Scientists reshape Y chromosome haplogroup tree gaining new insights into human ancestry

In addition to improving the resolution of branches, the latest reconstruction of the tree allows estimates of time to the most recent common ancestor of several haplogroups. “The age of [haplogroup] DE is about 65,000 years, just a bit younger than the other major lineage to leave Africa, which is assumed to be about 70,000 years old,” says Hammer, describing an example of the fine resolution of age that is now possible. “Haplogroup E is older than previously estimated, originating approximately 50,000 years ago.”

Furthermore, Hammer explains that this work has resulted in the addition of two new major haplogroups, S and T, with novel insights into the ancestry of both. “Haplogroup T, the clade that Thomas Jefferson’s Y chromosome belongs to, has a Middle Eastern affinity, while haplogroup S is found in Indonesia and Oceania.”

“More SNPs are being discovered, and we anticipate the rate to increase with the 1000 Genomes Project,” says Hammer, referring to the wealth of human genetic variation data that will soon be available. While this report represents a significant advance in mapping ancestry by Y chromosome polymorphisms, it is certain that future discoveries will necessitate continual revisions to the Y chromosome haplogroup tree, helping to further elucidate the mystery of our origins.

Scientists from the University of Arizona (Tuscon, AZ) and Stanford University (Stanford, CA) contributed to this study.

This work was supported by the Salus Mundi Foundation.

Media contacts:

Michael Hammer, Ph.D., has agreed to be contacted by email for more information ( ).

Interested reporters may obtain copies of the manuscript from Peggy Calicchia, Editorial Secretary, Genome Research ( ; +1-516-422-4012).

About the article:

The manuscript will be published online ahead of print on April 2, 2008. Its full citation is as follows: Karafet, T.M., Mendez, F.L., Meilerman, M.B., Underhill, P.A., Zegura, S.L., and Hammer, M.F. New binary polymorphisms reshape and increase resolution of the human Y-chromosomal haplogroup tree. Genome Res. doi:10.1101/gr.7172008.

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