Meiotic recombination differs between males and females; however, when and how these differences are established is unknown. Here we identify extensive sex differences at the initiation of recombination 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 fifteen-fold differences in hotspot usage between males and females. Indeed, most recombination occurs at sex-biased hotspots. Sex-biased hotspots seem to be partly determined by chromosome structure, and DNA methylation, which is absent in females at the onset of meiosis, has a substantial role. Sex differences are also evident later in meiosis as the rate at which meiotic breaks are repaired as crossovers differs between males and females in distal regions. The suppression of distal crossovers may help to minimize age-related aneuploidy that arises owing to cohesion loss during dictyate arrest in females.Differential DNA methylation and the long-range effects of chromatin organization lead to pronounced differences in recombination landscape between males and females.

中文翻译：

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基因重组开始时的广泛性别差异

雄性和雌性之间的减数分裂重组不同；然而，何时以及如何建立这些差异尚不清楚。在这里，我们通过绘制雄性和雌性小鼠减数分裂 DNA 双链断裂的热点来确定重组开始时的广泛性别差异。与过去在人类中的发现相反，很少有热点在两种性别中被独特地使用。相反，雄性和雌性之间的热点使用差异高达 15 倍，导致了截然不同的重组景观。事实上，大多数重组发生在有性别偏见的热点。性别偏见热点似乎部分由染色体结构决定，而在减数分裂开始时雌性不存在的 DNA 甲基化具有重要作用。性别差异在减数分裂后期也很明显，因为在远端区域的雄性和雌性之间的交叉不同，修复减数分裂断裂的速度不同。远端交叉的抑制可能有助于最大程度地减少由于女性听写停滞期间内聚力丧失而引起的与年龄相关的非整倍体。DNA 甲基化的差异和染色质组织的长期影响导致男性和女性之间重组景观的显着差异。