Ever since Darwin first addressed it, sexual reproduction reigns as the ‘queen’ of evolutionary questions. Multiple theories tried to explain how this apparently costly and cumbersome method has become the universal mode of eukaryote reproduction. Most theories stress the adaptive advantages of sex by generating variation, they fail however to explain the ubiquitous persistence of sexual reproduction also where adaptation is not an issue. I argue that the obstacle for comprehending the role of sex stems from the conceptual entanglement of two distinct processes – gamete production by meiosis and gamete fusion by mating (mixis). Meiosis is an ancient, highly rigid and evolutionary conserved process identical and ubiquitous in all eukaryotes. Mating, by contrast, shows tremendous evolutionary variability even in closely related clades and exhibits wonderful ecological adaptability. To appreciate the respective roles of these two processes, which are normally linked and alternating, we require cases where one takes place without the other. Such cases are rather common. The heteromorphic sex chromosomes Y and W, that do not undergo meiotic recombination are an evolutionary test case for demonstrating the role of meiosis. Substantial recent genomic evidence highlights the accelerated rates of change and attrition these chromosomes undergo in comparison to those of recombining autosomes. I thus propose that the most basic role of meiosis is conserving integrity of the genome. A reciprocal case of meiosis without bi‐parental mating, is presented by self‐fertilization, which is fairly common in flowering plants, as well as most types of apomixis. I argue that deconstructing sex into these two distinct processes – meiosis and mating – will greatly facilitate their analysis and promote our understanding of sexual reproduction.

中文翻译：

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关于古老性别的新时代观念：将减数分裂与交配分开可以解决一个世纪难题

自从达尔文首次提出这个问题以来，有性生殖一直是进化问题的“女王”。多种理论试图解释这种看似昂贵且繁琐的方法如何成为真核生物繁殖的普遍模式。大多数理论通过产生变异来强调性的适应性优势，然而它们未能解释在适应性不是问题的情况下有性繁殖的普遍存在。我认为，理解性别角色的障碍源于两个不同过程的概念纠缠——减数分裂产生的配子和交配（mixis）的配子融合。减数分裂是一个古老的、高度严格的和进化保守的过程，在所有真核生物中都相同且普遍存在。相比之下，交配，即使在密切相关的进化枝中也表现出巨大的进化变异性，并表现出极好的生态适应性。为了理解这两个过程的各自作用，这两个过程通常是相互联系和交替的，我们需要一个发生而另一个没有发生的情况。这样的情况比较常见。不进行减数分裂重组的异形性染色体 Y 和 W 是证明减数分裂作用的进化测试案例。最近的大量基因组证据强调，与重组常染色体相比，这些染色体经历的变化和磨损速度加快。因此，我提出减数分裂最基本的作用是保持基因组的完整性。没有双亲交配的减数分裂的相互案例是通过自我受精呈现的，这在开花植物中相当常见，以及大多数类型的无融合生殖。我认为，将性分解为这两个不同的过程——减数分裂和交配——将极大地促进它们的分析并促进我们对有性生殖的理解。