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Query: UMLS:C0155339 (Brown)
 12,436 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Alphoid satellite DNA is a family of sequences with an approximately 170 bp periodicity which is found near the centromere of all human chromosomes. The structure of the human Y-chromosome alphoid DNA has been studied in two somatic cell hybrids, 3E7 and 853 (Tyler-Smith & Brown, 1987). The 170 bp alphoid subunits are tandemly repeated and are organized into units approximately 5.7 kb long. A few variant units on the 3E7 Y chromosome contain two extra 170 bp subunits and are approximately 6.0 kb long; the variant units are present in two clusters at least 90 kb apart on the chromosome. On each Y chromosome there is a single major block of alphoid DNA: on the 3E7 Y chromosome it is approximately 440 kb long and on the 853 Y chromosome it is approximately 540 kb long. A long-range restriction map of the 853 block has been constructed covering approximately 1.1 mb of DNA. The distribution of restriction sites suggests that the sequences on one side of the alphoid block may be typical euchromatic DNA, while the sequences on the other side may be another satellite sequence.
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PMID:Structure of repeated sequences in the centromeric region of the human Y chromosome. 350 26

The purpose of the present study was to examine the ability of a tetraparental Chimera in producing IVF embryos. Cumulus oocytes complexes (COCs) were matured in vitro for 22 h. Frozen-thawed sperm of a Chimera (CH), as well as Japanese Black (JB), Limousin (L), Japanese Brown (JBr), Holstein (H) bulls were used for IVF. The chromosome preparations were made from peripheral lymphocytes. Based on chromosome analysis the Chimera had apparently normal chromosomes (29 acrocentric pairs, one large sub metacentric X chromosome and one small sub metacentric Y chromosome). The proportion of acrosome reacted spermatozoa after 1 h incubation was higher (P < 0.01) with the Chimera (CH) than with the Holstein and in Japanese Brown bulls, but did not differ from Japanese Black and Limousin bull sperm (79.0%, 71.2%, 72.5%, 57.8% and 57.0% for CH, JB, L, JBr and H sperm, respectively). Fertilization rates observed after 5 h of sperm-oocyte incubation with Chimera (O-CH) sperm were higher (P < 0.05) than with Japanese Brown (O-JBr) and (P < 0.01) than with Holstein (O-H) sperm, but did not differ from Japanese Black (O-JB) and Limousin (O-L) sperm (36/44, 81.8%; 28/35, 80.0%; 25/36, 69.4%; 19/43, 44.2% and 6/33, 18.2% for O-CH, O-JB, O-L, O-JBr and O-H, respectively). The cleavage rates of IVM oocytes inseminated with Chimera sperm were also higher (P < 0.001) than in Holstein, (P < 0.01) Japanese Brown and (P < 0.05) Limousin, but did not differ from Japanese Black sperm (181/239, 75.7%; 123/171, 71.9%; 108/186, 58.1%; 80/196, 40.8% and 30/186, 16.1% for O-CH, O-JB, O-L, O-JBr and O-H, respectively). The blastocyst rates of IVM oocytes inseminated with sperm were higher (P < 0.05) than in Limousin, Japanese Brown and Holstein, but did not differ from Japanese Black (69/181, 38.1%; 48/123, 39.0%; 27/108, 25.0%; 7/30, 23.3% and 16/80, 17.8% for O-CH, O-JB, O-L, O-JBr and O-H, respectively). Three findings suggested the sperm from this tetraparental Chimeric bull were able to be used for producing bovine IVF embryos.
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PMID:Fertility of sperm from a tetraparental chimeric bull. 923 Dec 45

