By Karl Leif Bates
Duke has a growing number of researchers looking into how genes are played differently from one organism to the next, based not on the spelling of their genes, but on cues their mothers gave them. The field is called epigenetics – epi meaning above or beyond the genes.
Your momma (and probably daddy) clamped some of these external molecules called “methyl groups” onto your DNA, based on the environmental conditions they were experiencing. Methyl groups are a way of turning down a gene’s activity without changing its spelling or taking it out. It’s a neat trick, but it creates a huge new layer of complexity above and beyond just the bare-bones spelling of your genome.
In a landmark 2003 epigenetics study Duke’s Randy Jirtle showed that the color and size of second-generation mice could be altered simply by changing their mother’s diets. Their genes were essentially the same as their pale, fat cousins, but their mothers had clamped epigenetic controls on their DNA that made them darker and skinnier. (see Jirtle on Duke’s Office Hours)
A Wednesday morning symposium kicked off the existence of DEEP, the Duke Epigenetics and Epigenomics Program and introduced more than 140 members of the campus community to some of our leading researchers in epigenomics, the broad-based search for epigenetic changes.
I missed the first half of the show, but caught Susan Murphy of Ob-Gyn talking about a huge epigenetic study she’s doing with 2000 human mother-baby pairs right now. They’re hoping to correlate environmental factors during the pregnancy – nutrition, stress, smoking, alcohol etc. – with epigenetic differences in the babies from birth to age 5. And then, hopefully, they’ll find some insights into developmental differences, obesity, ADHD, diabetes, asthma, autism, etc.
Murphy said there are already some diseases thought to stem from epigenetic imprinting, and she’d like to find more. (Yes, it’s always a bad idea to smoke during pregnancy, and she already has the low-birth-weight data to prove it.)
Greg Crawford of Pediatrics and IGSP finished the session with a view of the huge landscape to be explored. Only 2 percent of human DNA is genes that make proteins. In their search so far for other areas of DNA that may be sensitive to signaling (as from epigenetic changes), they’ve found that maybe 12 percent of the genome is involved in sending and receiving signals. That still leaves 86 percent mystery.