1992 had disappeared in 2012 once B chromosome frequency reached an upper limit at all sites sampled. This indicates that, during B chromosome invasion, transient clines for B chromosome frequency are formed at the invasion front on a microgeographic scale. Computer simulation experiments showed that the pattern of change observed for genotypic frequencies is consistent with the existence of B chromosome drive through females and selection against individuals with a high number of B chromosomes. PMID:26655780

  6. Mitosis. Microtubule detyrosination guides chromosomes during mitosis.

    Science.gov (United States)

    Barisic, Marin; Silva e Sousa, Ricardo; Tripathy, Suvranta K; Magiera, Maria M; Zaytsev, Anatoly V; Pereira, Ana L; Janke, Carsten; Grishchuk, Ekaterina L; Maiato, Helder

    2015-05-15

    Before chromosomes segregate into daughter cells, they align at the mitotic spindle equator, a process known as chromosome congression. Centromere-associated protein E (CENP-E)/Kinesin-7 is a microtubule plus-end-directed kinetochore motor required for congression of pole-proximal chromosomes. Because the plus-ends of many astral microtubules in the spindle point to the cell cortex, it remains unknown how CENP-E guides pole-proximal chromosomes specifically toward the equator. We found that congression of pole-proximal chromosomes depended on specific posttranslational detyrosination of spindle microtubules that point to the equator. In vitro reconstitution experiments demonstrated that CENP-E-dependent transport was strongly enhanced on detyrosinated microtubules. Blocking tubulin tyrosination in cells caused ubiquitous detyrosination of spindle microtubules, and CENP-E transported chromosomes away from spindle poles in random directions. Thus, CENP-E-driven chromosome congression is guided by microtubule detyrosination. PMID:25908662

  7. [The evolution of human Y chromosome].

    Science.gov (United States)

    Yang, Xianrong; Wang, Meiqin; Li, Shaohua

    2014-09-01

    The human Y chromosome is always intriguing for researchers, because of its role in gender determination and its unusual evolutionary history. The Y chromosome evolves from an autosome, and its evolution has been characterized by massive gene decay. The lack of recombination and protein-coding genes and high content of repetitive sequences have hindered the progress in our understanding of the Y chromosome biology. Recently, with the advances in comparative genomics and sequencing technology, the research on Y chromosome has become a hotspot, with an intensified debate about Y-chromosome final destination resulting from degeneration. This review focuses on the structure, inheritance characteristics, gene content, and the origin and evolution of Y chromosome. We also discuss the long-term destiny of Y chromosome. PMID:25252301

  8. Dynamics of chromosome segregation in Escherichia coli

    DEFF Research Database (Denmark)

    Nielsen, Henrik Jørck

    2007-01-01

    Since the 1960’es the conformation and segregation of the chromosome in Escherichia coli has been a subject of interest for many scientists. However, after 40 years of research, we still know incredibly little about how the chromosome is organized inside the cell, how it manages to duplicate this...... and reliable method enabled us to start the analysis on the distribution of various chromosomal loci inside slowly growing cells. With the actual counting and measuring no longer being any problem we could easily analyze 14 loci distributed on the E.coli chromosome. More than 15.000 cells were...... on the P1 par system. Using the new system, which is based on the pMT1 par system from Yersenia pestis, we labeled loci on opposite sides of the E.coli chromosome simultaneously and were able to show that the E.coli chromosome is organized with one chromosomal arm in each cell half. This astounding...

  9. 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...

  10. 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

    traits based on 54K markerdata, imputed 54K for test animals, and imputed 54K for half of referenceanimals. GBLUP models with or without residual polygenic effect were used forgenomic prediction. For all three data sets, genomic prediction using allmarkers gave slightly higher reliability than prediction...... 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...... autosomal component and an X chromosomal component did not led to betterprediction based on the present data where all animals were bulls. A modelincluding polygenic effect did not recover the loss of prediction accuracy dueto exclusion of the X chromosome. It is recommended using markers on the X...

  11. The evolution of X chromosome inactivation in mammals: the demise of Ohno's hypothesis?

    Science.gov (United States)

    Pessia, Eugénie; Engelstädter, Jan; Marais, Gabriel A B

    2014-04-01

    Ohno's hypothesis states that dosage compensation in mammals evolved in two steps: a twofold hyperactivation of the X chromosome in both sexes to compensate for gene losses on the Y chromosome, and silencing of one X (X-chromosome inactivation, XCI) in females to restore optimal dosage. Recent tests of this hypothesis have returned contradictory results. In this review, we explain this ongoing controversy and argue that a novel view on dosage compensation evolution in mammals is starting to emerge. Ohno's hypothesis may be true for a few, dosage-sensitive genes only. If so few genes are compensated, then why has XCI evolved as a chromosome-wide mechanism? This and several other questions raised by the new data in mammals are discussed, and future research directions are proposed. PMID:24173285

  12. Distinct nonrandom patterns of chromosomal deletions in giant-cell lesions of bone

    Directory of Open Access Journals (Sweden)

    Baruffi Marcelo Razera

    2002-01-01

    Full Text Available Cytogenetic analyses were performed on a bone giant cell reparative granuloma (GCRG and on three bone giant cell tumors (GCT. The present GCRG case is the second to be described cytogenetically. A modal chromosome number of 46 was observed in all samples. Clonal chromosome abnormalities were detected in all cases. The numerical alterations most frequently observed involved the loss of chromosomes 17 and 18. Among the structural anomalies observed, there was preferential involvement of chromosomes 6 and 10. Three GCT cases presented del(10(p13 and two cases presented del(6(q25 (1 GCRG and 1 GCT. These breakpoints mapped on 10p and 6q may harbour genes of importance in the development of bone giant cell tumors.

  13. Chromosome sites play dual roles to establish homologous synapsisduring meiosis in C. elegans

    Energy Technology Data Exchange (ETDEWEB)

    MacQueen, Amy J.; Phillips, Carolyn M.; Bhalla, Needhi; Weiser,Pinky; Villeneuve, Anne M.; Dernburg, Abby F.

    2005-06-05

    required for accurate segregation of homologous chromosomesduring meiosisin C. elegans. We find that these sites play two distinctroles that contribute to proper segregation. Chromosomes lacking PCsusually fail to synapse and also lack a synapsis-independentstabilization activity. The presence of a PC on justone copy of achromosome pair promotes synapsis but does not supportsynapsis-independent pairing stabilization, indicating that thesefunctions are separable. Once initiated, synapsis is highly processive,even between non homologous chromosomes of disparate lengths, elucidatinghow translocations suppress meiotic recombination in C. elegans. Thesefindings suggest a multistep pathway for chromosome synapsis in which PCsimpart selectivity and efficiency through a kinetic proofreadingmechanism. We speculate that concentration of these activities at oneregion per chromosome may have co-evolved with the loss of a pointcentromere to safeguard karyotype stability.

  14. The role of sex chromosomes in mammalian germ cell differentiation: can the germ cells carrying X and Y chromosomes differentiate into fertile oocytes?

    Directory of Open Access Journals (Sweden)

    Teruko Taketo

    2015-06-01

    Full Text Available The sexual differentiation of germ cells into spermatozoa or oocytes is strictly regulated by their gonadal environment, testis or ovary, which is determined by the presence or absence of the Y chromosome, respectively. Hence, in normal mammalian development, male germ cells differentiate in the presence of X and Y chromosomes, and female germ cells do so in the presence of two X chromosomes. However, gonadal sex reversal occurs in humans as well as in other mammalian species, and the resultant XX males and XY females can lead healthy lives, except for a complete or partial loss of fertility. Germ cells carrying an abnormal set of sex chromosomes are efficiently eliminated by multilayered surveillance mechanisms in the testis, and also, though more variably, in the ovary. Studying the molecular basis for sex-specific responses to a set of sex chromosomes during gametogenesis will promote our understanding of meiotic processes contributing to the evolution of sex determining mechanisms. This review discusses the fate of germ cells carrying various sex chromosomal compositions in mouse models, the limitation of which may be overcome by recent successes in the differentiation of functional germ cells from embryonic stem cells under experimental conditions.

  15. Novel balanced chromosomal translocations in females with recurrent spontaneous abortions: Two case studies

    Directory of Open Access Journals (Sweden)

    Puspal De

    2015-01-01

    Full Text Available Two couples with a history of recurrent pregnancy losses were referred to the Institute of Genetic Medicine and Genomic Science for cytogenetic evaluation. Chromosomal analysis of the phenotypically normal couples was done to investigate whether there are any new chromosomal abnormalities present in either of the couples caused recurrent pregnancy losses. Clinical and hormonal profile of the couples revealed normal parameters. The ultrasound scan of the females showed normal uterine and ovarian structures. Chromosomal analysis of the couples revealed normal 46, XY karyotypes in the both the male partners, and novel balanced reciprocal translocations 46, XX, t (5;8 (q35.3;q24.23 and 46, XX, t (4;13 (q12;q14 chromosomal constitutions in the female partners. Further, corroboration of the chromosome abnormalities was carried out by high resolution banding analysis. Unique and novel balanced reciprocal translocations were reported as an original investigation in two female partners from two different unrelated families both with the history of recurrent pregnancy losses.

  16. International workshop of chromosome 19

    Energy Technology Data Exchange (ETDEWEB)

    Pericak-Vance, M.A. (Duke Univ. Medical Center, Durham, NC (United States). Div. of Neurology); Carrano, A.J. (Lawrence Livermore National Lab., CA (United States))

    1991-09-16

    This document summarizes the workshop on physical and genetic mapping of chromosome 19. The first session discussed the major disease loci found on the chromosome. The second session concentrated on reference families, markers and linkage maps. The third session concentrated on radiation hybrid mapping, somatic cell hybrid panels, macro restriction maps and YACs, followed by cDNA and long range physical maps. The fourth session concentrated on compiling consensus genetic and physical maps as well as discussing regions of conflict. The final session dealt with the LLNL cosmid contig database and comparative mapping of homologous regions of the human and mouse genomes, and ended with a discussion of resource sharing. 18 refs., 2 figs. (MHB)

  17. Whole-genome sequence of a flatfish provides insights into ZW sex chromosome evolution and adaptation to a benthic lifestyle.

    Science.gov (United States)

    Chen, Songlin; Zhang, Guojie; Shao, Changwei; Huang, Quanfei; Liu, Geng; Zhang, Pei; Song, Wentao; An, Na; Chalopin, Domitille; Volff, Jean-Nicolas; Hong, Yunhan; Li, Qiye; Sha, Zhenxia; Zhou, Heling; Xie, Mingshu; Yu, Qiulin; Liu, Yang; Xiang, Hui; Wang, Na; Wu, Kui; Yang, Changgeng; Zhou, Qian; Liao, Xiaolin; Yang, Linfeng; Hu, Qiaomu; Zhang, Jilin; Meng, Liang; Jin, Lijun; Tian, Yongsheng; Lian, Jinmin; Yang, Jingfeng; Miao, Guidong; Liu, Shanshan; Liang, Zhuo; Yan, Fang; Li, Yangzhen; Sun, Bin; Zhang, Hong; Zhang, Jing; Zhu, Ying; Du, Min; Zhao, Yongwei; Schartl, Manfred; Tang, Qisheng; Wang, Jun

    2014-03-01

    Genetic sex determination by W and Z chromosomes has developed independently in different groups of organisms. To better understand the evolution of sex chromosomes and the plasticity of sex-determination mechanisms, we sequenced the whole genomes of a male (ZZ) and a female (ZW) half-smooth tongue sole (Cynoglossus semilaevis). In addition to insights into adaptation to a benthic lifestyle, we find that the sex chromosomes of these fish are derived from the same ancestral vertebrate protochromosome as the avian W and Z chromosomes. Notably, the same gene on the Z chromosome, dmrt1, which is the male-determining gene in birds, showed convergent evolution of features that are compatible with a similar function in tongue sole. Comparison of the relatively young tongue sole sex chromosomes with those of mammals and birds identified events that occurred during the early phase of sex-chromosome evolution. Pertinent to the current debate about heterogametic sex-chromosome decay, we find that massive gene loss occurred in the wake of sex-chromosome 'birth'. PMID:24487278

  18. Baseline chromosome aberrations in children

    Czech Academy of Sciences Publication Activity Database

    Merlo, D.F.; Ceppi, M.; Stagi, E.; Bocchini, V.; Šrám, Radim; Rössner st., Pavel

    2007-01-01

    Roč. 172, - (2007), s. 60-67. ISSN 0378-4274 Grant ostatní: EU(EU) 2002-02198; EU(EU) 2005-016320 Institutional research plan: CEZ:AV0Z50390512 Source of funding: R - rámcový projekt EK ; R - rámcový projekt EK Keywords : chromosome aberrations * children * molecular epidemiology Subject RIV: DN - Health Impact of the Environment Quality Impact factor: 2.826, year: 2007

  19. Clonality - X Chromosome Inactivation Assay

    OpenAIRE

    sprotocols

    2014-01-01

    Author: Molecular Profiling Initiative, NCI This method was successful in our lab using prostate tissue and for our specific objectives. Investigators must be aware that they will need to tailor the following protocol for their own research objectives and tissue under study. Investigators can utilize X chromosome inactivation (methylation) to determine the clonality status of a tumor or premalignant lesion in females. The technique is based on a methylation-sensitive restriction enzym...

  20. Hobo transposons causing chromosomal breakpoints.

    OpenAIRE

    Ladevèze, V; Aulard, S.; Chaminade, N; Périquet, G; Lemeunier, F

    1998-01-01

    Several laboratory surveys have shown that transposable elements (TEs) can cause chromosomal breaks and lead to inversions, as in dysgenic crosses involving P-elements. However, it is not presently clear what causes inversions in natural populations of Drosophila. The only direct molecular studies must be taken as evidence against the involvement of mobile elements. Here, in Drosophila lines transformed with the hobo transposable element, and followed for 100 generations, we show the appearan...

  1. Chromosomal instability determines taxane response

    OpenAIRE

    Swanton, Charles; Nicke, Barbara; Schuett, Marion; Eklund, Aron C.; Ng, Charlotte; Li, Qiyuan; Hardcastle, Thomas; Lee, Alvin; Roy, Rajat; East, Philip; Kschischo, Maik; Endesfelder, David; Wylie, Paul; Kim, Se Nyun; Chen, Jie-Guang

    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 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....

  2. Vision Loss, Sudden

    Science.gov (United States)

    ... of age-related macular degeneration. Spotlight on Aging: Vision Loss in Older People Most commonly, vision loss ... Some Causes and Features of Sudden Loss of Vision Cause Common Features* Tests Sudden loss of vision ...

  3. 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.

  4. Chromosome rearrangements and transposable elements.

    Science.gov (United States)

    Lonnig, Wolf-Ekkehard; Saedler, Heinz

    2002-01-01

    There has been limited corroboration to date for McClintock's vision of gene regulation by transposable elements (TEs), although her proposition on the origin of species by TE-induced complex chromosome reorganizations in combination with gene mutations, i.e., the involvement of both factors in relatively sudden formations of species in many plant and animal genera, has been more promising. Moreover, resolution is in sight for several seemingly contradictory phenomena such as the endless reshuffling of chromosome structures and gene sequences versus synteny and the constancy of living fossils (or stasis in general). Recent wide-ranging investigations have confirmed and enlarged the number of earlier cases of TE target site selection (hot spots for TE integration), implying preestablished rather than accidental chromosome rearrangements for nonhomologous recombination of host DNA. The possibility of a partly predetermined generation of biodiversity and new species is discussed. The views of several leading transposon experts on the rather abrupt origin of new species have not been synthesized into the macroevolutionary theory of the punctuated equilibrium school of paleontology inferred from thoroughly consistent features of the fossil record. PMID:12429698

  5. The impact of homologous recombination repair deficiency on depleted uranium clastogenicity in Chinese hamster ovary cells: XRCC3 protects cells from chromosome aberrations, but increases chromosome fragmentation

    Energy Technology Data Exchange (ETDEWEB)

    Holmes, Amie L. [Wise Laboratory of Environmental and Genetic Toxicology, University of Southern Maine, 96 Falmouth St., P.O. Box 9300, Portland, ME 04104-9300, United States of America (United States); Maine Center for Toxicology and Environmental Health, University of Southern Maine, 96 Falmouth St., P.O. Box 9300, Portland, ME 04104-9300, United States of America (United States); Department of Applied Medical Science, University of Southern Maine, 96 Falmouth Street, P.O. Box 9300, Portland, ME 04104-9300, United States of America (United States); Joyce, Kellie [Wise Laboratory of Environmental and Genetic Toxicology, University of Southern Maine, 96 Falmouth St., P.O. Box 9300, Portland, ME 04104-9300, United States of America (United States); Maine Center for Toxicology and Environmental Health, University of Southern Maine, 96 Falmouth St., P.O. Box 9300, Portland, ME 04104-9300, United States of America (United States); Xie, Hong [Wise Laboratory of Environmental and Genetic Toxicology, University of Southern Maine, 96 Falmouth St., P.O. Box 9300, Portland, ME 04104-9300, United States of America (United States); Maine Center for Toxicology and Environmental Health, University of Southern Maine, 96 Falmouth St., P.O. Box 9300, Portland, ME 04104-9300, United States of America (United States); Department of Applied Medical Science, University of Southern Maine, 96 Falmouth Street, P.O. Box 9300, Portland, ME 04104-9300, United States of America (United States); Falank, Carolyne [Wise Laboratory of Environmental and Genetic Toxicology, University of Southern Maine, 96 Falmouth St., P.O. Box 9300, Portland, ME 04104-9300, United States of America (United States); Maine Center for Toxicology and Environmental Health, University of Southern Maine, 96 Falmouth St., P.O. Box 9300, Portland, ME 04104-9300, United States of America (United States); and others

    2014-04-15

    Highlights: • The role of homologous recombination repair in DU-induced toxicity was examined. • Loss of RAD51D did not affect DU-induced cytotoxicity or genotoxicity. • XRCC3 protects cell from DU-induced chromosome breaks and fusions. • XRCC3 plays a role in DU-induced chromosome fragmentation of the X chromosome. - Abstract: Depleted uranium (DU) is extensively used in both industry and military applications. The potential for civilian and military personnel exposure to DU is rising, but there are limited data on the potential health hazards of DU exposure. Previous laboratory research indicates DU is a potential carcinogen, but epidemiological studies remain inconclusive. DU is genotoxic, inducing DNA double strand breaks, chromosome damage and mutations, but the mechanisms of genotoxicity or repair pathways involved in protecting cells against DU-induced damage remain unknown. The purpose of this study was to investigate the effects of homologous recombination repair deficiency on DU-induced genotoxicity using RAD51D and XRCC3-deficient Chinese hamster ovary (CHO) cell lines. Cells deficient in XRCC3 (irs1SF) exhibited similar cytotoxicity after DU exposure compared to wild-type (AA8) and XRCC3-complemented (1SFwt8) cells, but DU induced more break-type and fusion-type lesions in XRCC3-deficient cells compared to wild-type and XRCC3-complemented cells. Surprisingly, loss of RAD51D did not affect DU-induced cytotoxicity or genotoxicity. DU induced selective X-chromosome fragmentation irrespective of RAD51D status, but loss of XRCC3 nearly eliminated fragmentation observed after DU exposure in wild-type and XRCC3-complemented cells. Thus, XRCC3, but not RAD51D, protects cells from DU-induced breaks and fusions and also plays a role in DU-induced chromosome fragmentation.

  6. Comparative analysis of sex chromosomes in Leporinus species (Teleostei, Characiformes) using chromosome painting

    Science.gov (United States)

    2013-01-01

    Background The Leporinus genus, belonging to the Anostomidae family, is an interesting model for studies of sex chromosome evolution in fish, particularly because of the presence of heteromorphic sex chromosomes only in some species of the genus. In this study we used W chromosome-derived probes in a series of cross species chromosome painting experiments to try to understand events of sex chromosome evolution in this family. Results W chromosome painting probes from Leporinus elongatus, L. macrocephalus and L. obtusidens were hybridized to each others chromosomes. The results showed signals along their W chromosomes and the use of L. elongatus W probe against L. macrocephalus and L. obtusidens also showed signals over the Z chromosome. No signals were observed when the later aforementioned probe was used in hybridization procedures against other four Anostomidae species without sex chromosomes. Conclusions Our results demonstrate a common origin of sex chromosomes in L. elongatus, L. macrocephalus and L. obtusidens but suggest that the L. elongatus chromosome system is at a different evolutionary stage. The absence of signals in the species without differentiated sex chromosomes does not exclude the possibility of cryptic sex chromosomes, but they must contain other Leporinus W sequences than those described here. PMID:23822802

  7. 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

  8. Chromosome Studies in Patients with Polycythaemia Vera after Treatment with 32P

    International Nuclear Information System (INIS)

    The chromosomes of bone-marrow cells and blood lymphocytes of forty-six patients with polycythaemia vera were analysed to trace the sequence of events leading to the development of bone-marrow failure or 'leukaemia'. All except one of the patients had received radiophosphorus (32P). It might be expected that the yield of chromosomal aberrations of the two-break type (translocations etc.) from the low dose-rate beta radiation of 32P would be small. However, 'unstable' types of abnormality (dicentrics, fragments) and stable types (translocations, inversions, deletions) were observed in 6-25% of the blood lymphocytes; there was no evidence of clones of abnormal cells. In the majority of patients the bone marrow was predominantly normal diploid; occasional sporadic cells with 'stable' chromosomal abnormalities were seen in two-thirds of the cases, but 'unstable' aberrations were rare. In seven cases there were clones of cells characterised by deletions or translocations. All these chromosomal changes are probably radiation-induced. Clones of cells with a similar abnormality, an apparent deletion of one of the F-group chromosomes, were observed in the bone marrow in ten patients. Eight of these had received 32P and two busulphan. In two cases the clone appeared to develop after treatment. A similar anomaly has been reported in several cases of idiopathic sideroblastic anaemia who had not been irradiated. Progression into the leukaemic phase of the disease is associated in some cases with gross chromosomal abnormalities, such as shift of the stem line chromosome number and bizarre chromosome 'markers'. In other cases, some of whom have not been irradiated for several years, the chromosomal changes are less pronounced and may result from non-disjunctional gain of one or more chromosomes or chromosome loss. One case showed a step-by-step clonal evolution over a two-year period. None of the chromosomal abnormalities in the 'leukaemic' phase appear to be a direct result of

  9. Chromosome analysis of arsenic affected cattle

    Directory of Open Access Journals (Sweden)

    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.

  10. The peripheral chromosome scaffold, a novel structural component of mitotic chromosomes.

    Science.gov (United States)

    Sheval, Eugene V; Polyakov, Vladimir Y

    2008-06-01

    Using an original high-salt extraction protocol, we observed a novel chromosome substructure, referred to as the peripheral chromosome scaffold. This chromosome domain contained the perichromosomal layer proteins pKi-67, B23/nucleophosmin and fibrillarin, but no DNA fragments (i.e., the loop domain bases were not associated with the peripheral scaffold). Modern models of chromosome organization do not predict the existence of a peripheral chromosome scaffold domain, and thus our observations have conceptual implications for understanding chromosome architecture. PMID:18337132

  11. Chromosome numbers in three species groups of freshwater flatworms increase with increasing latitude.

    Science.gov (United States)

    Lorch, Sven; Zeuss, Dirk; Brandl, Roland; Brändle, Martin

    2016-03-01

    Polyploidy in combination with parthenogenesis offers advantages for plasticity and the evolution of a broad ecological tolerance of species. Therefore, a positive correlation between the level of ploidy and increasing latitude as a surrogate for environmental harshness has been suggested. Such a positive correlation is well documented for plants, but examples for animals are still rare. Species of flatworms (Platyhelminthes) are widely distributed, show a remarkably wide range of chromosome numbers, and offer therefore good model systems to study the geographical distribution of chromosome numbers. We analyzed published data on counts of chromosome numbers and geographical information of three flatworm "species" (Phagocata vitta, Polycelis felina and Crenobia alpina) sampled across Europe (220 populations). We used the mean chromosome number across individuals of a population as a proxy for the level of ploidy within populations, and we tested for relationships of this variable with latitude, mode of reproduction (sexual, asexual or both) and environmental variables (annual mean temperature, mean diurnal temperature range, mean precipitation and net primary production). The mean chromosome numbers of all three species increased with latitude and decreased with mean annual temperature. For two species, chromosome number also decreased with mean precipitation and net primary production. Furthermore, high chromosome numbers within species were accompanied with a loss of sexual reproduction. The variation of chromosome numbers within individuals of two of the three species increased with latitude. Our results support the hypothesis that polyploid lineages are able to cope with harsh climatic conditions at high latitudes. Furthermore, we propose that asexual reproduction in populations with high levels of polyploidization stabilizes hybridization events. Chromosomal irregularities within individuals tend to become more frequent at the extreme environments of high

  12. Misregulation of Scm3p/HJURP causes chromosome instability in Saccharomyces cerevisiae and human cells.

    Directory of Open Access Journals (Sweden)

    Prashant K Mishra

    2011-09-01

    Full Text Available The kinetochore (centromeric DNA and associated proteins is a key determinant for high fidelity chromosome transmission. Evolutionarily conserved Scm3p is an essential component of centromeric chromatin and is required for assembly and function of kinetochores in humans, fission yeast, and budding yeast. Overexpression of HJURP, the mammalian homolog of budding yeast Scm3p, has been observed in lung and breast cancers and is associated with poor prognosis; however, the physiological relevance of these observations is not well understood. We overexpressed SCM3 and HJURP in Saccharomyces cerevisiae and HJURP in human cells and defined domains within Scm3p that mediate its chromosome loss phenotype. Our results showed that the overexpression of SCM3 (GALSCM3 or HJURP (GALHJURP caused chromosome loss in a wild-type yeast strain, and overexpression of HJURP led to mitotic defects in human cells. GALSCM3 resulted in reduced viability in kinetochore mutants, premature separation of sister chromatids, and reduction in Cse4p and histone H4 at centromeres. Overexpression of CSE4 or histone H4 suppressed chromosome loss and restored levels of Cse4p at centromeres in GALSCM3 strains. Using mutant alleles of scm3, we identified a domain in the N-terminus of Scm3p that mediates its interaction with CEN DNA and determined that the chromosome loss phenotype of GALSCM3 is due to centromeric association of Scm3p devoid of Cse4p/H4. Furthermore, we determined that similar to other systems the centromeric association of Scm3p is cell cycle regulated. Our results show that altered stoichiometry of Scm3p/HJURP, Cse4p, and histone H4 lead to defects in chromosome segregation. We conclude that stringent regulation of HJURP and SCM3 expression are critical for genome stability.

