From: Mark Odegard
Message: 2770
Date: 2000-07-07
From: Piotr GasiorowskiBy contrast, there is no evidence of abnormally low genetic diversity for humans. I think it's highly likely that the total population of early anatomically modern Homo sapiens was fully sustainable (that is, rather large) at any time; and if so, then given the size of primitive social units, it was simply too large to support just one language community.
From everything I've heard, humanity is not abnormally low in terms of genetic diversity, and certainly not when compared to cheetahs. At the same time, it's been suggested (on TV shows with not-quite impeccable credentials) that (1) Homo sapiens sapiens went through a genetic bottleneck ca. 75,000 years ago (perhaps correlated with the eruption of the Toba volcano on Sumatra -- this is a 'super-volcano' like the Yellowstone volcano) and (2) the probable population of the community ancestral to all living humans was about 2,000. Through chance, only one female stands at the head of this family tree as the ancestress of every female human on the planet (mitochondrial DNA).The concept of 'proto-World' is not improbable, though it might possibly be better called 'neo-proto-World' in that language may have been invented before this genetic bottleneck, and only one branch survived.When speaking of 'genetic diversity', everything I've read says we are a young species, and compared to other older species, we have considerably less diversity. We are at best 150,000 years old.I found a link for Toba Volcano. Unfortunately, it's from Discover magazine, which makes the conclusions somewhat suspect (this is tabloid science). The Britannica site, however, lists it: