Sex chromosomes are typically comprised of a non-recombining region and a recombining pseudoautosomal region. Accurately quantifying the relative size of these regions is critical for sex chromosome biology both from a functional (i.e. number of sex-linked genes) and evolutionary perspective (i.e. extent of Y degeneration and X-Y heteromorphy). The evolution of the pseudoautosomal boundary (PAB) - the limit between the recombining and the non-recombining regions of the sex chromosomes - is well documented in haplorrhines (apes and monkeys) but not in strepsirrhines (lemurs and lorises), which represent almost 30% of all primates. Here we studied the PAB of seven species representing the main strepsirrhine lineages by sequencing a male and a female genome in each species and using sex differences in coverage to identify the PAB. We found that during primate evolution, the PAB has remained unchanged in strepsirrhines whereas several recombination suppression events moved the PAB and shortened the pseudoautosomal region in haplorrhines. Strepsirrhines are well known to have much lower sexual dimorphism than haplorrhines. We suggest that mutations with antagonistic effects between males and females have driven recombination suppression and PAB evolution in haplorrhines. Our work supports the view that sexually antagonistic mutations have influenced the evolution of sex chromosomes in primates.

中文翻译：

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strepsirrhine灵长类动物拟常染色体边界的进化停滞

性染色体通常由非重组区和重组假常染色体区组成。从功能（即与性相关的基因的数量）和进化的角度（即，Y变性和XY异质性的程度）来看，准确定量这些区域的相对大小对于性染色体生物学至关重要。假性常染色体边界（PAB）的进化-性染色体重组区和非重组区之间的界限-在单倍体（猿和猴）中有很好的记录，而在链脲类（如金牛座和猴中）则没有，这代表了近30个所有灵长类动物的百分比。在这里，我们通过对每种物种的雄性和雌性基因组进行测序，并利用覆盖范围的性别差异来识别PAB，研究了代表主要链霉菌谱系的7种PAB。我们发现，在灵长类动物进化过程中，链脲菌素中的PAB保持不变，而一些重组抑制事件使PAB发生移动，并缩短了单倍体中的假常染色体区域。众所周知，链脲菌素的性二态性比单倍体激素低得多。我们建议，在雄性和雌性之间具有拮抗作用的突变驱动了单倍体中的重组抑制和PAB的进化。我们的工作支持以下观点：性拮抗突变已影响灵长类动物性染色体的进化。我们建议，在雄性和雌性之间具有拮抗作用的突变驱动了单倍体中的重组抑制和PAB的进化。我们的工作支持以下观点：性拮抗突变已影响灵长类动物性染色体的进化。我们建议，在雄性和雌性之间具有拮抗作用的突变驱动了单倍体中的重组抑制和PAB的进化。我们的工作支持以下观点：性拮抗突变已影响灵长类动物性染色体的进化。