Quantitative genetics

Quantitative genetics is the study of the inheritance and evolution of continuous characteristics, coded for by many gene loci (polygenic) that interact (pleiotropy) in complex ways. Quantitative trait variation is a function of both genetic and environmental variance. The ability of a quantitative trait to respond to a selective pressure is intimately linked with its underlying additive genetic variance. Multivariate extensions of this principle take into consideration the fact that quantitative traits covary with each other (integration), thereby facilitating or limiting the effects of selection on individual traits in complex ways. Models developed to test for the effects of neutral diversification among taxa have been applied to extant primates, modern humans, and fossil hominins. In cases where such models are rejected, methods exist for establishing the effects of selection on the phenotype, taking trait covariance into account. Quantitative genetics is the basic conceptual toolkit for understanding how morphology evolves.