Speaking of stability ... evolution is still working away on us ..
Cochran, Harpending and their colleagues examined about 2000 examples of such sweeps in an African population and 2000 in the European population. They found strong evidence that advantageous alleles in these regions are sweeping through the human population - evidence of natural selection at work. These sweeps began earlier in Africa than in Europe, perhaps 80,000 and 40,000 years ago, respectively. They can be dated by looking at the degree to which the linked SNPs have started to break down through the continuing process of genetic recombination.
The authors conclude that these and other signs of more recent human evolution are the result of rapid cultural changes, triggered by the invention of agriculture and the urbanisation of our species. This can be seen in evidence of selection on specific genes such as those that influence our physical ability to form words or to metabolise new foods.