  13. Chromosomal imbalance in the progression of high-risk non-muscle invasive bladder cancer

    International Nuclear Information System (INIS)

    Non-muscle invasive bladder neoplasms with invasion of the lamina propria (stage T1) or high grade of dysplasia are at 'high risk' of progression to life-threatening cancer. However, the individual course is difficult to predict. Chromosomal instability (CI) is associated with high tumor stage and grade, and possibly with the risk of progression. To investigate the relationship between CI and subsequent disease progression, we performed a case-control-study of 125 patients with 'high-risk' non-muscle invasive bladder neoplasms, 67 with later disease progression, and 58 with no progression. Selection criteria were conservative (non-radical) resections and full prospective clinical follow-up (> 5 years). We investigated primary lesions in 59, and recurrent lesions in 66 cases. We used Affymetrix GeneChip® Mapping 10 K and 50 K SNP microarrays to evaluate genome wide chromosomal imbalance (loss-of-heterozygosity and DNA copy number changes) in 48 representative tumors. DNA copy number changes of 15 key instability regions were further investigated using QPCR in 101 tumors (including 25 tumors also analysed on 50 K SNP microarrays). Chromosomal instability did not predict any higher risk of subsequent progression. Stage T1 and high-grade tumors had generally more unstable genomes than tumors of lower stage and grade (mostly non-primary tumors following a 'high-risk' tumor). However, about 25% of the 'high-risk' tumors had very few alterations. This was independent of subsequent progression. Recurrent lesions represent underlying field disease. A separate analysis of these lesions did neither reflect any difference in the risk of progression. Of specific chromosomal alterations, a possible association between loss of chromosome 8p11 and the risk of progression was found. However, the predictive value was limited by the heterogeneity of the changes. Chromosomal instability (CI) was associated with 'high risk' tumors

  14. 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

  15. Chromosomal and Genetic Analysis of a Human Lung Adenocarcinoma Cell Line OM

    Institute of Scientific and Technical Information of China (English)

    Yong-Wu Li; Lin Bai; Lyu-Xia Dai; Xu He; Xian-Ping Zhou

    2016-01-01

    Background: Lung cancer has become the leading cause of death in many regions.Carcinogenesis is caused by the stepwise accumulation of genetic and chromosomal changes.The aim of this study was to investigate the chromosome and gene alterations in the human lung adenocarcinoma cell line OM.Methods: We used Giemsa banding and multiplex fluorescence in situ hybridization focusing on the human lung adenocarcinoma cell line OM to analyze its chromosome alterations.In addition, the gains and losses in the specific chromosome regions were identified by comparative genomic hybridization (CGH) and the amplifications of cancer-related genes were also detected by polymerase chain reaction (PCR).Results: We identified a large number of chromosomal numerical alterations on all chromosomes except chromosome X and 19.Chromosome 10 is the most frequently involved in translocations with six different interchromosomal translocations.CGH revealed the gains on chromosome regions of 3q25.3-28, 5p13, 12q22-23.24, and the losses on 3p25-26, 6p25, 6q26-27, 7q34-36, 8p22-23, 9p21-24, 10q25-26.3, 12p 13.31-13.33 and 17p 13.1-13.3.And PCR showed the amplification of genes: Membrane metalloendopeptidase (MME), sucrase-isomaltase (SI), butyrylcholinesterase (BCHE), and kininogen (KNG).Conclusions: The lung adenocarcinoma cell line OM exhibited multiple complex karyotypes, and chromosome 10 was frequently involved in chromosomal translocation, which may play key roles in tumorigenesis.We speculated that the oncogenes may be located at 3q25.3-28, 5p13, 12q22-23.24, while tumor suppressor genes may exist in 3p25-26, 6p25, 6q26-27, 7q34-36, 8p22-23, 9p21-24, 10q25-26.3, 12p 13.31-13.33, and 17p 13.1-13.3.Moreover, at least four genes (MME, SI, BCHE, and KNG) may be involved in the human lung adenocarcinoma cell line OM.

  16. Generation of large homozygous chromosomal segments by mitotic recombination during lymphomagenesis in F{sub 1} hybrid mice

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Doo-Pyo; Mori, Nobuko; Umesako, Seiichi; Okumoto, Masaaki [Osaka Prefectural Univ., Sakai (Japan). Research Inst. for Advanced Science and Technology; Kubo, Kihei; Tsugawa, Naomi [Osaka Prefectural Univ., Sakai (Japan). Graduate School of Agriculture and Biological Sciences; Song, Chang-Woo [Korea Research Inst. of Chemical Technology, Taejon (Korea, Republic of)

    2002-06-01

    The loss of heterozygosity (LOH) has been reported in numerous neoplasms in both human and animals, and has often been observed in chromosomal regions, which contain tumor-suppressor genes. We previously found frequent LOH on chromosomes 4, 12 and 19 in radiation-induced lymphomas from (BALB/cHeA x STS/A)F{sub 1} hybrid mice by allelotype analysis at polymorphic microsatellite loci. In this study, to elucidate the nature of allelic losses, we refined the loss regions on chromosomes 4, 12 and 19 of the tumors from the F{sub 1} mice and then analyzed them cytogenetically. The results represent evidence of a wide range of allelic losses owing to mitotic recombination on chromosomes 4 and 19 in the tumors, possibly reflecting functional losses of putative tumor-suppressor genes. It is suggested that the generation of these large homozygous chromosomal segments probably containing the affected genes is one of the genetic alterations responsible for tumorigenesis. (author)

  17. 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. PMID:20933291

  18. 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...

  19. Novel Gene Acquisition on Carnivore Y Chromosomes

    OpenAIRE

    Murphy, William J.; A J Pearks Wilkerson; Terje Raudsepp; Richa Agarwala; Schäffer, Alejandro A.; Roscoe Stanyon; Chowdhary, Bhanu P

    2006-01-01

    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...

  20. Identification of bacterial cells by chromosomal painting.

    OpenAIRE

    Lanoil, B. D.; Giovannoni, S J

    1997-01-01

    Chromosomal painting is a technique for the microscopic localization of genetic material. It has been applied at the subcellular level to identify regions of eukaryotic chromosomes. Here we describe the development of bacterial chromosomal painting (BCP), a related technology for the identification of bacterial cells. Purified genomic DNAs from six bacterial strains were labeled by nick translation with the fluorochrome Fluor-X, Cy3, or Cy5. The average size of the labeled fragments was ca. 5...

  1. Holoprosencephaly due to Numeric Chromosome Abnormalities

    OpenAIRE

    Solomon, Benjamin D.; Rosenbaum, Kenneth N.; Meck, Jeanne M.; Muenke, Maximilian

    2010-01-01

    Holoprosencephaly (HPE) is the most common malformation of the human forebrain. When a clinician identifies a patient with HPE, a routine chromosome analysis is often the first genetic test sent for laboratory analysis in order to assess for a structural or numerical chromosome anomaly. An abnormality of chromosome number is overall the most frequently identified etiology in a patient with HPE. These abnormalities include trisomy 13, trisomy 18, and triploidy, though several others have been ...

  2. How does DNA break during chromosomal translocations?

    OpenAIRE

    Nambiar, Mridula; Raghavan, Sathees C.

    2011-01-01

    Chromosomal translocations are one of the most common types of genetic rearrangements and are molecular signatures for many types of cancers. They are considered as primary causes for cancers, especially lymphoma and leukemia. Although many translocations have been reported in the last four decades, the mechanism by which chromosomes break during a translocation remains largely unknown. In this review, we summarize recent advances made in understanding the molecular mechanism of chromosomal t...

  3. Advances in plant chromosome genomics

    Czech Academy of Sciences Publication Activity Database

    Doležel, Jaroslav; Vrána, Jan; Cápal, Petr; Kubaláková, Marie; Burešová, Veronika; Šimková, Hana

    2014-01-01

    Roč. 32, č. 1 (2014), s. 122-136. ISSN 0734-9750 R&D Projects: GA ČR GAP501/10/1740; GA ČR GAP501/10/1778; GA ČR GBP501/12/G090; GA MŠk(CZ) LO1204 Grant ostatní: GA MŠk(CZ) ED0007/01/01 Institutional support: RVO:61389030 Keywords : BAC library * Chromosome sorting * Cytogenetics Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 9.015, year: 2014

  4. Multiple chromosomes of Azotobacter vinelandii.

    OpenAIRE

    1989-01-01

    The number of copies of the genes leuB, nifH, nifD, and nifK per cell of Azotobacter vinelandii has been determined to be about 80. A beta-lactamase gene was integrated into the A. vinelandii chromosome by single-point crossover. Subsequently, we have been able to detect nearly 80 copies of this beta-lactamase gene per cell of A. vinelandii when cultured for a large number of generations in the presence of ampicillin. The multiple copies of the beta-lactamase gene do not seem to be present on...

  5. Xeroderma pigmentosum and medulloblastoma: chromosomal damage to lymphocytes during radiotherapy

    International Nuclear Information System (INIS)

    The effects of radiotherapy on a patient with xeroderma pigmentosum (XP) of complementation group C and medulloblastoma are reported. His lymphocytes showed no x-ray-induced chromatid damage, but unstable chromosomal aberrations increased throughout the course of radiotherapy as observed also in two other children (patients 2 and 3) with a similar tumor. Such damage was more dependent on spinal than cranial irradiation, lowest in the XP patient and highest in patient 3. Interindividual differences seemed largely due to the relative volume of body irradiated, but the damage in patient 3 remained relatively high even after accounting for such a factor. A maximum of 36, 68, and 77% of lymphocytes had aberrations in the XP and patients 2 and 3, respectively, but chromosomal damage did not show a Poisson distribution and indicated admixture of irradiated and nonirradiated cells. The relative frequency of the irradiated cells was estimated and seemed proportional to the ratios of the average irradiated field to the total body area. The XP patient showed no preferential loss of highly damaged cells and seemed not to suffer excessive chromosomal damage; he had a normal clinical response to and a favorable outcome of radiotherapy. These findings reduce anxiety on the use of radiotherapy in XP patients or at least in those of group C

  6. Mechanisms and consequences of paternally transmitted chromosomal abnormalities

    Energy Technology Data Exchange (ETDEWEB)

    Marchetti, F; Wyrobek, A J

    2005-04-05

    Paternally transmitted chromosomal damage has been associated with pregnancy loss, developmental and morphological defects, infant mortality, infertility, and genetic diseases in the offspring including cancer. There is epidemiological evidence linking paternal exposure to occupational or environmental agents with an increased risk of abnormal reproductive outcomes. There is also a large body of literature on germ cell mutagenesis in rodents showing that treatment of male germ cells with mutagens has dramatic consequences on reproduction producing effects such as those observed in human epidemiological studies. However, we know very little about the etiology, transmission and early embryonic consequences of paternally-derived chromosomal abnormalities. The available evidence suggests that: (1) there are distinct patterns of germ cell-stage differences in the sensitivity of induction of transmissible genetic damage with male postmeiotic cells being the most sensitive; (2) cytogenetic abnormalities at first metaphase after fertilization are critical intermediates between paternal exposure and abnormal reproductive outcomes; and, (3) there are maternally susceptibility factors that may have profound effects on the amount of sperm DNA damage that is converted into chromosomal aberrations in the zygote and directly affect the risk for abnormal reproductive outcomes.

  7. Chromosome banding in Amphibia. XXIV. The B chromosomes of Gastrotheca espeletia (Anura, Hylidae).

    Science.gov (United States)

    Schmid, M; Ziegler, C G; Steinlein, C; Nanda, I; Haaf, T

    2002-01-01

    The mitotic chromosomes of an Ecuadorian population of the marsupial frog Gastrotheca espeletia were analyzed by means of banding techniques and fluorescence in situ hybridization. This species is characterized by unusual supernumerary (B) chromosomes. The maximum number of B chromosomes is 9 and they occur in three different morphological types. Banding analyses show that the B chromosomes are completely heterochromatic, consist of AT base pair-rich repeated DNA sequences, replicate their DNA in very late S-phase of the cell cycle, and are probably derived from a centromeric or paracentromeric region of a standard (A) chromosome. Exceptionally, the B chromosomes carry 18S + 28S ribosomal RNA genes and the conserved vertebrate telomeric DNA sequence appears to be underrepresented. Flow cytometric measurements of the nuclear DNA content differentiate between individuals with different numbers of B chromosomes. Significantly more B chromosomes are present in female than in male animals. PMID:12438715

  8. Giemsa C-banding of Barley Chromosomes. IV. Chromosomal Constitution of Autotetraploid Barley

    DEFF Research Database (Denmark)

    Linde-Laursen, Ib

    1984-01-01

    homologues of each of the chromosomes. The aneuploid C2--seedlings were fairly equally distributed on hypo-and hyperploids, and on the seven chromosome groups. This suggests that a particular chromosome is lost or gained at random in gametes and embryos. The 11 C3--seedlings comprised seven true euploids......The progeny of an autotetraploid barley plant (C1) consisted of 45 tetraploids and 33 aneuploids. Giemsa C-banding was used to identify each of the chromosomes in 20 euploid and 31 aneuploid C2--seedlings, and in 11 C3--offspring of aneuploid C2--plants. The euploid C2--seedlings all had four......, one seedling with 2n=28 having an extra chromosome 6 and missing one chromosome 3, and three seedlings with 2n=29. The chromosomal composition of aneuploid C3--seedlings did not reflect that of their aneuploid C2--parents with respect to missing or extra chromosomes. Two hypohexaploid C2--seedlings...

  9. Microtubule detyrosination guides chromosomes during mitosis

    OpenAIRE

    Barisic, Marin; Silva e Sousa, Ricardo; Tripathy, Suvranta K.; Magiera, Maria M.; Zaytsev, Anatoly V.; Pereira, Ana L.; Janke, Carsten; Grishchuk, Ekaterina L.; Maiato, Helder

    2015-01-01

    Before chromosomes segregate into daughter cells they align at the mitotic spindle equator, a process known as chromosome congression. CENP-E/Kinesin-7 is a microtubule plus-end-directed kinetochore motor required for congression of pole-proximal chromosomes. Because the plus-ends of many astral microtubules in the spindle point to the cell cortex, it remains unknown how CENP-E guides pole-proximal chromosomes specifically towards the equator. Here we found that congression of pole-proximal c...

  10. Exceptional Complex Chromosomal Rearrangements in Three Generations

    Directory of Open Access Journals (Sweden)

    Hannie Kartapradja

    2015-01-01

    Full Text Available We report an exceptional complex chromosomal rearrangement (CCR found in three individuals in a family that involves 4 chromosomes with 5 breakpoints. The CCR was ascertained in a phenotypically abnormal newborn with additional chromosomal material on the short arm of chromosome 4. Maternal karyotyping indicated that the mother carried an apparently balanced CCR involving chromosomes 4, 6, 11, and 18. Maternal transmission of the derivative chromosome 4 resulted in partial trisomy for chromosomes 6q and 18q and a partial monosomy of chromosome 4p in the proband. Further family studies found that the maternal grandmother carried the same apparently balanced CCR as the proband’s mother, which was confirmed using the whole chromosome painting (WCP FISH. High resolution whole genome microarray analysis of DNA from the proband’s mother found no evidence for copy number imbalance in the vicinity of the CCR translocation breakpoints, or elsewhere in the genome, providing evidence that the mother’s and grandmother’s CCRs were balanced at a molecular level. This structural rearrangement can be categorized as an exceptional CCR due to its complexity and is a rare example of an exceptional CCR being transmitted in balanced and/or unbalanced form across three generations.

  11. Chromosome heteromorphisms in the Japanese, 3

    International Nuclear Information System (INIS)

    The type and frequency of chromosome variants detected by the C-staining method were ascertained in 1,857 individuals residing in Hiroshima. The most frequent heteromorphic variant was the total inversion of the C-band in chromosome 9 found in 27 individuals (1.45%). The total inversion of the C-band in chromosome 1 was not seen in this sample, but the partial inversion of the C-band in chromosome 1 was found in 18 persons (0.97%). Partial inversion was also detected in the C-band in chromosome 9 in 22 individuals (1.18%). In chromosome 16, neither total nor partial inversion of the C-band was observed in the present study. The frequencies of chromosomes 1, 9, and 16 with a very large C-band were 0.70%, 0.22%, and 0.54%, respectively. Aside from these (1, 9, and 16) a very large C-band was found occasionally in chromosomes 4, 5, 6, 11, 12, 14, and 15, and an unusual insertion of the Y chromosome was observed. A total of 128 C-band variants (6.89%) was found in the 1,857 Hiroshima residents. (author)

  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. PMID:23622175

  13. Chromosomal aberrations in ore miners of Slovakia

    International Nuclear Information System (INIS)

    A pilot study was performed in which the incidence of chromosomal aberrations in lymphocytes of miners in ore mines located in Central Slovakia was monitored and related to lifetime underground radon exposure and to lifetime smoking. The conclusions drawn from the results of the study were as follows: the counts of chromosomal aberrations in lymphocytes of miners were significantly higher than in an age matched control group of white-collar staff; the higher counts of chromosomal aberrations could be ascribed to underground exposure of miners and to smoking; a dependence of chromosomal aberration counts on the exposure to radon could not be assessed. (A.K.)

  14. Genetic Causes of Recurrent Pregnancy Loss.

    Science.gov (United States)

    Page, Jessica M; Silver, Robert M

    2016-09-01

    Pregnancy loss is one of the most common obstetric complications, affecting over 30% of conceptions. A considerable proportion of losses are due to genetic abnormalities. Indeed, over 50% of early pregnancy losses have been associated with chromosomal abnormalities. Most are due to de novo nondisjunctional events but balanced parental translocations are responsible for a small but important percentage of genetic abnormalities in couples with recurrent pregnancy loss. In the past, assessment of genetic abnormalities was limited to karyotype performed on placental or fetal tissue. However, advances in molecular genetic technology now provide rich genetic information about additional genetic causes of and risk factors for pregnancy loss. In addition, the use of preimplantation genetic testing in couples undergoing in vitro fertilization has the potential to decrease the risk of pregnancy loss from genetic abnormalities. To date, efficacy is uncertain but considerable potential remains. This chapter will review what is known about genetic causes of recurrent pregnancy loss with a focus on novel causes and potential treatments. Remaining knowledge gaps will be highlighted. PMID:27414972

  15. A genome-wide map of aberrantly expressed chromosomal islands in colorectal cancer

    Directory of Open Access Journals (Sweden)

    Castanos-Velez Esmeralda

    2006-09-01

    Full Text Available Abstract Background Cancer development is accompanied by genetic phenomena like deletion and amplification of chromosome parts or alterations of chromatin structure. It is expected that these mechanisms have a strong effect on regional gene expression. Results We investigated genome-wide gene expression in colorectal carcinoma (CRC and normal epithelial tissues from 25 patients using oligonucleotide arrays. This allowed us to identify 81 distinct chromosomal islands with aberrant gene expression. Of these, 38 islands show a gain in expression and 43 a loss of expression. In total, 7.892 genes (25.3% of all human genes are located in aberrantly expressed islands. Many chromosomal regions that are linked to hereditary colorectal cancer show deregulated expression. Also, many known tumor genes localize to chromosomal islands of misregulated expression in CRC. Conclusion An extensive comparison with published CGH data suggests that chromosomal regions known for frequent deletions in colon cancer tend to show reduced expression. In contrast, regions that are often amplified in colorectal tumors exhibit heterogeneous expression patterns: even show a decrease of mRNA expression. Because for several islands of deregulated expression chromosomal aberrations have never been observed, we speculate that additional mechanisms (like abnormal states of regional chromatin also have a substantial impact on the formation of co-expression islands in colorectal carcinoma.

  16. Unique Case Reports Associated with Ovarian Failure: Necessity of Two Intact X Chromosomes

    Directory of Open Access Journals (Sweden)

    Lakshmi Rao Kandukuri

    2012-01-01

    Full Text Available Premature ovarian failure is defined as the loss of functional follicles below the age of 40 years and the incidence of this abnormality is 0.1% among the 30–40 years age group. Unexplained POF is clinically recognized as amenorrhoea (>6 months with low level of oestrogen and raised level of Luteinizing Hormone (LH and Follicle Stimulating Hormone (FSH > 20 IU/l occurring before the age of 40. It has been studied earlier that chromosomal defects can impair ovarian development and its function. Since there is paucity of data on chromosomal defects in Indian women, an attempt is made to carry out cytogenetic evaluation in patients with ovarian failure. Cytogenetic analysis of women with ovarian defects revealed the chromosome abnormalities to be associated with 14% of the cases analyzed. Interestingly, majority of the abnormalities involved the X-chromosome and we report two unique abnormalities, (46,XXdel(Xq21-22 and q28 and (mos,45XO/46,X+ringX involving X chromosome in association with ovarian failure. This study revealed novel X chromosome abnormalities associated with ovarian defects and these observations would be helpful in genetic counseling and apart from, infertility clinics using the information to decide suitable strategies to help such patients.

  17. Genetic divergence in domesticated and non-domesticated gene regions of barley chromosomes.

    Directory of Open Access Journals (Sweden)

    Songxian Yan

    Full Text Available Little is known about the genetic divergence in the chromosomal regions with domesticated and non-domesticated genes. The objective of our study is to examine the effect of natural selection on shaping genetic diversity of chromosome region with domesticated and non-domesticated genes in barley using 110 SSR markers. Comparison of the genetic diversity loss between wild and cultivated barley for each chromosome showed that chromosome 5H had the highest divergence of 35.29%, followed by 3H, 7H, 4H, 2H, 6H. Diversity ratio was calculated as (diversity of wild type - diversity of cultivated type/diversity of wild type×100%. It was found that diversity ratios of the domesticated regions on 5H, 1H and 7H were higher than those of non-domesticated regions. Diversity ratio of the domesticated region on 2H and 4H is similar to that of non-domesticated region. However, diversity ratio of the domesticated region on 3H is lower than that of non-domesticated region. Averaged diversity among six chromosomes in domesticated region was 33.73% difference between wild and cultivated barley, and was 27.56% difference in the non-domesticated region. The outcome of this study advances our understanding of the evolution of crop chromosomes.

  18. 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.

  19. Increased chromosome radiosensitivity during pregnancy

    International Nuclear Information System (INIS)

    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

  20. Retrospective dosimetry by chromosomal analysis

    International Nuclear Information System (INIS)

    The joint EU/CIS project ECP-6, was set up to examine whether cytogenetic dosimetry is possible for persons irradiated years previously at Chernobyl. The paper describes the possibility of achieving this by the examination of blood lymphocytes for unstable and stable chromosome aberrations; dicentrics and translocations. Emphasis was placed on the relatively new fluorescence in situ hybridization (FISH) method for rapid screening for stable translocations. In a collaborative experiment in vitro dose response calibration curves for dicentrics and FISH were produced with gamma radiation over the range 0-1.0 Gy. A pilot study of about 60 liquidators with registered doses ranging from 0-300 mSv was undertaken to determine whether the chromosomal methods may verify the recorded doses. It was concluded that the dicentric is no longer valid as a measured endpoint. Translocations may be used to verify early dosimetry carried out on highly irradiated persons. For the vast majority of lesser exposed subjects FISH is impractical as an individual dosimeter; it may have some value for comparing groups of subjects

  1. Chromosomal instability determines taxane response.

    Science.gov (United States)

    Swanton, Charles; Nicke, Barbara; Schuett, Marion; Eklund, Aron C; Ng, Charlotte; Li, Qiyuan; Hardcastle, Thomas; Lee, Alvin; Roy, Rajat; East, Philip; Kschischo, Maik; Endesfelder, David; Wylie, Paul; Kim, Se Nyun; Chen, Jie-Guang; Howell, Michael; Ried, Thomas; Habermann, Jens K; Auer, Gert; Brenton, James D; Szallasi, Zoltan; Downward, Julian

    2009-05-26

    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 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 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. PMID:19458043

  2. Chromosomal replicons of higher plants

    International Nuclear Information System (INIS)

    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

  3. The X chromosome of monotremes shares a highly conserved region with the eutherian and marsupial X chromosomes despite the absence of X chromosome inactivation

    Energy Technology Data Exchange (ETDEWEB)

    Watson, J.M.; Spencer, J.A.; Graves, J.A.M. (La Trobe Univ., Bundoora, Victoria (Australia)); Riggs, A.D. (Beckman Inst., Duarte, CA (USA))

    1990-09-01

    Eight genes, located on the long arm of the human X chromosome and present on the marsupial X chromosome, were mapped by in situ hybridization to the chromosomes of the platypus Ornithorhynchus anatinus, one of the three species of monotreme mammals. All were located on the X chromosome. The authors conclude that the long arm of the human X chromosome represents a highly conserved region that formed part of the X chromosome in a mammalian ancestor at least 150 million years ago. Since three of these genes are located on the long arm of the platypus X chromosome, which is G-band homologous to the Y chromosome and apparently exempt from X chromosome inactivation, the conservation of this region has evidently not depended on isolation by X-Y chromosome differentiation and X chromosome inactivation.

  4. Double and multiple chromosomal aneuploidies in spontaneous abortions: A single institutional experience

    Directory of Open Access Journals (Sweden)

    Shivakumar Subramaniyam

    2014-01-01

    Full Text Available Objective: To characterize double and multiple aneuploidies in spontaneous abortions (SAB. Materials and Methods: Retrospective analysis of cytogenetics data obtained by culturing/harvesting products of the conception material at our center from 2006 to 2009 was performed. The abnormal cytogenetic results, maternal age, gestational age, and previous pregnancy history were recorded and compared. Results: Double and multiple aneuploidies are rare, however, a high percentage of double (4.6% and multiple (0.4% chromosomal aneuploidies were observed in our study of 1502 cases of SAB. Of 1502 cases of SAB evaluated, 70 cases (4.6% showed double aneuploidy, whereas 6 cases (0.4% had multiple aneuploidies. The chromosomes most frequently involved in double aneuploidy in the decreasing order were 21, 16, ± X, 22, 18, 13, and 15. The most frequent chromosome combinations observed were: Loss of X/21 (8.5%, 21/22 (4.4%, 16/21 (4.4%, and 7/16 (4.4%. The chromosome combinations in multiple aneuploidy included trisomy of chromosomes X/5/8, 8/20/22, 16/20/22, 14/21/22, and loss of X with 21/21 and 7/21. These abnormalities were significantly observed in women between the age group 40-44 years (59.2%. A high success rate (94% of obtaining metaphase cells was observed in this study mainly due to the use of direct and long-term cultures. Conclusions: We observed a high percentage of double (4.6% and multiple (0.4% aneuploidies, frequently involving the acrocentic chromosomes 13, 15, 21, and 22 and nonacrocentric chromosomes X, 16, and 18.

  5. Evolution of diverse mechanisms for protecting chromosome ends by Drosophila TART telomere retrotransposons

    Science.gov (United States)

    George, Janet A.; Traverse, Karen L.; DeBaryshe, P. G.; Kelley, Kerry J.; Pardue, Mary-Lou

    2010-01-01

    The retrotransposons HeT-A, TART, and TAHRE, which maintain Drosophila telomeres, transpose specifically onto chromosome ends to form long arrays that extend the chromosome and compensate for terminal loss. Because they transpose by target-primed reverse transcription, each element is oriented so that its 5′ end serves as the extreme end of the chromosome until another element transposes to occupy the terminal position. Thus 5′ sequences are at risk for terminal erosion while the element is at the chromosome end. Here we report that TART elements in Drosophila melanogaster and Drosophila virilis show species-specific innovations in promoter architecture that buffer loss of sequence exposed at chromosome ends. The two elements have evolved different ways to effect this protection. The D. virilis TART (TARTvir) promoter is found in the 3′ UTR of the element directly upstream of the element transcribed. Transcription starts within the upstream element so that a “Tag” of extra sequence is added to the 5′ end of the newly transcribed RNA. This Tag provides expendable sequence to buffer end erosion of essential 5′ sequence after the RNA is reverse transcribed onto the chromosome. In contrast, the D. melanogaster TART (TARTmel) promoter initiates transcription deep within the 5′ UTR, but the element is able to replace and extend the 5′ UTR sequence by copying sequence from its 3′ UTR, we believe while being reverse transcribed onto the chromosome end. Astonishingly, end-protection in TARTvir and HeT-Amel are essentially identical (using Tags), whereas HeT-Avir is clearly protected from end erosion by an as-yet-unspecified program. PMID:21088221

  6. Living with vision loss

    Science.gov (United States)

    Diabetes - vision loss; Retinopathy - vision loss; Low vision; Blindness - vision loss ... Low vision is a visual disability. Wearing regular glasses or contacts does not help. People with low vision have ...

  7. 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.

