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Xiao Shi, David Yiu Leung Chan, Ming Peng Zhao, Carol Pui Shan Chan, Jin Huang, Tin-Chiu Li
RESEARCH QUESTION: Do spermatozoa with different sex chromosome complements (X and Y; aneuploidy and monosomy) exhibit different degrees of DNA damage? DESIGN: A prospective, observational study to measure the DNA fragmentation level and sex chromosome complement simultaneously using combined sperm chromosome dispersion (SCD) and fluorescence in-situ hybridization tests. Two methods were used to evaluate SCD images: a traditional semi-quantitative method to categorize halo size and a newly developed quantitative method based on the Matlab image analysis programme to more precisely measure the halo area and calculate the halo size index (HSI)...
November 20, 2018: Reproductive Biomedicine Online
Heïdi Serra, Kyuha Choi, Xiaohui Zhao, Alexander R Blackwell, Juhyun Kim, Ian R Henderson
During meiosis, chromosomes undergo DNA double-strand breaks (DSBs), which can be repaired using a homologous chromosome to produce crossovers. Meiotic recombination frequency is variable along chromosomes and tends to concentrate in narrow hotspots. We mapped crossover hotspots located in the Arabidopsis thaliana RAC1 and RPP13 disease resistance genes, using varying haplotypic combinations. We observed a negative non-linear relationship between interhomolog divergence and crossover frequency within the hotspots, consistent with polymorphism locally suppressing crossover repair of DSBs...
December 13, 2018: PLoS Genetics
Michael Habig, Gert Kema, Eva Holtgrewe Stukenbrock
Meiosis is a key cellular process of sexual reproduction involving the pairing of homologous sequences. In many species however, meiosis can also involve the segregation of supernumerary chromosomes, which can lack a homolog. How these unpaired chromosomes undergo meiosis is largely unknown. In this study we investigated chromosome segregation during meiosis in the haploid fungus Zymoseptoria tritici that possesses a large complement of supernumerary chromosomes. We used isogenic whole chromosome deletion strains to compare meiotic transmission of chromosomes when paired and unpaired...
December 13, 2018: ELife
Colin D Meiklejohn, Emily L Landeen, Kathleen E Gordon, Thomas Rzatkiewicz, Sarah B Kingan, Anthony J Geneva, Jeffrey P Vedanayagam, Christina A Muirhead, Daniel Garrigan, David L Stern, Daven C Presgraves
During speciation, sex chromosomes often accumulate interspecific genetic incompatibilities faster than the rest of the genome. The drive theory posits that sex chromosomes are susceptible to recurrent bouts of meiotic drive and suppression, causing the evolutionary build-up of divergent cryptic sex-linked drive systems and, incidentally, genetic incompatibilities. To assess the role of drive during speciation, we combine high-resolution genetic mapping of X-linked hybrid male sterility with population genomics analyses of divergence and recent gene flow between the fruitfly species, Drosophila mauritiana and D...
December 13, 2018: ELife
Yongjie Lu, Shunyao Liao, Wenling Tu, Bo Yang, Shasha Liu, Xue Pei, Dachang Tao, Yilu Lu, Yongxin Ma, Yuan Yang, Yunqiang Liu
Some X-linked genes necessary for spermiogenesis are specifically activated in the post-meiotic germ cells. However, the regulatory mechanism about this activation is not clearly understood. Here, we examined the potential mechanism controlling the transcriptional activation of the mouse testis specific gene A8 (Tsga8) gene in round spermatids. We observed that the Tsga8 expression was negatively correlated with the methylation level of the CpG sites in its core promoter. During spermatogenesis, the Tsga8 promoter was methylated in spermatogonia, and then demethylated in spermatocytes...
December 12, 2018: Biology of Reproduction
Tingting Zhao, Lijun Ren, Xiaojun Chen, Hengxiu Yu, Chengjie Liu, Yi Shen, Wenqing Shi, Ding Tang, Guijie Du, Yafei Li, Bojun Ma, Zhukuan Cheng
Response regulators play significant roles in controlling various biological processes; however, their roles in plant meiosis remain unclear. Here, we report the identification of OsRR24/LEPTOTENE1 (LEPTO1), a rice (Oryza sativa) type-B response regulator that participates in the establishment of key molecular and morphological features of chromosomes in leptotene, an early stage of prophase I in meiosis. Although meiosis initiates normally, as indicated by staining of the centromere-specific histone CENH3, the meiotic chromosomes in lepto1 mutant pollen mother cells (PMCs) fail to form the thin thread-like structures that are typical of leptotene chromosomes in wild-type PMCs...
