Neanderthals moved further east
2007-10-01 10:45
Paris - European Neanderthals, modern man's ill-fated cousins who died out mysteriously some 28 000 years ago, migrated much further east than previously thought, according to a study released on Sunday.
Remains from the slope-browed hominid have previously been found over an area stretching from Spain to Uzbekistan, but the new study extends the eastern boundary of their wanderings another 2 000km deep into southern Siberia, just above the western tip of what is today China.
The fossils underpinning the study are not new, but the techniques used to analyse them are.
Geneticist Svante Paabo of the Max Planck Institute for Evolutionary Anthropology and colleagues compared mitochondrial DNA (mtDNA) sequences from bones found from two sites - one in Teshik Tash, Uzbekistan and the other from the Altai Mountains in Siberia - with those of specimens from different European sites.
Scientists looking at the morphology of the remains from the central Asian sites have long disagreed as to whether they came from Neanderthals or Homo sapiens sapiens, the species name for modern man.
Paabo's results settle the debate.
The study, published in the British journal Nature, confirms that the adult fossils - about 40 000 years old - from Okladnikov Cave in Siberia genetically match the European Neanderthal.
"The fact that no deep mtDNA divergence is seen ... shows that they were not separated for a long time," supporting a theory that Neanderthals colonised most of the Russian plains during a warming period some 125 000 years ago, the researchers conclude.
Vanishing act sparked fierce debate
Every human cell contains thousands of mitochondria, tiny structures that convert the energy from food into a form that cells can use. Although most DNA is packaged in chromosomes within the nucleus, mitochondria also have a small amount of their own.
Mitochondrial DNA is more abundant than nuclear DNA, and is thus more likely to be recovered.
In addition, mtDNA is transmitted only from the mother so that changes from generation to generation result from mutation alone rather than recombination of the mother and father's DNA.
The presence of Neanderthals in Siberia "raises the possibility that they may have been present even farther to the east, in Mongolia and China", the study notes.
Smaller and squatter than modern man, Neanderthals lived in parts of what are today Europe, Central Asia and the Middle East for around 170 000 years.
Sometime between 28 000 and 30 000 years ago, these poorly understood hominids disappeared, a vanishing act that has sparked fierce debate among palaeontologists.
Some say that the Neanderthals were wiped out by a sudden cold snap. More recent research, however, points to another culprit: us.
Even here, there are broadly two lines of thought. One is that Neanderthals, vying for food and habitat, were slaughtered by modern humans armed with superior stone tools and weapons.
Another is that the two species intermingled and interbred, with the weaker, less numerous Neanderthals simply petering out as a distinct group.