The modulating influence of the rh5-HTTLPR on separation in infancy persists into later life, manifesting, for example, as higher ACTH responses to stress in S-carrier monkeys than LL homozygotes (87). It is important to underscore that these long-lasting phenotypic effects of the S allele only occur in monkeys exposed to maternal separation early life stress, echoing the G×E interaction observed in relation to human depression.
