Epigenetics

or...shut up already about nature versus nurture. The nature versus nurture debate has always bothered me because the two interact with each other and reducing humanity to one or the other seems pointless.

I found the following quote to be amusing: “DNA is destiny—until you get out the old methyl Magic Marker and start rewriting it” (162). It shows one of the ways that viewing DNA as destiny, even from a more biological/nature perspective misses the point.

I find it an interesting topic to include, however, it should have been introduced with (instead of waiting until the chapter was more than halfway over) his disclaimer: “Right now epigenetics is in a bit of a the-more-we-know-the-less-we-understand phase” (173).

Although this whole topic of epigenetics is in many ways really useful and interesting, it is problematic to bring in studies where the outcome is so unexplained. The case of smoking grandmothers and asthmatic grandchildren is what I was specifically thinking of. In this study, “children whose grandmothers smoked while pregnant were more likely to have asthma than children whose mothers smoked while pregnant” (166). This is supposedly because epigenetic responses were triggered in the already formed eggs of the grandchild which were within the ovaries of the fetus. Moalem then adds, “Incidentally, if you’re puzzled as to why the grandmother’s smoking habits affected their eggs more than their fetuses, you’re not alone; scientists haven’t figured that out yet.” (166). When considering this as an example, I find this scientific bafflement to be somewhat disappointing. In order to fully understand this example and how it relates to his theory, this is the key point! Understanding why epigenetic responses occur in the eggs of the fetus but not in the fetus is entirely baffling and makes this a not so useful example to bring.

I was curious whether NYU has any epigenetics research, so I looked it up and apparently we do it on ants here. http://www.med.nyu.edu/biochem/ReinbergLab/HTML/antsMain.html

So the next example I found particularly interesting was the Michael Meaney study. Moalem explains that, “Meaney’s study showed that the interaction between mothers and their offspring after birth provoked the placement of methyl markers that caused significant epigenetic changes” (168). The study showed that, “Pups that were gently licked by their mothers grew into confident rat babies that were relatively relaxed and could handle stressful situations. But rats that were ignored by their mothers grew to be nervous wrecks” (168). Moalem explains this through the lens of the methyl markers and states:

“The mothers’ gentle attention somehow triggered the removal of methyl markers that would otherwise have blocked or impeded the development of a part of their babies’ brains—almost as if they were licking them off. The part of the brain that dampened the stress response was more developed in those babies. This wasn't nature versus nurture’ this was nature and nurture.” (169)

This is an interesting case to look at. It shows how nature and the environment influence biology. To me, this doesn't seem like such a big shock. I view nature and nurture as in a complex relationship, not as two separate entities. However, apparently this idea is in fact shocking enough that, “One reviewer at a prominent journal actually went so far as to write that, despite the researchers’ carefully marshaled evidence, he refused to believe it could be true” (169). Does anyone want to comment on why the researcher found this evidence to be so incredibly problematic as to not even believe it?

****UPDATED*****

I just found this really interesting study which claims that women can produce NEW eggs during her lifetime. This is a really interesting idea in light of some of the above cases as well as medicine in general! I didn't get a chance to look into it too extensively, but it certainly has vast implications for many of the theories we have been discussing in class. Take a look!