Did drinking milk cause an evolutionary change in the human genome?

Question

In a recent Slate article "The Most Spectacular Mutation in Recent Human History. How did milk help found Western civilization?" (October 23, 2012), a claim was made that:

[Around 10,000 B.C.] a genetic mutation appeared, somewhere near modern-day Turkey, that jammed the lactase-production gene permanently in the “on” position. The original mutant was probably a male who passed the gene on to his children. People carrying the mutation could drink milk their entire lives. Genomic analyses have shown that within a few thousand years, at a rate that evolutionary biologists had thought impossibly rapid, this mutation spread throughout Eurasia, to Great Britain, Scandinavia, the Mediterranean, India and all points in between, stopping only at the Himalayas. Independently, other mutations for lactose tolerance arose in Africa and the Middle East, though not in the Americas, Australia, or the Far East. In an evolutionary eye-blink, 80 percent of Europeans became milk-drinkers; in some populations, the proportion is close to 100 percent.

The Human Culture, an Evolutionary Force (The New York Times, March 1, 2010) journalist, Nicholas Wade summarized the intriguing reciprocal interactions between human culture and human genes:

Lactose tolerance is now well recognized as a case in which a cultural practice — drinking raw milk — has caused an evolutionary change in the human genome.

So, I wonder, did drinking milk cause an evolutionary change in the human genome?

What is the evidence?

Answer 1

In this Nature Genetics paper, Gene-culture coevolution between cattle milk protein genes and human lactase genes Nature Genetics 35, 311 - 313 (2003), the variants in Cattle milk proteins and Human lactase persistence genes were analysed. (Lactase persistence means that adults can keep digesting lactose, while normally the lactase gene switches off after childhood, giving rise to lactose intolerance.)

They found that:

Milk from domestic cows has been a valuable food source for over 8,000 years, especially in lactose-tolerant human societies that exploit dairy breeds. We studied geographic patterns of variation in genes encoding the six most important milk proteins in 70 native European cattle breeds. We found substantial geographic coincidence between high diversity in cattle milk genes, locations of the European Neolithic cattle farming sites (>5,000 years ago) and present-day lactose tolerance in Europeans. This suggests a gene-culture coevolution between cattle and humans

This shows that not only did humans evolve in response to milk consumption, but the cattle evolved to better produce that milk, as cows were under selective pressure from human preferences.