A few years ago, researchers in Montreal produced a disturbing finding. By the simple act of neglecting her young, a mother rat could permanently change the expression of genes in her offspring. Dams that licked their pups only infrequently-the rat equivalent of bad maternal care-sent their little ones off into the world with a more anxious disposition than rats with dams that had lavished care on them. What is more, this lack of attention, the researchers discovered, had chemically altered a gene controlling an important stress hormone. It was a striking case of how nurture affects nature. And it made the researchers curious about whether the same could be happening in humans. Now, by studying the brains of suicide victims, they have begun to explore that question. The field they are investigating is known as epigenetics. This is the interface between our genes, which are fixed, and our environment, which is ever-changing. Although people are born with a complement of genes that they are stuck with for life, those genes can be switched on and off-and this can make a world of difference. All the more harrowing, then, that simple things like dietary supplements and stress have been […]