Genetic background and sex modify how one mouse's genes affect its cage-mates

A bioRxiv preprint investigates indirect genetic effects (IGE) — the phenomenon whereby the genes of one individual influence the observable traits of others in the same social group — focusing on the Epha4 gene in laboratory mice.

Epha4 encodes Ephrin type-A receptor 4, a cell-surface receptor previously associated with stress-related and social behaviours via direct genetic effects in individuals carrying the gene. The preprint reports that the magnitude and direction of IGE arising from Epha4 carriers vary with both the genetic background of the focal (receiving) individual — a form of social epistasis — and with the sex of the animals involved. These findings suggest that interpreting genotype-phenotype relationships in socially housed animals requires accounting not only for the focal animal's own genotype but also for the genotypes of its social partners.

The study is principally of interest to quantitative geneticists and animal behaviour researchers, and has methodological relevance for the design and analysis of mouse model experiments more broadly. The authors note that a better understanding of IGE may also inform models of how social environments mediate genetic influences on behaviour in other species. This is a preprint and has not yet been peer reviewed.