Geneticist Addresses Evolutionary Puzzle
Posted: Thursday, January 10, 2002
October 5, 1998, The University of Texas
A study involving the genetic profiles of more than two dozen Chinese populations supports a theory that modern Chinese people have descended from a common African ancestor. These findings mirror the commonly held belief that all the world’s races descended from the same ancestor.
Li Jin, Ph.D., an assistant professor at UT-Houston Human Genetics Center, School of Public Health http://www.uth.tmc.edu/uth_orgs/pub_affairs/facts/sph.html, spearheaded a collaborative five-year effort, the Chinese Human Genome Diversity Project. The work was funded by the National Natural Sciences Foundation of China. Twelve other researchers from seven institutions collaborated on the project. Jin’s article appears in the Sept. 29 issue of the Proceedings of the National Academy of Sciences, a biweekly journal.
Jin used recently discovered genetic markers known as "microsatellites." Microsatellites are repeats of short stretches of DNA that have high mutation rates. They contain more information per gene than traditional markers, and can help make distinctions between closely related population groups.
"The results of this study have strong implications for biomedical researchers," Jin said. "We have to know the genetic differences between populations, so we can find the correct target population in order to study complex diseases like diabetes."
Microsatellites were used to examine the genetic profiles of 28 of the 56 official Chinese ethnic groups, along with 15 worldwide populations. Study results indicate that the majority of the Chinese gene pool has African origins.
Anthropologists are divided over the origin of modern Chinese humans. Some claim human fossil remains unearthed in China point to the independent origin of Chinese Man, while others question the validity of those findings.
Jin stresses that genetic differences among individual human beings account for up to 85 percent of the entire genetic spectrum, while the genetic differences in the world population are only about 15 percent. "No matter which ethnic group you come from, we’re all pretty much the same."
The study also confirms a genetic distinction between northern and southern Chinese populations, and gives rise to the theory that Northern Chinese ethnic groups may actually be a subset of Southern Chinese. It was widely believed that since the origin of Chinese culture occurred in mid- to northern Asia, then modern Chinese Man must have originated there, also.
"Prehistoric migration patterns indicate Southern Chinese moving north probably about 50,000 years ago, and then becoming geographically isolated from their ancestors. So, the cultural and genetic histories of modern Chinese humans are apparently not one and the same," Jin said.
The study has not only stimulated new discussion of prehistoric migration patterns in East Asia, it has also proved the effectiveness of microsatellites in revealing major patterns of evolutionary history among closely related populations.
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