Brodie Edmund D
Department of Ecology and Evolution, University of Chicago, Chicago, Illinois, 60637.
Evolution. 1993 Jun;47(3):844-854. doi: 10.1111/j.1558-5646.1993.tb01238.x.
Quantitative genetic models of evolution rely on the genetic variance-covariance matrix to predict the phenotypic response to selection. Both prospective and retrospective studies of phenotypic evolution across generations rely on assumptions about the constancy of patterns of genetic covariance through time. In the absence of robust theoretical predictions about the stability of genetic covariances, this assumption must be tested with empirical comparisons of genetic parameters among populations and species. Genetic variance-covariance matrices were estimated for a suite of antipredator traits in two populations of the northwestern garter snake, Thamnophis ordinoides. The characters studied include color pattern and antipredator behaviors that interact to facilitate escape from predators. Significant heritabilities for all traits were detected in both populations. Genetic correlations and covariances were found among behaviors in both populations and between color pattern and behavior in one of the populations. Phenotypic means differed among populations, but pairwise comparisons revealed no heterogeneity of genetic parameters between the populations. The structure of the genetic variance-covariance matrix has apparently not changed significantly during the divergence of these two populations.
进化的数量遗传模型依靠遗传方差协方差矩阵来预测对选择的表型响应。对跨代表型进化的前瞻性和回顾性研究都依赖于关于遗传协方差模式随时间恒定的假设。在缺乏关于遗传协方差稳定性的可靠理论预测的情况下，必须通过对种群和物种间遗传参数的实证比较来检验这一假设。对西北束带蛇（Thamnophis ordinoides）两个种群的一系列反捕食性状估计了遗传方差协方差矩阵。所研究的性状包括颜色模式和相互作用以促进逃避捕食者的反捕食行为。在两个种群中均检测到所有性状的显著遗传力。在两个种群的行为之间以及其中一个种群的颜色模式与行为之间发现了遗传相关性和协方差。种群间的表型均值不同，但成对比较显示种群间遗传参数没有异质性。在这两个种群的分化过程中，遗传方差协方差矩阵的结构显然没有显著变化。
