Thinking About Epigenetics

March 1st, 2011

This morning, I was totally taken by the focus on epigenetics in this month’s issue of The Scientist magazine. It’s a fascinating area of study that looks at mechanisms of inheritance and development that fall outside the usual genetic mechanisms.

For years, researchers investigating inheritance focused solely on DNA and RNA as the blueprints for what makes us who we are. However, over the past 80 years research has amassed suggesting that there is much more to the picture. Namely, expression of genes can be controlled through one process termed imprinting or another called X-chromosome inactivation, and chemical modifications by structures, called histones, that wrap DNA into little bundles, and a process called methylation.

The various modifications to DNA or RNA affect the ways that genes get expressed (like if they get turned on or off, or are expressed more or less), but not the genes themselves. Darwinian natural selection and Mendelian genetics are still major forces acting on the genes themselves (so, don’t go off half cocked crying about Lamarckian ideas overturning over 100 years of evidence for the theory of evolution), but now we have a new tool to add to the toolbox to help us understand the very nuanced processes of adaptation and development.

From an article in The Scientist:

Eric Nestler, a psychiatrist at the Mount Sinai School of Medicine, explained that behavioral researchers “are moving to a far broader definition of epigenetics which simply refers to any lasting change in gene expression mediated by an alteration in chromosomal structure.” ”

What I find fascinating, is the idea that these modifications can arise during an individuals lifetime. It’s a mechanism that has the potential to explain how experience during someone’s lifetime can 1) effect changes in their behavior and 2) effect changes in the behavior of subsequent generations.

Epigenetics is no longer like genetics, which can look at individuals, but preferentially looks at changes to populations on a generational timescale. Rather, epigenetics diverges from genetics because it can explore changes within and between individuals on multiple timescales: second to second, minute to minute, year to year, or generation to generation.

Again, from The Scientist:

Szyf… speculates that behavioral epigenetics might end up showing that adult learning is simply development, continued. Perhaps, he says, “it’s all development, starting from preconception to death.” ”

If the articles from The Scientist aren’t enough for you, we did a review of epigenetic research on TWIS last year, and interviewed one of the leading epigenetic researchers, Dr. Andrew Feinberg, back in 2007. In both cases, the coverage starts in the second half of the program, so you will need to fast forward a little bit to get to the pertinent info.