Beyond genes and environments : indirect genetic effects and the evolution of behaviour

Like most undergraduates learning evolutionary genetics now, we (the authors) were taught the importance of recognizing that the expression of many phenotypic traits depends on both genetic and environmental effects. From this, it follows that some of the trait variation we see in a population can be due to genetic differences among individuals, but some will be driven by environments. Unfortunately, this has sometimes formed the crux of a misguided nature– nurture debate which influences public perception of behaviour to this day. The point that both genes and environments influence phenotype does not mean they offer mutually exclusive explanations for behavioural variation.