The evolutionary stability of cross-sex, cross-trait genetic covariances

Although knowledge of the selective agents behind the evolution of sexual dimorphism has advanced considerably in recent years, we still lack a clear understanding of the evolutionary durability of cross-sex genetic covariances that often constrain its evolution. We tested the relative stability of cross-sex genetic covariances for a suite of homologous contact pheromones of the fruit fly Drosophila serrata, along a latitudinal gradient that these traits have diverged in mean. Using a Bayesian framework, which allowed us to account for uncertainty in all parameter estimates, we compared divergence in the total amounts and orientations of genetic variance across populations, finding divergence in orientation but not total variance. We then statistically compared orientation divergence of within-sex (G) to cross-sex (B) covariance matrices. In line with a previous theoretical prediction, we find that the cross-sex covariance matrix, B, is more variable than either male or female within-se...尽管近年来我们对性二态性（sexual dimorphism）演化背后选择因子的认知已取得长足进展，但对于常常制约其演化的跨性遗传协方差（cross-sex genetic covariances）的进化持久性，我们仍缺乏清晰的认识。我们针对果蝇Drosophila serrata的一系列同源接触信息素（homologous contact pheromones），沿着这些性状均值发生分化的纬度梯度，检验了其跨性遗传协方差的相对稳定性。我们采用贝叶斯框架（Bayesian framework），该框架可让我们考量所有参数估计（parameter estimates）中的不确定性，借此比较了不同种群间遗传方差总量与取向的分化情况，结果发现仅在取向上存在分化，而非遗传方差总量。随后我们通过统计学方法，比较了性内（G）与跨性（B）协方差矩阵（covariance matrices）的取向分化程度。与此前的理论预测一致，我们发现跨性协方差矩阵B的变异程度高于雄性或雌性的性内协方差——