Previous studies with chromosome-Y consomic strains of spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats suggest that a quantitative trait locus for blood pressure regulation exists on chromosome Y. To test this hypothesis in the SHR-Brown Norway (BN) model and to study the effects of chromosome Y on lipid and carbohydrate metabolism, we produced a new consomic strain of SHR carrying the Y chromosome transferred from the BN rat. We found that replacing the SHR Y chromosome with the BN Y chromosome resulted in significant decreases in systolic and diastolic blood pressures in the SHR.BN-Y consomic strain (P<0.05). To elicit possible dietary-induced variation in lipid and glucose metabolism between the SHR progenitor and chromosome-Y consomic strains, we fed rats a high-fructose diet for 15 days in addition to the normal diet. On the high-fructose diet, the SHR.BN-Y consomic rats exhibited significantly increased levels of serum triglycerides and decreased levels of serum HDL cholesterol versus the SHR progenitor rats. Glucose tolerance and insulin/glucose ratios, however, were similar in both strains on both normal and high-fructose diets. These findings provide direct evidence that a gene or genes on chromosome Y contribute to the pathogenesis of spontaneous hypertension in the SHR-BN model. These results also indicate that transfer of the Y chromosome from the BN rat onto the SHR background exacerbates dietary-induced dyslipidemia in SHR. Thus, genetic variation in genes on the Y chromosome may contribute to variation in blood pressure and lipid levels and may influence the risk for cardiovascular disease.
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PMID:Y-chromosome transfer induces changes in blood pressure and blood lipids in SHR. 1130 17

The transplanted limb contains bone marrow tissue. The hematopoietic cells contained in the bone of the graft normally differentiate after transplantation and can be released to the recipient. The cells migrate to the recipient bone marrow cavities and lymphoid organs. This causes the immune reaction between the donor and the recipient, which develops not only in the graft itself but also in the recipient immune organs where donor bone marrow cells home. The purpose of this study was to investigate the process of migration of the hematopoietic cells from the donor limb to the recipient bone marrow cavities and lymphoid tissues. The questions the authors asked were: what is the rate of release of bone marrow cells from the transplanted bone, where do the released bone marrow cells home in the recipient, how fast are donor bone marrow cells rejected by the recipient, and can some bone marrow cells homing in the recipient tissues survive and create a state of microchimerism. Experiments were performed on Brown Norway and Lewis inbred rat strains (n = 30). Limb donors received intravenous chromium-51-labeled bone marrow cells. Twenty-four hours later, the limb with homing labeled bone marrow cells was transplanted to an allogeneic or syngeneic recipient. The rate of radioactivity of bone marrow cells released from the graft and homing in recipient tissues was measured after another 24 hours. To eliminate factors adversely affecting homing such as the "crowding effect" and allogeneic elimination of bone marrow cells by natural killer cells, total body irradiation and antiasialo-GM1 antiserum were applied to recipients before limb transplantation. In rats surviving with the limb grafts for 7 and 30 days, homing of donor bone marrow cells was studied by specific labeling of donor cells and flow cytometry as well as by detecting donor male Y chromosome. The authors found that transplantation of the limb with bone marrow in its natural spatial relationship with stromal cells and blood perfusion brings about immediate but low-rate release of bone marrow cells and their migration to recipient bone marrow and lymphoid tissues. Large portions of allogeneic bone marrow cells are rapidly destroyed in the mechanism of allogeneic elimination by radioresistant but antiasialo-GM1-sensitive natural killer cells. Some transplanted bone marrow cells remain in the recipient's tissues and create a state of cellular and DNA microchimerism. A low number of physiologically released donor bone marrow cells do not seem to adversely affect the clinical outcome of limb grafting. Quite the opposite, a slight prolongation of the graft survival time was observed.
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PMID:Biological aspects of limb transplantation: I. Migration of transplanted bone marrow cells into recipient. 1457 94

Previous studies using reciprocal crosses between the spontaneously hypertensive rat (SHR) and the normotensive Wistar-Kyoto (WKY) strain suggested a role for the Y chromosome in the SHR's exaggerated preference for saline solutions. We have reexamined the role of the Y chromosome in the salt preference of the SHR using a consomic strain derived from SHR and Brown Norway (BN-Lx) progenitors. We also studied congenic lines in which regions of BN-Lx chromosomes 8 and 20 had been introgressed into the SHR genome. Animals were given a choice of water and 0.9% saline to drink over a period of 7 days and their total fluid intake (TFI; water plus saline) and saline preference (proportion of the TFI taken as saline) calculated. SHR bearing the BN-Lx Y chromosome had a significantly reduced saline preference when compared to progenitor SHR. Evidence was also found for the existence of a region on chromosome 8, which influences fluid intake in the SHR. The causative genes involved in these effects however remain to be determined.
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PMID:Salt preference of congenic strains derived from the spontaneously hypertensive rat. 1498 94

