Wednesday, February 17, 2010

African gene trawl may provide secrets to long life

African gene trawl may provide secrets to long life
Maggie Fox
Feb 17, 2010

A genetic peek deep into the heart of Africa confirms that Africans have more genetic diversity than Europeans or Asians and provides insights into how to live a long life despite disease and famine.

Researchers sequenced the complete genomes of five southern Africans over the age of 80 -- Archbishop Desmond Tutu from South Africa and four Bushmen from Namibia.

"On average we found as many genetic differences between two Bushmen than between a European and an Asian," said Dr. Vanessa Hayes of the University of New South Wales in Australia, who worked on the study reported in Thursday's issue of the journal Nature...

Geneticists have long known that, on the level of DNA, there is no such thing as race.

They have also known that Africa, the source of all modern humans, also has more genetic diversity. This is probably because so many different peoples stayed and evolved there, while Europeans, Asians and other groups arose from smaller populations that migrated from the continent.

"To know how genes affect health we need to see the full range of human genetic variation, and Southern Africa is the place to look," said Webb Miller of Pennsylvania State University.

The team looked at some of the oldest Africans, both in terms of age and genetic roots. Tutu is an ethnic Bantu, while the four Bushmen all come from hunter-gatherer societies in the Kalahari desert of Namibia.

"The Bushmen participants have reached their advanced age despite living under harsh conditions due to periodical famine and untreated illness," the researchers wrote.

There were surprises. For instance, Tutu and one Bushman had many more different mutations known as single nucleotide polymorphisms or SNPs (pronounced "snips") than have been seen in sequencing other individuals.

They found differences in the genes that allow adults to digest cow milk, one related to having light-colored skin and SNPs that made all five men susceptible to malaria...

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