Environmental variation and quantitative genetic prameters in the feral pigeon, Columba livia

The estimation of quantitative genetic parameters and modes of selection in natural populations can provide critical information concerning both past and current evolution of mean phenotypes. We examine the influence of environmental variation on the genetic variance-covariance matrix ( G ) of external morphological traits in feral pigeons, and the degree of correspondence between phenotypic (r_p) and genetic correlations (r_g) of these characters. Our results suggest that adverse environmental conditions affect heritability, and that the correspondence between seasonal estimates of G based on midparent scores is low. There is, however, a strong correspondence between r_p and r_g. We suggest that, if environmental variation is relatively common, estimates of quantitative genetic parameters for prospective selection studies must be undertaken at each selection episode.