Inverted meiosis, in which sister chromatids segregate before homologous chromosomes, is a common aberration of conventional meiosis (in which sister chromatids segregate after homologous chromosomes) and is routinely observed in certain species. This raises an evolutionary mystery: what is the adaptive advantage of the more common, conventional order of segregation in meiosis? I use a population genetic model to show that asexual mutants arising from inverted meiosis are relatively immune from the deleterious effects of loss of complementation (heterozygosity), unlike the asexual mutants arising from conventional meiosis, in which loss of complementation can outweigh the two‐fold cost of meiosis. Hence, asexual reproduction can replace sexual reproduction with inverted meiosis, but not with conventional meiosis. The results are in line with analogous considerations on other alternative types of reproduction and support the idea that amphimixis is stable in spite of the two‐fold cost of meiosis because loss of complementation in mutant asexuals outweigh the two‐fold cost.

中文翻译：

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反向减数分裂和互补缺失导致的性别进化

反向减数分裂，其中姐妹染色单体在同源染色体之前分离，是常规减数分裂（其中姐妹染色单体在同源染色体之后分离）的常见异常，并且在某些物种中经常观察到。这提出了一个进化之谜：减数分裂中更常见的传统分离顺序的适应性优势是什么？我使用群体遗传模型表明，倒置减数分裂产生的无性突变体相对不受互补性丧失（杂合性）的有害影响，这与传统减数分裂产生的无性突变体不同，后者的互补性丧失可能超过两倍减数分裂的成本。因此，无性繁殖可以用倒置减数分裂代替有性繁殖，但不能用常规减数分裂代替。