Genes play an important role in explaining the appearance, behaviour and personality characteristics of people (Plomin et al. 2008). Behavioural geneticists and evolutionary biologists have long-since noted that genes also operate ‘beyond the skin’ and can play an important role in shaping the environment that an individual experiences (Dawkins 1982; Kendler and Baker 2007). Evidence for such phenomena in humans comes primarily from twin and family studies (Jaffee and Price 2007; Kendler and Baker 2007). Such studies have demonstrated the heritability of numerous environmental measures including the home environment (Saudino and Plomin 1997), life events (Button et al. 2008), parental discipline (Button et al. 2008), and bullying victimisation (Ball et al. 2008). Molecular genetic studies have also linked candidate genes with marital status (Dick et al. 2006), popularity within the peer group (Burt 2008), and negative parenting experiences (Lucht et al. 2006). Such findings are indicative of gene–environment correlation (rGE)—a relationship between genotype and environment.
