DNA Helps Trace History of Human Migration
Findings reveal how cultures interacted, adopted advances, study says
TUESDAY, Aug. 5, 2008 (HealthDay News) -- An analysis of human DNA has provided new information about how ancient people shared knowledge that helped advance civilization, say Stanford University researchers.
They found that animal-herding methods arrived in southern Africa about 2,000 years ago on a wave of human migration, rather than by movement of ideas between people. The discovery improves understanding of how early cultures interacted and how societies learned to adopt advances.
The study was published in the Aug. 5 advance online edition of the Proceedings of the National Academy of Sciences.
"There's a tradition in archaeology of saying people don't move very much; they just transfer ideas through space. We know that humans had to migrate at some point in their history, but we also know humans tend to stay put once they get someplace," study co-senior author Joanna Mountain, consulting assistant professor of anthropology, said in a Stanford news release.
Instead of using archaeological evidence alone in an attempt to determine whether humans migrated, "all of sudden, with genetics, you can actually address that question," Mountain said.
In this study, she and her colleagues tracked genetic variation on the Y chromosome, the sex chromosome passed from father to son that encodes maleness. The researchers decided to examine the Y chromosome for clues about migration, because it changes very little from one generation to the next.
The Stanford team analyzed Y chromosomes from men in 13 populations in Tanzania in eastern Africa and in the Namibia-Botswana-Angola border region of southern Africa. They identified a unique mutation shared by some men in both locations, indicating those men had a common ancestor. Further investigation showed the unique mutation arose in eastern Africa about 10,000 years ago and was carried by migration to southern Africa about 2,000 years ago.
The U.S. National Human Genome Research Institute has more about chromosomes.