Changing environments reveal innovative genetic variation in children’s cortisol responses

Abstract

Genetic associations with biopsychosocial phenotypes are often interpreted as evidence that the genome codes for fixed end-states. Instead, a given genotype might regulate a dynamic range of phenotypes in response to environmental change. We collected hair cortisol (n = 1,104), salivary cortisol in reaction to an in-laboratory stressor (n = 537), and diurnal salivary cortisol (n = 488) from twins aged 8-15 years in the Texas Twin Project. Baseline genetic variation in both salivary and hair cortisol was not simply magnified after stressor exposure or after waking. Rather, novel genetic influences on cortisol arose over time. Thus, environmental change can reveal genetic variation that would not otherwise be observed in static cortisol levels. These findings are in line with the notion that the genome regulates individuals' reactions to the environment that differ across environments.

Effects of stress on 6- and 7-year-old children’s emotional memory differs by gender

“…First, girls were more reactive to stress than boys: They reported higher subjective stress increases following stress exposure, and had higher cortisol stress responses. Several previous studies have reported higher cortisol stress responses in girls than boys, although the evidence overall is mixed and should be explored meta-analytically (Gunnar et al, 2009;Hatzinger et al, 2007Hatzinger et al, , 2013Hostinar et al, 2015;Quesada et al, 2012;Raffington et al, 2019;Räikkönen et al, 2010;Stroud et al, 2009;Yim et al, 2010).…”