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 do think this mechanism is relevant to humans and that epigenetic patterns may be established at specific development periods. “Maternal licking and grooming” are examples of physical care and affection from rat to pup. Analogous human behavior are hugs, patting on the back, and kisses.
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.
Gruenewald’s findings support the cumulative risk hypothesis, that greater experience of SES adversity across the life course may cumulate to have a greater negative effect on biological functioning in later adulthood. I think that Weaver and Gruenewalds findings complement one another. We know that epigenetic mechanisms are dynamic and therefore it is possible that cumulative explore of SES adversity may change epigenetics and therefore protein expression at different life points.
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?
In short, I think GxE interactions influence disparities observed in all dimensions. I believe that contexts, whether socially constructed (race/ethnicity), socioeconomic, or geographic are subject to epigenetic regulation simply due to the fact that these dimensions are a reflection of environment. Hence GxE is a major driver of disparities.