Washington - Neanderthals in Western Europe started disappearing long before Homo sapiens arrived on the scene, a new study has found.
It suggests that it may have been cold weather, rather than humans, that led to the disappearance of the Neanderthals.
âEven if the Neanderthals were capable of surviving periods of extreme cold, the game species they relied on likely could not, so their resource base would have been severely depleted,â
Discovery News quoted Love Dalen, lead author of the paper, as saying.
For the study, Dalen of the Swedish Museum of Natural History and his colleagues analyzed mitochondrial DNA sequences from 13 Neanderthal individuals, including a new sequence from the site of Valdegoba cave in northern Spain.
The researchers found that Neanderthals from Western Europe, Asia and the Middle East that were older than 50,000 years showed a high degree of genetic variation, on par with what might be expected from a species that had been abundant in those areas for a long period of time.
However, Neanderthals from Western Europe younger than 50,000 years ago showed an extremely reduced amount of genetic variation. The scientists believe this means the earlier
population of Neanderthals there was dwindling.
âWe argue that Neanderthals disappeared in Western Europe for a period of time,â said study co-author Rolf Quam, a Binghamton University anthropologist.
âSubsequently, the region was re-occupied by individuals from a surrounding region. It is not possible, based on the current genetic data, to determine the geographic region of this new
source population,â Quam added.
The scientists suspect that climatic conditions were not as extreme in the surrounding areas at the time, so that Neanderthals were able to move back into Western Europe.
At present, there is no clear evidence of Homo sapiens being in Europe earlier than about 35,000 to 40,000 years ago, according to Quam - so it seems humans did not play a role in the early
Neanderthal populationâs demise.
The latest findings may shed light on what ultimately happened to Neanderthals.
âThe fate of the Neanderthals is one of the greatest mysteries in paleoanthropology,â co-author Anders Gotherstrom said.
âTwo main hypotheses center on climatic factors and competition with modern humans. The results of our study suggest Neanderthals were susceptible to harsh climatic conditions,
independently of whether modern humans were present or not,â he added.
The findings were published in the journal Molecular Biology and Evolution.