PDF(Pubmed)
Abstract：
In evolutionary quantitative genetics, the genetic variance-covariance matrix, G, and the vector of directional selection gradients, β, are key parameters for predicting multivariate selection responses and genetic constraints. Historically, investigations of G and β have not overlapped with those dissecting the genetic basis of quantitative traits. Thus, it remains unknown whether these parameters reflect pleiotropic effects at individual loci. Here, we integrate multivariate genome-wide association study (GWAS) with G and β estimation in a well-studied system of multivariate constraint: sexual selection on male cuticular hydrocarbons (CHCs) in Drosophila serrata. In a panel of wild-derived re-sequenced lines, we augment genome-based restricted maximum likelihood to estimate G alongside multivariate single nucleotide polymorphism (SNP) effects, detecting 532 significant associations from 1 652 276 SNPs. Constraint was evident, with β lying in a direction of G with low evolvability. Interestingly, minor frequency alleles typically increased male CHC-attractiveness suggesting opposing natural selection on β. SNP effects were significantly misaligned with the major eigenvector of G, gmax, but well aligned to the second and third eigenvectors g2 and g3. We discuss potential factors leading to these varied results including multivariate stabilizing selection and mutational bias. Our framework may be useful as researchers increasingly access genomic methods to study multivariate selection responses in wild populations.
摘要：
在进化数量遗传学中，遗传方差-协方差矩阵，G,和方向选择梯度的向量，β,是预测多元选择响应和遗传约束的关键参数。历史上,G和β的研究与解剖数量性状的遗传基础没有重叠。因此，目前尚不清楚这些参数是否反映了个体位点的多效性效应.这里,我们将多变量全基因组关联研究（GWAS）与G和β估计整合到一个经过充分研究的多变量约束系统中：果蝇中雄性角质层碳氢化合物（CHCs）的性选择。在一组野生衍生的重新测序系中，我们增加了基于基因组的限制性最大似然估计G与多变量单核苷酸多态性（SNP）的影响，从1652276个SNP中检测到532个显著关联。约束是显而易见的，β位于G方向，演化能力低。有趣的是,次要频率等位基因通常会增加雄性CHC吸引力，表明对β的自然选择相反。SNP效应与G的主要特征向量显着错位，gmax,但是与第二和第三特征向量g2和g3很好地对齐。我们讨论了导致这些不同结果的潜在因素，包括多变量稳定选择和突变偏差。随着研究人员越来越多地使用基因组方法来研究野生种群中的多变量选择反应，我们的框架可能很有用。
