Wooly Mammoth Hairball

The latest issue of The Economist reports on the discovery of an ancient hairball (above) found inside a wooly mammoth buried in the Siberian permafrost; the story follows.

Mammoths

This is not any old hairball. It is a very old hairball. It comes from a woolly mammoth that was buried in the Siberian permafrost. An analysis of its DNA, and the DNA from 17 other mammoths, by Stephan Schuster, of Pennsylvania State University and published in the Proceedings of the National Academy of Sciences, suggests the species was composed of two genetically distinct groups. One of these groups became extinct 45,000 years ago, well before people arrived in the area mammoths inhabited. That re-opens the question of whether it was people or climate change that finally did the species in.

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The abstract of the scientific article cited above follows.

Intraspecific phylogenetic analysis of Siberian woolly mammoths using complete mitochondrial genomes

We report five new complete mitochondrial DNA (mtDNA) genomes of Siberian woolly mammoth (Mammuthus primigenius), sequenced with up to 73-fold coverage from DNA extracted from hair shaft material. Three of the sequences present the first complete mtDNA genomes of mammoth clade II. Analysis of these and 13 recently published mtDNA genomes demonstrates the existence of two apparently sympatric mtDNA clades that exhibit high interclade divergence. The analytical power afforded by the analysis of the complete mtDNA genomes reveals a surprisingly ancient coalescence age of the two clades, {approx}1–2 million years, depending on the calibration technique. Furthermore, statistical analysis of the temporal distribution of the 14C ages of these and previously identified members of the two mammoth clades suggests that clade II went extinct before clade I. Modeling of protein structures failed to indicate any important functional difference between genomes belonging to the two clades, suggesting that the loss of clade II more likely is due to genetic drift than a selective sweep.

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The entire article is here.