"Evolutionary implications of sex reducing heritable variation: Disaggregated individuals, haploid leks, and the Red Queen on asexual Red Bull"

“性别减少遗传变异的进化意义：分类个体、单倍体leks和无性红牛上的红皇后”

• 批准号: 341399-2012
• 负责人: Gorelick, Root
• 金额: $ 1.53万
• 依托单位: Carleton University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2014
• 资助国家: 加拿大
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=549336
• 关键词: Evolutionary; implications; sex; reducing; heritable

Previously we showed that, contrary to conventional thought, sex decreases heritable variation. Here we will investigate the implications of sex not being for genetic mixing, but rather the function of sex is to filter out new variation. First, we will use sex to demarcate new individuals and generations, while lack of sex defines an individual. Much of evolution and ecology depends on being able to identify individuals. A modified definition of individuals may have profound effects on our view of the world, such as instantly showing that obligately asexual organisms cannot be adaptive because their evolutionary trajectories are dominated by drift and mutation, not selection. Second, if individuals are demarcated by sex, then haploid organisms (e.g. animal eggs and sperm) can each be considered separate individuals. This implies that sexual conflict and sexual selection can be occurring inside of a fertilised egg cell, such as a female haploid nucleus deciding which male haploid nucleus to fuse with. We will look for such effects and model them mathematically. Third, probably the best place to see whether sex decreases heritable variation is in organisms that only have sex with themselves. Self-sex, including self-fertilisation, is a viable means of reproduction for many organisms, but details about their genetic diversity are seldom studied. Fourth, the Red Queen is a premier mathematical model of a co-evolutionary arms-race between two species, where the Red Queen (from Alice in Wonderland) runs as fast as she can to stay in place. In these models, increased heritable variation is the engine that keeps the queen running, with sex being the fuel for her engine. But, if sex reduces variation, then maybe the Red Queen should skip - skip sex - in order to run faster to keep up with her co-evolutionary adversaries. We will modify the mathematical models accordingly, so that the Red Queen does not crumble like a house of cards. This should have huge implications for theories of evolution of disease and evolution of sex.

之前我们表明，与传统观念相反，性别会减少遗传变异。在这里，我们将研究性别的含义不是基因混合，而是性别的功能是过滤掉新的变异。首先，我们将用性别来划分新的个体和世代，而缺乏性别则定义个体。进化论和生态学在很大程度上取决于识别个体的能力。对个体的修改定义可能会对我们的世界观产生深远的影响，例如立即表明，专性无性生物无法适应，因为它们的进化轨迹是由漂移和突变主导的，而不是选择。其次，如果个体按性别划分，那么单倍体生物（例如动物卵子和精子）可以被视为单独的个体。这意味着性冲突和性选择可能发生在受精卵细胞内部，例如雌性单倍体核决定与哪个雄性单倍体核融合。我们将寻找这种效应并对其进行数学建模。第三，观察性行为是否会减少遗传变异的最佳地点可能是在只与自身发生性行为的生物体中。自交，包括自体受精，是许多生物体的一种可行的繁殖方式，但有关其遗传多样性的详细信息却很少被研究。第四，红皇后是两个物种之间共同进化军备竞赛的首要数学模型，其中红皇后（来自爱丽丝梦游仙境）尽可能快地奔跑以保持原地不动。在这些模型中，增加的遗传变异是让女王继续运转的引擎，而性则是她引擎的燃料。但是，如果性行为减少了变异，那么也许红皇后应该跳过——跳过性行为——以便跑得更快，跟上她的共同进化对手。我们将相应地修改数学模型，使红皇后不会像纸牌屋一样倒塌。这应该对疾病进化和性别进化理论产生巨大影响。