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Unformatted text preview: www.sciencemag.org SCIENCE VOL 299 7 MARCH 2003 1525 T he Neanderthals are the longest known and best understood of all fos- sil humans. In 1856, quarry workers cleaning out a limestone cave in the Neander Valley, Germany, found a partial skeleton for which the group is named. Today, several thousand Neanderthal bones are known from more than 70 individual sites. Yet, paleoanthropologists still debate just how much the Neanderthals differed from living humans and whether the differ- ences help explain why the Neanderthals disappeared. Most Neanderthal specimens are isolat- ed skeletal elements, especially teeth and jaws, but nearly every part of the skeleton is represented in multiple copies. There are also more than 20 partial skeletons from individuals of both sexes and different ages ( 1 ). More than 300 archaeological sites have yielded artifacts and broken-up ani- mal bones that illuminate Neanderthal be- havior and ecology ( 2 ). The Neanderthals evolved in Europe. Some of their distinctive anatomical fea- tures already mark Euro- pean fossils that are more than 350,000 years old ( 3 ). Through a process of natu- ral selection and random genetic drift, they emerged in full-blown form by 130,000 years ago. From then on, they were distrib- uted more or less continu- ously from Spain to south- ern Russia; by 80,000 years ago, they had extended their range to western Asia (see the figure). They persisted in Europe and western Asia until at least 50,000 years ago and perhaps in some places until 30,000 years ago. Everywhere they lived, the Neander- thals were the immediate predecessors of modern humans, and it has often been sug- gested that they were ancestral to living populations. However, at the same time that the Neanderthals occupied Europe and western Asia, other kinds of people lived in the Far East and Africa ( 4 ). The Africans were anatomically much more modern than the Neanderthals, and are therefore more plausible ancestors of living humans. Furthermore, surveys show that variants of mitochondrial DNA ( 5 ) and the Y chromo- some ( 6 ) in living Eurasian humans derive exclusively from African variants that probably existed no more than 100,000 years ago. Further support for this argument comes from mitochondrial DNA extracted from Neanderthal bones. The data indicate that the last shared ancestor of Neanderthals and living humans lived 500,000 to 600,000 years ago ( 7 ). Nonsex chromosomes of liv- ing humans may conceivably retain some Neanderthal genes ( 8 ), but the combined fossil and genetic evidence suggests that any Neanderthal contribution to living pop- ulations was small. The Neanderthals may thus be regarded as a fascinating but extinct side branch of humanity....
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This note was uploaded on 09/25/2011 for the course ANTHROPOLO 111 taught by Professor Scott during the Spring '11 term at Rutgers.
- Spring '11