Week 5 homework

Week 5 homework

by Saba -
Number of replies: 1

1. A time sensitive mechanism is relevant to human beings. For children most physical, mental, and emotional developments are on a regulated time frame.  Children’s language development is one strong example of this. Infants and toddlers need to be spoken to constantly at these ages in order to develop strong language skills. Younger children also have a greater capacity to learn different languages. This pattern is seen in cradling babies as well. Children need to be held in order to have typical mental and physical development. “Many children who have not had ample physical and emotional attention are at higher risk for behavioral, emotional and social problems as they grow up” (Katherine Harmon, Scientific American How Important is Physical Contact with Your Infant?”). The last example I will mention is the time sensitive effects of breastfeeding infants. Children who have been breastfed have been shown to have better mental and physical health outcomes than their peers who have not been breastfed. As other posts have mentioned breast milk is able to provide children with the exact nutrients they need. 

2. Gruenewald’s findings are consistent with Weaver’s. Weaver develops a foundation of understanding the biology of genes and epigenetics. This foundation created by the Weaver paper can explain the biological mechanisms of the Gruenewald’s paper. An epigenetics mechanism could also explain the lack of significance between childhood and adulthood adverse experiences. 

3. The idea that the environment affects genes is not a new concept, but the understanding of epigenetic changes that take place in DNA over a life course is new. I believe that GxE interactions could influence developmental trajectories across generations. This could explain why certain populations of people do not seem to have the same upwards mobility as others. There needs to be more research done on the inherited epigenetic effects and their impact on a person’s environment. 

In reply to Saba

Re: Week 5 homework

by Maria Glymour -

Saba

Interesting comments - you seem to be arguing that almost all exposures follow a sensitive period model - that this  is the default rather than the exception.  So, how about poverty?  Do you think that poverty matters much more at certain ages than others?  Does poverty still affect health when encountered in adulthood?  

Regarding G by E interaction, it's important to distinguish whether the environmental factor is changing the actual genetic code (which is rare) or the environmental factor is changing the impact of the genetic code on health (which is probably common).  Epigenetic changes can be much more quickly erased or rewritten compared to changes to the genetic code.  There is some inheritance between generations, but this doesn't persist across all that many generations (we have from mom to kid, and maybe grandma to kid, but I do not *think* there is evidence on great-grandma to kid).  If you were going to study how, for example, poverty affects genetically-based risk of diabetes, how could you approach such a study?