The gene that came to stay
By Bruce Bower
A gene thought by some scientists to foster a bold, novelty-seeking personality, as well as attention-deficit hyperactivity disorder (ADHD), apparently spread substantially in human populations over roughly the past 40,000 years, according to a new study.
One form of the gene gained evolutionary favor near the end of the Stone Age because it enhanced survival and reproduction, proposes a team led by biologist Yuan-Chun Ding of the University of California, Irvine. The form is now the second-most-prevalent variant of the so-called DRD4 gene, which codes for a type of dopamine receptor (DRD4) found on brain cells.