In an earlier post today, we read about how polar bear metabolism has evolved in the past half-million years. A study of human metabolism shows how changing conditions can causes changes in just one generation. No, the genes themselves don't change, as the addition and/or subtraction of actual genes in a population takes many generations. However, the activation or de-activation of certain existing genes can be affected by environmental conditions. This story arose from the existence of busy diabetes clinics in Cambodia, where the previous generation suffered from starvation.
Despite the physical and mental insults of starvation, some women can still become pregnant and carry a child to term, even during extreme famine. Survival during times of starvation requires a person to conserve as much energy as possible, and if the mother is facing profound food shortages, it was historically likely that the child would, too. By epigenetically changing which genes are turned on and off, a person could make their metabolism as efficient as possible and maximize his or her chances of survival when food is scarce.
“As mammals, we try to anticipate our environment. The problems tend to occur when you program yourself for an environment that no longer exists,” Lane said, such as children who were conceived in famine and now live in a world where calorie-dense food is available 24/7.
In other words, children conceived by starving mothers may respond by changing their bodies’ metabolisms -for the rest of their lives. Read about how this happens at The Daily Beast.