No wonder we like cheeseburgers...

Deep down inside we're all dairy farmers.

The study adds to evidence that modern central and northern Europeans are mostly the descendents of a small group of dairy farmers found in the 5th millennium BC, he said.

"The ability to drink milk is the most advantageous trait that's evolved in Europeans in the recent past. Without the enzyme lactase, drinking milk in adulthood causes bloating and diarrhoea," said co-author Mark Thomas.

"The benefits of milk tolerance … include: the continuous supply of milk compared to the boom and bust of seasonal crops, its nourishing qualities and the fact that it's uncontaminated by parasites - unlike stream water - making it a safer drink. All in all, the ability to drink milk gave some early Europeans a big survival advantage," said Thomas [More]

The idea of milk being safer because it had been "filtered" through a cow never struck me. It's like how Chinese laborers fared better during the building of the Transcontinental Railroad because they drank tea which had been effectively sterilized by boiling instead of raw water .