Our ability to digest milk may not be the most exciting topic in the world for most of us but it leads to an interesting insight as to how and where Europeans — and thus most Americans — came from.
Until recently it was believed that Europeans mainly came from Anatolian farmers in Turkey, migrating eastwards about 8,000 years ago and largely displacing the hunter-gatherer Europeans — though intermarrying with some of them also — that had been here for about 40,000 years before that . Neither, however, could digest milk, according to DNA analysis of their fossil remains. They were in the same condition that their forebears had always been. This is that once a child had become warned from mother’s then the gene that could digest lactose was turned off permanently.
But DNA analysis also shows that the gene was turned on again in Europe about 4,500 years ago. It was therefore supposed that this happened among the farmers. It has now been proved that the awakened gene came from Great Steppe sheep herders in Russian who entered Europe. Their gene had already been turned on again permanently many thousands of years before that.
So Europeans stem from three main peoples. But the same DNA analysis — from research at the Australian Centre for Ancient DNA at the University of Adelaide — also gave clues as to genetic changes at thousands of other sites along the genome. In due course, when all these are analysed and enough fossils dug up, it will mean that each of us, once our DNA is known, would be able trace our ancestry — either through the male line or the female line — fairly accurately with relatively unimportant generation gaps. We’ll be able to identify each tribe our ancestors belonged to and their individual movements from place to place ever since we left Africa 60,000 years ago.