December 11, 2018: Plant Cell
Eric M Sawyer, Pallavi R Joshi, Victoria Jorgensen, Julius Yunus, Luke E Berchowitz, Elçin Ünal
Cellular differentiation involves remodeling cellular architecture to transform one cell type to another. By investigating mitochondrial dynamics during meiotic differentiation in budding yeast, we sought to understand how organelle morphogenesis is developmentally controlled in a system where regulators of differentiation and organelle architecture are known, but the interface between them remains unexplored. We analyzed the regulation of mitochondrial detachment from the cell cortex, a known meiotic alteration to mitochondrial morphology...
December 11, 2018: Journal of Cell Biology
Marion Delame, Emilce Prado, Sophie Blanc, Guillaume Robert-Siegwald, Christophe Schneider, Pere Mestre, Camille Rustenholz, Didier Merdinoglu
In grapevine interspecific hybrids, meiotic recombination is suppressed in homeologous regions and enhanced in homologous regions of recombined chromosomes, whereas crossover rate remains unchanged when chromosome pairs are entirely homeologous. Vitis rotundifolia, an American species related to the cultivated European grapevine Vitis vinifera, has a high level of resistance to several grapevine major diseases and is consequently a valuable resource for grape breeding. However, crosses between both species most often lead to very few poorly fertile hybrids...
December 8, 2018: TAG. Theoretical and Applied Genetics. Theoretische und Angewandte Genetik
Haoxuan Liu, Calum J Maclean, Jianzhi Zhang
Meiotic recombination comprises crossovers and non-crossovers. Recombination, crossover in particular, shuffles mutations and impacts both the level of genetic polymorphism and the speed of adaptation. In many species, the recombination rate varies across the genome with hot- and cold-spots. The hotspot paradox hypothesis asserts that recombination hotspots are evolutionarily unstable due to self-destruction. However, the genomic landscape of double-strand breaks (DSBs), which initiate recombination, is evolutionarily conserved among divergent yeast species, casting doubt on the hotspot paradox hypothesis...
December 7, 2018: Molecular Biology and Evolution
Karima Mohammad Sweify, Iman Abd El-Moneim Darwish, Dalia Demerdash Abd El-Monem Hafez
Ivermectin, a broad-spectrum anti-parasitic agent first used in veterinary medicine, is active against numerous species of helminths and arthropods. In this study, we aimed to demonstrate the effects of administration of ivermectin on secondary meiotic division and serum total proteins. Male mice treated with single injections of 200ug/kg b.w. IVM. Meiotic chromosomes were prepared after 6 hours, 2, 5, 10 and 12 days to cover the different phases of meiotic division. Blood samples were collected after 1, 7 and 14 days of the last injection to determine total protein content...
November 2018: Pakistan Journal of Pharmaceutical Sciences
Shengli Zhang, Kaiwen Yang, Yuqing Lei, Kang Song
Meiotic recombination plays an important role in the process of genetic evolution. Previous researches have shown that the recombination rates provide important information about the mechanism of recombination study. However, at present, most methods ignore the hidden correlation and spatial autocorrelation of the DNA sequence. In this study, we proposed a predictor called iRSpot-DTS to identify hot/cold spots based on the benchmark datasets. We proposed a feature extraction method called dinucleotide-based spatial autocorrelation(DSA) which can incorporate the original DNA properties and spatial information of DNA sequence...
December 6, 2018: Genomics
Yoon Jeon, Mi Kyung Park, Sun Mi Kim, June Sung Bae, Chang Woo Lee, Ho Lee
Topoisomerase IIβ-binding protein 1 (TopBP1) is BRCT domain-containing protein that is required for DNA double-strand break (DSB) repair and DNA damage responses; however, its function during the early stage of spermatogenesis is still unclear. To investigate the physiological role of TopBP1, we have generated germ cell-specific TopBP1-depleted mouse model. TopBP1-deleted mice were infertile, showed a loss of germ cells and had meiotic defects. Conditional TopBP1 deletion resulted in reduced testis size, reduced number of epididymal sperm, increased apoptosis, and severely compromised fertility...
December 6, 2018: Biochemical and Biophysical Research Communications
F Sadeghzadeh, M S Mehranjani, M Mahmoodi
BACKGROUND: Dexamethasone (DEX) is a common medicine that is capable of causing malformation in the male reproductive system. The aim of this study was to investigate the effect of vitamin C (Vit-C) on spermatogenesis indexes and daily sperm production (DSP) in adult mice treated with DEX. METHODS: Male Naval Medical Research Institute (NMRI) mice were divided into four groups: Control, DEX (7 mg/kg/day), Vit-C (100 mg/kg/day), and DEX +Vit-C and treated for 7 days with intraperitoneal injection...
