The most compelling and consistent evidence for genotype–sex interaction effects comes from studies of physiological, anatomical, and behavioral traits in model organisms, including fruitflies54,55, mice56-59, and rats60. For example, sex-specific effects in which QTLs have significantly different effects in males and females are a near-ubiquitous characteristic of the genetic architecture of complex traits in the Drosophila genus (reviewed in Mackay and Anholt55).
