Sexual selection on spontaneous mutations strengthens the between-sex genetic correlation for fitness
Sexual selection on spontaneous mutations strengthens the between-sex genetic correlation for fitness
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DOI：
10.1111/evo.13310
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发表时间：
2017-10-01
期刊：
影响因子：
3.3
通讯作者：
Chenoweth, Stephen F.
中科院分区：
文献类型：
--
作者：
Allen, Scott L.;McGuigan, Katrina;Chenoweth, Stephen F.
性选择的一个拟议的好处是它促进从种群中清除有害突变。为了实现这一好处，性选择（通常对男性更有利）必须清除对两性都有害的突变。在这里，我们通过实验检验了这样的假设：雄性的性选择清除了影响雄性和雌性健康的有害突变。我们测量了果蝇（Drosophila serrata）的两组自发突变积累系中的雄性和雌性适应性，每个系都源自共同的祖先。一组突变积累系限制自然选择和性选择（LS系），而另一组限制自然选择，但允许性选择发挥作用（SS系）。尽管突变积累导致 LS 和 SS 品系中雄性和雌性适应性的显着降低，但性选择对适应性降低的程度没有可检测到的影响。同样，尽管有证据表明两种治疗方法中男性和女性的适应性存在突变方差，但性选择对适应性突变遗传方差的量没有显着影响。然而，性选择确实重塑了性别之间的健康相关性：在 SS 系中显着加强了这种相关性。 25代后，适应度的性别间相关性为正，但远小于LS系中的1，这表明，尽管大多数突变具有性别一致的适应度效应，但性别限制和/或性别偏向突变对突变方差做出了重大贡献。在 SS 系中，这种相关性很强，无法与统一区分开来。模仿实验设置的基于个体的模拟揭示了可能推动我们结果的两个条件：（1）中到大量的突变具有性别限制（或高度性别偏见）的适应度效应，以及（2）性别限制突变的平均适应度效应大于对两性影响相似的突变的平均适应度效应。
A proposed benefit to sexual selection is that it promotes purging of deleterious mutations from populations. For this benefit to be realized, sexual selection, which is usually stronger on males, must purge mutations deleterious to both sexes. Here, we experimentally test the hypothesis that sexual selection on males purges deleterious mutations that affect both male and female fitness. We measured male and female fitness in two panels of spontaneous mutation-accumulation lines of the fly, Drosophila serrata, each established from a common ancestor. One panel of mutation accumulation lines limited both natural and sexual selection (LS lines), whereas the other panel limited natural selection, but allowed sexual selection to operate (SS lines). Although mutation accumulation caused a significant reduction in male and female fitness in both the LS and SS lines, sexual selection had no detectable effect on the extent of the fitness reduction. Similarly, despite evidence of mutational variance for fitness in males and females of both treatments, sexual selection had no significant impact on the amount of mutational genetic variance for fitness. However, sexual selection did reshape the between-sex correlation for fitness: significantly strengthening it in the SS lines. After 25 generations, the between-sex correlation for fitness was positive but considerably less than one in the LS lines, suggesting that, although most mutations had sexually concordant fitness effects, sex-limited, and/or sexbiased mutations contributed substantially to the mutational variance. In the SS lines this correlation was strong and could not be distinguished from unity. Individual-based simulations that mimick the experimental setup reveal two conditions that may drive our results: (1) a modest-to-large fraction of mutations have sex-limited (or highly sex-biased) fitness effects, and (2) the average fitness effect of sex-limited mutations is larger than the average fitness effect of mutations that affect both sexes similarly.