Laboratory of Genetics, University of Wisconsin - Madison, Madison, WI 53706, USA.
Genetics. 2021 Mar 3;217(1):1-11. doi: 10.1093/genetics/iyaa019.
In most species that reproduce sexually, successful gametogenesis requires recombination during meiosis. The number and placement of crossovers (COs) vary among individuals, with females and males often presenting the most striking contrasts. Despite the recognition that the sexes recombine at different rates (heterochiasmy), existing data fail to answer the question of whether patterns of genetic variation in recombination rate are similar in the two sexes. To fill this gap, we measured the genome-wide recombination rate in both sexes from a panel of wild-derived inbred strains from multiple subspecies of house mice (Mus musculus) and from a few additional species of Mus. To directly compare recombination rates in females and males from the same genetic backgrounds, we applied established methods based on immunolocalization of recombination proteins to inbred strains. Our results reveal discordant patterns of genetic variation in the two sexes. Whereas male genome-wide recombination rates vary substantially among strains, female recombination rates measured in the same strains are more static. The direction of heterochiasmy varies within two subspecies, Mus musculus molossinus and Mus musculus musculus. The direction of sex differences in the length of the synaptonemal complex and CO positions is consistent across strains and does not track sex differences in genome-wide recombination rate. In males, contrasts between strains with high recombination rate and strains with low recombination rate suggest more recombination is associated with stronger CO interference and more double-strand breaks. The sex-specific patterns of genetic variation we report underscore the importance of incorporating sex differences into recombination research.
在大多数有性繁殖的物种中，成功的配子发生需要减数分裂过程中的重组。交叉（COs）的数量和位置在个体之间有所不同，雌性和雄性通常表现出最显著的对比。尽管人们已经认识到性别以不同的速度进行重组（异质重组），但现有数据仍未能回答重组率遗传变异模式在两性中是否相似的问题。为了填补这一空白，我们从多个小家鼠亚种（Mus musculus）的野生衍生近交系和少数其他 Mus 物种的一个面板中测量了两性的全基因组重组率。为了直接比较来自相同遗传背景的雌性和雄性的重组率，我们应用了基于重组蛋白免疫定位的既定方法来对近交系进行研究。我们的结果揭示了两性中遗传变异的不协调模式。虽然雄性全基因组重组率在不同的品系中差异很大，但在相同品系中测量的雌性重组率则更为稳定。异质重组的方向在两个亚种Mus musculus molossinus 和 Mus musculus musculus 内有所不同。在同一品系中，联会复合体和 CO 位置的长度的性别差异方向与全基因组重组率的性别差异方向一致。在雄性中，高重组率品系与低重组率品系之间的对比表明，更多的重组与更强的 CO 干扰和更多的双链断裂有关。我们报告的性别特异性遗传变异模式强调了将性别差异纳入重组研究的重要性。