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

    Science.gov (United States)

    2011-01-01

    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. PMID:21787398

  9. Economic Loan Loss Provision and Expected Loss

    Directory of Open Access Journals (Sweden)

    Stefan Hlawatsch

    2010-10-01

    Full Text Available The intention of a loan loss provision is the anticipation of the loan's expected losses by adjusting the book value of the loan. Furthermore, this loan loss provision has to be compared to the expected loss according to Basel II and, in the case of a difference, liable equity has to be adjusted. This however assumes that the loan loss provision and the expected loss are based on a similar economic rationale, which is only valid conditionally in current loan loss provisioning methods according to IFRS. Therefore, differences between loan loss provisions and expected losses should only result from different approaches regarding the parameter estimation within each model and not due to different assumptions regarding the outcome of the model. The provisioning and accounting model developed in this paper overcomes the before-mentioned shortcomings and is consistent with an economic rationale of expected losses. Additionally, this model is based on a close-to-market valuation of the loan that is in favor of the basic idea of IFRS. Suggestions for changes in current accounting and capital requirement rules are provided.

  10. Independent clonal origin of multiple uterine leiomyomas that was determined by X chromosome inactivation and microsatellite analysis

    DEFF Research Database (Denmark)

    Canevari, Renata A; Pontes, Anaglória; Rosa, Fabíola E;

    2005-01-01

    OBJECTIVE: In an attempt to clarify the clonality and genetic relationships that are involved in the tumorigenesis of uterine leiomyomas, we used a total of 43 multiple leiomyomas from 14 patients and analyzed the allelic status with 15 microsatellite markers and X chromosome inactivation analysis....... STUDY DESIGN: We have used a set of 15 microsatellite polymorphism markers mapped on 3q, 7p, 11, and 15q by automated analysis. The X chromosome inactivation was evaluated by the methylation status of the X-linked androgen receptor gene. RESULTS: Loss of heterozygosity analysis showed a different...... pattern in 7 of the 8 cases with allelic loss for at least 1 of 15 microsatellite markers that were analyzed. A similar loss of heterozygosity findings at 7p22-15 was detected in 3 samples from the same patient. X chromosome inactivation analysis demonstrated the same inactivated allele in all tumors...

  11. Loss of HLTF function promotes intestinal carcinogenesis

    Directory of Open Access Journals (Sweden)

    Sandhu Sumit

    2012-03-01

    Full Text Available Abstract Background HLTF (Helicase-like Transcription Factor is a DNA helicase protein homologous to the SWI/SNF family involved in the maintenance of genomic stability and the regulation of gene expression. HLTF has also been found to be frequently inactivated by promoter hypermethylation in human colon cancers. Whether this epigenetic event is required for intestinal carcinogenesis is unknown. Results To address the role of loss of HLTF function in the development of intestinal cancer, we generated Hltf deficient mice. These mutant mice showed normal development, and did not develop intestinal tumors, indicating that loss of Hltf function by itself is insufficient to induce the formation of intestinal cancer. On the Apcmin/+ mutant background, Hltf- deficiency was found to significantly increase the formation of intestinal adenocarcinoma and colon cancers. Cytogenetic analysis of colon tumor cells from Hltf -/-/Apcmin/+ mice revealed a high incidence of gross chromosomal instabilities, including Robertsonian fusions, chromosomal fragments and aneuploidy. None of these genetic alterations were observed in the colon tumor cells derived from Apcmin/+ mice. Increased tumor growth and genomic instability was also demonstrated in HCT116 human colon cancer cells in which HLTF expression was significantly decreased. Conclusion Taken together, our results demonstrate that loss of HLTF function promotes the malignant transformation of intestinal or colonic adenomas to carcinomas by inducing genomic instability. Our findings highly suggest that epigenetic inactivation of HLTF, as found in most human colon cancers, could play an important role in the progression of colon tumors to malignant cancer.

  12. Chromosome 15q24 microdeletion syndrome

    Directory of Open Access Journals (Sweden)

    Magoulas Pilar L

    2012-01-01

    Full Text Available Abstract Chromosome 15q24 microdeletion syndrome is a recently described rare microdeletion syndrome that has been reported in 19 individuals. It is characterized by growth retardation, intellectual disability, and distinct facial features including long face with high anterior hairline, hypertelorism, epicanthal folds, downslanting palpebral fissures, sparse and broad medial eyebrows, broad and/or depressed nasal bridge, small mouth, long smooth philtrum, and full lower lip. Other common findings include skeletal and digital abnormalities, genital abnormalities in males, hypotonia, behavior problems, recurrent infections, and eye problems. Other less frequent findings include hearing loss, growth hormone deficiency, hernias, and obesity. Congenital malformations, while rare, can be severe and include structural brain anomalies, cardiovascular malformations, congenital diaphragmatic hernia, intestinal atresia, imperforate anus, and myelomeningocele. Karyotypes are typically normal, and the deletions were detected in these individuals by array comparative genomic hybridization (aCGH. The deletions range in size from 1.7-6.1 Mb and usually result from nonallelic homologous recombination (NAHR between paralogous low-copy repeats (LCRs. The majority of 15q24 deletions have breakpoints that localize to one of five LCR clusters labeled LCR15q24A, -B, -C, -D, and -E. The smallest region of overlap (SRO spans a 1.2 Mb region between LCR15q24B to LCR15q24C. There are several candidate genes within the SRO, including CYP11A1, SEMA7A, CPLX3, ARID3B, STRA6, SIN3A and CSK, that may predispose to many of the clinical features observed in individuals with 15q24 deletion syndrome. The deletion occurred as a de novo event in all of the individuals when parents were available for testing. Parental aCGH and/or FISH studies are recommended to provide accurate genetic counseling and guidance regarding prognosis, recurrence risk, and reproductive options. Management

  13. 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 that...

  14. Chromosome number9 specific repetitive DNA sequence

    International Nuclear Information System (INIS)

    Human repetitive DNA libraries have been constructed and various recombinant DNA clones isolated that are likely candidates for chromosome specific sequences. The first clone tested (pHuR 98; plasmid human repeat 98) was biotinylated and hybridized to human chromosomes in situ. The hybridized recombinant probe was detected with fluoresceinated avidin, and chromosomes were counter-stained with either propidium iodide or distamycin-DAPI. Specific hybridization to chromosome band 9q1 was obtained. The localization was confirmed by hybridizing radiolabeled pHuR 98 DNA to human chromosomes sorted by flow cytometry. Various methods, including orthogonal field pulsed gel electrophoresis analysis indicate that 75 kilobase blocks of this sequence are interspersed with other repetitive DNA sequences in this chromosome band. This study is the first to report a human repetitive DNA sequence uniquely localized to a specific chromosome. This clone provides an easily detected and highly specific chromosomal marker for molecular cytogenetic analyses in numerous basic research and clinical studies

  15. Chromosomal characterization of Pseudonannolene strinatii (Spirostreptida, Pseudonannolenidae

    Directory of Open Access Journals (Sweden)

    Kleber Agari Campos

    2004-03-01

    Full Text Available The chromosomes of the cave millipede Pseudonannolene strinatii Mauriès, 1974 were investigated. The diploid chromosome number was found to be 2n=16, XX/XY; the C-banding technique revealed a large amount of heterochromatin while the silver staining technique (Ag-NOR evidenced the presence of heteromorphism of the NORs in some cells.

  16. 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.

  17. 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. PMID:27263828

  18. Physical map of the Bacillus cereus chromosome.

    OpenAIRE

    Kolstø, A B; Grønstad, A; Oppegaard, H

    1990-01-01

    A physical map of the Bacillus cereus chromosome has been constructed by aligning 11 NotI fragments, ranging in size from 200 to 1,300 kilobases. The size of the chromosome is about 5.7 megabases. This is the first Bacillus genome of which a complete physical map has been described.

  19. Compositions for chromosome-specific staining

    Science.gov (United States)

    Gray, Joe W.; Pinkel, Daniel

    1998-01-01

    Methods and compositions for staining based upon nucleic acid sequence that employ nucleic acid probes are provided. Said methods produce staining patterns that can be tailored for specific cytogenetic analyses. Said probes are appropriate for in situ hybridization and stain both interphase and metaphase chromosomal material with reliable signals. The nucleic acid probes are typically of a complexity greater than 50 kb, the complexity depending upon the cytogenetic application. Methods are provided to disable the hybridization capacity of shared, high copy repetitive sequences and/or remove such sequences to provide for useful contrast. Still further methods are provided to produce chromosome-specific staining reagents which are made specific to the targeted chromosomal material, which can be one or more whole chromosomes, one or more regions on one or more chromosomes, subsets of chromosomes and/or the entire genome. Probes and test kits are provided for use in tumor cytogenetics, in the detection of disease related loci, in analysis of structural abnormalities, such as translocations, and for biological dosimetry. Further, methods and prenatal test kits are provided to stain targeted chromosomal material of fetal cells, including fetal cells obtained from maternal blood. Still further, the invention provides for automated means to detect and analyse chromosomal abnormalities.

  20. Mapping of human chromosomal regions related to neoplasia: evidence from chromosomes 1 and 17

    Energy Technology Data Exchange (ETDEWEB)

    Rowley, J.D.

    1977-12-01

    In clonal aberrations leading to an excess or partial excess of chromosome I, trisomy for bands 1q25-1q32 was noted in the myeloid cells from all of 34 patients who had various disorders such as acute leukemia, polycythemia vera, and myelofibrosis. This was not the result of a particularly fragile site in that region of the chromosome because the break points in reciprocal translocations that involve it occurred almost exclusively in the short arm. Two consistent rearrangements that have been observed in chromosome 17 produced either duplication of the entire long arm or a translocation of the distal portion of the long arm to chromosome 15. The nonrandom chromosomal changes found in hematologic disorders can now be correlated with the gene loci on these chromosomes or chromosomal segments. Seventy-five genes related to various metabolic enzymes have been mapped; it may be significant that chromosomes carrying gene loci related to nucleic acid metabolism are more frequently involved in hematologic disorders (and other malignancies as well) than are gene loci related to intermediary or carbohydrate metabolism. Furthermore, the known virus-human chromosome associations are closely correlated with the chromosomes affected in hematologic disorders. If one of the effects of carcinogens (including viruses) is to activate genes that regulate host cell DNA synthesis, and if translocations or duplications of specific chromosomal segments produce the same effect, then either of these mechanisms might provide the affected cell with a proliferative advantage.

  1. 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.

  2. Genetic conflict and sex chromosome evolution

    Science.gov (United States)

    Meiklejohn, Colin D; Tao, Yun

    2009-01-01

    Chromosomal sex determination systems create the opportunity for the evolution of selfish genetic elements that increase the transmission of one sex chromosome at the expense of its homolog. Because such selfish elements on sex chromosomes can reduce fertility and distort the sex ratio of progeny, unlinked suppressors are expected to evolve, bringing different regions of the genome into conflict over the meiotic transmission of the sex chromosomes. Here we argue that recurrent genetic conflict over sex chromosome transmission is an important evolutionary force that has shaped a wide range of seemingly disparate phenomena including the epigenetic regulation of genes expressed in the germline, the distribution of genes in the genome, and the evolution of hybrid sterility between species. PMID:19931208

  3. 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.

  4. 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.

  5. Y-chromosome evolution: emerging insights into processes of Y-chromosome degeneration.

    Science.gov (United States)

    Bachtrog, Doris

    2013-02-01

    The human Y chromosome is intriguing not only because it harbours the master-switch gene that determines gender but also because of its unusual evolutionary history. The Y chromosome evolved from an autosome, and its evolution has been characterized by massive gene decay. Recent whole-genome and transcriptome analyses of Y chromosomes in humans and other primates, in Drosophila species and in plants have shed light on the current gene content of the Y chromosome, its origins and its long-term fate. Furthermore, comparative analysis of young and old Y chromosomes has given further insights into the evolutionary and molecular forces triggering Y-chromosome degeneration and into the evolutionary destiny of the Y chromosome. PMID:23329112

  6. Novel gene acquisition on carnivore Y chromosomes.

    Directory of Open Access Journals (Sweden)

    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.

  7. Chromosome differentiation patterns during cichlid fish evolution

    Directory of Open Access Journals (Sweden)

    Nirchio Mauro

    2010-06-01

    Full Text Available Abstract Background Cichlid fishes have been the subject of increasing scientific interest because of their rapid adaptive radiation which has led to an extensive ecological diversity and their enormous importance to tropical and subtropical aquaculture. To increase our understanding of chromosome evolution among cichlid species, karyotypes of one Asian, 22 African, and 30 South American cichlid species were investigated, and chromosomal data of the family was reviewed. Results Although there is extensive variation in the karyotypes of cichlid fishes (from 2n = 32 to 2n = 60 chromosomes, the modal chromosome number for South American species was 2n = 48 and the modal number for the African ones was 2n = 44. The only Asian species analyzed, Etroplus maculatus, was observed to have 46 chromosomes. The presence of one or two macro B chromosomes was detected in two African species. The cytogenetic mapping of 18S ribosomal RNA (18S rRNA gene revealed a variable number of clusters among species varying from two to six. Conclusions The karyotype diversification of cichlids seems to have occurred through several chromosomal rearrangements involving fissions, fusions and inversions. It was possible to identify karyotype markers for the subfamilies Pseudocrenilabrinae (African and Cichlinae (American. The karyotype analyses did not clarify the phylogenetic relationship among the Cichlinae tribes. On the other hand, the two major groups of Pseudocrenilabrinae (tilapiine and haplochromine were clearly discriminated based on the characteristics of their karyotypes. The cytogenetic mapping of 18S ribosomal RNA (18S rRNA gene did not follow the chromosome diversification in the family. The dynamic evolution of the repeated units of rRNA genes generates patterns of chromosomal distribution that do not help follows the phylogenetic relationships among taxa. The presence of B chromosomes in cichlids is of particular interest because they may not be represented in

  8. Menopause and Bone Loss

    Science.gov (United States)

    Fact Sheet & Menopause Bone Loss How are bone loss and menopause related? Throughout life your body keeps a balance between the loss ... The sooner you take steps to prevent bone loss, the lower your risk of osteoporosis later in life. If you are skipping menstrual periods, have had ...

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

    OpenAIRE

    Yerle Martine; Ducos Alain; Pinton Alain

    2003-01-01

    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...

  10. Sex chromosome evolution: platypus gene mapping suggests that part of the human X chromosome was originally autosomal.

    OpenAIRE

    Watson, J M; Spencer, J. A.; Riggs, A D; Graves, J.A.

    1991-01-01

    To investigate the evolution of the mammalian sex chromosomes, we have compared the gene content of the X chromosomes in the mammalian groups most distantly related to man (marsupials and monotremes). Previous work established that genes on the long arm of the human X chromosome are conserved on the X chromosomes in all mammals, revealing that this region was part of an ancient mammalian X chromosome. However, we now report that several genes located on the short arm of the human X chromosome...

  11. Hair loss in women.

    Science.gov (United States)

    Harfmann, Katya L; Bechtel, Mark A

    2015-03-01

    Hair loss is a common cause of morbidity for many women. As a key member of the woman's health care team, the obstetrician/gynecologist may be the first person to evaluate the complaint of hair loss. Common types of nonscarring hair loss, including female pattern hair loss and telogen effluvium, may be diagnosed and managed by the obstetrician/gynecologist. A systematic approach to diagnosis and management of these common forms of hair loss is presented. PMID:25517757

  12. Nonrandom chromosomal changes in human malignant cells

    Energy Technology Data Exchange (ETDEWEB)

    Rowley, J D

    1977-01-01

    The role of chromosomal changes in human malignant cells has been the subject of much debate. The observation of nonrandom chromosomal changes has become well recognized in chronic myelogenous leukemia, and more recently in acute myelogenous leukemia. In the present report, data are presented on the sites of duplication of chromosome No. 1 in hematologic disorders. Trisomy for region lq25 to lq32 was observed in every one of 34 patients whose cells showed duplication of some part of chromosome No. 1. Adjacent regions lq21 to lq25, and lq32 to lqter, also were trisomic in the majority of patients. Two patients had deletions, one of lq32 to qter, and the other, of lp32 to pter. The sites of chromosomal breaks leading to trisomy differ from those involved in balanced reciprocal translocations. Some of these sites are sometimes, but not always, vulnerable in constitutional chromosomal abnormalities. The nature of the proliferative advantage conferred on myeloid cells by these chromosomal changes is unknown.

  13. Chromosome number evolution in skippers (Lepidoptera, Hesperiidae).

    Science.gov (United States)

    Lukhtanov, Vladimir A

    2014-01-01

    Lepidoptera (butterflies and moths), as many other groups of animals and plants, simultaneously represent preservation of ancestral karyotype in the majority of families with a high degree of chromosome number instability in numerous independently evolved phylogenetic lineages. However, the pattern and trends of karyotype evolution in some Lepidoptera families are poorly studied. Here I provide a survey of chromosome numbers in skippers (family Hesperiidae) based on intensive search and analysis of published data. I demonstrate that the majority of skippers preserve the haploid chromosome number n=31 that seems to be an ancestral number for the Hesperiidae and the order Lepidoptera at whole. However, in the tribe Baorini the derived number n=16 is the most typical state which can be used as a (syn)apomorphic character in further phylogenetic investigations. Several groups of skippers display extreme chromosome number variations on within-species (e.g. the representatives of the genus Carcharodus Hübner, [1819]) and between-species (e.g. the genus Agathymus Freeman, 1959) levels. Thus, these groups can be used as model systems for future analysis of the phenomenon of chromosome instability. Interspecific chromosomal differences are also shown to be useful for discovering and describing new cryptic species of Hesperiidae representing in such a way a powerful tool in biodiversity research. Generally, the skipper butterflies promise to be an exciting group that will significantly contribute to the growing knowledge of patterns and processes of chromosome evolution. PMID:25610542

  14. Chromosome number evolution in skippers (Lepidoptera, Hesperiidae

    Directory of Open Access Journals (Sweden)

    Vladimir Lukhtanov

    2014-11-01

    Full Text Available Lepidoptera (butterflies and moths, as many other groups of animals and plants, simultaneously represent preservation of ancestral karyotype in the majority of families with a high degree of chromosome number instability in numerous independently evolved phylogenetic lineages. However, the pattern and trends of karyotype evolution in some Lepidoptera families are poorly studied. Here I provide a survey of chromosome numbers in skippers (family Hesperiidae based on intensive search and analysis of published data. I demonstrate that the majority of skippers preserve the haploid chromosome number n=31 that seems to be an ancestral number for the Hesperiidae and the order Lepidoptera at whole. However, in the tribe Baorini the derived number n=16 is the most typical state which can be used as a (synapomorphic character in further phylogenetic investigations. Several groups of skippers display extreme chromosome number variations on within-species (e.g. the representatives of the genus Carcharodus Hübner, [1819] and between-species (e.g. the genus Agathymus Freeman, 1959 levels. Thus, these groups can be used as model systems for future analysis of the phenomenon of chromosome instability. Interspecific chromosomal differences are also shown to be useful for discovering and describing new cryptic species of Hesperiidae representing in such a way a powerful tool in biodiversity research. Generally, the skipper butterflies promise to be an exciting group that will significantly contribute to the growing knowledge of patterns and processes of chromosome evolution.

  15. Group 3 chromosome bin maps of wheat and their relationship to rice chromosome 1.

    Science.gov (United States)

    Munkvold, J D; Greene, R A; Bermudez-Kandianis, C E; La Rota, C M; Edwards, H; Sorrells, S F; Dake, T; Benscher, D; Kantety, R; Linkiewicz, A M; Dubcovsky, J; Akhunov, E D; Dvorák, J; Miftahudin; Gustafson, J P; Pathan, M S; Nguyen, H T; Matthews, D E; Chao, S; Lazo, G R; Hummel, D D; Anderson, O D; Anderson, J A; Gonzalez-Hernandez, J L; Peng, J H; Lapitan, N; Qi, L L; Echalier, B; Gill, B S; Hossain, K G; Kalavacharla, V; Kianian, S F; Sandhu, D; Erayman, M; Gill, K S; McGuire, P E; Qualset, C O; Sorrells, M E

    2004-10-01

    The focus of this study was to analyze the content, distribution, and comparative genome relationships of 996 chromosome bin-mapped expressed sequence tags (ESTs) accounting for 2266 restriction fragments (loci) on the homoeologous group 3 chromosomes of hexaploid wheat (Triticum aestivum L.). Of these loci, 634, 884, and 748 were mapped on chromosomes 3A, 3B, and 3D, respectively. The individual chromosome bin maps revealed bins with a high density of mapped ESTs in the distal region and bins of low density in the proximal region of the chromosome arms, with the exception of 3DS and 3DL. These distributions were more localized on the higher-resolution group 3 consensus map with intermediate regions of high-mapped-EST density on both chromosome arms. Gene ontology (GO) classification of mapped ESTs was not significantly different for homoeologous group 3 chromosomes compared to the other groups. A combined analysis of the individual bin maps using 537 of the mapped ESTs revealed rearrangements between the group 3 chromosomes. Approximately 232 (44%) of the consensus mapped ESTs matched sequences on rice chromosome 1 and revealed large- and small-scale differences in gene order. Of the group 3 mapped EST unigenes approximately 21 and 32% matched the Arabidopsis coding regions and proteins, respectively, but no chromosome-level gene order conservation was detected. PMID:15514041

  16. Sequencing of rhesus macaque Y chromosome clarifies origins and evolution of the DAZ (Deleted in AZoospermia) genes.

    Science.gov (United States)

    Hughes, Jennifer F; Skaletsky, Helen; Page, David C

    2012-12-01

    Studies of Y chromosome evolution often emphasize gene loss, but this loss has been counterbalanced by addition of new genes. The DAZ genes, which are critical to human spermatogenesis, were acquired by the Y chromosome in the ancestor of Old World monkeys and apes. We and our colleagues recently sequenced the rhesus macaque Y chromosome, and comparison of this sequence to human and chimpanzee enables us to reconstruct much of the evolutionary history of DAZ. We report that DAZ arrived on the Y chromosome about 38 million years ago via the transposition of at least 1.1 megabases of autosomal DNA. This transposition also brought five additional genes to the Y chromosome, but all five genes were subsequently lost through mutation or deletion. As the only surviving gene, DAZ experienced extensive restructuring, including intragenic amplification and gene duplication, and has been the target of positive selection in the chimpanzee lineage. Editor's suggested further reading in BioEssays Should Y stay or should Y go: The evolution of non-recombining sex chromosomes Abstract. PMID:23055411

  17. A defined chromosome 6q fragment (at D6S310) harbors a putative tumor suppressor gene for breast cancer.

    Science.gov (United States)

    Theile, M; Seitz, S; Arnold, W; Jandrig, B; Frege, R; Schlag, P M; Haensch, W; Guski, H; Winzer, K J; Barrett, J C; Scherneck, S

    1996-08-15

    Recent evidence obtained by cytogenetic and molecular studies indicates that in breast cancer chromosome 6q is often affected by genetic changes suggesting the existence of putative tumor suppressor genes (TSGs). However the function of gene(s) on this chromosome in breast cancer suppression is not understood. To substantiate further the presence of breast cancer related TSGs at 6q and to define their location, we first performed microcell-mediated transfer of chromosome 6 to CAL51 breast cancer cells for studying possible suppression of malignant phenotype and secondly, we analysed DNAs from 46 primary breast cancers for loss of constitutive heterozygosity (LOH) using 24 poly-morphic microsatellite markers. The chromosome transfer resulted in loss of tumorigenicity and reversion of other neoplastic properties of the microcell hybrids. Polymorphism analysis of single hybrids revealed that they harbored only a small donor chromosome fragment defined by the marker D6S310 (6q23.3-q25) and flanked by D6S292 and D6S311. The LOH data suggest that four tumor suppressor gene loci mapped to the central and distal portion of 6q may be independently deleted in breast cancer. One of these regions corresponds to the region identified by chromosome transfer. PMID:8761288

  18. Chromosome heteromorphism quantified by high-resolution bivariate flow karyotyping.

    Science.gov (United States)

    Trask, B; van den Engh, G; Mayall, B; Gray, J W

    1989-11-01

    Maternal and paternal homologues of many chromosome types can be differentiated on the basis of their peak position in Hoechst 33258 versus chromomycin A3 bivariate flow karyotypes. We demonstrate here the magnitude of DNA content differences among normal chromosomes of the same type. Significant peak-position differences between homologues were observed for an average of four chromosome types in each of the karyotypes of 98 different individuals. The frequency of individuals with differences in homologue peak positions varied among chromosome types: e.g., chromosome 15, 61%; chromosome 3, 4%. Flow karyotypes of 33 unrelated individuals were compared to determine the range of peak position among normal chromosomes. Chromosomes Y, 21, 22, 15, 16, 13, 14, and 19 were most heteromorphic, and chromosomes 2-8 and X were least heteromorphic. The largest chromosome 21 was 45% larger than the smallest 21 chromosome observed. The base composition of the variable regions differed among chromosome types. DNA contents of chromosome variants determined from flow karyotypes were closely correlated to measurements of DNA content made of gallocyanin chrome alum-stained metaphase chromosomes on slides. Fluorescence in situ hybridization with chromosome-specific repetitive sequences indicated that variability in their copy number is partly responsible for peak-position variability in some chromosomes. Heteromorphic chromosomes are identified for which parental flow karyotype information will be essential if de novo rearrangements resulting in small DNA content changes are to be detected with flow karyotyping. PMID:2479266

  19. HPV type-related chromosomal profiles in high-grade cervical intraepithelial neoplasia

    Directory of Open Access Journals (Sweden)

    Bierkens Mariska

    2012-01-01

    Full Text Available Abstract Background The development of cervical cancer and its high-grade precursor lesions (Cervical Intraepithelial Neoplasia grade 2/3 [CIN2/3] result from a persistent infection with high-risk human papillomavirus (hrHPV types and the accumulation of (epigenetic host cell aberrations. Epidemiological studies have demonstrated variable CIN2/3 and cancer risks between different hrHPV types. Recent genomic profiling studies revealed substantial heterogeneity in the chromosomal aberrations detected in morphologically indistinguishable CIN2/3 suggestive of varying cancer risk. The current study aimed to investigate whether CIN2/3 with different hrHPV types vary with respect to their chromosomal profiles, both in terms of the number of aberrations and chromosomal loci affected. Methods Chromosomal profiles were determined of 43 p16INK4a-immunopositive CIN2/3 of women with long-term hrHPV infection (≥ 5 years. Sixteen lesions harboured HPV16, 3 HPV18, 14 HPV31, 1 HPV33, 4 HPV45, 1 HPV51, 2 HPV52 and 2 HPV58. Results Unsupervised hierarchical clustering analysis of the chromosomal profiles revealed two major clusters, characterised by either few or multiple chromosomal aberrations, respectively. A majority of 87.5% of lesions with HPV16 were in the cluster with relatively few aberrations, whereas no such unbalanced distribution was seen for lesions harbouring other hrHPV types. Analysis of the two most prevalent types (HPV16 and HPV31 in this data set revealed a three-fold increase in the number of losses in lesions with HPV31 compared to HPV16-positive lesions. In particular, losses at chromosomes 2q, 4p, 4q, 6p, 6q, 8q & 17p and gain at 1p & 1q were significantly more frequent in HPV31-positive lesions (FDR Conclusions Chromosomal aberrations in CIN2/3 are at least in part related to the hrHPV type present. The relatively low number of chromosomal aberrations observed in HPV16-positive CIN2/3 suggests that the development of these lesions is

  20. Adaptation through chromosomal inversions in Anopheles

    Directory of Open Access Journals (Sweden)

    Diego eAyala

    2014-05-01

    Full Text Available Chromosomal inversions have been repeatedly involved in local adaptation in a large number of animals and plants. The ecological and behavioral plasticity of Anopheles species - human malaria vectors - is mirrored by high amounts of polymorphic inversions. The adaptive significance of chromosomal inversions has been consistently attested by strong and significant correlations between their frequencies and a number of phenotypic traits. Here, we provide an extensive literature review of the different adaptive traits associated with chromosomal inversions in the genus Anopheles. Traits having important consequences for the success of present and future vector control measures, such as insecticide resistance and behavioral changes, are discussed.

