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“Show me a face and I can tell if it’s from north China or south China,” says Li Jin, a human geneticist at University of Texas at Houston. “You can clearly see the difference.”
People from northern China tend to be bigger, and their faces are flatter. Those from southern China tend to be shorter and darker. A new genetic study shows the differences aren’t just skin deep.
Jin, along with researchers from several Chinese institutions participating in the Chinese Human Genome Diversity Project, have mapped out differences in gene patterns among people from 43 ethnic groups in China and Asia.
Ranjan Deka also said, the paper also “overwhelmingly supports” the “out of Africa” theory that modern humans all descended from a common ancestor who evolved in Africa about 200,000 years ago.
Because Homo erectus, the predecessor of Homo sapiens (modern humans), had earlier migrated from Africa to China, some paleontologists would like to argue that modern humans evolved independently in Africa and Asia and perhaps other places of the world as well. If this were true however, genes from people in one part of the world would be very different from people in another part of the world.
The gene data from the Chinese, Deka says, “shows genetic continuity with other global populations,” which argues that modern humans evolved once in Africa and then supplanted earlier hominids in a second wave of migrations.
Migration clues can be found in parts of DNA called microsatellites where a short genetic code is repeated several times. Microsatellites change quickly over time, and by comparing differences between different populations, researchers can deduce the migration paths taken by ancient humans.
Those genetic clues indicate that humans spread from the western Asia through Pakistan and India along the Indian Ocean coastline, arriving in Southeast Asia some 60,000 to 70,000 years ago. From there, the populations spread north and northwest into China, Siberia and eventually crossing the Bering Strait into North America.
The south-to-north migration pattern runs counter to common beliefs. “This is because the Chinese culture was originated in the northern part of China and then expanded,” Jin says, “but that was much later.”
Some paleontologists had also speculated northern Chinese were a separate people who took a more northern route across Kazakhstan into Asia, but the genetic study indicates that this smaller, later migration spread only as far as western China.
Although almost all Chinese originated from a common southern Chinese population, geographic barriers such as mountains and rivers soon split them. “Then the genetic differentiation really occurred,” Jin says. “They are very different.”
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