LISTEN UP, COUCH POTATOES: ACCORDING TO THE SCIENCE OF EPIGENETICS, HOW PARENTS ACT INFLUENCES THE BEHAVIOR OF THE GENES THEIR CHILDREN INHERIT
You had the talent to be a sports star, but you lacked the discipline. You couldn't bring yourself to go to bed early or pick up a barbell instead of an Oreo. On the bright side, your kid gets to start from square one: He or she inherits your talent but not the repercussions of your lackluster approach.
Or maybe not. Research in the growing science of epigenetics—which, among other things, looks at how genes can be switched on and off—suggests that your actions could have genetics-related consequences for your child. Better think twice before pounding down that next cookie.
At the turn of the 19th century, French naturalist Jean-Baptiste Lamarck proposed a theory of evolution that said animals quickly adapt to their environment and pass the adaptations along to their progeny; for example, giraffes acquired long necks because their ancestors stretched to reach leaves high on trees. But Lamarckian evolution was eclipsed in 1859 when Charles Darwin published his theory of evolution by natural selection, which says traits are acquired over millions of years as random genetic changes that happen to be beneficial are passed on. Today, however, the idea at the heart of Lamarck's theory—that our choices can affect our children's genes—is making a comeback.
Your behavior will not change the sequence of your child's DNA, but it might change the action of certain molecules—called epigenetic marks—that attach to DNA and signal genes to turn on and off. Consider a study, published in 2008, of adults in the Netherlands whose mothers had suffered through a German-imposed food embargo in the winter of 1944--45. Six decades later, those whose mothers were in the early stages of pregnancy during the Dutch Hunger Winter had fewer "turn off" signaling methyl molecules attached to their IGF2 genes than did their siblings. The IGF2 gene is a key component in growth and development, and the study may help explain why children of mothers who experience famine during pregnancy have a higher risk of developing obesity, schizophrenia and diabetes later in life.
Studies now under way should further illuminate the epigenetic link to sports prowess. In one study published last year, rats that exercised regularly and rats that didn't were twice thrown into beakers of water. On the first go-round, all the rats struggled vigorously to swim and attempt to escape the beaker. A day later, when they were again put into the water, the regularly exercised rats displayed better stress-coping mechanisms: Instead of clawing at a glass wall they could not climb, these rats, having learned from the previous day's experience, conserved energy by floating. When their brains were examined afterward, researchers found that the exercised rats had altered epigenetic marks that in turn affected gene expression in a part of the brain that helps form memories. "Exercise has a great impact on the brain, not just the muscles," says Johannes Reul, one of the researchers and a neuroscientist at the University of Bristol, England.
Perhaps one day a similar epigenetic explanation of memory will help us understand why great cornerbacks don't get beat the same way twice.