This is a link to the article in Science Magazine:

A consortium of scientists examined ancient teeth for evidence of beta-lactoglobulin, the dominant whey protein. When making cheese or yoghurt, much of this protein seems to be lost, so this was a way of distinguishing between dairy consumption and actual milk drinking.

They maintain that it only happened within the last 5,000 years, so 3000 BC more or less, which seems to me to tie into the movement of Indo-Europeans into Europe, but the article also says this: "Professor Dallas Swallow, from the Research Department of Genetics, Evolution and Environment at UCL, added: "It is only within the last several thousand years that genetic mutations arose in Europe, East Africa, and the Arabian Peninsula that allowed lactase to persist into adulthood, a genetic trait that enables lifelong milk consumption."

Are they saying that the mutation that confers lactase tolerance on the Bedouin and the East Africans also arose in the last 5000 years? What can they have to do with the Indo-Europeans? Plus, those are different mutations altogether, to my recollection, so why would they have evolved in the same time frame?

I can't find the actual article. If someone has institutional access and can read it, it would be great if you would post any information you can glean as to the precise cultures and dates for it in Europe, and any clarification of their findings about the Bedouin and East African mutations.