Mostly due to changes in diet, scientists have say they "have found more than 700 genetic variants that evolution may have favored during the past 10,000 years, illustrating how human evolution is continuing."

Basically, the less "gene shuffling that occurs each generation, called recombination", there is, the more recent the genetic variation should be.

The most convincing and most easily understood is the "lactase mutation, which lets adults digest milk, appeared in about 90 percent of Europeans". This would have begun with humans domesticating animals that can be milked. Lactose intolerance would have been the norm prior to agriculture.

Source: World-Science