Sachin Garg
Week 5 Forum Post
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. I can imagine that if you compare two genetically similar children (i.e., twins) who are separated at birth. One twin remains with the mother during infancy while the other is not and grows up in a communal environment without a primary paternal and/or maternal presence but returns to the mother at some arbitrary age (say 3 years old). Given that neither twin was exposed to extreme environmental conditions, it is not impossible to surmise that perhaps the emotional stability, coping and security of one twin is different from the other for the rest of their lives. ALSO, their attachment to their mother may also be different for the rest of their lives, representing a missed opportunity.
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.
I do think they are consistent in that the findings of the Weaver study represent a critical factor that may be driving the SES Adversity score that is being calculated in Gruenewald. That not all life events and adversity is treated equally and some are more pivotal than others. I think the Gruenewald model seems more believable and comprehensive, allowing for the law of averages and exceptions to occur.
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?
While I think GxE interactions are certainly plausible, I do think that environment alone is likely playing a stronger role than genes or GxE in explaining major disparities along the above mentioned dimensions.