  1. 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

  2. Cholinergic degeneration and memory loss delayed by vitamin E in a Down syndrome mouse model

    OpenAIRE

    Lockrow, Jason; Prakasam, Annamalai; Huang, Peng; Bimonte-Nelson, Heather; Sambamurti, Kumar; Granholm, Ann-Charlotte

    2008-01-01

    Down syndrome (DS) individuals develop several neuropathological hallmarks seen in Alzheimer's disease, including cognitive decline and the early loss of cholinergic markers in the basal forebrain. These deficits are replicated in the Ts65Dn mouse, which contains a partial trisomy of murine chromosome 16, the orthologous genetic segment to human chromosome 21. Oxidative stress levels are elevated early in DS, and may contribute to the neurodegeneration seen in these individuals. We evaluated ...

  3. Corona helps curb losses

    Energy Technology Data Exchange (ETDEWEB)

    Laasonen, M.; Lahtinen, M.; Lustre, L.

    1996-11-01

    The greatest power losses in electricity transmission arise through a phenomenon called load losses. Corona losses caused by the surface discharge of electricity also constitute a considerable cost item. IVS, the nationwide network company, is investigating corona- induced losses, and has also commissioned similar research from IVO International, the Technical Research Centre of Finland (VTT) and from Tampere University of Technology. The research work strives to gain more in-depth knowledge on the phenomenon of frosting and its impact on corona losses. The correct prediction of frost helps reduce corona losses, while also cutting costs considerably. (orig.)

  4. 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. PMID:25394583

  5. Visualization of yeast chromosomal DNA

    Science.gov (United States)

    Lubega, Seth

    1990-01-01

    The DNA molecule is the most significant life molecule since it codes the blue print for other structural and functional molecules of all living organisms. Agarose gel electrophoresis is now being widely used to separate DNA of virus, bacteria, and lower eukaryotes. The task was undertaken of reviewing the existing methods of DNA fractionation and microscopic visualization of individual chromosonal DNA molecules by gel electrophoresis as a basis for a proposed study to investigate the feasibility of separating DNA molecules in free fluids as an alternative to gel electrophoresis. Various techniques were studied. On the molecular level, agarose gel electrophoresis is being widely used to separate chromosomal DNA according to molecular weight. Carl and Olson separate and characterized the entire karyotype of a lab strain of Saccharomyces cerevisiae. Smith et al. and Schwartz and Koval independently reported the visualization of individual DNA molecules migrating through agarose gel matrix during electrophoresis. The techniques used by these researchers are being reviewed in the lab as a basis for the proposed studies.

  6. Dynamic changes in paternal X-chromosome activity during imprinted X-chromosome inactivation in mice

    OpenAIRE

    Patrat, Catherine; Okamoto, Ikuhiro; Diabangouaya, Patricia; Vialon, Vivian; Le Baccon, Patricia; Chow, Jennifer; Heard, Edith

    2009-01-01

    In mammals, X-chromosome dosage compensation is achieved by inactivating one of the two X chromosomes in females. In mice, X inactivation is initially imprinted, with inactivation of the paternal X (Xp) chromosome occurring during preimplantation development. One theory is that the Xp is preinactivated in female embryos, because of its previous silence during meiosis in the male germ line. The extent to which the Xp is active after fertilization and the exact time of onset of X-linked gene si...

  7. Tracking Chromosome Evolution in Southern African Gerbils Using Flow-Sorted Chromosome Paints

    OpenAIRE

    Knight, L.I.; Ng, B. L.; Cheng, W; Fu, B.; Yang, F.; Rambau, R V

    2013-01-01

    Desmodillus and Gerbilliscus (formerly Tatera) comprise a monophyletic group of gerbils (subfamily Gerbillinae) which last shared an ancestor approximately 8 million years ago; diploid chromosome number variation among the species ranges from 2n = 36 to 2n = 50. In an attempt to shed more light on chromosome evolution and speciation in these rodents, we compared the karyotypes of 7 species, representing 3 genera, based on homology data revealed by chromosome painting with probes derived from ...

  8. Sex Chromosome Evolution in Amniotes: Applications for Bacterial Artificial Chromosome Libraries

    OpenAIRE

    Janes, Daniel E.; Nicole Valenzuela; Tariq Ezaz; Chris Amemiya; Edwards, Scott V.

    2011-01-01

    Variability among sex chromosome pairs in amniotes denotes a dynamic history. Since amniotes diverged from a common ancestor, their sex chromosome pairs and, more broadly, sex-determining mechanisms have changed reversibly and frequently. These changes have been studied and characterized through the use of many tools and experimental approaches but perhaps most effectively through applications for bacterial artificial chromosome (BAC) libraries. Individual BAC clones carry 100–200 kb of seque...

  9. A universe of dwarfs and giants: genome size and chromosome evolution in the monocot family Melanthiaceae.

    Science.gov (United States)

    Pellicer, Jaume; Kelly, Laura J; Leitch, Ilia J; Zomlefer, Wendy B; Fay, Michael F

    2014-03-01

    • Since the occurrence of giant genomes in angiosperms is restricted to just a few lineages, identifying where shifts towards genome obesity have occurred is essential for understanding the evolutionary mechanisms triggering this process. • Genome sizes were assessed using flow cytometry in 79 species and new chromosome numbers were obtained. Phylogenetically based statistical methods were applied to infer ancestral character reconstructions of chromosome numbers and nuclear DNA contents. • Melanthiaceae are the most diverse family in terms of genome size, with C-values ranging more than 230-fold. Our data confirmed that giant genomes are restricted to tribe Parideae, with most extant species in the family characterized by small genomes. Ancestral genome size reconstruction revealed that the most recent common ancestor (MRCA) for the family had a relatively small genome (1C = 5.37 pg). Chromosome losses and polyploidy are recovered as the main evolutionary mechanisms generating chromosome number change. • Genome evolution in Melanthiaceae has been characterized by a trend towards genome size reduction, with just one episode of dramatic DNA accumulation in Parideae. Such extreme contrasting profiles of genome size evolution illustrate the key role of transposable elements and chromosome rearrangements in driving the evolution of plant genomes. PMID:24299166

  10. A new assay for measuring chromosome instability (CIN) and identification of drugs that elevate CIN in cancer cells

    International Nuclear Information System (INIS)

    Aneuploidy is a feature of most cancer cells that is often accompanied by an elevated rate of chromosome mis-segregation termed chromosome instability (CIN). While CIN can act as a driver of cancer genome evolution and tumor progression, recent findings point to the existence of a threshold level beyond which CIN becomes a barrier to tumor growth and therefore can be exploited therapeutically. Drugs known to increase CIN beyond the therapeutic threshold are currently few in number, and the clinical promise of targeting the CIN phenotype warrants new screening efforts. However, none of the existing methods, including the in vitro micronuclei (MNi) assay, developed to quantify CIN, is entirely satisfactory. We have developed a new assay for measuring CIN. This quantitative assay for chromosome mis-segregation is based on the use of a non-essential human artificial chromosome (HAC) carrying a constitutively expressed EGFP transgene. Thus, cells that inherit the HAC display green fluorescence, while cells lacking the HAC do not. This allows the measurement of HAC loss rate by routine flow cytometry. Using the HAC-based chromosome loss assay, we have analyzed several well-known anti-mitotic, spindle-targeting compounds, all of which have been reported to induce micronuclei formation and chromosome loss. For each drug, the rate of HAC loss was accurately measured by flow cytometry as a proportion of non-fluorescent cells in the cell population which was verified by FISH analysis. Based on our estimates, despite their similar cytotoxicity, the analyzed drugs affect the rates of HAC mis-segregation during mitotic divisions differently. The highest rate of HAC mis-segregation was observed for the microtubule-stabilizing drugs, taxol and peloruside A. Thus, this new and simple assay allows for a quick and efficient screen of hundreds of drugs to identify those affecting chromosome mis-segregation. It also allows ranking of compounds with the same or similar mechanism of

  11. Cancer chromosomal instability: therapeutic and diagnostic challenges

    OpenAIRE

    McGranahan, Nicholas; Burrell, Rebecca A.; Endesfelder, David; Novelli, Marco R; Swanton, Charles

    2012-01-01

    This review provides a much-needed translational perspective into the issue of aneuploidy and chromosomal instability, discussing the prognostic value of CIN assessment in human tumours, methods to analyze it and how it could be therapeutically targeted.

  12. Lattice animal model of chromosome organization

    Science.gov (United States)

    Iyer, Balaji V. S.; Arya, Gaurav

    2012-07-01

    Polymer models tied together by constraints of looping and confinement have been used to explain many of the observed organizational characteristics of interphase chromosomes. Here we introduce a simple lattice animal representation of interphase chromosomes that combines the features of looping and confinement constraints into a single framework. We show through Monte Carlo simulations that this model qualitatively captures both the leveling off in the spatial distance between genomic markers observed in fluorescent in situ hybridization experiments and the inverse decay in the looping probability as a function of genomic separation observed in chromosome conformation capture experiments. The model also suggests that the collapsed state of chromosomes and their segregation into territories with distinct looping activities might be a natural consequence of confinement.

  13. Chromosome studies in the genus Jatropha L.

    Directory of Open Access Journals (Sweden)

    R.Sasikala and M.Paramathma

    2010-07-01

    Full Text Available The inflorescences of ten species of the genus Jatropha were fixed in Cornoy’s fluid (6:3:1. Acetocarmine stain (2% wasused for staining the pollen mother cells. Seven species exhibited 11 bivalents and 2n =22 and x=11. But the two otherspecies, J.villosa var. villosa and J.villosa var. ramnadensis showed only 10 bivalents and 2n number of 20 chromosomesand x=10. The study concluded the occurrence of two kinds of haploid chromosome numbers of n =10 and n =11. ExceptJatropha tanjorensis, cytological investigation in all species exhibited normal and complete pairing and bivalent formationin metaphase I and equal separation of chromosome in anaphase and indicated that the course of meiosis was normal.Jatropha tanjorensis did not exhibit normal course of meiosis and no proper count of chromosomes could be made. Presentchromosomal studies in Jatropha revealed the existence of two basic chromosomes numbers x = 5 and x = 6.

  14. System for the analysis of plant chromosomes

    International Nuclear Information System (INIS)

    The paper describes a computer system for the automation workers of recognition analysis and interpretation of plant chromosomes. This system permit to carry out the analysis in a more comfortable and faster way, using the image processing techniques

  15. Label Free Chromosome Translocation Detection with Silicon nanowires

    DEFF Research Database (Denmark)

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

    HROMOSOME translocation, which is a rearrangement of arms between two chromosomes, is a major group of chromosome abnormalities leading to cancer. As a result, two derivative chromosomes with sequences coming from both chromosomes are formed. The current translocation detection method is a Fluore...

  16. Methods and compositions for chromosome-specific staining

    Science.gov (United States)

    Gray, Joe W.; Pinkel, Daniel

    2003-07-22

    Methods and compositions for chromosome-specific staining are provided. Compositions comprise heterogenous mixtures of labeled nucleic acid fragments having substantially complementary base sequences to unique sequence regions of the chromosomal DNA for which their associated staining reagent is specific. Methods include methods for making the chromosome-specific staining compositions of the invention, and methods for applying the staining compositions to chromosomes.

  17. Genetics of Hearing Loss

    Science.gov (United States)

    ... in Latin America Information For... Media Policy Makers Genetics of Hearing Loss Language: English Español (Spanish) Recommend ... of hearing loss in babies is due to genetic causes. There are also a number of things ...

  18. Pregnancy Loss and Miscarriage

    Science.gov (United States)

    ... Share this: Page Content What is pregnancy loss/miscarriage? A miscarriage, also called pregnancy loss or spontaneous abortion, is ... D.A.M. Medical Encyclopedia. (2010, November 21). Miscarriage . Retrieved May 21, 2012, from http://www.ncbi. ...

  19. Hair Loss (Alopecia Areata)

    Science.gov (United States)

    ... rash and rashes clinical tools newsletter | contact Share | Hair Loss (Alopecia Areata) Information for adults A A A This ... scalp with a round area of non-scarring hair loss typical of alopecia areata. Overview Alopecia areata is ...

  20. Coping with Memory Loss

    Science.gov (United States)

    ... Consumers Home For Consumers Consumer Updates Coping With Memory Loss Share Tweet Linkedin Pin it More sharing ... a health professional. back to top What Causes Memory Loss? Anything that affects cognition—the process of ...

  1. Hair Loss (Alopecia)

    Science.gov (United States)

    ... Eating disorder: When a person has an eating disorder, hair loss is common. Anorexia (not eating enough) and bulimia (vomiting after eating) can cause hair loss. Medicine Some prescription medicines can cause ...

  2. Genes and Hearing Loss

    Science.gov (United States)

    ... Meeting Calendar Find an ENT Doctor Near You Genes and Hearing Loss Genes and Hearing Loss Patient ... mutation may only have dystopia canthorum. How Do Genes Work? Genes are a road map for the ...

  3. The hierarchically organized splitting of chromosomal bands for all human chromosomes

    Directory of Open Access Journals (Sweden)

    Liehr Thomas

    2009-01-01

    Full Text Available Abstract Background Chromosome banding is widely used in cytogenetics. However, the biological nature of hierarchically organized splitting of chromosomal bands of human chromosomes is an enigma and has not been, as yet, studied. Results Here we present for the first time the hierarchically organized splitting of chromosomal bands in their sub-bands for all human chromosomes. To do this, array-proved multicolor banding (aMCB probe-sets for all human chromosomes were applied to normal metaphase spreads of three different G-band levels. We confirmed for all chromosomes to be a general principle that only Giemsa-dark bands split into dark and light sub-bands, as we demonstrated previously by chromosome stretching. Thus, the biological band splitting is in > 50% of the sub-bands different than implemented by the ISCN nomenclature suggesting also a splitting of G-light bands. Locus-specific probes exemplary confirmed the results of MCB. Conclusion Overall, the present study enables a better understanding of chromosome architecture. The observed difference of biological and ISCN band-splitting may be an explanation why mapping data from human genome project do not always fit the cytogenetic mapping.

  4. Y chromosome evolution: emerging insights into processes of Y chromosome degeneration

    Science.gov (United States)

    Bachtrog, Doris

    2014-01-01

    The human Y chromosome is intriguing not only because it harbours the master-switch gene determining gender but also because of its unusual evolutionary trajectory. Previously an autosome, Y chromosome evolution has been characterized by massive gene decay. Recent whole-genome and transcriptome analyses of Y chromosomes in humans and other primates, in Drosophila species as well as in plants have shed light on the current gene content of the Y, its origins and its long-term fate. Comparative analysis of young and old Y chromosomes have given further insights into the evolutionary and molecular forces triggering Y degeneration and its evolutionary destiny. PMID:23329112

  5. Numerical chromosome errors in day 7 somatic nuclear transfer bovine blastocysts

    DEFF Research Database (Denmark)

    Booth, Paul J; Viuff, Dorthe; Tan, Shijian;

    2003-01-01

    Day 7 bovine somatic nuclear transfer (NT) embryos reconstructed from granulosa cells were examined for numerical chromosome aberrations as a potential cause of the high embryonic and fetal loss observed in such embryos after transfer. The NT embryos were reconstructed using a zona-free manipulat......Day 7 bovine somatic nuclear transfer (NT) embryos reconstructed from granulosa cells were examined for numerical chromosome aberrations as a potential cause of the high embryonic and fetal loss observed in such embryos after transfer. The NT embryos were reconstructed using a zona...... families, consisting of 112 blastocysts reconstructed from five different primary granulosa cell cultures, were examined. Overall, the mean chromosome complement within embryos was 86.9 +/- 3.7% (mean +/- SEM) diploid, 2.6 +/- 0.5% triploid, 10.0 +/- 3.1% tetraploid, and 0.5 +/- 0.2% pentaploid or greater......; the vast majority (>75%) of the abnormal nuclei were tetraploid. Completely diploid and mixoploid embryos represented 22.1 +/- 4.5% and 73.7 +/- 5.5%, respectively, of all clones. Six totally polyploid blastocysts, containing or=5N chromosome complements, respectively) between two clone families were...

  6. Chromosomal aberrations in benign and malignant Bilharzia-associated bladder lesions analyzed by comparative genomic hybridization

    International Nuclear Information System (INIS)

    Bilharzia-associated bladder cancer (BAC) is a major health problem in countries where urinary schistosomiasis is endemic. Characterization of the genetic alterations in this cancer might enhance our understanding of the pathogenic mechanisms of the disease but, in contrast to nonbilharzia bladder cancer, BAC has rarely been the object of such scrutiny. In the present study, we aimed to characterize chromosomal imbalances in benign and malignant post-bilharzial lesions, and to determine whether their unique etiology yields a distinct cytogenetic profile as compared to chemically induced bladder tumors. DNAs from 20 archival paraffin-embedded post-bilharzial bladder lesions (6 benign and 14 malignant) obtained from Sudanese patients (12 males and 8 females) with a history of urinary bilharziasis were investigated for chromosomal imbalances using comparative genomic hybridization (CGH). Subsequent FISH analysis with pericentromeric probes was performed on paraffin sections of the same cases to confirm the CGH results. Seven of the 20 lesions (6 carcinomas and one granuloma) showed chromosomal imbalances varying from 1 to 6 changes. The most common chromosomal imbalances detected were losses of 1p21-31, 8p21-pter, and 9p and gain of 19p material, seen in three cases each, including the benign lesion. Most of the detected imbalances have been repeatedly reported in non-bilharzial bladder carcinomas, suggesting that the cytogenetic profiles of chemical- and bilharzia-induced carcinomas are largely similar. However, loss of 9p seems to be more ubiquitous in BAC than in bladder cancer in industrialized countries

  7. Localization of topoisomerase II in mitotic chromosomes

    OpenAIRE

    1985-01-01

    In the preceding article we described a polyclonal antibody that recognizes cSc-1, a major polypeptide component of the chicken mitotic chromosome scaffold. This polypeptide was shown to be chicken topoisomerase II. In the experiments described in the present article we use indirect immunofluorescence and immunoelectron microscopy to examine the distribution of topoisomerase II within intact chromosomes. We also describe a simple experimental protocol that differentiates antigens that are int...

  8. 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.

  9. 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....

  10. Y chromosome microdeletions in Turkish infertile men

    OpenAIRE

    Zamani Ayse; Kutlu Ruhusen; Durakbasi-Dursun H; Gorkemli Huseyin; Acar Aynur

    2006-01-01

    AIMS: To detect the frequency and types of both chromosomal abnormalities and Y chromosome microdeletions in infertile men attending to our university intracytoplasmic sperm injection ICSI/IVF centre and fertile control subjects in our patient population. SETTINGS AND DESIGN: A total of 50 infertile men who were referred to IVF center of Meram medical faculty were selected for the molecular azospermia factor (AZF) screening program. MATERIALS AND METHODS: Karyotype analysis and polymeras...

  11. Delayed chromosomal instability induced by DNA damage.

    OpenAIRE

    Marder, B A; Morgan, W. F.

    1993-01-01

    DNA damage induced by ionizing radiation can result in gene mutation, gene amplification, chromosome rearrangements, cellular transformation, and cell death. Although many of these changes may be induced directly by the radiation, there is accumulating evidence for delayed genomic instability following X-ray exposure. We have investigated this phenomenon by studying delayed chromosomal instability in a hamster-human hybrid cell line by means of fluorescence in situ hybridization. We examined ...

  12. 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...

  13. Principles of chromosomal organization: lessons from yeast

    OpenAIRE

    Zimmer, Christophe; Fabre, Emmanuelle

    2011-01-01

    The spatial organization of genes and chromosomes plays an important role in the regulation of several DNA processes. However, the principles and forces underlying this nonrandom organization are mostly unknown. Despite its small dimension, and thanks to new imaging and biochemical techniques, studies of the budding yeast nucleus have led to significant insights into chromosome arrangement and dynamics. The dynamic organization of the yeast genome during interphase argues for both the physica...

  14. Bacterial Artificial Chromosome Mutagenesis Using Recombineering

    OpenAIRE

    Kumaran Narayanan; Qingwen Chen

    2011-01-01

    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...

  15. Assembly of Lampbrush Chromosomes from Sperm Chromatin

    OpenAIRE

    Gall, Joseph G.; Murphy, Christine

    1998-01-01

    We have examined the behavior of demembranated sperm heads when injected into the germinal vesicle (GV) of amphibian oocytes. Xenopus sperm heads injected into Xenopus GVs swelled immediately and within hours began to stain with an antibody against RNA polymerase II (Pol II). Over time each sperm head became a loose mass of chromosome-like threads, which by 24–48 h resolved into individually recognizable lampbrush chromosomes (LBCs). Although LBCs derived from sperm are unreplicated single ch...

  16. Sequence conservation on the Y chromosome

    Energy Technology Data Exchange (ETDEWEB)

    Gibson, L.H.; Yang-Feng, L. [Yale Univ. School of Medicine, New Haven, CT (United States); Lau, C. [Univ. of California, San Francisco, CA (United States)

    1994-09-01

    The Y chromosome is present in all mammals and is considered to be essential to sex determination. Despite intense genomic research, only a few genes have been identified and mapped to this chromosome in humans. Several of them, such as SRY and ZFY, have been demonstrated to be conserved and Y-located in other mammals. In order to address the issue of sequence conservation on the Y chromosome, we performed fluorescence in situ hybridization (FISH) with DNA from a human Y cosmid library as a probe to study the Y chromosomes from other mammalian species. Total DNA from 3,000-4,500 cosmid pools were labeled with biotinylated-dUTP and hybridized to metaphase chromosomes. For human and primate preparations, human cot1 DNA was included in the hybridization mixture to suppress the hybridization from repeat sequences. FISH signals were detected on the Y chromosomes of human, gorilla, orangutan and baboon (Old World monkey) and were absent on those of squirrel monkey (New World monkey), Indian munjac, wood lemming, Chinese hamster, rat and mouse. Since sequence analysis suggested that specific genes, e.g. SRY and ZFY, are conserved between these two groups, the lack of detectable hybridization in the latter group implies either that conservation of the human Y sequences is limited to the Y chromosomes of the great apes and Old World monkeys, or that the size of the syntenic segment is too small to be detected under the resolution of FISH, or that homologeous sequences have undergone considerable divergence. Further studies with reduced hybridization stringency are currently being conducted. Our results provide some clues as to Y-sequence conservation across species and demonstrate the limitations of FISH across species with total DNA sequences from a particular chromosome.

  17. 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.

  18. Die Haplotypisierung des Y-Chromosoms

    OpenAIRE

    Roewer, Lutz

    2001-01-01

    Haploid vererbte Polymorphismen des Y-Chromosoms sind wichtige diagnostische Werkzeuge der forensischen Genetik und verwandter Disziplinen, insbesondere der Anthropologie. Geschlechtsspezifität und uniparentaler Erbgang der Merkmale ermöglichen eine Reihe von Untersuchungen, die mit autosomalen Markern erfolglos bleiben müssen. Kurze tandem-repetitive STR-Sequenzen, die polymorphen Marker der Wahl im forensischen Labor, sind auch auf dem Y-Chromosom nachzuweisen. Aufgrund der rekombinationsfr...

  19. The X chromosome of monotremes shares a highly conserved region with the eutherian and marsupial X chromosomes despite the absence of X chromosome inactivation.

    OpenAIRE

    Watson, J M; Spencer, J. A.; Riggs, A D; Graves, J.A.

    1990-01-01

    Eight genes, located on the long arm of the human X chromosome and present on the marsupial X chromosome, were mapped by in situ hybridization to the chromosomes of the platypus Ornithorhynchus anatinus, one of the three species of monotreme mammals. All were located on the X chromosome. We conclude that the long arm of the human X chromosome represents a highly conserved region that formed part of the X chromosome in a mammalian ancestor at least 150 million years ago. Since three of these g...

  20. Characterizing the chromosomes of the platypus (Ornithorhynchus anatinus).

    Science.gov (United States)

    McMillan, Daniel; Miethke, Pat; Alsop, Amber E; Rens, Willem; O'Brien, Patricia; Trifonov, Vladimir; Veyrunes, Frederic; Schatzkamer, Kyriena; Kremitzki, Colin L; Graves, Tina; Warren, Wesley; Grützner, Frank; Ferguson-Smith, Malcolm A; Graves, Jennifer A Marshall

    2007-01-01

    Like the unique platypus itself, the platypus genome is extraordinary because of its complex sex chromosome system, and is controversial because of difficulties in identification of small autosomes and sex chromosomes. A 6-fold shotgun sequence of the platypus genome is now available and is being assembled with the help of physical mapping. It is therefore essential to characterize the chromosomes and resolve the ambiguities and inconsistencies in identifying autosomes and sex chromosomes. We have used chromosome paints and DAPI banding to identify and classify pairs of autosomes and sex chromosomes. We have established an agreed nomenclature and identified anchor BAC clones for each chromosome that will ensure unambiguous gene localizations. PMID:18185982

  1. Chromosomal variations in the primate Alouatta seniculus seniculus.

    Science.gov (United States)

    Yunis, E J; Torres de Caballero, O M; Ramírez, C; Ramírez, Z E

    1976-01-01

    Chromosome analysis in 23 specimens of Alouatta s. seniculus trapped in different localities of Colombia were examined with the C- and Q-banding techniques. The chromosome numbers (2n=44) showed variations from 2n = 43 to 2n = 45 involving three and five microchromosomes, respectively. Two specimens also showed a structural chromosome variation involving a pericentric inversion of the chromosome No. 13. Chromosome measurements revealed an X chromosome with a value significantly smaller to that established for the standard mammalian X chromosome. PMID:817992

  2. Reprogramming to pluripotency can conceal somatic cell chromosomal instability.

    Directory of Open Access Journals (Sweden)

    Masakazu Hamada

    Full Text Available The discovery that somatic cells are reprogrammable to pluripotency by ectopic expression of a small subset of transcription factors has created great potential for the development of broadly applicable stem-cell-based therapies. One of the concerns regarding the safe use of induced pluripotent stem cells (iPSCs in therapeutic applications is loss of genomic integrity, a hallmark of various human conditions and diseases, including cancer. Structural chromosome defects such as short telomeres and double-strand breaks are known to limit reprogramming of somatic cells into iPSCs, but whether defects that cause whole-chromosome instability (W-CIN preclude reprogramming is unknown. Here we demonstrate, using aneuploidy-prone mouse embryonic fibroblasts (MEFs in which chromosome missegregation is driven by BubR1 or RanBP2 insufficiency, that W-CIN is not a barrier to reprogramming. Unexpectedly, the two W-CIN defects had contrasting effects on iPSC genomic integrity, with BubR1 hypomorphic MEFs almost exclusively yielding aneuploid iPSC clones and RanBP2 hypomorphic MEFs karyotypically normal iPSC clones. Moreover, BubR1-insufficient iPSC clones were karyotypically unstable, whereas RanBP2-insufficient iPSC clones were rather stable. These findings suggest that aneuploid cells can be selected for or against during reprogramming depending on the W-CIN gene defect and present the novel concept that somatic cell W-CIN can be concealed in the pluripotent state. Thus, karyotypic analysis of somatic cells of origin in addition to iPSC lines is necessary for safe application of reprogramming technology.

