CSUN research finds genetic decline may have doomed Neanderthals

NORTHRIDGE, Calif. (KESQ) - A Cal State Northridge anthropologist and an international team of researchers have found that a lack of genetic diversity among the last Neanderthals in Europe may have contributed to their extinction, according to a study announced today.

The research, led by CSUN's Helene Rougier, found that late Neanderthals descended from a single genetic lineage following a sharp population decline linked to a major ice age.

Using DNA analysis and archaeological evidence from bone fragments, some no larger than a finger, researchers determined that Neanderthal populations contracted significantly after a period of climate deterioration beginning roughly 75,000 years ago.

"Combining the genetic data with the archaeological data, we were able to see a contraction in the distribution of Neanderthal sites that corresponded to a dramatic change in the climate, an ice age,'' Rougier said. "The data shows that some of the Neanderthals found refuge in southwestern Europe, taking shelter in the valleys of southwestern France, while dying out in the rest of the continent."

However, by that time, they shared a much more limited gene pool, Rougier added.  

Researchers said the population later experienced a rapid collapse between roughly 45,000 and 42,000 years ago.   

"It was like they went off a cliff,'' Rougier said. "The population just collapsed. In about 2,000 years they were gone."  

Rougier said the decline coincided with the arrival of early Homo sapiens in Europe, raising the possibility that competition for resources may have played a role.

She added that reduced genetic diversity may have made Neanderthals more vulnerable to environmental pressures and other threats.   

The findings were published in the journal Proceedings of the National Academy of Sciences.