Search

 

PressCNRS international magazine

Table of contents

Paleoanthropology

Neanderthal Subgroups

Genetic modeling has allowed Marseille-based CNRS researchers (1) to confirm what paleoanthropologists have long suspected: The Neanderthal population was not homogenous, but split into three–perhaps even four–subgroups.

Paleoanthropological data suggests that during the Middle Pleistocene era, Neanderthals inhabited a geographical area that “stretched from Portugal to Western Siberia, and from Northern Europe to the Middle East.”2 It is believed that the Neanderthal population evolved from Homo heidelbergensis, a species also present in Africa, about 400,000 years ago. Approximately 130,000 years ago, this population became what we now refer to as “classic” Neanderthals and began to spread beyond the borders of present-day Europe. The population shift towards Western Asia and the Middle East, and the resulting geographically separated groupings, has left evidence that made researchers question (as early as the 1950s) whether this Neanderthal population might have evolved into different subgroups.
“These regions are geographically distant from one another and are, above all, separated by a number of environmental barriers,” says Virginie Fabre. Her work with two other researchers, Silvana Condemi and Anna Degioanni, has now confirmed what many paleoanthropologists believed: There were indeed three different Neanderthal subgroups, one in Western Europe, one around the Mediterranean, and one in Western Asia. “Since current estimates show that the roaming range of Neanderthal subgroups rarely exceeded 10,000 km2, it isn't surprising that there was little genetic exchange between distant regions,” says Fabre.
The team reached its conclusions by first establishing four measures of genetic variation in DNA sequence including nucleotide diversity and pairwise differences, then creating six population models using non-nucleotidic data provided by paleoanthropology, such as fossils of teeth, limbs, or skulls. Based on these population models, the researchers performed 200 simulations, which included parameters like differing growth and migration rates, or initial population sizes, to create a measure of possible genetic diversity. Once the simulation results were analyzed, the best correspondence with the actual genetic diversity–measured using 15 sequenced samples taken from 12 Neanderthal fossil specimens found since 1997–was the scenario of three derived populations. In fact, the results suggest that there may have even been a fourth subgroup in the Near East, but a lack of genetic material from fossils in the region makes this impossible to confirm for now. They also proved that while there were no substantial migrations between distant populations, there was a certain amount of genetic exchange between localized Neanderthal groups.
While the study concentrated, as Fabre explains, “exclusively on the analysis of Neanderthal population structure and never aimed to deal with the question of the replacement of the Neanderthals by Homo sapiens, over 30,000 years ago, our method is appropriate for demographic scenarios and models that simulate the decrease and extinction of a population. It could thus prove very useful to researchers working on the question of Neanderthal extinction.”

Tom Ridgway

Notes :

1. Laboratoire Anthropologie bioculturelle (CNRS / Université de la Méditerranée / Établissement français du sang).
2. V. Fabre et al., “Genetic Evidence of Geographical Groups among Neanderthals,” PloS One, 2009. 4: e5151.

Contacts :

Virginie Fabre,
Anthropologie Bioculturelle, Marseille.
mellefabrev@aol.com


Top

Back to homepageContactcredits