Relationship of Neanderthals to Modern Humans
Relationship of Neanderthals to Modern Humans After extracting ancient DNA from the 40,000-year-old bones of Neanderthals, scientists have obtained a draft sequence of the Neanderthal genome, yielding important new insights into the evolution of modern humans. No other ancient people have aroused more controversy and confusion over the last century and a half than have the Neanderthals (3,4). There is an on-going debate as to whether they should be considered Homo sapiens. While the idea that modern humans originated in Africa and spread out to other parts of the world is widely accepted, several scenarios have been proposed to account for the replacement of neanderthal populations. The multi regional hypothesis holds that neanderthal populations in Eurasia and Africa were held together by gene flow. Fossil and genetic evidence supports an African origin for Modern Humans (1,3,5,9,10). A decade after scientists first cracked the human genome, researchers announced that they have done the same for Neanderthals, the species of hominid that existed from roughly 400,000 to 30,000 years ago, when their closest relatives, early modern humans, may have driven them to extinction (1,3,5,9,10). Led by ancient-DNA expert Svante Pääbo of Germany's Max Planck Institute for Evolutionary Anthropology, scientists reconstructed about 60% of the Neanderthal genome by analyzing tiny chains of ancient DNA extracted from bone fragments of three female Neanderthals excavated in the late 1970s and early '80s from a cave in Croatia (6,8). The bones are 38,000 to 44,000 years old. The genetic information turned up some intriguing findings, indicating, for instance, that at some point after early modern humans migrated out of Africa, they mingled and mated with Neanderthals, possibly in the Middle East or North Africa as much as 80,000 years ago (5,7,10). If that is the case, it occurred significantly earlier than scientists who support the interbreeding hypothesis would have