Human brain still evolving, who knows what the future has to offer!

Sep 10 2005

According to a team of University of Chicago scientists they have found strong evidence that the human brain is still evolving.

The Chicago team discovered, by comparing modern man with our ancestors of 37,000 years ago, that there are big changes in two genes linked to brain size.

They say they believe that one of the new variants emerged only 5,800 years ago, yet is present in 30% of today's humans, which is relatively short in evolutionary terms.

It seems each gene variant emerged around the same time as the advent of so called "cultural" behaviours.

One variant, the microcephalin, appeared along with the emergence of traits such as art and music, religious practices and sophisticated tool-making techniques, which date back to about 50,000 years ago.

That variant is now present in about 70% of humans alive today.

The other, called the ASPM variant, originated at a time that coincides with the spread of agriculture, settled cities and the first record of written language.

According to researcher Dr Bruce Lahn, the big question is whether the genetic evolution seen, had actually caused the cultural evolution of humans or was merely chance.

They guess that it might have something to do with the important role that these genes play in brain size, but stress that did not necessarily mean better intelligence.

Dr Lahn says that just because these genes are still evolving it does not necessarily mean they make you any smarter.

He adds that their studies indicate that the trend that is the defining characteristic of human evolution, the growth of brain size and complexity, is likely to be still ongoing.

He speculates that if our species survives for another million years or so, the brain by then might show significant structural differences from the human brain of today.

The next step say the researchers will be to figure our what biological difference imparted by the genetic differences, caused natural selection to favour that variation over others.

They say they must have conferred some evolutionary advantage, such as a desired change in cognition, personality, motor control or resilience to neurological or psychiatric diseases.

http://www.uchicago.edu/