  3. 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. PMID:26702042

  4. Elevated tolerance to aneuploidy in cancer cells: estimating the fitness effects of chromosome number alterations by in silico modelling of somatic genome evolution.

    Science.gov (United States)

    Valind, Anders; Jin, Yuesheng; Gisselsson, David

    2013-01-01

    An unbalanced chromosome number (aneuploidy) is present in most malignant tumours and has been attributed to mitotic mis-segregation of chromosomes. However, recent studies have shown a relatively high rate of chromosomal mis-segregation also in non-neoplastic human cells, while the frequency of aneuploid cells remains low throughout life in most normal tissues. This implies that newly formed aneuploid cells are subject to negative selection in healthy tissues and that attenuation of this selection could contribute to aneuploidy in cancer. To test this, we modelled cellular growth as discrete time branching processes, during which chromosome gains and losses were generated and their host cells subjected to selection pressures of various magnitudes. We then assessed experimentally the frequency of chromosomal mis-segregation as well as the prevalence of aneuploid cells in human non-neoplastic cells and in cancer cells. Integrating these data into our models allowed estimation of the fitness reduction resulting from a single chromosome copy number change to an average of ≈30% in normal cells. In comparison, cancer cells showed an average fitness reduction of only 6% (p = 0.0008), indicative of aneuploidy tolerance. Simulations based on the combined presence of chromosomal mis-segregation and aneuploidy tolerance reproduced distributions of chromosome aberrations in >400 cancer cases with higher fidelity than models based on chromosomal mis-segregation alone. Reverse engineering of aneuploid cancer cell development in silico predicted that aneuploidy intolerance is a stronger limiting factor for clonal expansion of aneuploid cells than chromosomal mis-segregation rate. In conclusion, our findings indicate that not only an elevated chromosomal mis-segregation rate, but also a generalised tolerance to novel chromosomal imbalances contribute to the genomic landscape of human tumours. PMID:23894657

  5. Hearing loss and music

    Science.gov (United States)

    Noise induced hearing loss - music; Sensory hearing loss - music ... damaged by loud sounds. The human ear is like any other body part -- too much use can damaged it. Over time, repeated exposure to loud noise and music can cause hearing loss.

  6. Chromosome abnormalities in colorectal adenomas: two cytogenetic subgroups characterized by deletion of 1p and numerical aberrations

    DEFF Research Database (Denmark)

    Bomme, L; Bardi, G; Pandis, N;

    1996-01-01

    Cytogenetic analysis of short-term cultures from 34 benign colorectal polyps, all histologically verified as adenomas, revealed clonal chromosome aberrations in 21 of them. Eight polyps had structural rearrangements, whereas only numerical changes were found in 13. A combination of structural and...... changes were +20, +13, and monosomy 18, found in six, five, and two adenomas, respectively. Rearrangement of chromosome 1 was the most common structural change. Abnormalities involving 1p were seen in six adenomas, leading to visible loss of material in three. One adenoma had one clone with a large and...... another with a small 1p deletion. In three adenomas, del(1)(p36) was the only cytogenetic aberration, supporting the authors' previous conclusion that loss of one or more gene loci in band 1p36 is a common early change in colorectal tumorigenesis. Chromosome 8 was involved in structural changes in two...

  7. Recurrent chromosomal aberrations in intravenous leiomyomatosis of the uterus: high-resolution array comparative genomic hybridization study.

    Science.gov (United States)

    Buza, Natalia; Xu, Fang; Wu, Weiqing; Carr, Ryan J; Li, Peining; Hui, Pei

    2014-09-01

    Uterine intravenous leiomyomatosis (IVL) is a distinct smooth muscle neoplasm with a potential of clinical aggressiveness due to its ability to extend into intrauterine and extrauterine vasculature. In this study, chromosomal alterations analyzed by oligonucleotide array comparative genomic hybridization were performed in 9 cases of IVL. The analysis was informative in all cases with multiple copy number losses and/or gains observed in each tumor. The most frequent recurrent loss of 22q12.3-q13.1 was observed in 6 tumors (66.7%), followed by losses of 22q11.23-q13.31, 1p36.13-p33, 2p25.3-p23.3, and 2q24.2-q32.2 and gains of 6p22.2, 2q37.3 and 10q22.2-q22.3, in decreasing order of frequency. Copy number variants were identified at 14q11.2, 15q11.1-q11.2, and 15q26.2. Genes mapping to the regions of loss include CHEK2, EWS, NF2, PDGFB, and MAP3K7IP1 on chromosome 22q, HEI10 on chromosome 14q, and succinate dehydrogenase subunit B, E2F2, ARID1A KPNA6, EIF3S2 , PTCH2, and PIK3R3 on chromosome 1p. Regional losses on chromosomes 22q and 1p and gains on chromosomes 12q showed overlaps with those previously observed in uterine leiomyosarcomas. In addition, presence of multiple chromosomal aberrations implies a higher level of genetic instability. Follow-up polymerase chain reaction (PCR) sequencing analysis of MED12 gene revealed absence of G> A transition at nucleotides c.130 or c.131 in all 9 cases, a frequent mutation found in uterine leiomyoma and its variants. In conclusion, this is the first report of high-resolution, genome-wide investigation of IVL by oligonucleotide array comparative genomic hybridization. The presence of high frequencies of recurrent regional loss involving several chromosomes is an important finding and likely related to the pathogenesis of the disease. PMID:25033729

  8. Chromosomal changes detected by fluorescence in situ hybridization in patients with acute lymphoblastic leukemia

    Institute of Scientific and Technical Information of China (English)

    ZHANG Lijun 张丽君; PARKHURST JB; KERN WF; SCOTT KV; NICCUM D; MULVIHILL JJ; LI Shibo 李师伯

    2003-01-01

    pediatric patients with pre-T or T cell lineage and the six adults were negative for TEL/AML1 fusion. One patient had double Philadelphia chromosomes, three had a rearrangement or a deletion of the MLL gene, one had t (4;11) and two had a deletion of the MLL. One of the patients with an MLL deletion also had a large ring of chromosome 21, and r (21) was caused by AML1 gene tandemly duplicated at least five times. The second case with the MLL deletion was also unique, the patient had a t (12;21) as well. A total of 20 patients had numerical changes (gain or loss) of chromosomes 4, 10, 17 and 21. Eight patients were found to have trisomies of three or four different chromosomes. Interestingly, seven of these patients did not have TEL/AML1, BCR/ABL or the MLL gene rearrangement; one did have the TEL/AML1 gene fusion. Eleven patients with pro-B cell or B cell type ALL (9 children with ALL, 2 adults with ALL) had numerical changes of chromosome 21 (gain 1 or 2 chromosome 21), among them, 10 patients had no structural alteration of chromosome 21, and one was combined by t (12; 21). Four patients had a monosomy of chromosome 17 and three out of these patients with monosomy 17 also had a fusion signal of TEL/AML1.Conclusions FISH plays an important role in detecting chromosome changes, especially in some cryptic chromosome translocations and patients with culture failures. This study found a trend towards a division between patients who had structural changes such as t (12;21) or a ring chromosome 21 and those who had numerical changes of chromosome 21 as well as the patients with TEL/AML1 fusion and patients with the coexistence of numerical chromosomal changes of chromosomes 4, 10 and 17. In our opinion there are two separate mechanisms which lead to the development or progression of leukemia.

  9. Localization of ecdysterone on polytene chromosomes of Drosophila melanogaster.

    OpenAIRE

    Gronemeyer, H; Pongs, O

    1980-01-01

    Ecdysterone has been crosslinked in situ to polytene chromosomes of salivary glands of Drosophila melanogaster by photoactivation. The crosslinked hormone has been localized on the chromosomes by indirect immunofluorescence microscopy. At different developmental stages the hormone was detected at different chromosomal loci. These chromosomal sites correspond to ecdysterone-inducible puff sites. Thus, the hormone binds directly to chromosomal loci, whose transcription depends on the presence o...

  10. Positional cloning of disease genes on chromosome 16

    Energy Technology Data Exchange (ETDEWEB)

    Doggett, N. [Los Alamos National Lab., NM (United States); Bruening, M. [Leiden Univ. (Netherlands); Callen, D. [Adelaide Women`s and Children`s Hospital, North Adelaide, South Australia (Australia); Gardiner, M. [University Coll., London (United Kingdom); Lerner, T. [Massachusetts General Hospital, Boston, MA (United States)

    1996-04-01

    The project seeks to elucidate the molecular basis of an important genetic disease (Batten`s disease) by molecular cloning of the affected gene by utilizing an overlapping clone map of chromosome 16. Batten disease (also known as juvenile neuronal ceroid lipofuscinosis) is a recessively inherited neurodegenerative disorder of childhood characterized by progressive loss of vision, seizures, and psychomoter disturbances. The Batten disease gene was genetically mapped to the chromosome region 16p 12.1 in close linkage with the genetic markers D16S299 and D16S298. Exon amplification of a cosmid containing D16S298 yielded a candidate gene that was disrupted by a 1 kb genomic deletion in all patients containing the most common haplotype for the disease. Two separate deletions and a point mutation altering a splice site in three unrelated families have confirmed the gene as the Batten disease gene. The disease gene encodes a novel 438 amino acid membrane binding protein of unknown function.

  11. Beam Loss in Linacs

    CERN Document Server

    Plum, M A

    2016-01-01

    Beam loss is a critical issue in high-intensity accelerators, and much effort is expended during both the design and operation phases to minimize the loss and to keep it to manageable levels. As new accelerators become ever more powerful, beam loss becomes even more critical. Linacs for H- ion beams, such as the one at the Oak Ridge Spallation Neutron Source, have many more loss mechanisms compared to H+ (proton) linacs, such as the one being designed for the European Spallation Neutron Source. Interesting H- beam loss mechanisms include residual gas stripping, H+ capture and acceleration, field stripping, black-body radiation and the recently discovered intra-beam stripping mechanism. Beam halo formation, and ion source or RF turn on/off transients, are examples of beam loss mechanisms that are common for both H+ and H- accelerators. Machine protection systems play an important role in limiting the beam loss.

  12. The human homologue of unc-93 maps to chromosome 6q27 - characterisation and analysis in sporadic epithelial ovarian cancer

    DEFF Research Database (Denmark)

    Liu, Ying; Dodds, Phillippa; Emilion, Gracy;

    2002-01-01

    In sporadic ovarian cancer, we have previously reported allele loss at D6S193 (62%) on chromosome 6q27, which suggested the presence of a putative tumour suppressor gene. Based on our data and that from another group, the minimal region of allele loss was between D6S264 and D6S149 (7.4 cM). To id...

  13. Sodium Iodide Symporter and Phosphatase and Tensin Homolog Deleted on Chromosome Ten Expression in Cholangiocarcinoma Analysis with Clinicopathological Parameters

    OpenAIRE

    Han, Sang Young; Lee, Sung Wook; Baek, Yang Hyun; Kim, Ha Yoen; Kim, Jong Han; Jeong, Jin Sook; Roh, Young Hoon; Kim, Young Hoon; Park, Byung Ho; Kwon, Hee Jin; Cho, Jin Han; Nam, Kyung Jin

    2012-01-01

    Background/Aims This study was performed to investigate the correlation of sodium iodide symporter (NIS) expression with the functionality and loss of phosphatase and tensin homolog deleted on chromosome ten (PTEN) expression in human cholangiocarcinoma (CCA). Methods Immunohistochemistry for the expression of NIS and PTEN was performed in 60 biopsy specimens of CCA. The clinicopathological parameters were retrospectively identified from medical records. The expression pattern of NIS and loss...

  14. Msc1 Acts Through Histone H2A.Z to Promote Chromosome Stability in Schizosaccharomyces pombe

    OpenAIRE

    Ahmed, Shakil; Dul, Barbara; Qiu, Xinxing; Walworth, Nancy C.

    2007-01-01

    As a central component of the DNA damage checkpoint pathway, the conserved protein kinase Chk1 mediates cell cycle progression when DNA damage is generated. Msc1 was identified as a multicopy suppressor capable of facilitating survival in response to DNA damage of cells mutant for chk1. We demonstrate that loss of msc1 function results in an increased rate of chromosome loss and that an msc1 null allele exhibits genetic interactions with mutants in key kinetochore components. Multicopy expres...

  15. Congenital diaphragmatic hernia interval on chromosome 8p23.1 characterized by genetics and protein interaction networks

    DEFF Research Database (Denmark)

    Longoni, Mauro; Hansen, Kasper Lage; Russell, Meaghan K.;

    2012-01-01

    Chromosome 8p23.1 is a common hotspot associated with major congenital malformations, including congenital diaphragmatic hernia (CDH) and cardiac defects. We present findings from high‐resolution arrays in patients who carry a loss (n = 18) or a gain (n = 1) of sub‐band 8p23.1. We confirm a regio...

  16. Endocrine abnormalities in ring chromosome 11: a case report and review of the literature

    OpenAIRE

    Lange, Renata; Von Linsingen, Caoê; Mata, Fernanda; Moraes, Aline Barbosa; Arruda, Mariana; Vieira Neto, Leonardo

    2015-01-01

    Summary Ring chromosomes (RCs) are uncommon cytogenetic findings, and RC11 has only been described in 19 cases in the literature. Endocrine abnormalities associated with RC11 were reported for two of these cases. The clinical features of RC11 can result from an alteration in the structure of the genetic material, ring instability, mosaicism, and various extents of genetic material loss. We herein describe a case of RC11 with clinical features of 11q-syndrome and endocrine abnormalities that h...

  17. Prognostic values of chromosome 18q microsatellite alterations in stage Ⅱ colonic carcinoma

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    AIM: To investigate the prognostic value of chromosome 18q microsatellite alterations (MA) in stage Ⅱ colon cancer. METHODS: One hundred and six patients with sporadic stage Ⅱ colon cancer were enrolled in this study. DNA was extracted from formalin-fixed, paraffin-embedded tumor and adjacent normal mucosal tissue samples. MA, including loss of heterozygosity (LOH) and microsatellite instability (MSI), was analyzed by polymerase chain reaction, polyacrylamide gel-electrophoresis and DNA sequencing at 5 micr...

  18. Association between Y-chromosome AZFc region micro-deletions with recurrent miscarriage

    OpenAIRE

    Saeede Soleimanian; Seyyed Mahdi Kalantar; Mohamad Hasan Sheikhha; Mohamad Ali Zaimy; Azam Rasti; Hossein Fazli

    2013-01-01

    Background: In human, about 25% of implanted embryos are losing 1-2 week following attachment to the uterus. A subset of this population will have three or more consecutive miscarriages which define as repeated pregnancy loss (RPL). Introducing the assisted reproductive technologies (ARTS) made a chance for infertile couples to solve their childless problem. Objective: This study was conducted to evaluate the incidence of Y-chromosome AZF region's micro-deletions in male partners of couples w...

  19. c.G2114A MYH9 mutation (DFNA17) causes non-syndromic autosomal dominant hearing loss in a Brazilian family

    Science.gov (United States)

    Dantas, Vitor G.L.; Lezirovitz, Karina; Yamamoto, Guilherme L.; Moura de Souza, Carolina Fischinger; Ferreira, Simone Gomes; Mingroni-Netto, Regina C.

    2014-01-01

    We studied a family presenting 10 individuals affected by autosomal dominant deafness in all frequencies and three individuals affected by high frequency hearing loss. Genomic scanning using the 50k Affymetrix microarray technology yielded a Lod Score of 2.1 in chromosome 14 and a Lod Score of 1.9 in chromosome 22. Mapping refinement using microsatellites placed the chromosome 14 candidate region between markers D14S288 and D14S276 (8.85 cM) and the chromosome 22 near marker D22S283. Exome sequencing identified two candidate variants to explain hearing loss in chromosome 14 [PTGDR – c.G894A:p.R298R and PTGER2 – c.T247G:p.C83G], and one in chromosome 22 [MYH9, c.G2114A:p.R705H]. Pedigree segregation analysis allowed exclusion of the PTGDR and PTGER2 variants as the cause of deafness. However, the MYH9 variant segregated with the phenotype in all affected members, except the three individuals with different phenotype. This gene has been previously described as mutated in autosomal dominant hereditary hearing loss and corresponds to DFNA17. The mutation identified in our study is the same described in the prior report. Thus, although linkage studies suggested a candidate gene in chromosome 14, we concluded that the mutation in chromosome 22 better explains the hearing loss phenotype in the Brazilian family. PMID:25505834

  20. Hearing loss among patients with Turner's syndrome: literature review

    OpenAIRE

    Cresio Alves; Conceição Silva Oliveira

    2014-01-01

    INTRODUCTION: Turner's syndrome (TS) is caused by a partial or total deletion of an X chromosome, occurring in 1:2,000 to 1:5,000 live born females. Hearing loss is one of its major clinical manifestations. However, there are few studies investigating this problem. OBJECTIVES: To review the current knowledge regarding the epidemiology, etiology, clinical manifestations and diagnosis of hearing impairment in patients with TS. METHODS: A bibliographic search was performed in the Medlin...

  1. Investigation of Partamona helleri (Apidae, Meliponini) B chromosome origin. An approach by microdissection and whole chromosome painting

    OpenAIRE

    Martins, Cinthia; Diniz, Debora; Sobrinho-Scudeler, Patricia; Foresti, Fausto; Campos, Lucio; Costa, Marco

    2012-01-01

    The stingless bee Partamona helleri in southeast Brazil shows the regular chromosome number 2n = 34 and a variable number of up to four minute B1 or B2 chromosomes. Previous cytogenetic analyses have indicated morphological similarities between the B1 chromosome and chromosome segments in the regular karyotype. In this study, microdissection and chromosome painting were employed along with C banding, NOR banding, and base-specific fluorochrome staining to investigate the origin of the B1 chro...

  2. The Program of Sex Chromosome Pairing in Meiosis Is Highly Conserved Across Marsupial Species: Implications for Sex Chromosome Evolution

    OpenAIRE

    Page, Jesús; Berríos, Soledad; Parra, María Teresa; Viera, Alberto; Suja, José Ángel; Prieto, Ignacio; Barbero, José Luis; Rufas, Julio S; Fernández-Donoso, Raúl

    2005-01-01

    Marsupials present a series of genetic and chromosomal features that are highly conserved in very distant species. One of these features is the absence of a homologous region between X and Y chromosomes. According to this genetic differentiation, sex chromosomes do not synapse during the first meiotic prophase in males, and a special structure, the dense plate, maintains sex chromosome association. In this report we present results on the process of meiotic sex chromosome pairing obtained fro...

  3. 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

  4. Chromosomal organization of adrenergic receptor genes

    International Nuclear Information System (INIS)

    The adrenergic receptors (ARs) (subtypes α1, α2, β1, and β2) are a prototypic family of guanine nucleotide binding regulatory protein-coupled receptors that mediate the physiological effects of the hormone epinephrine and the neurotransmitter norepinephrine. The authors have previously assigned the genes for β2-and α2-AR to human chromosomes 5 and 10, respectively. By Southern analysis of somatic cell hybrids and in situ chromosomal hybridization, they have now mapped the α1-AR gene to chromosome 5q32→q34, the same position as β2-AR, and the β1-AR gene to chromosome 10q24→q26, the region where α2-AR, is located. In mouse, both α2-and β1-AR genes were assigned to chromosome 19, and the α1-AR locus was localized to chromosome 11. Pulsed field gel electrophoresis has shown that the α1-and β2-AR genes in humans are within 300 kilobases (kb) and the distance between the α2- and β1-AR genes is <225 kb. The proximity of these two pairs of AR genes and the sequence similarity that exists among all the ARs strongly suggest that they are evolutionarily related. Moreover, they likely arose from a common ancestral receptor gene and subsequently diverged through gene duplication and chromosomal duplication to perform their distinctive roles in mediation the physiological effects of catecholamines. The AR genes thus provide a paradigm for understanding the evolution of such structurally conserved yet functionally divergent families off receptor molecules

  5. 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.

  6. The impact of homologous recombination repair deficiency on depleted uranium clastogenicity in Chinese hamster ovary cells: XRCC3 protects cells from chromosome aberrations, but increases chromosome fragmentation.

    Science.gov (United States)

    Holmes, Amie L; Joyce, Kellie; Xie, Hong; Falank, Carolyne; Hinz, John M; Wise, John Pierce

    2014-04-01

    Depleted uranium (DU) is extensively used in both industry and military applications. The potential for civilian and military personnel exposure to DU is rising, but there are limited data on the potential health hazards of DU exposure. Previous laboratory research indicates DU is a potential carcinogen, but epidemiological studies remain inconclusive. DU is genotoxic, inducing DNA double strand breaks, chromosome damage and mutations, but the mechanisms of genotoxicity or repair pathways involved in protecting cells against DU-induced damage remain unknown. The purpose of this study was to investigate the effects of homologous recombination repair deficiency on DU-induced genotoxicity using RAD51D and XRCC3-deficient Chinese hamster ovary (CHO) cell lines. Cells deficient in XRCC3 (irs1SF) exhibited similar cytotoxicity after DU exposure compared to wild-type (AA8) and XRCC3-complemented (1SFwt8) cells, but DU induced more break-type and fusion-type lesions in XRCC3-deficient cells compared to wild-type and XRCC3-complemented cells. Surprisingly, loss of RAD51D did not affect DU-induced cytotoxicity or genotoxicity. DU induced selective X-chromosome fragmentation irrespective of RAD51D status, but loss of XRCC3 nearly eliminated fragmentation observed after DU exposure in wild-type and XRCC3-complemented cells. Thus, XRCC3, but not RAD51D, protects cells from DU-induced breaks and fusions and also plays a role in DU-induced chromosome fragmentation. PMID:24561002

  7. Chromosomal geometry in the interface from the frequency of the radiation induced chromosome aberrations

    International Nuclear Information System (INIS)

    Ionizing radiation induces DNA double-strand breaks (DSBs) and their interaction and illegitimate recombination produces chromosomal aberrations. Stable chromosomal aberrations comprise inter-chromosomal events (translocations) and intra-chromosomal events (inversions). When DSBs induction and interaction is done at random, and the proximity effects are neglected, the expected relation between translocations and inversions is F=86, based on chromosome arm length. The number of translocations and inversions is analyzed by using G-banding in 16 lymphocytes cultures from blood samples acutely irradiated with γ-rays (dose range: 0,5 Gy - 3 Gy). The result obtained was: F=13,5, significantly smaller than F=86. Literature data show similar small F values, but strongly spread. The excess of inversions could be explained by a 'proximity effect', it means that more proximate DSBs have more interaction probability. Therefore, it is possible to postulate a special chromosome arrangement during irradiation and the subsequent interval. We propose a model where individual chromosomes show spherical confinement with some degree of overlapping and DSBs induction proportional to cross section. A DSBs interaction probability function with cut-off length= 1μ is assumed. According to our results, the confinement volume is ≅ 6.4% of the nuclear volume. Nevertheless, we presume that large spread in F data could be due to temporal variation in overlapping and spatial chromosomal confinement. (authors). 14 refs

  8. Chromosome and genome size variation in Luzula (Juncaceae), a genus with holocentric chromosomes

    Czech Academy of Sciences Publication Activity Database

    Bozek, M.; Leitch, A. R.; Leitch, I. J.; Záveská Drábková, Lenka; Kuta, E.

    2012-01-01

    Roč. 170, č. 4 (2012), s. 529-541. ISSN 0024-4074 R&D Projects: GA ČR GP206/07/P147 Institutional support: RVO:67985939 Keywords : chromosomal evolution * endopolyploidy * holokinetic chromosome * karyotype evolution * tetraploides * centromeres * TRNF intergenic spacer Subject RIV: EF - Botanics Impact factor: 2.589, year: 2012

  9. 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. PMID:22869747

  10. Chromosome painting in biological dosimetry: Semi-automatic system to score stable chromosome aberrations

    International Nuclear Information System (INIS)

    From the beginning of the description of the procedure of chromosome painting by fluorescence in situ hybridization (FISH), it was thought its possible application to score induced chromosomal aberrations in radiation exposition. With chromosome painting it is possible to detect changes between chromosomes that has been validated in radiation exposition. Translocation scoring by FISH, contrarily to the unstable dicentrics, mainly detect stable chromosome aberrations that do not disappear, it allows the capability of quantify delayed acute expositions or chronic cumulative expositions. The large number of cells that have to be analyzed for high accuracy, specially when dealing with low radiation doses, makes it almost imperative to use an automatic analysis system. After validate translocation scoring by FISH in our, we have evaluated the ability and sensitivity to detect chromosomal aberrations by chromosome using different paint probes used, showing that any combination of paint probes can be used to score induced chromosomal aberrations. Our group has developed a FISH analysis that is currently being adapted for translocation scoring analysis. It includes systematic error correction and internal control probes. The performance tests carried out show that 9,000 cells can be analyzed in 10 hr. using a Sparc 4/370. Although with a faster computer, a higher throughput is expected, for large population screening or very low radiation doses, this performance still has to be improved. (author)

  11. Genetic imbalance on chromosome 17 in papillary serous carcinoma of the peritoneum.

    Science.gov (United States)

    Bandera, C A; Muto, M G; Welch, W R; Berkowitz, R S; Mok, S C

    1998-07-01

    We extend the evaluation of allelic loss patterns on chromosome 17 to papillary serous carcinoma of the peritoneum (PSCP) which is histologically identical to papillary serous ovarian carcinoma (PSOC). DNA was obtained from 11 archival cases of PSCP, with 1-11 tumor sites per case. Using ten loci spanning chromosome 17, loss of heterozygosity (LOH) was identified in all 11 cases (100%). Furthermore, 75-100% of informative cases exhibited LOH at the loci p53, D17S1322 (intragenic to the tumor suppressor gene BRCA1), D17S1327 and MPO. PSCP cases exhibit a higher rate of LOH at most loci when compared with PSOC. Alternating allelic loss at different tumor sites was identified in three cases supporting a multifocal origin of PSCP. Microsatellite instability (MI) is an uncommon event which was identified in four cases. These data implicate chromosome 17 as a potential location of genetic events important in the pathogenesis of PSCP as well as ovarian cancer. PMID:9692553

  12. Genomic imbalances in 5918 malignant epithelial tumors: an explorative meta-analysis of chromosomal CGH data

    International Nuclear Information System (INIS)

    Chromosomal abnormalities have been associated with most human malignancies, with gains and losses on some genomic regions associated with particular entities. Of the 15429 cases collected for the Progenetix molecular-cytogenetic database, 5918 malignant epithelial neoplasias analyzed by chromosomal Comparative Genomic Hybridization (CGH) were selected for further evaluation. For the 22 clinico-pathological entities with more than 50 cases, summary profiles for genomic imbalances were generated from case specific data and analyzed. With large variation in overall genomic instability, recurring genomic gains and losses were prominent. Most entities showed frequent gains involving 8q2, while gains on 20q, 1q, 3q, 5p, 7q and 17q were frequent in different entities. Loss 'hot spots' included 3p, 4q, 13q, 17p and 18q among others. Related average imbalance patterns were found for clinically distinct entities, e.g. hepatocellular carcinomas (ca.) and ductal breast ca., as well as for histologically related entities (squamous cell ca. of different sites). Although considerable case-by-case variation of genomic profiles can be found by CGH in epithelial malignancies, a limited set of variously combined chromosomal imbalances may be typical for carcinogenesis. Focus on the respective regions should aid in target gene detection and pathway deduction

  13. 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

    ), resulting in deletion of varying amounts of 21q22.1 to 21qter. The data from one individual who had a Down syndrome phenotype were consistent with asymmetric breakage and reunion of 21q sequences from an intermediate isochromosome or Robertsonian translocation chromosome as reported by Wong et al. Another......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......). The phenotype of patients correlated well with the extent of deletion or duplication of chromosome 21 sequences. These data demonstrate three mechanisms of r(21) formation and show that the phenotype of r(21) patients varies with the extent of chromosome 21 monosomy or trisomy....

