Neandertals and Their Mitochondria
At the International Palaeontological Congress this morning, I attended a wonderful presentation by Svante Pääbo of the Max Planck Institute. Pääbo is the leader of the team that is studying the genome of Neandertals, trying to understand how this extinct group is related to modern humans.
This research group has found evidence that Neandertals interbred with modern humans, and that some Neandertal inheritance can be found in people from Europe and Asia. I thought that the entire presentation was quite compelling, but Pääbo made one statement that really made me think: apparently there is no evidence for Neandertal genes in the mitochondrial DNA of modern humans.* Mitochondrial DNA is different from our other genetic material in that it passes to a child only from the mother, not from both parents.
I have a question for the geneticists and statisticians: if many humans carry Neandertal DNA in our genomes but lack it in our mitochondria, what is the cause of this distinction? What is the likelihood that this pattern arose as a result of Neandertal men breeding with Homo sapiens women, but not vice versa? And if that was the case, then what does that tell the anthropologists about the nature of ancient societies in both groups?
Please let us know when you have an answer.
* And if I misinterpreted Pääbo’s statement, please let me know so that I can re-phrase the question!
Ancient Shore 
At first glance this finding (if found to be supported by further study) would indicate that the old European folk tales of “the Other people” kidnapping women might have some foundation. But considering that their offspring would need to leave the Neandertal group and reintegrate with an early Sapiens group, it seems a difficult interpretation. Neandertal groups might have resorted to stealing women from nearby Sapiens groups as their numbers dwindled, but this kind of interbreeding could not have lasted long. How much of Neandertal DNA can be found in European and Asian modern human genomes?
A first-generation hybrid would probably have been more muscular and hardier, yet just as versatile and adaptable as the newcomers, if they had inherited the “best of both worlds,” but these individuals would have to have found mates in Sapiens groups, rather than stay with their adopted Neandertal group to preserve their genes to this day. Perhaps the sample size of individual Neandertal DNA is not enough to give a clear picture of real interactions, which should be analyzed chronologically as well.
As to the culture, I suppose the Neandertal peoples must have gone through a breakdown in their society as their groups became fewer and father apart; thus it is not far fetched to consider a Sabine strategy. Most likely it was a mixed bag of interactions, though no doubt hostility must have been foremost. Neither of these physically and mentally far more different peoples than any modern humans were likely to have cooperated in any significant way. Or perhaps Sapiens men did produce offspring with Neandertal women, but none of their DNA survives to modern day. As to why, that’s an open question. The quick thought for a Northern European like me is the “trolls” taking women “into the mountain”, and replacing Sapiens babies with their own as a survival strategy, an old theme in folk tales. But these tales might just as well be a way later developement, and have nothing to do with the prehistoric human cousins that shared the harsh environment of post-glacial Europe and Asia with us for thousands of years before dwindling away.