In fact, the variations were so common they couldn't be accidental mutations but instead were probably due to natural selection, where genetic changes that are favorable to a species quickly gain a foothold and begin to spread, the researchers report.Lahn offers an analogy: Medieval monks would copy manuscripts and each copy would inevitably contain errors — accidental mutations.Aside from not knowing what the gene variants actually do, no one knows how precise the model Lahn used to date them is, Collins added.
Then modern scientists had to come up with their own brand of dating, and that is where the Before Present (BP) terminology started.
Using methods of dating ancient objects such as Carbon Dating indicated not a calendar date, but an amount of years before the testing was done.
That does not mean one population is smarter than another, Lahn and other scientists stressed, noting that numerous other genes are key to brain development.
"There's just no correlation," said Duke's Wray, calling education and other environmental factors more important for intelligence than DNA anyway. The information contained in the AP News report may not be published, broadcast, rewritten or redistributed without the prior written authority of The Associated Press.
"The genetic evolution of humans in the very recent past might in some ways be linked to the cultural evolution," he said.