  14. Dielectrophoretic manipulation of human chromosomes in microfluidic channels: extracting chromosome dielectric properties

    DEFF Research Database (Denmark)

    Clausen, Casper Hyttel; Dimaki, Maria; Buckley, Sonia; Svendsen, Winnie Edith

    2011-01-01

    An investigation of the dielectric properties of polyamine buffer prepared human chromosomes is presented in this paper. Chromosomes prepared in this buffer are only a few micrometers in size and shaped roughly like spherical discs. Dielectrophoresis was therefore chosen as the method of manipula......An investigation of the dielectric properties of polyamine buffer prepared human chromosomes is presented in this paper. Chromosomes prepared in this buffer are only a few micrometers in size and shaped roughly like spherical discs. Dielectrophoresis was therefore chosen as the method of...... manipulation combined with a custom designed microfluidic system containing the required electrodes for dielectrophoresis experiments. Our results show that although this system is presently not able to distinguish between the different chromosomes, it can provide average data for the dielectric properties of...

  15. Neo-sex chromosomes in the black muntjac recapitulate incipient evolution of mammalian sex chromosomes

    DEFF Research Database (Denmark)

    Zhou, Qi; Wang, Jun; Huang, Ling; Nie, Wenhui; Wang, Jinhuan; Liu, Yan; Zhao, Xiangyi; Yang, Fengtang; Wang, Wen

    2008-01-01

    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...... 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...

  16. Sex Chromosome Evolution in Amniotes: Applications for Bacterial Artificial Chromosome Libraries

    Science.gov (United States)

    Janes, Daniel E.; Valenzuela, Nicole; Ezaz, Tariq; Amemiya, Chris; Edwards, Scott V.

    2011-01-01

    Variability among sex chromosome pairs in amniotes denotes a dynamic history. Since amniotes diverged from a common ancestor, their sex chromosome pairs and, more broadly, sex-determining mechanisms have changed reversibly and frequently. These changes have been studied and characterized through the use of many tools and experimental approaches but perhaps most effectively through applications for bacterial artificial chromosome (BAC) libraries. Individual BAC clones carry 100–200 kb of sequence from one individual of a target species that can be isolated by screening, mapped onto karyotypes, and sequenced. With these techniques, researchers have identified differences and similarities in sex chromosome content and organization across amniotes and have addressed hypotheses regarding the frequency and direction of past changes. Here, we review studies of sex chromosome evolution in amniotes and the ways in which the field of research has been affected by the advent of BAC libraries. PMID:20981143

  17. Analysis of the Ceratitis capitata y chromosome using in situ hybridization to mitotic chromosomes

    International Nuclear Information System (INIS)

    In Ceratitis capitata the Y chromosome is responsible for sex-determination. We used fluorescence in situ hybridization (FISH) for cytogenetic analysis of mitotic chromosomes. FISH with the wild-type strain EgyptII and two repetitive DNA probes enabled us to differentiate between the short and the long arm of the Y chromosome and gives a much better resolution than C-banding of mitotic chromosomes. We identified the Y-chromosomal breakpoints in Y-autosome translocations using FISH. Even more complex rearrangements i.e. deletions and insertions in some translocation strains were detected by this method. A strategy for mapping the primary sex determination factor in Ceratitis capitata by FISH is presented. (author)

  18. Genomic Restructuring in the Tasmanian Devil Facial Tumour: Chromosome Painting and Gene Mapping Provide Clues to Evolution of a Transmissible Tumour

    OpenAIRE

    Deakin, Janine E.; Bender, Hannah S.; Pearse, Anne-Maree; Rens, Willem; O'Brien, Patricia C.M.; Ferguson-Smith, Malcolm A.; Cheng, Yuanyuan; Morris, Katrina; Taylor, Robyn; Stuart, Andrew; Belov, Katherine; Amemiya, Chris T.; Murchison, Elizabeth P.; Papenfuss, Anthony T.; Marshall Graves, Jennifer A.

    2012-01-01

    Author Summary The world's largest carnivorous marsupial, the Tasmanian devil, is threatened with extinction due to the emergence of devil facial tumour disease (DFTD), a fatal transmissible tumour. Critical loss of genetic diversity has rendered the devil vulnerable to transmission of tumour cells by grafting or transplanting the cells while biting and jaw wrestling. Initial studies of DFTD tumours revealed rearrangements among tumour chromosomes, with several missing chromosomes and four ad...

  19. Plant sex chromosomes: molecular structure and function.

    Science.gov (United States)

    Jamilena, M; Mariotti, B; Manzano, S

    2008-01-01

    Recent molecular and genomic studies carried out in a number of model dioecious plant species, including Asparagus officinalis, Carica papaya, Silene latifolia, Rumex acetosa and Marchantia polymorpha, have shed light on the molecular structure of both homomorphic and heteromorphic sex chromosomes, and also on the gene functions they have maintained since their evolution from a pair of autosomes. The molecular structure of sex chromosomes in species from different plant families represents the evolutionary pathway followed by sex chromosomes during their evolution. The degree of Y chromosome degeneration that accompanies the suppression of recombination between the Xs and Ys differs among species. The primitive Ys of A. officinalis and C. papaya have only diverged from their homomorphic Xs in a short male-specific and non-recombining region (MSY), while the heteromorphic Ys of S. latifolia, R. acetosa and M. polymorpha have diverged from their respective Xs. As in the Y chromosomes of mammals and Drosophila, the accumulation of repetitive DNA, including both transposable elements and satellite DNA, has played an important role in the divergence and size enlargement of plant Ys, and consequently in reducing gene density. Nevertheless, the degeneration process in plants does not appear to have reached the Y-linked genes. Although a low gene density has been found in the sequenced Y chromosome of M. polymorpha, most of its genes are essential and are expressed in the vegetative and reproductive organs in both male and females. Similarly, most of the Y-linked genes that have been isolated and characterized up to now in S. latifolia are housekeeping genes that have X-linked homologues, and are therefore expressed in both males and females. Only one of them seems to be degenerate with respect to its homologous region in the X. Sequence analysis of larger regions in the homomorphic X and Y chromosomes of papaya and asparagus, and also in the heteromorphic sex chromosomes

  20. Deficit of mitonuclear genes on the human X chromosome predates sex chromosome formation.

    Science.gov (United States)

    Dean, Rebecca; Zimmer, Fabian; Mank, Judith E

    2015-02-01

    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. PMID:25637223

  1. Confirmation of the synteny between human chromosome 22 and mouse chromosome 11

    Energy Technology Data Exchange (ETDEWEB)

    Claudio, J.O.; Rouleau, G.A.; Malo, D. [McGill Univ., Quebec (Canada)

    1994-09-01

    Comparative mapping based on the existence of conserved synteny between human and mouse chromosomes is a useful strategy in determining the chromosomal location of a gene. Using recombinant inbred (RI) strains of mice derived from AKR/J and DBA/2J cross (AKXD), we confirmed the existence of a small area of synteny between the chromosome 22 segment carrying the gene for neurofibromatosis type 2 (NF2) and the most proximal region of mouse chromosome 11 containing its homologue (Nf2). By analyzing the allele distribution pattern of 24 AKXD RI mice using a novel polymorphic dinucleotide (CT){sub n} repeat (D11Mcg1) in the 3{prime} untranslated region of the mouse Nf2 gene and PCR-based simple sequence repeat markers (Research Genetics), we established the chromosomal position of Nf23 on mouse chromosome 11. Minimizing the number of double recombinants in the RI strains analyzed suggests tight linkage of Nf2 to D11Mit1 and D11Mit72 which map to a region containing the genes for leukemia inhibitory factor (Lif) and neurofilament heavy chain polypeptide (Nfh). This region is syntenic to the segment carrying the genes LIF, NF2 and NEFH on human chromosome 22q. We show that D11Mcg1 will be useful for mapping of genes and closely linked loci on the proximal region of mouse chromosome 11. Our data demonstrate the predictive value of comparative mapping and confirm that human chromosome 22q12 is syntenic to the most proximal region of mouse chromosome 11.

  2. Chromosome misalignments induce spindle-positioning defects.

    Science.gov (United States)

    Tame, Mihoko A; Raaijmakers, Jonne A; Afanasyev, Pavel; Medema, René H

    2016-03-01

    Cortical pulling forces on astral microtubules are essential to position the spindle. These forces are generated by cortical dynein, a minus-end directed motor. Previously, another dynein regulator termed Spindly was proposed to regulate dynein-dependent spindle positioning. However, the mechanism of how Spindly regulates spindle positioning has remained elusive. Here, we find that the misalignment of chromosomes caused by Spindly depletion is directly provoking spindle misorientation. Chromosome misalignments induced by CLIP-170 or CENP-E depletion or by noscapine treatment are similarly accompanied by severe spindle-positioning defects. We find that cortical LGN is actively displaced from the cortex when misaligned chromosomes are in close proximity. Preventing the KT recruitment of Plk1 by the depletion of PBIP1 rescues cortical LGN enrichment near misaligned chromosomes and re-establishes proper spindle orientation. Hence, KT-enriched Plk1 is responsible for the negative regulation of cortical LGN localization. In summary, we uncovered a compelling molecular link between chromosome alignment and spindle orientation defects, both of which are implicated in tumorigenesis. PMID:26882550

  3. Ambiguous genitalia: a clinical and chromosomal study

    Directory of Open Access Journals (Sweden)

    V. Anantha Kumari

    2015-12-01

    Methods: The study is undertaken with forty cases with ages ranging from new borne to 20 yrs. Out of these 40 cases eight cases are below one year. In these cases physical examination is correlated with ultrasonography and chromosomal analysis. Results: In chromosomal analysis three persons out of forty cases were mosaics with 45, XO/46, twenty one cases who showed the chromosomal pattern as 46, XY mostly showed with no mullarian reminents. On examination palpable gonads were found in labio-scrotal sacs in seventeen cases. One of these cases was reared as girl found cytogenetically as 46, XY with the ultrasonographic impression as small uterus with no ovaries. Nineteen cases who with ambiguous genitalia showed the chromosomal pattern as 46, XX one out of these cases showed enlargement of the breast, and on examination of external genitalia found enlarged clitoris with labiamajora and minora. The child was brought up as male. Genitogram showed the absence of uterus. Conclusions: Chromosomal studies with ultrasonography can help in rearing a child male or female in young generation by surgical and Hormonal therapy. This prevents many problems in later life. This fact should be advertised openly in the public so that illiterate people should be alert. [Int J Res Med Sci 2015; 3(12.000: 3743-3748

  4. Deep Roots for Aboriginal Australian Y Chromosomes.

    Science.gov (United States)

    Bergström, Anders; Nagle, Nano; Chen, Yuan; McCarthy, Shane; Pollard, Martin O; Ayub, Qasim; Wilcox, Stephen; Wilcox, Leah; van Oorschot, Roland A H; McAllister, Peter; Williams, Lesley; Xue, Yali; Mitchell, R John; Tyler-Smith, Chris

    2016-03-21

    Australia was one of the earliest regions outside Africa to be colonized by fully modern humans, with archaeological evidence for human presence by 47,000 years ago (47 kya) widely accepted [1, 2]. However, the extent of subsequent human entry before the European colonial age is less clear. The dingo reached Australia about 4 kya, indirectly implying human contact, which some have linked to changes in language and stone tool technology to suggest substantial cultural changes at the same time [3]. Genetic data of two kinds have been proposed to support gene flow from the Indian subcontinent to Australia at this time, as well: first, signs of South Asian admixture in Aboriginal Australian genomes have been reported on the basis of genome-wide SNP data [4]; and second, a Y chromosome lineage designated haplogroup C(∗), present in both India and Australia, was estimated to have a most recent common ancestor around 5 kya and to have entered Australia from India [5]. Here, we sequence 13 Aboriginal Australian Y chromosomes to re-investigate their divergence times from Y chromosomes in other continents, including a comparison of Aboriginal Australian and South Asian haplogroup C chromosomes. We find divergence times dating back to ∼50 kya, thus excluding the Y chromosome as providing evidence for recent gene flow from India into Australia. PMID:26923783

  5. 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.

  6. 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.

  7. Deep Roots for Aboriginal Australian Y Chromosomes

    Science.gov (United States)

    Bergström, Anders; Nagle, Nano; Chen, Yuan; McCarthy, Shane; Pollard, Martin O.; Ayub, Qasim; Wilcox, Stephen; Wilcox, Leah; van Oorschot, Roland A.H.; McAllister, Peter; Williams, Lesley; Xue, Yali; Mitchell, R. John; Tyler-Smith, Chris

    2016-01-01

    Summary Australia was one of the earliest regions outside Africa to be colonized by fully modern humans, with archaeological evidence for human presence by 47,000 years ago (47 kya) widely accepted [1, 2]. However, the extent of subsequent human entry before the European colonial age is less clear. The dingo reached Australia about 4 kya, indirectly implying human contact, which some have linked to changes in language and stone tool technology to suggest substantial cultural changes at the same time [3]. Genetic data of two kinds have been proposed to support gene flow from the Indian subcontinent to Australia at this time, as well: first, signs of South Asian admixture in Aboriginal Australian genomes have been reported on the basis of genome-wide SNP data [4]; and second, a Y chromosome lineage designated haplogroup C∗, present in both India and Australia, was estimated to have a most recent common ancestor around 5 kya and to have entered Australia from India [5]. Here, we sequence 13 Aboriginal Australian Y chromosomes to re-investigate their divergence times from Y chromosomes in other continents, including a comparison of Aboriginal Australian and South Asian haplogroup C chromosomes. We find divergence times dating back to ∼50 kya, thus excluding the Y chromosome as providing evidence for recent gene flow from India into Australia. PMID:26923783

  8. Origin and significance of chromosomal alterations

    International Nuclear Information System (INIS)

    The spontaneous frequency of chromsomal changes (structural and numerical aberations) in humans is in the order of 6 in 1,000 newborn. Chromosomal analysis of spontaneous abortuses indicate that about 50% of all spontaneous abortions are chromsomally abnormal. Populations exposed to ionizing radiations (atom bomb survivors) or chemical mutagens (e.g., workers occupational.y exposed to vinyl chloride or benzene) show increased frequencies of chromosomal aberrations in their peripheral blood lymphocytes. Many types of human cancer are associated with specific or non-specific chromosomal aberrations. Several human recessive diseases, such as ataxia telangiectasia (A-T), Faconi's anemia (FA) and Bloom's syndrome (BS) are associated with increased frequencies of chromosomal aberrations. However, no detectable increase in the frequency of spontaneous point mutations in human populations exposed to ionizing radiations or chemical mutagens has been demonstrated so far. These observations point to the importance of understanding the mechanism involved in the origin of chromosomal alterations and their significance, which the author discusses in this paper

  9. Deletion of 1p36 as a primary chromosomal aberration in intestinal tumorigenesis

    DEFF Research Database (Denmark)

    Bardi, G; Pandis, N; Fenger, C;

    1993-01-01

    Cytogenetic analysis of short-term cultures from benign intestinal tumors revealed clonal chromosome aberrations in five colorectal adenomas, one adenoma of the papilla Vateri, and one hyperplastic polyp of the rectum. One adenoma had numerical aberrations only, but in all other tumors structural...... hyperplastic polyp. Both adenomas that had additional aberrations beyond the 1p loss showed severe dysplasia. We conclude that cytogenetically detectable loss of genetic information from 1p36 is an early, seemingly primary, premalignant event in intestinal tumorigenesis. The fact that the adenomas with 1p- as...

  10. Degeneration of the Y chromosome in evolutionary aging models

    Science.gov (United States)

    Lobo, M. P.; Onody, R. N.

    2005-06-01

    The Y chromosomes are genetically degenerated and do not recombine with their matching partners X. Recombination of XX pairs is pointed out as the key factor for the Y chromosome degeneration. However, there is an additional evolutionary force driving sex-chromosomes evolution. Here we show this mechanism by means of two different evolutionary models, in which sex chromosomes with non-recombining XX and XY pairs of chromosomes is considered. Our results show three curious effects. First, we observed that even when both XX and XY pairs of chromosomes do not recombine, the Y chromosomes still degenerate. Second, the accumulation of mutations on Y chromosomes followed a completely different pattern then those accumulated on X chromosomes. And third, the models may differ with respect to sexual proportion. These findings suggest that a more primeval mechanism rules the evolution of Y chromosomes due exclusively to the sex-chromosomes asymmetry itself, i.e., the fact that Y chromosomes never experience female bodies. Over aeons, natural selection favored X chromosomes spontaneously, even if at the very beginning of evolution, both XX and XY pairs of chromosomes did not recombine.

  11. Detection of chromosome aneuploidy in breast lesions with fluorescence in situ hybridization: Comparison of whole nuclei to thin tissue sections and correlation with flow cytometric DNA analysis

    Energy Technology Data Exchange (ETDEWEB)

    Visscher, D.W.; Wallis, T.; Ritchie, C.A. [Wayne State Univ., Detroit, MI (United States)

    1995-09-01

    We compared flow-cytometric DNA histogram pattern to counts of 4 fluorescent-labelled centromeric probes (chromosomes 1, 7, 8, and 17) in whole nuclei (WN) and in nuclei from formalin-fixed deparaffinized thin tissue section (TS) in 25 breast lesions. In benign lesions, signal gains (i.e., trisomic nuclei) were never observed in greater than 10% of nuclei from either WN or TS preparations. Loss of signal in benign breast lesions, however, varied considerably (0-43%) between individual case and between chromosome probes. The mean incidence of signal loss in WN of benign lesions ranged from 8.9% (chromosome 7) to 14.4 % (chromosome 1) of nuclei. These signal loss frequencies exceeded those of benign lymphoid control cells. In three benign lesions, signal loss in WN (with one probe) was observed in at least 25% of nuclei. Signal losses in benign TS, on average, were 50-150% greater than in matched WN preparations (chromosome 1: 21.7%, chromosome 7: 21.5%). Malignant lesions generally, but not always, displayed fewer monosomic nuclei and more trisomic nuclei in compared to TS, compatible with a slicing (i.e., nuclear truncation) artifact. Signal counts in carcinomas correlated well with flow cytometric DNA index; however, they were also characterized by evidence of genetic instability, manifest as signal gains in a subset of nuclei (10-25%) with individual probes in diploid range cases, as well as intratumoral heterogeneity, reflected as discrepancies in probe counts between WN and TS samples. We conclude that signal losses with centromeric probes are largely, but not entirely, explained by nuclear slicing. The minimum signal loss threshold for establishment of monosomy using interphase cytogenetics is thus unclear, even in WN. Signal gains indicative of trisomy, in contrast, are reliably associated with malignancy and may reflect gross DNA aneuploidy as well as genetic instability. 10 refs., 1 fig., 3 tabs.

  12. Chromosomal imbalances in four new uterine cervix carcinoma derived cell lines

    Directory of Open Access Journals (Sweden)

    Vázquez Guelaguetza

    2003-03-01

    Full Text Available Abstract Background Uterine cervix carcinoma is the second most common female malignancy worldwide and a major health problem in Mexico, representing the primary cause of death among the Mexican female population. High risk human papillomavirus (HPV infection is considered to be the most important risk factor for the development of this tumor and cervical carcinoma derived cell lines are very useful models for the study of viral carcinogenesis. Comparative Genomic Hybridization (CGH experiments have detected a specific pattern of chromosomal imbalances during cervical cancer progression, indicating chromosomal regions that might contain genes that are important for cervical transformation. Methods We performed HPV detection and CGH analysis in order to initiate the genomic characterization of four recently established cervical carcinoma derived cell lines from Mexican patients. Results All the cell lines were HPV18 positive. The most prevalent imbalances in the cell lines were gains in chromosomes 1q23-q32, 3q11.2-q13.1, 3q22-q26.1, 5p15.1-p11.2, this alteration present as a high copy number amplification in three of the cell lines, 7p15-p13, 7q21, 7q31, 11q21, and 12q12, and losses in 2q35-qter, 4p16, 6q26-qter, 9q34 and 19q13.2-qter. Conclusions Analysis of our present findings and previously reported data suggest that gains at 1q31-q32 and 7p13-p14, as well as losses at 6q26-q27 are alterations that might be unique for HPV18 positive cases. These chromosomal regions, as well as regions with high copy number amplifications, coincide with known fragile sites and known HPV integration sites. The general pattern of chromosomal imbalances detected in the cells resembled that found in invasive cervical tumors, suggesting that the cells represent good models for the study of cervical carcinoma.

  13. Chromosome instability in human hepatocellular carcinoma depends on p53 status and aflatoxin exposure.

    Science.gov (United States)

    Pineau, Pascal; Marchio, Agnès; Battiston, Carlo; Cordina, Emilie; Russo, Alessandro; Terris, Benoît; Qin, Lun-Xiu; Turlin, Bruno; Tang, Zhao-You; Mazzaferro, Vincenzo; Dejean, Anne

    2008-05-31

    Hepatocellular carcinoma (HCC) is a heterogeneous disease triggered by various risk factors and frequently characterized by chromosome instability. This instability is considered to be caused primarily by Hepatitis B virus (HBV), although aflatoxin B1 (AFB1), a potent fungal mutagen is also suspected to influence chromosomal repair. We studied 90 HCCs from Italy, the country with the highest incidence of hepatocellular carcinoma in Europe, 81 samples from France and 52 specimens from Shanghai, in a region where intake of AFB1 via the diet is known to be high. All 223 tumours were characterized for 15 different genomic targets, including allelic loss at 13 chromosome arms and mutations of beta-catenin and p53 genes. Despite disparity in risk-factor distribution, Italian and French cases did not significantly differ for 14 of the 15 targets tested. beta-Catenin and p53 displayed moderate and similar mutation rates (18-29% of cases) in European series. By contrast, tumours from Shanghai were significantly different, with a lower mutation rate for beta-catenin (4% vs. 26%, p<0.0003) and a higher mutation rate for p53 (48% vs. 22%, p<0.0001) when compared with tumours of European origin. The Arg249Ser mutation, hallmark of exposure to AFB1, represented half of the changes in p53 in Shanghai. Furthermore, when stratified for the presence of HBV or p53 mutations, chromosome instability was always higher in Chinese than in European patients. This difference was particularly strong in p53-wildtype tumours (fractional allelic loss, 29.4% vs. 16.7%, p<0.0001). We suggest that AFB1-associated mutagenesis represents a plausible cause for the higher chromosome instability observed in Chinese HCCs, when compared with European primary liver carcinomas. PMID:18467159

  14. ParABS system in chromosome partitioning in the bacterium Myxococcus xanthus.

    Directory of Open Access Journals (Sweden)

    Antonio A Iniesta

    Full Text Available Chromosome segregation is an essential cellular function in eukaryotic and prokaryotic cells. The ParABS system is a fundamental player for a mitosis-like process in chromosome partitioning in many bacterial species. This work shows that the social bacterium Myxococcus xanthus also uses the ParABS system for chromosome segregation. Its large prokaryotic genome of 9.1 Mb contains 22 parS sequences near the origin of replication, and it is shown here that M. xanthus ParB binds preferentially to a consensus parS sequence in vitro. ParB and ParA are essential for cell viability in M. xanthus as in Caulobacter crescentus, but unlike in many other bacteria. Absence of ParB results in anucleate cells, chromosome segregation defects and loss of viability. Analysis of ParA subcellular localization shows that it clusters at the poles in all cells, and in some, in the DNA-free cell division plane between two chromosomal DNA masses. This ParA localization pattern depends on ParB but not on FtsZ. ParB inhibits the nonspecific interaction of ParA with DNA, and ParA colocalizes with chromosomal DNA only when ParB is depleted. The subcellular localization of ParB suggests a single ParB-parS complex localized at the edge of the nucleoid, next to a polar ParA cluster, with a second ParB-parS complex migrating after the replication of parS takes place to the opposite nucleoid edge, next to the other polar ParA cluster.

  15. Unique signatures of natural background radiation on human Y chromosomes from Kerala, India.

    Directory of Open Access Journals (Sweden)

    Sanjay Premi

    Full Text Available BACKGROUND: The most frequently observed major consequences of ionizing radiation are chromosomal lesions and cancers, although the entire genome may be affected. Owing to its haploid status and absence of recombination, the human Y chromosome is an ideal candidate to be assessed for possible genetic alterations induced by ionizing radiation. We studied the human Y chromosome in 390 males from the South Indian state of Kerala, where the level of natural background radiation (NBR is ten-fold higher than the worldwide average, and that from 790 unexposed males as control. RESULTS: We observed random microdeletions in the Azoospermia factor (AZF a, b and c regions in >90%, and tandem duplication and copy number polymorphism (CNP of 11 different Y-linked genes in about 80% of males exposed to NBR. The autosomal homologues of Y-linked CDY genes largely remained unaffected. Multiple polymorphic copies of the Y-linked genes showing single Y-specific signals suggested their tandem duplication. Some exposed males showed unilocus duplication of DAZ genes resulting in six copies. Notably, in the AZFa region, approximately 25% of exposed males showed deletion of the DBY gene, whereas flanking genes USP9Y and UTY remained unaffected. All these alterations were detected in blood samples but not in the germline (sperm samples. CONCLUSIONS: Exposure to high levels of NBR correlated with several interstitial polymorphisms of the human Y chromosome. CNPs and enhanced transcription of the SRY gene after duplication are envisaged to compensate for the loss of Y chromosome in some cells. The aforesaid changes, confined to peripheral blood lymphocytes, suggest a possible innate mechanism protecting the germline DNA from the NBR. Genome analysis of a larger population focusing on greater numbers of genes may provide new insights into the mechanisms and risks of the resultant genetic damages. The present work demonstrates unique signatures of NBR on human Y chromosomes

  16. BUBR1 recruits PP2A via the B56 family of targeting subunits to promote chromosome congression

    Directory of Open Access Journals (Sweden)

    Peng Xu

    2013-03-01

    BUBR1 is a mitotic phosphoprotein essential for the maintenance of chromosome stability by promoting chromosome congression and proper kinetochore–microtubule (K-fiber attachment, but the underlying mechanism(s has remained elusive. Here we identify BUBR1 as a binding partner of the B56 family of Protein Phosphatase 2A regulatory subunits. The interaction between BUBR1 and the B56 family is required for chromosome congression, since point mutations in BUBR1 that block B56 binding abolish chromosome congression. The BUBR1:B56-PP2A complex opposes Aurora B kinase activity, since loss of the complex can be reverted by inhibiting Aurora B. Importantly, we show that the failure of BUBR1 to recruit B56-PP2A also contributes to the chromosome congression defects found in cells derived from patients with the Mosaic Variegated Aneuploidy (MVA syndrome. Together, we propose that B56-PP2A is a key mediator of BUBR1's role in chromosome congression and functions by antagonizing Aurora B activity at the kinetochore for establishing stable kinetochore–microtubule attachment at the metaphase plate.

  17. Autosomal location of genes from the conserved mammalian X in the platypus (Ornithorhynchus anatinus): implications for mammalian sex chromosome evolution.

