Diversity of Human Gene Pool - Are we more immune to epidemics?

[Surreal]

See this abstract:

http://www.pnas.org/content/106/1/33

Abstract
Paleogenomic research has shown that modern humans, Neanderthals, and their most recent common ancestor have displayed less genetic diversity than living great apes. The traditional interpretation that low levels of genetic diversity in modern humans resulted from a relatively recent demographic bottleneck cannot account for similarly low levels of genetic diversity in Middle Pleistocene hominins. A more parsimonious hypothesis proposes that the effective population size of the human lineage has been low for more than 500,000 years, but the mechanism responsible for suppressing genetic diversity in Pleistocene hominin populations without similarly affecting that of their hominoid contemporaries remains unknown. Here we use agent-based simulation to study the effect of culturally mediated migration on neutral genetic diversity in structured populations. We show that, in populations structured by culturally mediated migration, selection can suppress neutral genetic diversity over thousands of generations, even in the absence of bottlenecks or expansions in census population size. In other words, selection could have suppressed the effective population size of Pleistocene hominins for as long as the degree of cultural similarity between regionally differentiated groups played an important role in mediating intraspecific gene flow.

[John_Mace]

@Surreal

See this abstract:

http://www.pnas.org/content/106/1/33

OK. Can’t read the whole article, but I have to wonder just how much “paleogenomic” data they have. I don’t think we’ve extracted DNA from more than a dozen Neanderthals. Compare that the tens of thousands of modern humans we have DNA from. And “middle Pleistocene” narrows it down to something more reasonable.

[John_Mace]

Here is an interesting article I dug up on the subject of Neanderthal diversity. It quantifies things fairly well and also talks about some of the limitations of the data.

Scientists have estimated that fewer than 3,500 breeding Neanderthal females lived in Europe at any one time between about 38,000 and 70,000 years ago — using a faster and potentially much cheaper method than sequencing whole genomes.

<snip>

But anthropologist Anna Degioanni at the University of the Mediterranean in Marseilles, France, notes that the region of mtDNA the Briggs group studied does not vary as much as other regions, such as the one her group used to identify different subgroups of Neanderthals earlier this year4. That may mean that the new study underestimates the genetic diversity of Neanderthals, she believes.