Anthropologist John Hawks is interviewed in the latest issue of Nature talking about how humans have been undergoing accelerated evolution over the past 40,000 years, largely due to cultural shifts affecting our genes.
Nature's Erica Check Hayden sums up Hawks' position:
[C]urrent human populations are much more genetically diverse than this hypothesis predicts, so Moyzis and Hawks have concluded that evolution must have ramped up over the past 40,000 years. They chalk some of this acceleration up to human population growth, which exposed the species to more new mutations and created more raw material for selection. But the other reason, Hawks thinks, is culture - because although the physiology of humans has not changed much in the past 40,000 years, their expansion and migration means that lifestyles, languages and technologies certainly have.
Although not everyone agrees with Hawks's claims, the best understood example of recent human evolution does seem to fit. Genetic mutations that allow adults to digest lactose, a sugar found in milk, have emerged independently in different populations in response to the same cultural innovation - cattle domestication. "I don't see culture as an alternative to genetics, I see culture as being the explanatory factor for these genetic changes," says Hawks. "There is no explanation for change without the gene–environment interaction."
You can read the entire article from Nature.