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livescience
Three Subgroups of Neanderthals Identified

By Clara Moskowitz, LiveScience Staff Writer

posted: 14 April 2009 08:17 pm ET
A Neanderthal Family. Credit: NASA/JPL-Caltech

We tend to think of Neanderthals as one species of cavemen-like creatures, but 
now scientists say there were actually at least three different subgroups of 
Neanderthals.

Using computer simulations to analyze DNA sequence fragments from 12 
Neanderthal fossils, researchers found that the species can be separated into 
three, or maybe four, distinct genetic groups.

The evidence points to a subgroup of Neanderthals in Western Europe, another in 
Southern Europe near the Mediterranean, a third in Eastern Europe and the 
Middle East, and possibly a fourth in Western Asia. These groups have been 
postulated before, but this is the first study analyzing DNA data to look for 
genetic variations differentiating the subgroups.

Neanderthals are a hominid species that lived between about 130,000 and 30,000 
years ago. They coexisted with humans for a while, and may even have interbred 
with us.

"Because the Neanderthals lived in a very vast territory, and their evolution 
took place over a very long time, we wonder if there were sub-populations, or 
if it was a unique population," said researcher Silvana Condemi, a 
paleoanthropologist at the Universite de la Mediterranee-CNRS-EFS in France. 
"Other studies show differences between Neanderthals and modern humans. For the 
first time we are working just within Neanderthals and taking into account the 
diversity within that group."

Condemi and Virginie Fabre and Anna Degioanni, also of the Universite de la 
Mediterranee, describe their findings in the April 13 issue of the journal PLoS 
ONE.

The researchers tested various hypotheses, including that all Neanderthals 
belonged to a single homogeneous population, or that Neanderthals could be 
divided into two, three, or more subgroups. They found that the three- and 
four-group model best fit the data by accounting for the genetic discrepancies 
seen in the samples.

The authors admit that their categorization is based on limited data, since 
they only have fragments of mitochondrial DNA sequences from a small sample of 
individuals.

Princeton University paleoanthropologist Alan Mann agreed, and said it's too 
early to draw bounds around sub-populations because we don't have any data from 
individuals outside of the bounds, such as from Neanderthals in Africa or 
Southeast Asia.

"My view is this is very interesting research but it's very premature in our 
study to be able to draw any but the most generalized and preliminary 
conclusions," he said in a phone interview. "I like the data they present. But 
at the moment we have to be extremely careful about exactly what we make of 
this."

In the future, the researchers would like to compare their genetic data to what 
is known about physical distinctions among Neanderthals from different regions, 
as well as cultural differences, such as unique tool use among various 
populations.

"What is nice is that there are some variations in the genetics, and we see 
also from the bones and teeth that there is some variation," Condemi told 
LiveScience. "We give a confirmation that the Neanderthals are not one 
homogeneous group."

It is not known for sure what eventually caused Neanderthals to die out, while 
we Homo sapiens have survived to this day. Likely reasons for their demise are 
competition with humans and climate change.


© Imaginova Corp. All rights reserved.


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