共查询到20条相似文献,搜索用时 31 毫秒
1.
Background
Paucity of male-biased genes on the Drosophila X chromosome is a well-established phenomenon, thought to be specifically linked to the role of these genes in reproduction and/or their expression in the meiotic male germline. In particular, meiotic sex chromosome inactivation (MSCI) has been widely considered a driving force behind depletion of spermatocyte-biased X-linked genes in Drosophila by analogy with mammals, even though the existence of global MCSI in Drosophila has not been proven. 相似文献2.
Background
The vast majority of oocytes formed in the fetal ovary do not survive beyond birth. Possible reasons for their loss include the elimination of non-viable genetic constitutions arising through meiosis, however, the precise relationship between meiotic stages and prenatal apoptosis of oocytes remains elusive. We studied oocytes in mouse fetal and neonatal ovaries, 14.5–21 days post coitum, to examine the relationship between oocyte development and programmed cell death during meiotic prophase I. 相似文献3.
Background
Thousands of parthenogenetic animal species have been described and cytogenetic manifestations of this reproductive mode are well known. However, little is understood about the molecular determinants of parthenogenesis. The Daphnia pulex genome must contain the molecular machinery for different reproductive modes: sexual (both male and female meiosis) and parthenogenetic (which is either cyclical or obligate). This feature makes D. pulex an ideal model to investigate the genetic basis of parthenogenesis and its consequences for gene and genome evolution. Here we describe the inventory of meiotic genes and their expression patterns during meiotic and parthenogenetic reproduction to help address whether parthenogenesis uses existing meiotic and mitotic machinery, or whether novel processes may be involved. 相似文献4.
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érica Duarte Silveira Márcio Alves-Ferreira Larissa Arrais Guimar?es Felipe Rodrigues da Silva de Campos Vera Tavares de Campos Carneiro 《BMC plant biology》2009,9(1):84
Background
Brachiaria brizantha is an important forage grass. The occurrence of both apomictic and sexual reproduction within Brachiaria makes it an interesting system for understanding the molecular pathways involved in both modes of reproduction. Quantitative real time PCR (qRT-PCR) has emerged as an important technique to compare expression profile of target genes and, in order to obtain reliable results, it is important to have suitable reference genes. In this work, we evaluated eight potential reference genes for B. brizantha qRT-PCR experiments, isolated from cDNA ovary libraries. Vegetative and reproductive tissues of apomictic and sexual B. brizantha were tested to validate the reference genes, including the female gametophyte, where differences in the expression profile between sexual and apomictic plants must occur. 相似文献6.
Changbin Chen Andrew D Farmer Raymond J Langley Joann Mudge John A Crow Gregory D May James Huntley Alan G Smith Ernest F Retzel 《BMC plant biology》2010,10(1):280
Background
Meiosis is a critical process in the reproduction and life cycle of flowering plants in which homologous chromosomes pair, synapse, recombine and segregate. Understanding meiosis will not only advance our knowledge of the mechanisms of genetic recombination, but also has substantial applications in crop improvement. Despite the tremendous progress in the past decade in other model organisms (e.g., Saccharomyces cerevisiae and Drosophila melanogaster), the global identification of meiotic genes in flowering plants has remained a challenge due to the lack of efficient methods to collect pure meiocytes for analyzing the temporal and spatial gene expression patterns during meiosis, and for the sensitive identification and quantitation of novel genes. 相似文献7.
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David H Lunt 《BMC evolutionary biology》2008,8(1):194
Background
The existence of "ancient asexuals", taxa that have persisted for long periods of evolutionary history without sexual recombination, is both controversial and important for our understanding of the evolution and maintenance of sexual reproduction. A lack of sex has consequences not only for the ecology of the asexual organism but also for its genome. Several genetic signatures are predicted from long-term asexual (apomictic) reproduction including (i) large "allelic" sequence divergence (ii) lack of phylogenetic clustering of "alleles" within morphological species and (iii) decay and loss of genes specific to meiosis and sexual reproduction. These genetic signatures can be hard to assess since it is difficult to demonstrate the allelic nature of very divergent sequences, divergence levels may be complicated by processes such as inter-specific hybridization, and genes may have secondary roles unrelated to sexual reproduction. Apomictic species of Meloidogyne root knot nematodes have been suggested previously to be ancient asexuals. Their relatives reproduce by meiotic parthenogenesis or facultative sexuality, which in combination with the abundance of nematode genomic sequence data, makes them a powerful system in which to study the consequences of reproductive mode on genomic divergence. 相似文献10.
