Monday, July 18, 2011

Non-African X Chromosome Heavy In Neanderthal DNA

A previously direct comparison of recovered ancient Neanderthal DNA to the whole human genome found an average of 1.5% to 4% Neanderthal DNA in all non-Africans, with an overall average of 2.5% and no clear regional preferences. A new study (discussed here) finds an average of 9% Neanderthal DNA in non-African X chromosomes with a similar geographic distribution, using a much larger sample size, but without direct comparison to the Neanderthal DNA sample, using another statistical method to identify the ancient X chromosome haplotype.

There is no evidence that any modern humans have either a Neanderthal patrilineal ancestor or a Neanderthal matrilineal ancestor, lineages that are tracked with non-recombining Y-DNA and mitchondrial DNA respectively.

Ancient Denisovian DNA from hominins of unknown affiliatioon who yielded an ancient DNA sample in an Altai Mountain cave from 38,000 years ago or so, when compared to modern human populations, showed Denisovian admixture in Melanesians (who also have Neanderthal DNA components) and populations admixted with them, but not other modern humans.

1 comment:

Maju said...

Not new: published on January and discussed here by me. It is not fully demonstrated but it's likely. Actually the matter was raised years ago because the haplotype B006 was almost not found in Africa (but it was found there, in Benin, at low frequencies) and it was very basally divergent in the overall X-DNA tree.