2014-12-04. Dwindling African tribe may have been most populous group on planet.

posted Dec 7, 2014, 9:26 AM by Alan Gould
By Ann Gibbons, Science. For GSS Life and Climate chapter 1. Excerpt: The famous Kalahari Bushmen of southern Africa have long been in decline. For more than a century, the people, who speak Khoisan languages, have been pushed off their land by farmers and brutalized by colonialists. Yet for tens of thousands of years, the Khoisan’s ancestors were members of “the largest population” on the planet, according to a new study. ...The Khoisan have long stood apart from other groups within Africa. They look distinct, speak in “click” languages, and have also maintained the greatest genetic diversity known among human populations. ...the 100,000 Khoisan speakers in Africa today are far outnumbered by other groups, such as the 45 million Bantu speakers and their 180 million descendants who now speak Swahili and other languages.  ...In the new study, published online today in Nature Communications, biochemist Stephan Schuster of Nanyang Technological University in Singapore and colleagues sequenced the complete genomes of five Khoisan hunter-gatherers from Namibia and compared them with the DNA from 1462 genomes of people from around the world.  ...population sizes for the ancestors of the Khoisan, as well as for Europeans, Asians, and another African group, the Yoruba... declined ... between 120,000 and 30,000 years ago. ...The researchers uncovered declines in population in all four groups, likely tied into periods of dry climate in Africa. But the Khoisan suffered the least, perhaps because their huge ancestral population was buffered from droughts that winnowed other groups, such as the Yoruba and the African ancestors of Europeans and Asians, because the Khoisan lived farther south in Africa where rainfall actually increased. The Khoisan then began a more drastic decline in the past 20,000 years or so, with a major blow when the Bantu farmers spread through Africa 4000 years ago. “This shows us how much climate can influence populations,” says genomicist Webb Miller of Pennsylvania State University, University Park, a co-author....  http://news.sciencemag.org/africa/2014/12/dwindling-african-tribe-may-have-been-most-populous-group-planet *.

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