Summary : A recurrent question in biology is whether observed variation in a particular trait is due to environmental or genetic factors, sometimes expressed as the nature vs. nurture debate. The question implies that these two driving forces may be analyzed separately and it assumes that gene¬ environment interactions are usually of so little importance that they could be safely ignored. The true story is more complicated, genes and environment must work together to produce the phenotypic outcomes of all life forms. If we were at a Nature versus Nurture match and it was half time, the score would seem to be tied because we are based in large part on the genes we inherit from our parents, certainly a point for Nature, but also our everyday experienc...