For the evolution debate, the importance of the epigenome — with its crucial role in gene expression — is that it lies beyond the reach of the random genetic variation that supplies the raw material for natural selection to “select.” But in concrete terms, understanding what that means is tough. Here’s a clever solution.
As we mentioned earlier today, our friend Dr. Tom Woodward has just launched DNA & Beyond, a website devoted to showcasing new discoveries pushing the frontiers of what we know about genetic information. The launch was timed to coincide with today’s anniversary of the description of the DNA molecule’s double-helix structure (April 25, 1953).
Part of the challenge with epigenetics is picturing it — and Woodward has come up with the idea of marketing a three-foot model of DNA complete with epigenetic markers. Yeah, you wish you’d thought of that:
Each model is equipped with a pair of tiny methyl molecules, a “carbon-head-with-three-hydrogen-ears.” The methyl tags have two options. They can be plugged into the two tiny holes on a pair of adjacent-and-cater-corner “C” letters, to show how a gene sequence can be “methylated” — causing it to “rest” or be switched off. The other option is to reverse this action: the methyl tags can be removed from those two “C” half-rungs, making the gene sequence “unmethylated,” which has the effect of “waking up” the gene. It is then activated and ready for transcription into RNA!
Previously, even equipped with a DNA model, a teacher could describe what “methylated” refers to, as opposed to “unmethylated,” but the description would necessarily have to be somewhat abstract. For educators that is remarkably helpful.
Here, meanwhile, is Tom Woodward with a “plunge” into a human cell. With his co-author, Dr. James Gills, he discusses the “dance” of DNA at the direction of the “conductor,” the epigenome:
They point out that while genetic mutation is of course irreversible, and typically harmful, epigenetic change can be reversed to our benefit — through lifestyle changes. Hey, that’s more good news.