1. Weaver et al propose that among rats, maternal behavior towards newborn pups influences their cortisol response to stress via epigenetic mechanisms that change the expression of glucocorticoid receptor gene for the rest of the pup’s life. They argue that because epigenetic patterns are established at specific developmental periods, there is extreme time sensitivity to when the pup is exposed to particular maternal behaviors (licking and grooming, in this case), and maternal behavior before or after that sensitive period window is not as important. Do you think this mechanism is relevant in humans? If so, what behaviors are most analogous to “maternal licking and grooming”?
I think this mechanism is relevant to human because, in this study, authors tried to understand the biological mechanisms of social determinants. Even though it could not apply "licking and grooming" in humans, there could be analogous, for example, the early skin-skin contact mother-baby and breastfeeding. This study can help us to understand how these behaviors, could play a key role in epigenetics and alteration in DNA methylation in new-born babies.
2. Gruenewald, in contrast, emphasize the cumulative effects of SES adversity on a multi-system allostatic load measure. Do you think that the Gruenewald findings are consistent, inconsistent, or unrelated to the Weaver findings? Explain.
It is difficult to contrast two studies that evaluated different determinants and were done in different populations. I think that both studies could be valid: SES adversity and well as mother behaviors can influence biological regulatory systems. Furthermore, it is also possible that SES variables also affect the SES adversity across the life course and also influence mother behaviors; however, it was not the objective of any of two studies to evaluate this association.
3. Hertzmann and Boyce argue that “it is not genes or environment, nor is it genes and environment, but rather it is gene-by-environment interactions that influence developmental trajectories.” To what extent do you think that GxE interactions can contribute to major disparities along racial/ethnic, socioeconomic, or geographic dimensions?
I think that social factors contribute to the larger amount of health disparities but, it is also important to considerate the interaction gen-environment. The authors gave a clear example in the interaction of genetic polymorphism in association with maltreatment in childhood led to antisocial outcomes. However, even though those cases constituted with 27% of all the cases, there was not any case in which the genetic polymorphism in the absence of child maltreatment leads to antisocial outcomes. Therefore, I think that it is essential to understand the gen-environment interactions to detect population with a higher risk of adverse outcome, but given that gen is a component cause but not a sufficient nor necessary cause in most of the outcomes, we should study and track all the social factors to prevent the disease.