Thursday, April 16, 2009

New Study Merges Genetics, Demography and Paleoanthropology

Mitochondrial DNA from twelve Neanderthal fossil assemblages was sequenced, compared and correlated with morphological data from fossil skulls, limbs and dentary remains to render evidence for multiple demes of Neanderthals from across Asia and Europe.

According to the authors, this “…approach to Neanderthal variability, based on nucleotide sequences analysis, confirms from a genetic point of view the morphological variations between western and eastern Neanderthals and the existence of a southern group…”

The mtDNA portion of the study therefore supports prior determinations based on morphological analysis that at least three separate Neanderthal sub-groups (and possibly a fourth group from western Asia) emerged from an ancestral population approximately 130,000 years ago. Furthermore, there is evidence that these populations existed in a dynamic state of migration.

Figure 2. Neanderthal Group Distribution

The Neanderthals are a well-distinguished Middle Pleistocene population which inhabited a vast geographical area extending from Europe to western Asia and the Middle East. Since the 1950s paleoanthropological studies have suggested variability in this group. Different sub-groups have been identified in Western Europe, in southern Europe and in the Middle East. On the other hand, since 1997, research has been published in paleogenetics, carried out on 15 mtDNA sequences from 12 Neanderthals. In this paper we used a new methodology derived from different bioinformatic models based on data from genetics, demography and paleoanthropology. The adequacy of each model was measured by comparisons between simulated results (obtained by BayesianSSC software) and those estimated from nucleotide sequences (obtained by DNAsp4 software). The conclusions of this study are consistent with existing paleoanthropological research and show that Neanderthals can be divided into at least three groups: one in western Europe, a second in the Southern area and a third in western Asia. Moreover, it seems from our results that the size of the Neanderthal population was not constant and that some migration occurred among the demes.

In case you were wondering about genetic links to modern Homo sapiens, the study was limited to “…what occurred previous to the arrival of modern humans in the Neanderthal landscape and we therefore do not consider the potential phylogenetic relationship between Neanderthals and modern Humans.”

The article, in its entirety, is available at the below referenced link.

Fabre, V., Condemi, S., & Degioanni, A. (2009). Genetic Evidence of Geographical Groups among Neanderthals PLoS ONE, 4 (4) DOI: 10.1371/journal.pone.0005151

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