Genetic correlations: Transient truths of adaptive evolution

Abstract

The concept of ‘truth’, arguably, exists only in the discourse of poets and mathematicians. The rest of us have to make do by replacing the sublime ‘truth’ by the more mundane ‘consistency’. Much thinking in evolution is based on the implicit notion of consistency in the relationship among fitness traits, relationships that can either facilitate or constrain certain evolutionary trajectories being taken by a population. Such thinking is exemplified by the notion of tradeoffs that is ubiquitous in the study of life-history evolution (Prasad and Joshi 2003). Formal theory, on the other hand, clearly suggests that genetic correlations can change in the process of adaptive evolution, being partly a function of allele frequencies (Falconer 1981). Thus, the question remains as to whether, genetic correlations among traits are really consistent across populations and evolutionary time, at least in the short to medium term? Though several studies have previously addressed the issue of consistency of trait correlations within and across environments