    Science.gov (United States)

    Waters, Paul D; Delbridge, Margaret L; Deakin, Janine E; El-Mogharbel, Nisrine; Kirby, Patrick J; Carvalho-Silva, Denise R; Graves, Jennifer A Marshall

    2005-01-01

    Mammalian sex chromosomes evolved from an ancient autosomal pair. Mapping of human X- and Y-borne genes in distantly related mammals and non-mammalian vertebrates has proved valuable to help deduce the evolution of this unique part of the genome. The platypus, a monotreme mammal distantly related to eutherians and marsupials, has an extraordinary sex chromosome system comprising five X and five Y chromosomes that form a translocation chain at male meiosis. The largest X chromosome (X1), which lies at one end of the chain, has considerable homology to the human X. Using comparative mapping and the emerging chicken database, we demonstrate that part of the therian X chromosome, previously thought to be conserved across all mammals, was lost from the platypus X1 to an autosome. This region included genes flanking the XIST locus, and also genes with Y-linked homologues that are important to male reproduction in therians. Since these genes lie on the X in marsupials and eutherians, and also on the homologous region of chicken chromosome 4, this represents a loss from the monotreme X rather than an additional evolutionary stratum of the human X. PMID:15973504

  18. 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).

  19. 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.

  20. 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 chromosomes from prokaryotic organisms. All known plasmid-encoded par loci specify three components: a cis-acting centromere-like site and two trans-acting proteins that form a nucleoprotein complex at the centromere (i.e. the partition complex). The proteins are encoded by two genes in an operon...... that is autoregulated by the par-encoded proteins. In all cases, the upstream gene encodes an ATPase that is essential for partitioning. Recent cytological analyses indicate that the ATPases function as adaptors between a host-encoded component and the partition complex and thereby tether plasmids and chromosomal...

  1. The DNA sequence of human chromosome 7.

    Science.gov (United States)

    Hillier, Ladeana W; Fulton, Robert S; Fulton, Lucinda A; Graves, Tina A; Pepin, Kymberlie H; Wagner-McPherson, Caryn; Layman, Dan; Maas, Jason; Jaeger, Sara; Walker, Rebecca; Wylie, Kristine; Sekhon, Mandeep; Becker, Michael C; O'Laughlin, Michelle D; Schaller, Mark E; Fewell, Ginger A; Delehaunty, Kimberly D; Miner, Tracie L; Nash, William E; Cordes, Matt; Du, Hui; Sun, Hui; Edwards, Jennifer; Bradshaw-Cordum, Holland; Ali, Johar; Andrews, Stephanie; Isak, Amber; Vanbrunt, Andrew; Nguyen, Christine; Du, Feiyu; Lamar, Betty; Courtney, Laura; Kalicki, Joelle; Ozersky, Philip; Bielicki, Lauren; Scott, Kelsi; Holmes, Andrea; Harkins, Richard; Harris, Anthony; Strong, Cynthia Madsen; Hou, Shunfang; Tomlinson, Chad; Dauphin-Kohlberg, Sara; Kozlowicz-Reilly, Amy; Leonard, Shawn; Rohlfing, Theresa; Rock, Susan M; Tin-Wollam, Aye-Mon; Abbott, Amanda; Minx, Patrick; Maupin, Rachel; Strowmatt, Catrina; Latreille, Phil; Miller, Nancy; Johnson, Doug; Murray, Jennifer; Woessner, Jeffrey P; Wendl, Michael C; Yang, Shiaw-Pyng; Schultz, Brian R; Wallis, John W; Spieth, John; Bieri, Tamberlyn A; Nelson, Joanne O; Berkowicz, Nicolas; Wohldmann, Patricia E; Cook, Lisa L; Hickenbotham, Matthew T; Eldred, James; Williams, Donald; Bedell, Joseph A; Mardis, Elaine R; Clifton, Sandra W; Chissoe, Stephanie L; Marra, Marco A; Raymond, Christopher; Haugen, Eric; Gillett, Will; Zhou, Yang; James, Rose; Phelps, Karen; Iadanoto, Shawn; Bubb, Kerry; Simms, Elizabeth; Levy, Ruth; Clendenning, James; Kaul, Rajinder; Kent, W James; Furey, Terrence S; Baertsch, Robert A; Brent, Michael R; Keibler, Evan; Flicek, Paul; Bork, Peer; Suyama, Mikita; Bailey, Jeffrey A; Portnoy, Matthew E; Torrents, David; Chinwalla, Asif T; Gish, Warren R; Eddy, Sean R; McPherson, John D; Olson, Maynard V; Eichler, Evan E; Green, Eric D; Waterston, Robert H; Wilson, Richard K

    2003-07-10

    Human chromosome 7 has historically received prominent attention in the human genetics community, primarily related to the search for the cystic fibrosis gene and the frequent cytogenetic changes associated with various forms of cancer. Here we present more than 153 million base pairs representing 99.4% of the euchromatic sequence of chromosome 7, the first metacentric chromosome completed so far. The sequence has excellent concordance with previously established physical and genetic maps, and it exhibits an unusual amount of segmentally duplicated sequence (8.2%), with marked differences between the two arms. Our initial analyses have identified 1,150 protein-coding genes, 605 of which have been confirmed by complementary DNA sequences, and an additional 941 pseudogenes. Of genes confirmed by transcript sequences, some are polymorphic for mutations that disrupt the reading frame. PMID:12853948

  2. Chromosomal aberrations induced by alpha particles

    International Nuclear Information System (INIS)

    The chromosomal aberrations produced by the ionizing radiation are commonly used when it is necessary to establish the exposure dose of an individual, it is a study that is used like complement of the traditional physical systems and its application is only in cases in that there is doubt about what indicates the conventional dosimetry. The biological dosimetry is based on the frequency of aberrations in the chromosomes of the lymphocytes of the individual in study and the dose is calculated taking like reference to the dose-response curves previously generated In vitro. A case of apparent over-exposure to alpha particles to which is practiced analysis of chromosomal aberrations to settle down if in fact there was exposure and as much as possible, to determine the presumed dose is presented. (Author)

  3. 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.

  4. Telomeric fusion and chromosome instability in multiple tissues of a patient with mosaic Ullrich-Turner syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Sawyer, J.R.; North, P.E.; Hassed, S.J. [Univ. of Arkansas for Medical Sciences, Little Rock, AR (United States)] [and others

    1997-04-14

    We describe the cytogenetic evolution of multiple cell lines in the gonadal tissue of a 10-year-old girl with mosaic Ullrich-Turner syndrome (UTS) involving clonal telomeric associations (tas) of the Y chromosome. G-band analysis of all tissues showed at least 2 cell lines; 45,X and 46,X,tas(Y;21)(q12;p13). However, analysis of left gonadal tissue of this patient showed the evolution of 2 additional cell lines, one designated 45,X,tas(Y;21)(q12;p13),-22 and the other 46,X,tas(Y;21)(q12;p13),+tas(Y;14)(q12;p13),-22. Fluorescence in situ hybridization (FISH) analysis of interphase nuclei from uncultured gonadal tissue confirmed the findings of aneuploidy in the left gonadal tissue and extended the findings of aneuploidy to the tissue of the right gonad. The chromosome findings in the gonadal tissue of this patient suggest a preneoplastic karyotype relating to several distinct tumor associations. The clonal evolution of telomeric fusions indicates chromosome instability and suggests the extra copy of the Y chromosome may have resulted from a fusion-related malsegregation. In addition, the extra Y suggests low-level amplification of a putative gonadoblastoma gene, while the loss of chromosome 22 suggests the loss of heterozygosity for genes on chromosome 22. This case demonstrates the utility of the study of gonadal tissue in 45X46,XY UTS patients, and provides evidence that clonal telomeric fusions may, in rare cases, be associated with chromosomal malsegregation and with the subsequent evolution of unstable karyotypes. 27 refs., 3 figs.

  5. Chromosome aberration analysis for biological dosimetry: a review

    International Nuclear Information System (INIS)

    Among various biological dosimetry techniques, dicentric chromosome aberration method appears to be the method of choice in analysing accidental radiation exposure in most of the laboratories. The major advantage of this method is its sensitivity as the number of dicentric chromosomes present in control population is too small and more importantly radiation induces mainly dicentric chromosome aberration among unstable aberration. This report brings out the historical development of various cytogenetic methods, the basic structure of DNA, chromosomes and different forms of chromosome aberrations. It also highlights the construction of dose-response curve for dicentric chromosome and its use in the estimation of radiation dose. (author)

  6. An approach to automated chromosome analysis

    International Nuclear Information System (INIS)

    The methods of approach developed with a view to automatic processing of the different stages of chromosome analysis are described in this study divided into three parts. Part 1 relates the study of automated selection of metaphase spreads, which operates a decision process in order to reject ail the non-pertinent images and keep the good ones. This approach has been achieved by Computing a simulation program that has allowed to establish the proper selection algorithms in order to design a kit of electronic logical units. Part 2 deals with the automatic processing of the morphological study of the chromosome complements in a metaphase: the metaphase photographs are processed by an optical-to-digital converter which extracts the image information and writes it out as a digital data set on a magnetic tape. For one metaphase image this data set includes some 200 000 grey values, encoded according to a 16, 32 or 64 grey-level scale, and is processed by a pattern recognition program isolating the chromosomes and investigating their characteristic features (arm tips, centromere areas), in order to get measurements equivalent to the lengths of the four arms. Part 3 studies a program of automated karyotyping by optimized pairing of human chromosomes. The data are derived from direct digitizing of the arm lengths by means of a BENSON digital reader. The program supplies' 1/ a list of the pairs, 2/ a graphic representation of the pairs so constituted according to their respective lengths and centromeric indexes, and 3/ another BENSON graphic drawing according to the author's own representation of the chromosomes, i.e. crosses with orthogonal arms, each branch being the accurate measurement of the corresponding chromosome arm. This conventionalized karyotype indicates on the last line the really abnormal or non-standard images unpaired by the program, which are of special interest for the biologist. (author)

  7. Chromosome Evolution and Genome Miniaturization in Minifish

    Science.gov (United States)

    Liu, Shaojun; Hui, Tan Heok; Tan, Sze Ley; Hong, Yunhan

    2012-01-01

    Background Paedocypris is a newly established genus of fish in Southeast Asia. Paedocypris is characterized by several unique features, including a tiny adult size (thus named miniature fish or minifish), fragmentary habitats of acidic peat blackwater swamps, an unusual reproduction mode and truncated development. These peculiarities lend themselves excellent for studying chromosome evolution and rapid speciation in vertebrates but also make them highly controversial for the phylogenetic position. Methodology and Principal Findings We have established an organ procedure to prepare chromosome spreads from tiny organs of minifish and performed a cytogenetic study on two species of the genus Paedocypris, namely P. carbunculus (Pc) and P. sp. “Singkep” (Ps). We found 30 and 34 chromosomes in diploid cells of Pc and Ps, respectively, which are unusual in teleost fishes. The diploid metaphase has 5 pairs of metacentrics and 7 pairs of subtelocentrics in Pc compared to 3 pairs of metacentrics and 11 pairs of subtelocentrics in Ps, whereas the haploid metaphase contains 5 metacentrics and 7 subtelocentrics in Pc compared to 3 metacentrics and 11 subtelocentrics Ps. Chromosome behavior in first meiosis revealed the presence of a chromosomal ring consisting of 2 metacentrics in Pc, suggesting that centric fusion rather than fission was responsible for the karyotypic evolution from Ps to Pc. Flow cytometry revealed that Pc had a 45% nuclear staining intensity relative to medaka whose genome is 700 Mb in size and contains 0.81 pg DNA. The Pc genome should have 315 Mb in length and 0.36 pg of DNA, which represent one of the smallest values in vertebrates, suggesting genome miniaturization in this organism. Conclusions Our data demonstrate that gross chromosome rearrangements and genome miniaturization have accompanied the evolution of Paedocypris fishes. Our data also place Paedocypris outside currently described taxa of the Cypriniformes. PMID:22615970

  8. Horizontal transfer of supernumerary chromosomes in fungi.

    Science.gov (United States)

    van der Does, H Charlotte; Rep, Martijn

    2012-01-01

    Several species of filamentous fungi contain so-called dispensable or supernumerary chromosomes. These chromosomes are dispensable for the fungus to survive, but may carry genes required for specialized functions, such as infection of a host plant. It has been shown that at least some dispensable chromosomes are able to transfer horizontally (i.e., in the absence of a sexual cycle) from one fungal strain to another. In this paper, we describe a method by which this can be shown. Horizontal chromosome transfer (HCT) occurs during co-incubation of two strains. To document the actual occurrence of HCT, it is necessary to select for HCT progeny. This is accomplished by transforming two different drug-resistance genes into the two parent strains before their co-incubation. In one of the strains (the "donor"), a drug-resistance gene should be integrated in a chromosome of which the propensity for HCT is under investigation. In the "tester" or "recipient" strain, another drug-resistance gene should be integrated somewhere in the core genome. In this way, after co-incubation, HCT progeny can be selected on plates containing both drugs. HCT can be initiated with equal amounts of asexual spores of both strains, plated on regular growth medium for the particular fungus, followed by incubation until new asexual spores are formed. The new asexual spores are then harvested and plated on plates containing both drugs. Double drug-resistant colonies that appear should carry at least one chromosome from each parental strain. Finally, double drug-resistant strains need to be analysed to assess whether HCT has actually occurred. This can be done by various genome mapping methods, like CHEF-gels, AFLP, RFLP, PCR markers, optical maps, or even complete genome sequencing. PMID:22183669

  9. Chromosome anomalies in mouse oocytes after irradiation

    International Nuclear Information System (INIS)

    We investigated the cytogenetic effects of X-rays on unfertilized mouse oocytes. NMRI females received an irradiation with 0, 22.2, 66.6, 200, and 600 R during the preovulatory phase 3 hrs after HCG (human chorionic gonadotrophin). This is a stage during oogenesis in which the oocytes pass from late dictyotene to diakinesis. Chromosome anlysis was per formed after ovulation at metaphase II. From these experiments we can draw the following conclusions: X-rays induced during the preovulatory phase a high number of chromosome anomalies. Among these, structural anomalies prevail. 7 out of 144 ovulated oocytes in matched controls carried such an abnormality, whereas after irradiation we observed with 22.2, 66.6, 200, and 600 R, 11 out of 72, 34 out of 108, 89 out of 102, and 122 out of 124, respectively. Irradiation seems also to affect the chromosome segregation during the 1. meiotic division, as we observed after 22.2, 66.6 and 200 R a total of 6 oocytes out of 204 with a supernummary chromosome. In controls, however, no hyperploidy was found in 143 ova. This increase, however, was not significant. Chromosome anomalies, e.g. breaks and deletions that go back to a one-break event increased linearly with increasing dose. Exchanges, however, going back to two-break events fittet best to the linear-quadratic dose-response model. The dose of 600 R seems to represent a kind of borderline in this experiment, because nearly all (122 out 124) carried at least one structural chromosome anomaly. It is also this dose after which the highest frequency of reciprocal translocations was observed in a humpshaped slope in spermatocytes after irradiation of spermatogonia (Preston and Brewen, 1973). With an increasing dosage up to 1,200 R the frequency of translocations decrease again. The elimination of cells, crossing this borderline, might be due to genetic or non-genetic effects. (orig./GSE)

  10. Chromosomal phylogeny and evolution of gibbons (Hylobatidae).

    Science.gov (United States)

    Müller, Stefan; Hollatz, Melanie; Wienberg, Johannes

    2003-11-01

    Although human and gibbons are classified in the same primate superfamily (Hominoidae), their karyotypes differ by extensive chromosome reshuffling. To date, there is still limited understanding of the events that shaped extant gibbon karyotypes. Further, the phylogeny and evolution of the twelve or more extant gibbon species (lesser apes, Hylobatidae) is poorly understood, and conflicting phylogenies have been published. We present a comprehensive analysis of gibbon chromosome rearrangements and a phylogenetic reconstruction of the four recognized subgenera based on molecular cytogenetics data. We have used two different approaches to interpret our data: (1) a cladistic reconstruction based on the identification of ancestral versus derived chromosome forms observed in extant gibbon species; (2) an approach in which adjacent homologous segments that have been changed by translocations and intra-chromosomal rearrangements are treated as discrete characters in a parsimony analysis (PAUP). The orangutan serves as an "outgroup", since it has a karyotype that is supposed to be most similar to the ancestral form of all humans and apes. Both approaches place the subgenus Bunopithecus as the most basal group of the Hylobatidae, followed by Hylobates, with Symphalangus and Nomascus as the last to diverge. Since most chromosome rearrangements observed in gibbons are either ancestral to all four subgenera or specific for individual species and only a few common derived rearrangements at subsequent branching points have been recorded, all extant gibbons may have diverged within relatively short evolutionary time. In general, chromosomal rearrangements produce changes that should be considered as unique landmarks at the divergence nodes. Thus, molecular cytogenetics could be an important tool to elucidate phylogenies in other species in which speciation may have occurred over very short evolutionary time with not enough genetic (DNA sequence) and other biological divergence to

  11. 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.

  12. CADM1 is a strong neuroblastoma candidate gene that maps within a 3.72 Mb critical region of loss on 11q23

    OpenAIRE

    Eggert Angelika; De Paepe Anne; Brichard Bénédicte; Schramm Alexander; De Preter Katleen; Hoebeeck Jasmien; Michels Evi; Laureys Geneviève; Vandesompele Jo; Speleman Frank

    2008-01-01

    Abstract Background Recurrent loss of part of the long arm of chromosome 11 is a well established hallmark of a subtype of aggressive neuroblastomas. Despite intensive mapping efforts to localize the culprit 11q tumour suppressor gene, this search has been unsuccessful thus far as no sufficiently small critical region could be delineated for selection of candidate genes. Methods To refine the critical region of 11q loss, the chromosome 11 status of 100 primary neuroblastoma tumours and 29 cel...

  13. Tracking chromosome evolution in southern African gerbils using flow-sorted chromosome paints.

    Science.gov (United States)

    Knight, L I; Ng, B L; Cheng, W; Fu, B; Yang, F; Rambau, R V

    2013-01-01

    Desmodillus and Gerbilliscus (formerly Tatera) comprise a monophyletic group of gerbils (subfamily Gerbillinae) which last shared an ancestor approximately 8 million years ago; diploid chromosome number variation among the species ranges from 2n = 36 to 2n = 50. In an attempt to shed more light on chromosome evolution and speciation in these rodents, we compared the karyotypes of 7 species, representing 3 genera, based on homology data revealed by chromosome painting with probes derived from flow-sorted chromosomes of the hairy footed gerbil, Gerbillurus paeba (2n = 36). The fluorescent in situ hybridization data revealed remarkable genome conservation: these species share a high proportion of conserved chromosomes, and differences are due to 10 Robertsonian (Rb) rearrangements (3 autapomorphies, 3 synapomorphies and 4 hemiplasies/homoplasies). Our data suggest that chromosome evolution in Desmodillus occurred at a rate of ~1.25 rearrangements per million years (Myr), and that the rate among Gerbilliscus over a time period spanning 8 Myr is also ~1.25 rearrangements/Myr. The recently diverged Gerbillurus (G. tytonis and G. paeba) share an identical karyotype, while Gerbilliscus kempi, G. afra and G. leucogaster differ by 6 Rb rearrangements (a rate of ~1 rearrangement/Myr). Thus, our data suggests a very slow rate of chromosomal evolution in Southern African gerbils. PMID:23652816

  14. 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 that...

  15. 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

  16. Hereditary Hearing Loss.

    Science.gov (United States)

    Tran, LenhAnh P.; Grundfast, Kenneth M.

    1997-01-01

    This article discusses inheritance patterns in hearing loss, epidemiology, clues to genetic causes, locating genes that cause hereditary disorders, genes related to hearing loss disorders in individuals with Usher syndrome, Waardenburg syndrome, Treacher-Collins syndrome, Branchio-oto-renal and Pendred syndromes, and the significance of finding…

  17. Understanding Rural Population Loss.

    Science.gov (United States)

    McGranahan, David A.; Beale, Calvin L.

    2002-01-01

    A quarter of nonmetro counties lost population in the 1990s, but population loss was not related to poverty rate or low educational levels, perhaps because low-skill workers can no longer expect better wages in urban areas. Population loss was related to low population density and remoteness (which decrease access to services), lack of natural…

  18. Loss muinasjuturaamatust / Agu Veetamm

    Index Scriptorium Estoniae

    Veetamm, Agu, 1953-

    2004-01-01

    Ballindaloch on üks väheseid Shoti losse, kus omanikud aastaringselt elavad. 450 aastat on loss kuulunud Macpherson-Grantide suguvõsale. Praegu on lossi omanikuks Clare Nancy Macpherson-Grant Russell, kelle kujundatud on kiviktaimla ja rosaarium. Lossi ajaloost, omanikest, ümberehitustest, ringkäigust lossis, pargist. 14 ill

  19. Help! It's Hair Loss!

    Science.gov (United States)

    ... Homework? Here's Help White House Lunch Recipes Help! It's Hair Loss! KidsHealth > For Kids > Help! It's Hair Loss! Print A A A Text Size ... part above the skin, is dead. (That's why it doesn't hurt to get a haircut!) This ...

  20. Weight Loss Surgery

    Science.gov (United States)

    Weight loss surgery helps people with extreme obesity to lose weight. It may be an option if you cannot lose weight through diet and exercise or have serious health problems caused by obesity. There are different types of weight loss surgery. They often limit the ...

  1. [Inner Ear Hearing Loss].

    Science.gov (United States)

    Hesse, G

    2016-06-01

    Hearing loss is one of the most dominant handicaps in modern societies, which additionally very often is not realized or not admitted. About one quarter of the general population suffers from inner ear hearing loss and is therefore restricted in communicational skills. Demographic factors like increasing age play an important role as well as environmental influences and an increasing sound and noise exposure especially in leisure activities. Thus borders between a "classical" presbyacusis - if it ever existed - and envirionmentally induced hearing loss disappear. Today restrictions in hearing ability develop earlier in age but at the same time they are detected and diagnosed earlier. This paper can eventually enlighten the wide field of inner ear hearing loss only fragmentarily; therefore mainly new research, findings and developments are reviewed. The first part discusses new aspects of diagnostics of inner ear hearing loss and different etiologies. PMID:27259171

  2. Acute loss of consciousness.

    Science.gov (United States)

    Tristán, Bekinschtein; Gleichgerrcht, Ezequiel; Manes, Facundo

    2015-01-01

    Acute loss of consciousness poses a fascinating scenario for theoretical and clinical research. This chapter introduces a simple yet powerful framework to investigate altered states of consciousness. We then explore the different disorders of consciousness that result from acute brain injury, and techniques used in the acute phase to predict clinical outcome in different patient populations in light of models of acute loss of consciousness. We further delve into post-traumatic amnesia as a model for predicting cognitive sequels following acute loss of consciousness. We approach the study of acute loss of consciousness from a theoretical and clinical perspective to conclude that clinicians in acute care centers must incorporate new measurements and techniques besides the classic coma scales in order to assess their patients with loss of consciousness. PMID:25702218

  3. Human chromosome 'painting' probes used to measure chromosome translocations in non-human primates: extrapolations from monkey to man

    International Nuclear Information System (INIS)

    Chromosome painting with a probe specific for human chromosome 4 was used to 'paint' monkey chromosomes to measure the persistence of translocations in peripheral blood lymphocytes of a rhesus monkey exposed to ionising radiation more than 25 years ago. The human probe painted the entire length of two large rhesus and cynomolgus monkey chromosomes with no cross hybridisation to other chromosomes, facilitating rapid detection of chromosome translocations. Translocation frequency measured in one monkey was significantly higher than that for unirradiated animals. The use of human probes to obtain cytogenetic data from Macaca species irradiated years previously or exposed to chemical clastogens makes this genus an excellent model for studying genetic damage. (author)

  4. Female chromosome X mosaicism is age-related and preferentially affects the inactivated X chromosome

    OpenAIRE

    Machiela, Mitchell J.; Zhou, Weiyin; Karlins, Eric; Sampson, Joshua N.; Neal D Freedman; Yang, Qi; Hicks, Belynda; Dagnall, Casey; Hautman, Christopher; Jacobs, Kevin B.; Abnet, Christian C.; Aldrich, Melinda C; Amos, Christopher; Amundadottir, Laufey T.; Arslan, Alan A.

    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 ...

  5. Familial predisposition to Wilms' tumour does not map to the short arm of chromosome 11.

    Science.gov (United States)

    Grundy, P; Koufos, A; Morgan, K; Li, F P; Meadows, A T; Cavenee, W K

    1988-11-24

    Wilms' tumour of the kidney usually occurs sporadically, but can also segregate as an autosomal dominant trait with incomplete penetrance. Patients with the WAGR syndrome of aniridia, genitourinary anomalies, mental retardation and high risk of Wilms' tumour have overlapping deletions of chromosome 11p13 which has suggested a possible location for a Wilms' tumour locus. Moreover, many sporadic tumours have lost a portion of chromosome 11p. A second locus at 11p15 is implicated by association of the tumour with the Wiedemann-Beckwith syndrome and by tumour-specific losses of chromosome 11 confined to 11p15. Here we report a multipoint linkage analysis of a family segregating for Wilms' tumour, using polymorphic DNA markers mapped to chromosome 11p. The results exclude the predisposing mutation from both locations. In a second family, the 11p15 alleles lost in the tumour were derived from the affected parent, thus precluding this region as the location of the inherited mutation. These findings imply an aetiological heterogeneity for Wilms' tumour and raise questions concerning the general applicability of the carcinogenesis model that has been useful in the understanding of retinoblastoma. PMID:2848199

  6. Complete paternal uniparental isodisomy of chromosome 1 resulting in Herlitz junctional epidermolysis bullosa.

    Science.gov (United States)

    Fassihi, H; Wessagowit, V; Ashton, G H S; Moss, C; Ward, R; Denyer, J; Mellerio, J E; McGrath, J A

    2005-01-01

    Herlitz junctional epidermolysis bullosa (JEB) is an autosomal recessive mechanobullous disorder that results from loss-of-function mutations in the genes encoding the basement membrane component, laminin 5. Typically, there are frameshift, splice site or nonsense mutations on both alleles of either the LAMA3, LAMB3 or LAMC2 genes, with affected individuals inheriting one mutated allele from each parent. In this report, we describe a patient with Herlitz JEB in whom DNA analysis revealed homozygosity for the recurrent nonsense mutation R635X in LAMB3, located on chromosome 1q32.2. However, screening of parental DNA showed that although the patient's father was a heterozygous carrier of this mutation, the mother's DNA showed only wild-type sequence. Subsequent genotype analysis using 13 microsatellite markers spanning chromosome 1 revealed that the affected child was homozygous for the entire series of markers tested and that all of the alleles originated from the father. These results indicate that the Herlitz JEB phenotype in this patient is due to complete paternal isodisomy of chromosome 1 and reduction to homozygosity of the mutant LAMB3 gene locus. This is the fourth case of uniparental disomy to be described in Herlitz JEB, but it represents the first example of complete paternal isodisomy for chromosome 1 with a pathogenic mutation in the LAMB3 gene. These findings have important implications for mutation screening in JEB and for genetic counselling. PMID:15663509

  7. Mapping the chromosome 16 cadherin gene cluster to a minimal deleted region in ductal breast cancer.

    Science.gov (United States)

    Chalmers, I J; Aubele, M; Hartmann, E; Braungart, E; Werner, M; Höfler, H; Atkinson, M J

    2001-04-01

    The cadherin family of cell adhesion molecules has been implicated in tumor metastasis and progression. Eight family members have been mapped to the long arm of chromosome 16. Using radiation hybrid mapping, we have located six of these genes within a cluster at 16q21-q22.1. In invasive lobular carcinoma of the breast frequent LOH and accompanying mutation affect the CDH1 gene, which is a member of this chromosome 16 gene cluster. CDH1 LOH also occurs in invasive ductal carcinoma, but in the absence of gene mutation. The proximity of other cadherin genes to 16q22.1 suggests that they may be affected by LOH in invasive ductal carcinomas. Using the mapping data, microsatellite markers were selected which span regions of chromosome 16 containing the cadherin genes. In breast cancer tissues, a high rate of allelic loss was found over the gene cluster region, with CDH1 being the most frequently lost marker. In invasive ductal carcinoma a minimal deleted region was identified within part of the chromosome 16 cadherin gene cluster. This provides strong evidence for the existence of a second 16q22 suppressor gene locus within the cadherin cluster. PMID:11343777

  8. A yeast artificial chromosome contig of the critical region for cri-du-chat syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Goodart, S.A.; Rojas, K.; Overhauser, J. [Thomas Jefferson Univ., Philadelphia, PA (United States)] [and others

    1994-11-01

    Cri-du-chat is a chromosomal deletion syndrome characterized by partial deletion of the short arm of chromosome 5. The clinical symptoms include growth and mental retardation, microcephaly, hypertelorism, epicanthal folds, hyptonia, and a high-pitched monochromatic cry that is usually considered diagnostic for the syndrome. Recently, a correlation between clinical features and the extent of the chromosome 5 deletions has identified two regions of the short arm that appear to be critical for the abnormal development manifested in this syndrome. Loss of a small region in 5p15.2 correlates with all of the clinical features of cri-du-chat with the exception of the cat-like cry, which maps to 5p15.3. Here the authors report the construction of a YAC contig that spans the chromosomal region in 5p15.2 that plays a major role in the etiology of the cri-du-chat syndrome. YACs that span the 2-Mb cri-du-chat critical region have been identified and characterized. This YAC contig lays the groundwork for the construction of a transcriptional map of this region and the eventual identification of genes involved in the clinical features associated with the cri-du-chat syndrome. It also provides a new diagnostic tool for cri-du-chat in the shape of a YAC clone that may span the entire critical region. 24 refs., 4 figs., 2 tabs.

