Houle David
Department of Statistics, North Carolina State University, Raleigh, NC, 27695, USA.
Department of Ecology and Evolution, State University of New York, Stony Brook, NY, 11794, USA.
Evolution. 1991 May;45(3):630-648. doi: 10.1111/j.1558-5646.1991.tb04334.x.
The genetic variance-covariance matrix, G, is determined in part by functional architecture, the pathways by which variation in genotype influences phenotype. I develop a simple architectural model for G for two traits under directional selection constrained by their dependence on a common limiting resource. I assume that genetic variance is maintained by mutation-selection balance. The relative numbers of loci that play a role in acquiring versus allocating a limiting resource play a crucial role in determining genetic covariance. If many loci are involved in acquiring a resource, genetic covariance may be either negative or positive at equilibrium, depending on the fitness function and the input of mutational variance. The form of G does not necessarily reveal the constraint on resource acquisition inherent in the system, and therefore studies estimating G do not test for the existence of life-history tradeoffs. Characters may evolve in patterns that are unpredictable from G. Experiments are suggested that would indicate if this model could explain observations of positive genetic covariance.
遗传方差协方差矩阵G部分由功能结构决定，即基因型变异影响表型的途径。我针对在依赖共同有限资源的定向选择下的两个性状，开发了一个简单的G的结构模型。我假设遗传方差由突变-选择平衡维持。在获取与分配有限资源中起作用的基因座的相对数量，在确定遗传协方差方面起着关键作用。如果许多基因座参与获取资源，平衡时遗传协方差可能为负或为正，这取决于适合度函数和突变方差的输入。G的形式不一定揭示系统中资源获取所固有的限制，因此估计G的研究并未检验生活史权衡的存在。性状可能以G无法预测的模式进化。建议进行实验，以表明该模型是否能解释正遗传协方差的观察结果。
