A New, Older y-Chromosomal Adam

23 05 2011

Image via Wikipedia. Though it couldn't be more obvious, am I right?

Researchers believe they have identified an earlier “y-chromosomal Adam,” the earliest human male from whom we are all descended. This isn’t a literal individual they’ve identified, but a genetic fingerprint of one. Where once this “chromosomal Adam” was believed to have lived about 60,000 years ago in some part of southern or southeastern Africa, a new paper published in the Journal of Human Genetics puts his life at about 140,000 years ago. The research also suggests that the male seems to be from northwest Africa, not the eastern or southern portion as has long been suspected:

“The number of deep branchings leading to African-specific clades has doubled, further strengthening the MSY-based evidence for a modern human origin in the African continent. An analysis of 2204 African DNA samples showed that the deepest clades of the revised MSY phylogeny are currently found in central and northwest Africa, opening new perspectives on early human presence in the continent.”

(That’s how scientists express excitement).

This discovery can alter a number of things about our understanding of human evolution and development: if the chromosomal Adam had lived only 60,000 years, it would compress significantly the time period human had to migrate from Africa and populate the rest of the world, and begin the phenotypic variations we see in people today. Given that the agricultural revolution started about 15,000 years ago, that’s not a lot of time. The current time frame was also a point of dispute between physical anthropologists and their molecular counterparts, as the former believed they had evidence of modern humans as far as Australia as long ago as 100,000 years.

More than doubling the distance between ourselves and Adam also puts chromosomal him closer in time to the mother of humanity, Mitochondrial Eve, who lived about 200,000 or so years ago, making her the earliest recorded instance of a cougar.

To keep my jokes from confusing you further, may I suggest actually going to the article itself?

For the research itself, check here. For a better explanation, go here.



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