December 9, 2018: Human & Experimental Toxicology
Ali Reza Eftekhari Moghadam, Ghasem Saki, Masoud Hemadi, Zohre Mazaheri, Ali Khodadadi
Objectives: Dehydroepiandrosterone (DHEA) has been reported to improve pregnancy chances in women with diminished ovarian reserve (DOR) and to reduce miscarriage rates by 50-80%. This study, therefore, assesses effects of DHEA on number of retrieved oocytes and meiotic spindles. Materials and Methods: A randomized, prospective, controlled study was conducted on eight groups, four groups of young mice and four elderly. All young and old groups received different oral doses (35, 50, 75 mg/kg) of DHEA for 3 months...
October 2018: Iranian Journal of Basic Medical Sciences
Arkadiy Reunov, Yana Alexandrova, Yulia Reunova, Alina Komkova, Liliana Milani
SummaryGerm plasm-related structures (GPRS) are known to accompany meiotic cell differentiation but their dynamics are still poorly understood. In this study, we analyzed the ultrastructural mechanisms of GPRS transformation during oogenesis and spermatogenesis of the bivalve mollusc Ruditapes philippinarum (Manila clam), exploring patterns of GPRS activity occurring at meiosis onset, sex-specific difference/similarity of such patterns, and the involvement of mitochondria during GPRS-assigned events. In the two sexes, the zygotene-pachytene stage of meiosis is anticipated by three shared steps...
December 7, 2018: Zygote: the Biology of Gametes and Early Embryos
Weipeng Mu, Joshua Starmer, Della Yee, Terry Magnuson
BACKGROUND: Polycomb repressive complex 2 (PRC2) is responsible for establishing and maintaining histone H3K27 methylation during cell differentiation and proliferation. H3K27 can be mono-, di-, or trimethylated, resulting in differential gene regulation. However, it remains unknown how PRC2 specifies the degree and biological effects of H3K27 methylation within a given cellular context. One way to determine PRC2 specificity may be through alternative splicing of Ezh2, PRC2's catalytic subunit, during cell differentiation and tissue maturation...
December 6, 2018: Epigenetics & Chromatin
Narathid Muakrong, Shinji Kikuchi, Shuto Fukuhara, Patcharin Tanya, Peerasak Srinives
Jatropha (Jatropha curcas) is an oil-bearing plant used for biodiesel production. Construction of its standard karyotype and identification of the euchromatin/heterochromatin distribution associated with gene expression and meiotic recombination are essential to fully characterize its genome. Here, we developed a J. curcas karyotype based on meiotic pachytene chromosomes. In addition, a karyotype of J. integerrima, a useful species for jatropha breeding, was also constructed. Five out of eleven J. curcas chromosomes were metacentric, but only two were metacentric in J...
2018: PloS One
Sabela García-Oro, Diana Valverde
SummaryThe aim of this study was to determine the capacity of the meiotic spindle (MS) to predict embryo implantation and live birth rates. For this purpose, we performed a broad systematic literature search. Of all publications retrieved, only those in which the implantation rates were related to some characteristics of the MS were evaluated. Despite the different methodology used in all the chosen studies, presence of the MS in oocytes was found to be positively associated with embryo implantation. Moreover, high retardance values, as well as strict criteria of normality in the MS structure, are significantly related to higher embryo implantation numbers and live birth rates...
December 5, 2018: Zygote: the Biology of Gametes and Early Embryos
Eric Ch Chen, Stephanie Mathieu, Anne Hoffrichter, Kinga Sedzielewska-Toro, Max Peart, Adrian Pelin, Steve Ndikumana, Jeanne Ropars, Steven Dreissig, Jorg Fuchs, Andreas Brachmann, Nicolas Corradi
Eukaryotes thought to have evolved clonally for millions of years are referred to as ancient asexuals. The oldest group among these are the arbuscular mycorrhizal fungi (AMF), which are plant symbionts harboring hundreds of nuclei within one continuous cytoplasm. Some AMF strains (dikaryons) harbor two co-existing nucleotypes but there is no direct evidence that such nuclei recombine in this life-stage, as is expected for sexual fungi. Here, we show that AMF nuclei with distinct genotypes can undergo recombination...
December 5, 2018: ELife
Jun-Yu Ma, Li-Ying Yan, Zhen-Bo Wang, Shi-Ming Luo, William S B Yeung, Xiang-Hong Ou, Qing-Yuan Sun, Jie Qiao
BACKGROUND: The human oocyte transmits one set of haploid genome into female pronucleus (FPN) while discards the remaining genome into the first polar body (PB1) and the second polar body (PB2). The FPN genome carries an assembly of maternal and paternal genome that resulted from homologous recombination during the prophase of the first meiosis. However, how parental genome has been shuffled and transmitted is difficult to assess by analysing only the progeny's genome. OBJECTIVE: To assess meiotic chromatid recombination and segregation in human oocytes...
December 4, 2018: Journal of Medical Genetics
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