Questions Related to Week 5 Readings:
- 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”?
It would be interesting to see this experiment replicated in a model organism more closely related to humans (monkeys). Despite study being done on rats, their findings are relevant to humans given that we, humans and rats, both share similar mechanistic responses to stress. Maternal licking in rats can be analogous to breastfeeding and cradling babies could be similar to grooming. Again, window period may also apply in humans and in order to avoid stressed babies, the US can adopt UK’s system where a mother gets a year off after baby is born. This may have a positive impact on the baby and lower it’s stress levels throughout the course of the baby’s life.
- 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 and Weaver et al’s findings complement each other. Weaver establishes that individuals are already predisposed to worse health outcomes, due to higher stress responses, if a caring mother was not present during a critical window period very early in the infant’s life. Gruenewald continues on to say that SES in childhood also has a negative impact on health throughout adulthood. Both articles argument align with each other by stating that stress is detrimental to one’s health and the only difference between both is that while Weaver et al’s focuses on the effects of stress very early on in life, Gruenewald focuses on stress through childhood.
- 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?
GxE plays a major role in social disparities as demonstrated by Gruenewald and Weaver. It was shown in both experiments that environment had a major impact in epigenetics and worse health outcomes later on in life. It would be interesting to look at the epigenome and health outcomes of progeny of mothers and fathers who have a high SES record to see the multigenerational impact of environment on epigenetics and health outcomes as a result.