But hair sample could have been from a wandering mercenary. An early wave of migration into the New World and the Arctic has been identified by sequencing a genome from a frozen hair excavated in Greenland. Archaeological evidence shows that there were two waves of migration to Greenland starting 4,500 years ago, first with the Saqqaq and then the Dorset groups, collectively known as the Paleo-Eskimos. Later, around 1,000 years ago, came the Thule culture which led to the current native population. The relationship between these three groups has been uncertain. Some theories hold that Paleo-Eskimos derived from the populations...