  9. Understanding Chromosome Disorders and their Implications for Special Educators

    Directory of Open Access Journals (Sweden)

    Linda Gilmore

    2014-03-01

    Full Text Available More children are now being diagnosed with chromosome abnormalities. Some chromosome disorder syndromes are relatively well known; while others are so rare that there is only limited evidence about their likely impact on learning and development. For educators, a basic level of knowledge about chromosome abnormalities is important for understanding the literature and communicating with families and professionals. This paper describes chromosomes, and the numerical and structural anomalies that can occur, usually spontaneously during early cell division. Distinctive features of various chromosome syndromes are summarised before a discussion of the rare chromosome disorders that are labelled, not with a syndrome name, but simply by a description of the chromosome number, size and shape. Because of the potential within-group variability that characterises syndromes, and the scarcity of literature about the rare chromosome disorders, expectations for learning and development of individual students need to be based on the range of possible outcomes that may be achievable.

  10. Function of the Sex Chromosomes in Mammalian Fertility

    OpenAIRE

    Heard, Edith; Turner, James

    2011-01-01

    In female germ cells, the inactive X chromosome is reactivated before meiosis and thereafter remains active. In contrast, the X chromosome in males is inactivated during meiosis, and silencing is largely maintained during spermiogenesis.

  11. Mapping and ordered cloning of the human X chromosome

    Energy Technology Data Exchange (ETDEWEB)

    Caskey, C.T.; Nelson, D.L.

    1992-12-01

    Progress is reported on gathering X chromosome specific libraries and integrating those with the library produced in this project. Further studies on understanding Fragile X Syndrome and other hereditary diseases related to the X chromosome are described. (DT)

  12. Analysis and visualization of chromosomal abnormalities in SNP data with SNPscan

    Directory of Open Access Journals (Sweden)

    Thomas George H

    2006-01-01

    Full Text Available Abstract Background A variety of diseases are caused by chromosomal abnormalities such as aneuploidies (having an abnormal number of chromosomes, microdeletions, microduplications, and uniparental disomy. High density single nucleotide polymorphism (SNP microarrays provide information on chromosomal copy number changes, as well as genotype (heterozygosity and homozygosity. SNP array studies generate multiple types of data for each SNP site, some with more than 100,000 SNPs represented on each array. The identification of different classes of anomalies within SNP data has been challenging. Results We have developed SNPscan, a web-accessible tool to analyze and visualize high density SNP data. It enables researchers (1 to visually and quantitatively assess the quality of user-generated SNP data relative to a benchmark data set derived from a control population, (2 to display SNP intensity and allelic call data in order to detect chromosomal copy number anomalies (duplications and deletions, (3 to display uniparental isodisomy based on loss of heterozygosity (LOH across genomic regions, (4 to compare paired samples (e.g. tumor and normal, and (5 to generate a file type for viewing SNP data in the University of California, Santa Cruz (UCSC Human Genome Browser. SNPscan accepts data exported from Affymetrix Copy Number Analysis Tool as its input. We validated SNPscan using data generated from patients with known deletions, duplications, and uniparental disomy. We also inspected previously generated SNP data from 90 apparently normal individuals from the Centre d'Étude du Polymorphisme Humain (CEPH collection, and identified three cases of uniparental isodisomy, four females having an apparently mosaic X chromosome, two mislabelled SNP data sets, and one microdeletion on chromosome 2 with mosaicism from an apparently normal female. These previously unrecognized abnormalities were all detected using SNPscan. The microdeletion was independently

  13. Chromosome segregation: learning to let go.

    Science.gov (United States)

    Higgins, Jonathan M G

    2013-10-01

    To ensure accurate chromosome segregation, cohesion between sister chromatids must be released in a controlled manner during mitosis. A new study reveals how distinct centromere populations of the cohesin protector Sgo1 are regulated by microtubule attachments, cyclin-dependent kinases, and the kinetochore kinase Bub1. PMID:24112985

  14. Improved prenatal detection of chromosomal anomalies

    DEFF Research Database (Denmark)

    Frøslev-Friis, Christina; Hjort-Pedersen, Karina; Henriques, Carsten U;

    2011-01-01

    Prenatal screening for karyotype anomalies takes place in most European countries. In Denmark, the screening method was changed in 2005. The aim of this study was to study the trends in prevalence and prenatal detection rates of chromosome anomalies and Down syndrome (DS) over a 22-year period....

  15. Precise Centromere Positioning on Chicken Chromosome 3

    NARCIS (Netherlands)

    Zlotina, A.; Galkina, S.A.; Krasikova, A.; Crooijmans, R.P.M.A.; Groenen, M.A.M.; Gaginskaya, E.; Deryusheva, S.

    2010-01-01

    Despite the progress of the chicken (Gallus gallus) genome sequencing project, the centromeric sequences of most macrochromosomes remain unknown. This makes it difficult to determine centromere positions in the genome sequence assembly. Using giant lampbrush chromosomes from growing oocytes, we anal

  16. Y chromosome microdeletions in Turkish infertile men

    Directory of Open Access Journals (Sweden)

    Zamani Ayse

    2006-01-01

    Full Text Available AIMS: To detect the frequency and types of both chromosomal abnormalities and Y chromosome microdeletions in infertile men attending to our university intracytoplasmic sperm injection ICSI/IVF centre and fertile control subjects in our patient population. SETTINGS AND DESIGN: A total of 50 infertile men who were referred to IVF center of Meram medical faculty were selected for the molecular azospermia factor (AZF screening program. MATERIALS AND METHODS: Karyotype analysis and polymerase chain reaction amplification using 15 Y-specific sequence-tagged sites of AZF region were done. RESULTS: The total prevalence of chromosomal abnormalities was found to be 10% (5/50, including 4 patients with numerical and 1 patient with structural abnormalities. Overall, 4 of the 50 patients tested (8% exhibited deletions of the Y chromosome, 3 of them being azospermic and 1 of them oligospermic men. The frequency of the microdeletions in subgroups with azospermia and oligozoospermia was found to be 10.7% (3/29 and 4.7% (1/21 respectively. Microdeletions of AZFb and AZFc regions were detected in all of the 4 patients. Neither AZFa nor AZFd microdeletions were indicated. CONCLUSIONS: Our findings suggest that one must know whether there is a genetic cause for male infertility before patients can be subjected to ISCI or testicular sperm extraction (TESE/ISCI treatment.

  17. Johannsen's criticism of the chromosome theory.

    Science.gov (United States)

    Roll-Hansen, Nils

    2014-01-01

    The genotype theory of Wilhelm Johannsen (1857-1927) was an important contribution to the founding of classical genetics. This theory built on Johannsen's experimental demonstration that hereditary change is discontinuous, not continuous as had been widely assumed. Johannsen is also known for his criticism of traditional Darwinian evolution by natural selection, as well as his criticism of the classical Mendelian chromosome theory of heredity. He has often been seen as one of the anti-Darwinians that caused the "eclipse of Darwinism" in the early 20th century, before it was saved by the Modern Synthesis. This article focuses on Johannsen's criticism of the chromosome theory. He was indeed skeptical of the notion of the chromosomes as the sole carriers of heredity, but he praised the mapping of Mendelian genes on the chromosomes as a major step forward. Johannsen objected that these genes could not account for the whole of heredity, and that the stability of the genotype depended on much more than the stability of Mendelian genes. For Johannsen, the genotype, as a property of the whole organism, was the fundamental and empirically well-established entity. PMID:25345701

  18. Chameleons out of disguise: sex chromosomes revealed

    Czech Academy of Sciences Publication Activity Database

    Rovatsos, M.; Johnson Pokorná, Martina; Altmanová, M.; Kratochvíl, L.

    Brno: Ústav biologie obratlovců AV ČR, 2015 - (Bryja, J.; Řehák, Z.; Zukal, J.). s. 212-212 ISBN 978-80-87189-18-4. [Zoologické dny. 12.02.2015-13.02.2015, Brno] Institutional support: RVO:67985904 Keywords : sex chromosomes Subject RIV: EG - Zoology

  19. The evolution of sex chromosomes in papaya

    Czech Academy of Sciences Publication Activity Database

    Yu, Qingyi; Moore, Paul H.; Alam, Maqsudul; Jiang, Jiming; Paterson, Andrew H.; Vyskot, Boris; Ming, Ray

    San Diego, 2006. W340-W340. [Plant & Animal Genomes XIV Conference. 14.01.2006-18.01.2006, San Diego] R&D Projects: GA ČR(CZ) GA521/06/0056; GA MŠk(CZ) LC06004 Institutional research plan: CEZ:AV0Z50040507 Keywords : evolution * sex chromosomes * papaya Subject RIV: BO - Biophysics

  20. 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. .

  1. Ring Chromosome 7 in an Indian Woman

    Science.gov (United States)

    Kaur, Anupam; Dhillon, Sumit; Garg, P. D.; Singh, Jai Rup

    2008-01-01

    Background: Ring chromosome 7 [r(7)] is a rare cytogenetic aberration, with only 16 cases (including 3 females) reported in the literature to date. This is the first reported case of r(7) from India. Method: Clinical and cytogenetic investigations were carried out in an adult female with microcephaly and intellectual disability. Results: Ring…

  2. IAPT/IOPB chromosome data 20

    Czech Academy of Sciences Publication Activity Database

    Altinordu, F.; Šumberová, Kateřina; Ankova, T.; Erst, A. S.; Kuzmin, I. V.; Shaulo, D. N.; Plugatar, Y. V.; Baltisberger, M.; Deldago, L.; Gallego Martín, F.; Rico, E.; Lavia, G. I.; Krapovickas, A.; de los Angeles Martines, M.; Lazaroff, Y.; Solis Neffa, V. G.; Ortiz, A. M.; Sivestri, M. C.; Pavlova, D.; Bani, A.; Polido, C. A.; Moraes, A. P.; Forni-Martins, E. R.; Probatova, N. S.; Kazanovsky, S. G.; Barkalov, V. Y.; Rudyka, E. G.; Shatokhina, A. V.; Krivenko, D. A.; Verkhozina, A. V.; Nechaev, V. A.; Romero-da Cruz, M. V.; Wefferling, K. M.; Owen, H. A.; Hoot, S. B.

    2015-01-01

    Roč. 64, č. 6 (2015), s. 1344-1350. ISSN 0040-0262 R&D Projects: GA ČR GB14-36079G Institutional support: RVO:67985939 Keywords : chromosome count * plant s Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.299, year: 2014

  3. Making the Chromosome-Gene-Protein Connection.

    Science.gov (United States)

    Mulvihill, Charlotte

    1996-01-01

    Presents an exercise that demonstrates the chromosome-gene-protein connection using sickle-cell anemia, a genetic disease with a well-characterized molecular basis. Involves connecting changes in DNA to protein outcomes and tying them into the next generation by meiosis and gamete formation with genetic crosses. Motivates students to integrate…

  4. Chromosome Analysis and Sorting Using Flow Cytometry

    Czech Academy of Sciences Publication Activity Database

    Doležel, Jaroslav; Kubaláková, Marie; Čihalíková, Jarmila; Suchánková, Pavla; Šimková, Hana

    New Jersey : Humana Press, 2011 - (Birchler, J.), s. 221-237 ISBN 978-1-61737-956-7 R&D Projects: GA ČR GA521/07/1573; GA MŠk(CZ) LC06004 Institutional research plan: CEZ:AV0Z50380511 Keywords : Chromosome analysis * flow cytometry * root meristems Subject RIV: EB - Genetics ; Molecular Biology

  5. The chromosome 9q subtelomere deletion syndrome

    NARCIS (Netherlands)

    Stewart, D.R.; Kleefstra, T.

    2007-01-01

    The chromosome 9q subtelomere deletion syndrome (9qSTDS) is among the first and most common clinically recognizable syndromes to arise from widespread testing by fluorescent in situ hybridization (FISH) of subtelomere deletions. There are about 50 reported cases worldwide. Affected individuals invar

  6. 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...

  7. The genomics of plant sex chromosomes

    Czech Academy of Sciences Publication Activity Database

    Vyskot, Boris; Hobza, Roman

    2015-01-01

    Roč. 236, JUL 2015 (2015), s. 126-135. ISSN 0168-9452 R&D Projects: GA ČR(CZ) GBP501/12/G090; GA ČR(CZ) GAP501/12/2220 Institutional support: RVO:68081707 Keywords : Y-CHROMOSOME * SILENE-LATIFOLIA * DIOECIOUS PLANT Subject RIV: BO - Biophysics Impact factor: 3.607, year: 2014

  8. 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…

  9. SWI1 Is Required for Meiotic Chromosome Remodeling Events

    Institute of Scientific and Technical Information of China (English)

    Kingsley A.Boateng; Xiaohui Yang; Fuqui Dong; Heather A.Owen; Christopher A.Makaroff

    2008-01-01

    The Arabidopsis dsy10 mutant was previously identified as being defective in the synapsis of meiotic chromosomes resulting in male and female sterility.We report:here the molecular analysis of the mutation and show that it represents a T-DNA insertion in the third exon of the SWI1 gene.Four mutations have now been identified in SWI1, several of which exhibit different phenotypes.For example.the swi1-1 and dyad mutations only affect meiosis in megasporocytes,while the swi1-2 and dsy10 mutations block both male and female meiosis.Furthermore,as part of a detailed cytological characterization of dsy10 meiocytes,we identified several differences during male meiosis between the swi1-2 and dys10 mutants, including variations in the formation of axial elements,the distribution of cohesin proteins and the timing of the premature loss of sister chromatid cohesion.We demonstrate that dsy10 represents a complete loss-of-function mutation,while a truncated form of SWI1 iS expressed during meiosis in swi1-2 plants.We further show that dys10 meiocytes exhibit alterations in modified histone patterns.including acetylated histone H3 and dimethylated histone H3-Lysine 4.

  10. Non-SMC condensin I complex proteins control chromosome segregation and survival of proliferating cells in the zebrafish neural retina

    Directory of Open Access Journals (Sweden)

    Harris William A

    2009-07-01

    Full Text Available Abstract Background The condensation of chromosomes and correct sister chromatid segregation during cell division is an essential feature of all proliferative cells. Structural maintenance of chromosomes (SMC and non-SMC proteins form the condensin I complex and regulate chromosome condensation and segregation during mitosis. However, due to the lack of appropriate mutants, the function of the condensin I complex during vertebrate development has not been described. Results Here, we report the positional cloning and detailed characterization of retinal phenotypes of a zebrafish mutation at the cap-g locus. High resolution live imaging reveals that the progression of mitosis between prometa- to telophase is delayed and that sister chromatid segregation is impaired upon loss of CAP-G. CAP-G associates with chromosomes between prometa- and telophase of the cell cycle. Loss of the interaction partners CAP-H and CAP-D2 causes cytoplasmic mislocalization of CAP-G throughout mitosis. DNA content analysis reveals increased genomic imbalances upon loss of non-SMC condensin I subunits. Within the retina, loss of condensin I function causes increased rates of apoptosis among cells within the proliferative ciliary marginal zone (CMZ whereas postmitotic retinal cells are viable. Inhibition of p53-mediated apoptosis partially rescues cell numbers in cap-g mutant retinae and allows normal layering of retinal cell types without alleviating their aberrant nuclear sizes. Conclusion Our findings indicate that the condensin I complex is particularly important within rapidly amplifying progenitor cell populations to ensure faithful chromosome segregation. In contrast, differentiation of postmitotic retinal cells is not impaired upon polyploidization.

  11. A computer simulation of chromosomal instability

    Science.gov (United States)

    Goodwin, E.; Cornforth, M.

    The transformation of a normal cell into a cancerous growth can be described as a process of mutation and selection occurring within the context of clonal expansion. Radiation, in addition to initial DNA damage, induces a persistent and still poorly understood genomic instability process that contributes to the mutational burden. It will be essential to include a quantitative description of this phenomenon in any attempt at science-based risk assessment. Monte Carlo computer simulations are a relatively simple way to model processes that are characterized by an element of randomness. A properly constructed simulation can capture the essence of a phenomenon that, as is often the case in biology, can be extraordinarily complex, and can do so even though the phenomenon itself is incompletely understood. A simple computer simulation of one manifestation of genomic instability known as chromosomal instability will be presented. The model simulates clonal expansion of a single chromosomally unstable cell into a colony. Instability is characterized by a single parameter, the rate of chromosomal rearrangement. With each new chromosome aberration, a unique subclone arises (subclones are defined as having a unique karyotype). The subclone initially has just one cell, but it can expand with cell division if the aberration is not lethal. The computer program automatically keeps track of the number of subclones within the expanding colony, and the number of cells within each subclone. Because chromosome aberrations kill some cells during colony growth, colonies arising from unstable cells tend to be smaller than those arising from stable cells. For any chosen level of instability, the computer program calculates the mean number of cells per colony averaged over many runs. These output should prove useful for investigating how such radiobiological phenomena as slow growth colonies, increased doubling time, and delayed cell death depend on chromosomal instability. Also of

  12. Cytogenetic characterization and AFLP-based genetic linkage mapping for the butterfly Bicyclus anynana, covering all 28 karyotyped chromosomes.

    Directory of Open Access Journals (Sweden)

    Arjen E Van't Hof

    Full Text Available BACKGROUND: The chromosome characteristics of the butterfly Bicyclus anynana, have received little attention, despite the scientific importance of this species. This study presents the characterization of chromosomes in this species by means of cytogenetic analysis and linkage mapping. METHODOLOGY/PRINCIPAL FINDINGS: Physical genomic features in the butterfly B. anynana were examined by karyotype analysis and construction of a linkage map. Lepidoptera possess a female heterogametic W-Z sex chromosome system. The WZ-bivalent in pachytene oocytes of B. anynana consists of an abnormally small, heterochromatic W-chromosome with the Z-chromosome wrapped around it. Accordingly, the W-body in interphase nuclei is much smaller than usual in Lepidoptera. This suggests an intermediate stage in the process of secondary loss of the W-chromosome to a ZZ/Z sex determination system. Two nucleoli are present in the pachytene stage associated with an autosome and the WZ-bivalent respectively. Chromosome counts confirmed a haploid number of n = 28. Linkage mapping had to take account of absence of crossing-over in females, and of our use of a full-sib crossing design. We developed a new method to determine and exclude the non-recombinant uninformative female inherited component in offspring. The linkage map was constructed using a novel approach that uses exclusively JOINMAP-software for Lepidoptera linkage mapping. This approach simplifies the mapping procedure, avoids over-estimation of mapping distance and increases the reliability of relative marker positions. A total of 347 AFLP markers, 9 microsatellites and one single-copy nuclear gene covered all 28 chromosomes, with a mapping distance of 1354 cM. Conserved synteny of Tpi on the Z-chromosome in Lepidoptera was confirmed for B. anynana. The results are discussed in relation to other mapping studies in Lepidoptera. CONCLUSIONS/SIGNIFICANCE: This study adds to the knowledge of chromosome structure and

  13. Molecular Characterisation of Structural Chromosomal Abnormalities Associated with Congenital Disorders

    OpenAIRE

    Mansouri, Mahmoud R.

    2006-01-01

    Chromosomal abnormalities are defined as changes in the chromosome structure and fall in one of two categories. The first category is numerical alterations while the second category consists of structural abnormalities. Structural chromosomal abnormalities do not always interrupt genes in order to cause disease. They can also affect gene expression by separating a gene and its promoter element from distant regulatory elements. We have used characterisation of structural chromosomal abnormalit...

  14. The Evolutionary Pathway of X Chromosome Inactivation in Mammals

    OpenAIRE

    Shevchenko, A.; Zakharova, I.; Zakian, S.

    2013-01-01

    X chromosome inactivation is a complex process that occurs in marsupial and eutherian mammals. The process is thought to have arisen during the differentiation of mammalian sex chromosomes to achieve an equal dosage of X chromosome genes in males and females. The differences in the X chromosome inactivation processes in marsupial and eutherian mammals are considered, and the hypotheses on its origin and evolution are discussed in this review.

  15. Characterization of Chenopodium quinoa chromosomes using fish and repetitive sequences

    International Nuclear Information System (INIS)

    Quinoa is one of the underestimated crops, which recently attracted attention. During last few years many efforts were done to save the natural genetic diversity of quinoa cultivars and landraces as well as to obtained new variability by mutagenesis. Plant characteristics based mainly on morphological and molecular markers. Cytogenetic analysis was not used for these studies. Quinoa is an allotetraploid species with 36 small chromosomes. To follow the chromosomal rearrangement cause by spontaneous or induced mutations it is necessary to find cytogenetics markers for chromosomes and chromosome arms. The physical mapping of repetitive DNAs by fluorescent in situ hybridization (FISH) can provide a valuable tool in studies of genome organization and chromosome rearrangements. To characterized quinoa genome several repetitive sequences were used as DNA probes for FISH. Double FISH with rRNA genes as probes allowed to distinguished three pairs of homologue chromosomes. Telomeric repeats hybridisation signals were present only in terminal part of all chromosome arms and no intercalar position was observed. Other tandem repetitive sequence - minisatellite was characteristic for centromeric and pericentromeric region of all quinoa chromosomes although number of repeats differ between loci. It allowed to divided quinoa chromosomes into few groups. Disperse repetitive sequences such as mobile element-like sequences used in this study were detected in all eighteen chromosome pairs. Hybridization signals were characteristics for pericentromeric region of one or both chromosome arms as relatively weak but discrete signals although few chromosomes exhibited signals in intercalary position. Two others repetitive sequences also exhibited disperse organization; however they are not mobile elements. Their FISH signals were spread throughout whole chromosome arms but only one was present on all quinoa chromosomes. The other revealed hybridization signals only on the half of the

  16. On the origin of sex chromosomes from meiotic drive

    OpenAIRE

    Úbeda, Francisco; Patten, Manus M.; Wild, Geoff

    2015-01-01

    Most animals and many plants make use of specialized chromosomes (sex chromosomes) to determine an individual's sex. Best known are the XY and ZW sex-determination systems. Despite having evolved numerous times, sex chromosomes present something of an evolutionary puzzle. At their origin, alleles that dictate development as one sex or the other (primitive sex chromosomes) face a selective penalty, as they will be found more often in the more abundant sex. How is it possible that primitive sex...

  17. Sonographically determined anomalies and outcome in 170 chromosomally abnormal fetuses

    OpenAIRE

    Wladimiroff, Juriy; Bhaggoe, W.; Kristelijn, M. J E; Cohen-Overbeek, Titia; Hollander, Nicolette; Brandenburg, Helen; Los, F.J.

    1995-01-01

    textabstractStructural pathology and outcome were studied in 170 chromosomally abnormal fetuses. Numerical chromosomal abnormalities were established in 158 (93 per cent) cases, of which 110 (71 per cent) represented trisomies, 30 (18 per cent) Turner syndrome, and 18 (11 per cent) triploidy. Structural chromosomal abnormalities were diagnosed in 12 (7 per cent) cases. Gestational age at referral was significantly shorter for pregnancies with Turner syndrome than for the other chromosomal abn...

  18. Balanced Chromosomal Rearrangement in Recurrent Spontaneous Abortions: A Case Report

    OpenAIRE

    Zarifian, Ahmadreza; Farhoodi, Zeinab; Amel, Roya; Mirzaee, Salmeh; Hassanzadeh-Nazarabadi, Mohammad

    2012-01-01

    One of the major causes of spontaneous abortion before the fourth month of pregnancy is chromosomal abnormalities. We report an unusual case of a familial balanced chromosomal translocation in a consanguineous couple who experienced 4 spontaneous abortions. Chromosomal studies were performed on the basis of G-banding technique at high resolution and revealed 46, XX, t (16; 6) (p12; q26) and 46, XY, t (16; 6) (p12; q26) in both partners, which induced such pregnancy complications. Chromosomal ...

  19. Diffusing Polymers in Confined Microdomains and Estimation of Chromosomal Territory Sizes from Chromosome Capture Data

    Science.gov (United States)

    Amitai, A.; Holcman, D.

    2013-06-01

    Is it possible to extract the size and structure of chromosomal territories (confined domain) from the encounter frequencies of chromosomal loci? To answer this question, we estimate the mean time for two monomers located on the same polymer to encounter, which we call the mean first encounter time in a confined microdomain (MFETC). We approximate the confined domain geometry by a harmonic potential well and obtain an asymptotic expression that agrees with Brownian simulations for the MFETC as a function of the polymer length, the radius of the confined domain, and the activation distance radius ɛ at which the two searching monomers meet. We illustrate the present approach using chromosome capture data for the encounter rate distribution of two loci depending on their distances along the DNA. We estimate the domain size that restricts the motion of one of these loci for chromosome II in yeast.

  20. Chromosomes. A comprehensive Xist interactome reveals cohesin repulsion and an RNA-directed chromosome conformation.

    Science.gov (United States)

    Minajigi, Anand; Froberg, John E; Wei, Chunyao; Sunwoo, Hongjae; Kesner, Barry; Colognori, David; Lessing, Derek; Payer, Bernhard; Boukhali, Myriam; Haas, Wilhelm; Lee, Jeannie T

    2015-07-17

    The inactive X chromosome (Xi) serves as a model to understand gene silencing on a global scale. Here, we perform "identification of direct RNA interacting proteins" (iDRiP) to isolate a comprehensive protein interactome for Xist, an RNA required for Xi silencing. We discover multiple classes of interactors-including cohesins, condensins, topoisomerases, RNA helicases, chromatin remodelers, and modifiers-that synergistically repress Xi transcription. Inhibiting two or three interactors destabilizes silencing. Although Xist attracts some interactors, it repels architectural factors. Xist evicts cohesins from the Xi and directs an Xi-specific chromosome conformation. Upon deleting Xist, the Xi acquires the cohesin-binding and chromosomal architecture of the active X. Our study unveils many layers of Xi repression and demonstrates a central role for RNA in the topological organization of mammalian chromosomes. PMID:26089354