Since the completion of the Human Genome Project, there seems to be a growing sense that everything, including our behavior, can be explained by our genes. According to this idea, there's a gene (or genes) for addiction, for sexual orientation, even for altruism. Now that we know the human genetic code, we can understand everything about our nature.
Recent work in epigenetics is undermining such determinism. Epigenetics is the study of those influences that act “over and above” genetics. For example, one study showed certain genetic mutations that normally lead to obesity in rats can be turned off by a modification in diet. The same amounts of food were given, but expression of the abnormal gene was blocked by changing the type of food.
In another study performed in mice, more intimate behavior of mothers towards their offspring led to increases in the size of the hippocampal region of the brain, a change that would normally have been ascribed to genetics alone.
The point is that DNA is not destiny. In the words of one writer, “Free will is not only real; to a yet undetermined extent, it can override DNA.” The implications for ethics and behavior are obvious. In contrast to the reductionism of secular science, free will is not an illusion, and our choices matter.
Original article: http://www.tothesource.org/11_22_2006/11_22_2006.htm