Jim Foley at Panda’s Thumb, reports on new research published in the journal Cell in August [1], which identifies the genetic differences between human and Neandertal mitochondrial DNA (mtDNA^*).

From the summary of the paper:

A complete mitochondrial (mt) genome sequence was reconstructed from a 38,000 year-old Neandertal individual with 8341 mtDNA sequences identified among 4.8 Gb of DNA generated from 0.3 g of bone. Analysis of the assembled sequence unequivocally establishes that the Neandertal mtDNA falls outside the variation of extant human mtDNAs, and allows an estimate of the divergence date between the two mtDNA lineages of 660,000 ± 140,000 years. Of the 13 proteins encoded in the mtDNA, subunit 2of cytochrome c oxidase of the mitochondrial electron transport chain has experienced the largest number of amino acid substitutions in human ancestors since the separation from Neandertals. There is evidence that purifying selection in the Neandertal mtDNA was reduced compared with other primate lineages, suggesting that the effective population size of Neandertals was small.

Notice the term “unequivocally”. More and more conclusive evidence from the field of genetics strengthen the already well established scientific theory for the descent of human. As Jim Foley says:

[this research] strengthens the view that Neandertals should be designated a separate species Homo neanderthalensis, because even if they could interbreed with the ancestors of modern humans (and they probably could, and possibly did on occasion 3) there does not seem to have been a significant amount of genetic interflow happening between the two populations. We don’t find Neandertal mtDNA in modern humans, and vice versa. Humans and Neandertals seem to have split off around 600,000 years ago and developed separately thereafter.

I wonder what the creationists will make of this…

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Footnotes:

1. * mtDNA is DNA extracted from the mitochondria of our cells, small organelles that produce the cellular energy required by the cell to function properly. “Normal” (nuclear) DNA, which determines our characteristics, is found in the nuclei of our cells. [↩]

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References:

1. Green R., Malaspinas A-S, Krause J., Briggs A., et al. A Complete Neandertal Mitochondrial Genome Sequence Determined by High-Throughput Sequencing, Cell, 134 (2008), pp. 416–426 [↩]