Pleiotropy Modulates the Efficacy of Selection in Drosophila melanogaster
Pleiotropy Modulates the Efficacy of Selection in Drosophila melanogaster
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DOI：
10.1093/molbev/msy246
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发表时间：
2019-03-01
影响因子：
10.7
通讯作者：
Vicoso, Beatriz
中科院分区：
文献类型：
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作者：
Fraisse, Christelle;Sala, Gemma Puixeu;Vicoso, Beatriz
多效性是一个公认的观点，即单个突变影响多个表型。如果突变在不同的环境中表达时对适应性产生相反的影响，那么就会出现遗传冲突。多效性冲突预计会通过适应限制有益突变的固定，并通过纯化选择去除有害突变，从而降低选择的效率。尽管这已经被广泛讨论，特别是在假定的性别负担的背景下，但它尚未得到系统量化。在这项工作中，我们凭经验估计了不同的多效性机制在多大程度上阻碍了果蝇的选择功效。我们使用来自单个非洲种群的全基因组多态性数据和来自模拟拟蜥蜴的分歧数据来估计适应性固定的分数 ()、适应率 (A) 和选择方向 (DoS)。在控制混杂协变量后，我们发现不同的多效性方案对选择功效的影响相对较小，但显着。具体来说，我们的结果表明，多效性对抗可能会限制选择的功效，但是可以通过将基因的表达限制在有益的性别上来解决这种冲突。由于低效的纯化选择和低频率的突变（赋予选择优势），跨组织和生命阶段的中等水平的多效性也可能导致黑腹果蝇的适应不良。因此，我们的研究强调需要考虑在拮抗性多效性和一般遗传冲突的背景下选择的功效。
Pleiotropy is the well-established idea that a single mutation affects multiple phenotypes. If a mutation has opposite effects on fitness when expressed in different contexts, then genetic conflict arises. Pleiotropic conflict is expected to reduce the efficacy of selection by limiting the fixation of beneficial mutations through adaptation, and the removal of deleterious mutations through purifying selection. Although this has been widely discussed, in particular in the context of a putative gender load, it has yet to be systematically quantified. In this work, we empirically estimate to which extent different pleiotropic regimes impede the efficacy of selection in Drosophila melanogaster. We use whole-genome polymorphism data from a single African population and divergence data from D. simulans to estimate the fraction of adaptive fixations (), the rate of adaptation (A), and the direction of selection (DoS). After controlling for confounding covariates, we find that the different pleiotropic regimes have a relatively small, but significant, effect on selection efficacy. Specifically, our results suggest that pleiotropic sexual antagonism may restrict the efficacy of selection, but that this conflict can be resolved by limiting the expression of genes to the sex where they are beneficial. Intermediate levels of pleiotropy across tissues and life stages can also lead to maladaptation in D. melanogaster, due to inefficient purifying selection combined with low frequency of mutations that confer a selective advantage. Thus, our study highlights the need to consider the efficacy of selection in the context of antagonistic pleiotropy, and of genetic conflict in general.