Out of Africa: Startling New Genetics of Human Origins [View all]

[xchrom]

http://blogs.scientificamerican.com/talking-back/2012/07/26/out-of-africa-startling-new-genetics-of-human-origins/

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Please describe the research that led to the paper that was published today:

We’re the first ones to look at these diverse groups of hunter-gathers in Africa who descend from some of the most ancestral lineages in the world. They’re interesting because they have very unique and distinct lifestyles There are few populations that maintain this active hunter-gatherer lifestyle.

This is the most extensive study in Africa using high-coverage deeply detailed sequence data. We focused on three groups because they’re anthropologically interesting. They’re thought to be descended from groups that are ancestral to all modern humans. We wanted to understand the genetic basis of adaptation to their local environment including, for instance the short stature trait in Pygmies.

So what did you find?

We discovered 13 million variants and, of those variants, greater than 3 million are completely novel, meaning that they have not been reported in any database. The current public database has 40 million variants. So we found 3 million novel variants by simply sequencing 15 individuals. That increases by about 8 percent all known human genetic variation. It also demonstrates that we’re missing a lot of really important variation that’s out there, particularly in Africa, which is the homeland of modern humans and a place where there’s been a lot of time for differentiation to have occurred in very diverse environments. What this means is that there’s s probably a lot of regional or population-specific variation out there that has not been that well characterized, some of which is functionally very important.