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Marissa A Bowden Ying Li Yi-Xun Liu Jock K Findlay Lois A Salamonsen Guiying Nie 《Reproductive biology and endocrinology : RB&E》2008,6(1):22
Background
HTRA3 is a recently identified member of the mammalian serine protease family HTRA (high temperature requirement factor A). In both the rodent and the human HTRA3 is transcribed into two mRNA species (long and short) through alternative splicing. We have previously shown that HTRA3 is expressed in the mature rat ovary and may be involved in folliculogenesis and luteinisation. HTRA3 is also upregulated during mouse and human placental development. The current study investigated whether HTRA3 is also localised in the primate ovary (rhesus monkey n = 7). In addition, we examined the non-pregnant rhesus monkey endometrium (n = 4) and maternal-fetal interface during early pregnancy (n = 5) to further investigate expression of HTRA3 in primate endometrium and placentation. 相似文献12.
Background
Large-scale compilation of gene expression microarray datasets across diverse biological phenotypes provided a means of gathering a priori knowledge in the form of identification and annotation of bimodal genes in the human and mouse genomes. These switch-like genes consist of 15% of known human genes, and are enriched with genes coding for extracellular and membrane proteins. It is of interest to determine the prediction potential of bimodal genes for class discovery in large-scale datasets. 相似文献13.
Conserved and divergent patterns of expression of DAZL,VASA and OCT4 in the germ cells of the human fetal ovary and testis 总被引:1,自引:0,他引:1
Richard A Anderson Norma Fulton Gillian Cowan Shona Coutts Philippa TK Saunders 《BMC developmental biology》2007,7(1):136
Background
Germ cells arise from a small group of cells that express markers of pluripotency including OCT4. In humans formation of gonadal compartments (cords in testis, nests in ovary) takes place during the 1st trimester (6–8 weeks gestation). In the 2nd trimester germ cells can enter meiotic prophase in females whereas in males this does not occur until puberty. We have used qRTPCR, Westerns and immunohistochemical profiling to determine which of the germ cell subtypes in the human fetal gonads express OCT4, DAZL and VASA, as these have been shown to play an essential role in germ cell maturation in mice. 相似文献14.
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John D Brannian Kathleen M Eyster Mitch Weber Maureen Diggins 《Reproductive biology and endocrinology : RB&E》2008,6(1):10
Background
Women with polycystic ovary syndrome (PCOS) are often treated with insulin-sensitizing agents, e.g. thiazolidinediones (TZD), which have been shown to reduce androgen levels and improved ovulatory function. Acting via peroxisome proliferator-activated receptor (PPAR) gamma, TZD alter the expression of a large variety of genes. Lethal yellow (LY; C57BL/6J Ay/a) mice, possessing a mutation (Ay) in the agouti gene locus, exhibit progressive obesity, reproductive dysfunction, and altered metabolic regulation similar to women with PCOS. The current study was designed to test the hypothesis that prolonged treatment of aging LY mice with the TZD, pioglitazone, alters the ovarian expression of genes that may impact reproduction. 相似文献16.
Hong Zhao Joy Innes David C Brooks Scott Reierstad Mehmet B Yilmaz Zhihong Lin Serdar E Bulun 《Reproductive biology and endocrinology : RB&E》2009,7(1):37
Background
Aromatase, the key enzyme in estrogen biosynthesis, is encoded by the Cyp19a1 gene. Thus far, 3 unique untranslated first exons associated with distinct promoters in the mouse Cyp19a1 gene have been described (brain, ovary, and testis-specific). It remains unknown whether aromatase is expressed in other mouse tissues via novel and tissue-specific promoters. 相似文献17.
Manuela Sironi Giorgia Menozzi Giacomo P Comi Matteo Cereda Rachele Cagliani Nereo Bresolin Uberto Pozzoli 《Genome biology》2007,7(12):R120
Background
Transposable elements (TEs) represent more than 45% of the human and mouse genomes. Both parasitic and mutualistic features have been shown to apply to the host-TE relationship but a comprehensive scenario of the forces driving TE fixation within mammalian genes is still missing. 相似文献18.
Fahimeh Ramezani Tehrani Masoumeh Simbar Maryam Tohidi Farhad Hosseinpanah Fereidoun Azizi 《Reproductive biology and endocrinology : RB&E》2011,9(1):39
Background
Despite the heavy burden and impact of the polycystic ovary syndrome (PCOS) in reproduction and public health, estimates regarding its prevalence at community levels are limited. We aimed to ascertain prevalence of PCOS in a community based sample using the National Institute of Health (NIH), the Rotterdam consensus (Rott.) and the Androgen Excess Society (AES) criteria. 相似文献19.
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