Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario M5S3B2, Canada.
Am Nat. 2009 Dec;174(6):863-74. doi: 10.1086/645088.
Understanding the nature of selection against deleterious alleles is central to determining how populations are affected by the constant influx of new mutations. Important progress has been made in estimating basic attributes of the distribution of selection coefficients and gene interaction effects (epistasis). Although most aspects of selection are likely to be context dependent, little is known about the effect of stress on selection and epistasis at the level of individual genes, especially in multicellular organisms. Using Drosophila melanogaster, we measure how selection on 20 mutant alleles is affected by direct and indirect genetic factors across two environments. We find that environmental stress increases selection against individual mutations but reduces selection against combinations of mutations (i.e., epistasis becomes more positive). In addition, we find a high incidence of indirect genetic effects whereby the strength of selection against the alleles carried by offspring is dependent on the genotypes of their parents.
理解对有害等位基因选择的本质是确定种群如何受到不断涌入的新突变影响的核心。在估计选择系数和基因相互作用效应（上位性）分布的基本属性方面已经取得了重要进展。尽管选择的大多数方面可能取决于具体情况，但对于应激对个体基因水平选择和上位性的影响知之甚少，尤其是在多细胞生物中。使用黑腹果蝇，我们测量了在两种环境下，20 个突变等位基因的选择如何受到直接和间接遗传因素的影响。我们发现，环境应激增加了对单个突变的选择，但减少了对突变组合的选择（即上位性变得更积极）。此外，我们还发现了高比例的间接遗传效应，即对后代携带的等位基因的选择强度取决于其父母的基因型。
