The Use of Selection to Probe Patterns of Pleiotropy in Fitness Characters

Abstract

One of the more interesting questions in evolutionary biology is to what extent different characters are evolutionarily interdependent because of alleles having effects on multiple characters, or pleiotropy. A number of characters may evolve in a correlated manner, as witness the allometric patterns to be found among many vertebrate attributes (see e.g. Sacher 1959), but this does not necessarily implicate pleiotropy. The correlation could instead be due to correlated patterns of selection, such as an ecological association between two different types of selection. It is conceivable that one predator could select on both sprint speed and endurance in a prey species, producing a correlated response that has nothing to do with any common effects of alleles. Such correlated responses are not considered here. The problem of interest is the ways in which fitness characters can be correlated with each other because of pleiotropy.