Well, according to Ernst Mayr’s Biological Species Concept, which holds that species are “groups of actually or potentially interbreeding natural populations, which are reproductively isolated from other such groups,” the newest genetic data (see a previous post on this blog) suggest that perhaps they should be considered the same species. A nice summary of the debate is provided by Ann Gibbons in Science. While some paleoanthropologists (including our keynote speaker John Hawks, who is quoted in the piece; check out his blog post on the subject) consider Neandertals and modern humans to be the same species, others maintain that the two are distinct species because the anatomical, developmental, and behavioral differences between Neandertals and modern humans are much greater than what we see among any modern population.
Check out Gibbons’s piece and tell us what you think. Are we the same species or not (remember, it also depends on what species definition you decide to use)?
It is likely that Dr. Hawks will be addressing some of these issues in his keynote lecture (we now have a title for the talk: “Neandertime: Deciphering the Secrets of Ancient Genomes.”)
Gibbons, A. (2011). A new view of the birth of Homo sapiens. Science 331: 392-394.
UPDATE 2.10.2011. Dr. Hawks has blogged about the applicability of the Biological Species Concept for extinct human groups.
Just as we are trying to digest the implications of the draft Neandertal genome (which, by the way, suggests that Neandertals contributed up to 4% of their genomes to non-African modern human populations), a new study published in Nature by David Reich (Harvard Med School) and colleagues reports the genome of an unclassified (all we have is a pinky bone and an isolated tooth) ca. 40,000-year-old hominin from Denisova Cave in southern Siberia. The genome appears distinct both from that of European Neandertals and contemporary modern humans. However, there is evidence that early modern human populations interbred with these “Denisovans” and, in fact, modern Melanesian populations (represented in the paper by genomes from Papua New Guinea and Bougainville) appear to have received approximately 4% of their genomes from this extinct group of humans.
So, taken together, these genetic data seem to indicate that modern Melanesians derive up to 8% of their genomes (4% Neandertal and 4% “Denisovan”) from now-extinct human groups. Pretty cool stuff.
Check out the summaries from Science News and Nature for more information, and our keynote speaker John Hawks’s weblog provides very detailed commentary on these exciting findings.
UPDATE 12.23.11. Dr. Hawks is also interviewed in an NPR story from Dec. 23 that summarizes the implications of these data.
Green, R.E., et al. (2010). A draft sequence of the Neandertal genome. Science 328: 710-722.
Krause, J., et al. (2010). The complete mitochrondrial DNA genome of an unknown hominin from southern Siberia. Nature 464: 894-897.
Reich, D., et al. (2010). Genetic history of an archaic hominin group from Denisova Cave in Siberia. Nature 468: 1053-1060.