SCIENTISTS REVEAL ANCIENT MAN' S ROUTE TO EAST ASIA
Chinese scientists reveal ancient man’s route to East Asia.
The research results of human molecular genetics support the theory that human beings originated in Africa, which means modern humans living on Earth are all descendants of prehistoric humans who originated in Africa about 50,000 to 100,000 years ago. Which route did China's ancestors travel along when they migrated from Africa to East Asia?
To provide new scientific evidence to solve this question, Ma Runlin, researcher from the Institute of Genetics and Developmental Biology under the Chinese Academy of Sciences (CAS), and Su Bing, researcher from the Kunming Institute of Zoology under the CAS, recently cooperated with other scientists to conduct sampling research on the genetic materials of modern humans in the East Asia region.
Ma noted that there are two hypotheses about the route taken by the ancient Chinese as they migrated from Africa to East Asia, namely, the "South Route" and the "North Route." According to the South Route hypothesis, the ancestors of modern humans in East Asia first traveled to the Arabian Peninsula after they left East Africa, and then migrated into the Southeast Asia region (including Yunnan Province of China) along the coastline of the Indian Ocean.
Afterward, these populations gradually spread north to the interior area. Supporters of the South Route hypothesis theorize that the ancestors of people in East Asia migrated from the south to the north. The follow-up research results of human geneticists have supported this hypothesis.
However, as the research progressed, scientists found that there are significant differences between the genetic information contained in Y-chromosomal haplogroups of the Chinese people living in the north and south parts of China divided by the Yangtze River. Haplogroups is a scientific term for a grouping of haplotypes, which are a combination of DNA sequences that are transmitted together in linked genes.
They discovered many genetic signals in people living in the northern regions of East Asia that were previously thought to be exclusive to Central Asian and European people. Therefore, they began studying again the possibilities that East Asians took a northern route.
According to this theory, ancient Asians moved out of North Africa to the northern Mediterranean regions and then to Central Asia and Europe, respectively. Nevertheless, the North Route theory is still just a hypothesis because scientists cannot rule out that the genetic signs are a result of the gene flow from Central Asia and Europe to East Asia in recent times rather than in prehistoric times.
How did our ancestors migrate to East Asia? In addition to archaeological research, human geneticists and other researchers also chose to collect a large enough sample of Y-chromosomal haplogroups to carry out comparative studies and to identify the formation time of those Y-chromosomal haplogroups.
The group of researchers led by Ma sampled the DNA of 3,826 men from the Korean Peninsula and from 116 regions in both southern and northern China, mapped the geographical distribution of Y-chromosomal haplogroup variants and identified the formation time of related haplotypes.
The researchers also analyzed the mitochondrial DNA of the men sampled because mitochondrial genetic information is inherited only from the mother, which is called "matrilineal inheritance." This way, scientists found out where our "mothers" came from.
Research results show that about 93 percent of the Y-chromosomal haplogroups of people sampled contained genetic information that supports the South Route theory, while some 7 percent of the results show that there is indeed a gene inflow from Central Asia and Europe.
Guangming Daily contributes to this report.