Multi-copied gene families are prevalent in mammalian genomes, especially within the Y chromosome. Testis specific protein Y-encoded (TSPY) is present in variable copy number in many mammalian species. Previous studies have estimated that TSPY ranges from 50-200 copies in cattle. To examine TSPY localization on the Y chromosome we employed fluorescence in situ hybridization (FISH) and fiber-FISH. The results show a strong signal on the short arm of the Y chromosome (Yp). To investigate TSPY copy number we used relative real-time polymerase chain reaction (PCR) to analyze the DNA of 14 different cattle breeds. Variation both within and between breeds was observed. All breeds show significant variation in TSPY copy number among individual members. Brown Swiss (161 copies, CI = 133-195) had higher average levels of TSPY and Western Fjord Cattle (63 copies, CI = 45-86) had lower levels than some breeds. Overall, however, most breeds had a similar average TSPY copy number. The pooled average was 94 copies (CI = 88-100). The significance of the TSPY array remains uncertain, but as the function of TSPY is unraveled the purpose of the array may become clearer.
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PMID:Copy number variation of testis-specific protein, Y-encoded (TSPY) in 14 different breeds of cattle (Bos taurus). 1975

The present study was undertaken to investigate aneuploidy rates in the sperm populations of 2 cattle (Bos taurus) breeds by using dual color fluorescent in situ hybridization (FISH) with Xcen and Y chromosome-specific painting probes, obtained by chromosome microdissection and DOP-PCR. Frozen semen from 10 Italian Friesian and 10 Italian Brown testing bulls was used for the investigation. For each bull, more than 5,000 sperm were analyzed, for a total of 52,586 and 51,342 sperm cells for the 2 breeds, respectively. The present study revealed - in both breeds - a preponderance of the Y-bearing sperm compared to the X-bearing sperm. Within each breed, a statistically significant variation in the various classes of aneuploidy (XX, YY and XY) was found: differences were found in the Friesian breed among the 3 diploidy classes, and in the Brown breed, among the 3 disomy classes (p < 0.05) as well as among the 3 diploidy classes (p < 0.01). However, the 2 breeds did not differ significantly in the overall mean rates of X-Y aneuploidy (disomy + diploidy) which amounts to 0.162% in the Italian Friesian and 0.142% in the Italian Brown. When meiosis I (MI) and II (MII) errors were compared, statistically significant differences (p < 0.01) were found in the disomy classes and in both breeds, whereas the differences between diploidy classes were not significant. Compared to humans, a lower level of aneuploidy has been found in the domestic species analyzed so far. The present study contributes to the establishment of a baseline level of aneuploidy in the sperm populations of 2 cattle breeds which could be used for monitoring future trends of reproductive health, especially in relation to environmental changes and mutagens.
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PMID:X-Y sperm aneuploidy in 2 cattle (Bos taurus) breeds as determined by dual color fluorescent in situ hybridization (FISH). 2001 73

Brown and polar bears have become prominent examples in phylogeography, but previous phylogeographic studies relied largely on maternally inherited mitochondrial DNA (mtDNA) or were geographically restricted. The male-specific Y chromosome, a natural counterpart to mtDNA, has remained underexplored. Although this paternally inherited chromosome is indispensable for comprehensive analyses of phylogeographic patterns, technical difficulties and low variability have hampered its application in most mammals. We developed 13 novel Y-chromosomal sequence and microsatellite markers from the polar bear genome and screened these in a broad geographic sample of 130 brown and polar bears. We also analyzed a 390-kb-long Y-chromosomal scaffold using sequencing data from published male ursine genomes. Y chromosome evidence support the emerging understanding that brown and polar bears started to diverge no later than the Middle Pleistocene. Contrary to mtDNA patterns, we found 1) brown and polar bears to be reciprocally monophyletic sister (or rather brother) lineages, without signals of introgression, 2) male-biased gene flow across continents and on phylogeographic time scales, and 3) male dispersal that links the Alaskan ABC islands population to mainland brown bears. Due to female philopatry, mtDNA provides a highly structured estimate of population differentiation, while male-biased gene flow is a homogenizing force for nuclear genetic variation. Our findings highlight the importance of analyzing both maternally and paternally inherited loci for a comprehensive view of phylogeographic history, and that mtDNA-based phylogeographic studies of many mammals should be reevaluated. Recent advances in sequencing technology render the analysis of Y-chromosomal variation feasible, even in nonmodel organisms.
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PMID:Brown and polar bear Y chromosomes reveal extensive male-biased gene flow within brother lineages. 2466 25