Blows Mark W, Chenoweth Stephen F, Hine Emma
Department of Zoology and Entomology, University of Queensland, Brisbane, Queensland 4072, Australia.
Am Nat. 2004 Mar;163(3):329-40. doi: 10.1086/381941. Epub 2004 Mar 9.
Stabilizing selection has been predicted to change genetic variances and covariances so that the orientation of the genetic variance-covariance matrix (G) becomes aligned with the orientation of the fitness surface, but it is less clear how directional selection may change G. Here we develop statistical approaches to the comparison of G with vectors of linear and nonlinear selection. We apply these approaches to a set of male sexually selected cuticular hydrocarbons (CHCs) of Drosophila serrata. Even though male CHCs displayed substantial additive genetic variance, more than 99% of the genetic variance was orientated 74.9 degrees away from the vector of linear sexual selection, suggesting that open-ended female preferences may greatly reduce genetic variation in male display traits. Although the orientation of G and the fitness surface were found to differ significantly, the similarity present in eigenstructure was a consequence of traits under weak linear selection and strong nonlinear (convex) selection. Associating the eigenstructure of G with vectors of linear and nonlinear selection may provide a way of determining what long-term changes in G may be generated by the processes of natural and sexual selection.
据预测，稳定选择会改变遗传方差和协方差，从而使遗传方差 - 协方差矩阵（G）的方向与适应度曲面的方向对齐，但定向选择如何改变G则不太清楚。在这里，我们开发了统计方法来比较G与线性和非线性选择向量。我们将这些方法应用于一组锯缘果蝇雄性的性选择表皮碳氢化合物（CHC）。尽管雄性CHC表现出大量的加性遗传方差，但超过99%的遗传方差方向与线性性选择向量相差74.9度，这表明开放式的雌性偏好可能会大大减少雄性展示性状的遗传变异。虽然发现G的方向与适应度曲面有显著差异，但特征结构中的相似性是弱线性选择和强非线性（凸）选择下性状的结果。将G的特征结构与线性和非线性选择向量相关联，可能提供一种确定自然选择和性选择过程可能产生的G的长期变化的方法。
