Project description:Meiotic recombination differs between males and females, however, when and how these differences are established is unknown. We identify extensive sex differences at recombination initiation by mapping hotspots of meiotic DNA double strand breaks in male and female mice. Contrary to past findings in humans, few hotspots are used uniquely in either sex. Instead, grossly different recombination landscapes result from up to 15-fold differences in hotspot use between males and females. Indeed, most recombination occurs at sex-biased hotspots. Sex biased hotspots appear to be partly determined by chromosome structure, and DNA methylation, absent in females at the onset of meiosis, plays a substantial role. Sex differences are also evident later in meiosis as the repair frequency of distal meiotic breaks as crossovers diverges in males and females. Suppression of distal crossovers may help to minimize age-related aneuploidy that arises due to cohesion loss during dictyate arrest in females.

2018-09-20 | GSE99921 | GEO

Genome-wide survey of post-meiotic segregation during yeast recombination.

Project description: Not available

| S-EPMC3218862 | biostudies-literature

Characterization of chromosome stability in diploid, polyploid and hybrid yeast cells.

Project description: Not available

| S-EPMC3707968 | biostudies-literature

Heterochronic meiotic misexpression in an interspecific yeast hybrid

Project description:Changes in gene regulation rapidly accumulate between species and may contribute to reproductive isolation through misexpression of genes in interspecific hybrids. Hybrid misexpression, defined by expression levels outside the range of both parental species, is thought to be a result of cis- and trans-acting regulatory changes that interact in the hybrid, or arise from changes in the relative abundance of various tissues or cell types due to defects in developmental. Here, we show that misexpressed genes in a sterile interspecific Saccharomyces yeast hybrid result from a heterochronic shift in the timing of the normal meiotic gene expression program. By tracking nuclear divisions, we find that S. cerevisiae initiates meiosis earlier than its closest known relative, S. paradoxus, yet both species complete meiosis at the same time. Although the hybrid up- and down-regulates genes in a similar manner to both parents, the hybrid meiotic program occurs earlier than both parents. The timing shift results in a heterochronic pattern of misexpression throughout meiosis I and the beginning of meiosis II. Coincident with the timing of misexpression, we find an increase in the relative abundance of opposing cis and trans-acting changes and compensatory changes, as well as a transition from predominantly trans-acting to cis-acting expression divergence over the course of meiosis. However, misexpression does not appear to be a direct consequence of cis- and trans-acting regulatory divergence. Our results demonstrate that hybrid misexpression in yeast results from a heterochronic shift in the meiotic gene expression program.

2013-10-31 | GSE51809 | GEO

Budding yeast Pch2, a widely conserved meiotic protein, is involved in the initiation of meiotic recombination.

Project description: Not available

| S-EPMC3382142 | biostudies-literature

Meiotic Recombination in Neurospora crassa Proceeds by Two Pathways with Extensive Holliday Junction Migration.

Project description: Not available

| S-EPMC4727923 | biostudies-literature