Castellano et al. provide the first comparison of the full distribution of fitness effects (including deleterious, neutral but also beneficial mutations) in the great apes. The authors investigate which aspects of the full DFE are likely... The distribution of fitness effects (DFE) is central to many questions in evolutionary biology. However, little is known about the differences in DFE between closely related species. We use >9000 coding genes orthologous one-to-one across great apes, gibbons, and macaques to assess the stability of the DFE across great apes. We use the unfolded site frequency spectrum of polymorphic mutations (n = 8 haploid chromosomes per population) to estimate the DFE. We find that the shape of the deleterious DFE is strikingly similar across great apes. We confirm that effective population size (Ne) is a strong predictor of the strength of negative selection, consistent with the nearly neutral theory. However, we also find that the strength of negative selection varies more than expected given the differences in Ne between species. Across species, mean fitness effects of new deleterious mutations covaries with Ne, consistent with positive epistasis among deleterious mutations. We find that the strength of negative selection for the smallest populations, bonobos and western chimpanzees, is higher than expected given their Ne. This may result from a more efficient purging of strongly deleterious recessive variants in these populations. Forward simulations confirm that these findings are not artifacts of the way we are inferring Ne and DFE parameters. All findings are replicated using only GC-conservative mutations, thereby confirming that GC-biased gene conversion is not affecting our conclusions.

中文翻译：

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类人猿新氨基酸突变健身效果的全面分布比较。


卡斯特拉诺等人。首次比较了类人猿适应性效应的完整分布（包括有害、中性和有益的突变）。作者研究了完整 DFE 的哪些方面可能......适应度效应 (DFE) 的分布是进化生物学中许多问题的核心。然而，人们对密切相关物种之间 DFE 的差异知之甚少。我们使用超过 9000 个在类人猿、长臂猿和猕猴中一对一直系同源的编码基因来评估类人猿 DFE 的稳定性。我们使用多态性突变的未折叠位点频谱（每个群体 n = 8 个单倍体染色体）来估计 DFE。我们发现，类人猿中有害的 DFE 的形状惊人地相似。我们证实，有效种群规模（Ne）是负选择强度的有力预测因子，与近中性理论一致。然而，我们还发现，考虑到物种之间 Ne 的差异，负选择强度的变化超出预期。在物种之间，新的有害突变的平均适应度效应与 Ne 共变，与有害突变之间的正上位性一致。我们发现，对于最小种群（倭黑猩猩和西部黑猩猩）的负选择强度高于其 Ne 的预期。这可能是由于更有效地清除这些群体中强烈有害的隐性变异的结果。正向模拟证实，这些发现并不是我们推断 Ne 和 DFE 参数的方式造成的。所有发现均仅使用 GC 保守突变进行复制，从而证实 GC 偏向基因转换不会影响我们的结论。