School of Biological Sciences, The University of Queensland, Brisbane QLD 4072, Australia.
Evolution. 2012 Jul;66(7):2106-16. doi: 10.1111/j.1558-5646.2012.01579.x.
The extent to which sexual dimorphism can evolve within a population depends on an interaction between sexually divergent selection and constraints imposed by a genetic architecture that is shared between males and females. The degree of constraint within a population is normally inferred from the intersexual genetic correlation, r(mf) . However, such bivariate correlations ignore the potential constraining effect of genetic covariances between other sexually coexpressed traits. Using the fruit fly Drosophila serrata, a species that exhibits mutual mate preference for blends of homologous contact pheromones, we tested the impact of between-sex between-trait genetic covariances using an extended version of the genetic variance-covariance matrix, G, that includes Lande's (1980) between-sex covariance matrix, B. We find that including B greatly reduces the degree to which male and female traits are predicted to diverge in the face of divergent phenotypic selection. However, the degree to which B alters the response to selection differs between the sexes. The overall rate of male trait evolution is predicted to decline, but its direction remains relatively unchanged, whereas the opposite is found for females. We emphasize the importance of considering the B-matrix in microevolutionary studies of constraint on the evolution of sexual dimorphism.
在一个种群中，性二型性能够进化到何种程度，取决于性趋异选择与由雌雄共享的遗传结构所施加的约束之间的相互作用。种群内的约束程度通常从两性间的遗传相关性 r(mf) 推断得出。然而，这种双变量相关性忽略了其他性表达特征之间遗传协方差的潜在约束作用。利用表现出同源接触信息素混合物的相互交配偏好的果蝇 Drosophila serrata，我们使用遗传方差-协方差矩阵 G 的扩展版本（包括 Lande 的 1980 年两性间协方差矩阵 B）测试了两性间特征间遗传协方差的影响。我们发现，包含 B 极大地降低了在面临趋异表型选择时雄性和雌性特征预计会出现分歧的程度。然而，B 对选择响应的改变程度在两性之间存在差异。雄性特征进化的总体速度预计会下降，但方向仍然相对不变，而对于雌性则相反。我们强调了在性二型性进化的约束的微观进化研究中考虑 B 矩阵的重要性。
