Are Chinese descendants of an African Eve?
0 
Tracing human migration routes using DNA
Besides trying to find evidence to prove one way or another whether Chinese people had an independent origin, Jin and his team wanted to study the genetic differences among people living in different parts of China by investigating the distribution frequency of the three ancient Y-chromosomes.
 |
|
Tracing human migration routes using DNA |
The molecular genetic structure of each ethnic group has its own particular characteristics. By analyzing the mutation process of M89, M130 and YAP, they figured out the distribution and migration routes of the different ethnic groups in China. For example, most samples that mutated into M89T, M130C and YAP- were from Han Chinese individuals. The other two types of mutation were more common in ethnic minorities.
Li Hui tested his own DNA to see where his ancestors came from. His Y-chromosome is type 01, which originated around Beibu Bay and the west of Hainan Province about 20,000 years ago. Type 01 then traveled to Guangdong, Taiwan and Fujian about 10,000 years ago and moved to the coastal areas of Jiangsu and Zhejiang 8,000 years ago. So Li's ancestors must have followed the same route.
Scientists use similar methods to tell how the original Africans migrated around the world. Li Shilin, a teacher at RCCASFU, says human ancestors didn't have any specific destination. They roamed wherever was favorable for their survival. Judging by the geographic and environmental conditions at the time, our African ancestors probably traveled along the coast where they could find food both on land and in the sea. As the population increased they moved to other parts of the world, including China. Why did the African migrants survive but not the original Chinese? Though ancient Africans survived the formidable difficulties and managed to travel to China thousands of years ago, why do geneticists claim they are ancestors of Chinese? What happened to the original primitive human inhabitants of China? Is it possible that modern Chinese people are descendents of these early native hominids or the result of interbreeding between them and the African migrants? Jin and his team originally took this possibility into consideration. After all, many ancient human fossils had been discovered in Asia, especially in China. Their shapes and timelines displayed continuity and the inheritance of traits. To allow for this possibility, Jin's team collected their samples from all over China to see if they could find a different mutation of M168. But they found nothing new. Their conclusion remained that the ancestor of all modern Chinese people was a pure-blooded African. How did the original human population of China disappear?
Regarding the question, what happened to the original hominid population of China, Jin Li pointed out that there is a 60,000 year gap in the human fossil record. All ancient human fossils are older than 100,000 years, while modern human fossils are all less than 40,000 years old (and mostly 10,000 to 30,000 years old). That means no human fossils from 50,000 to 100,000 years old, that might support the hypothesis of multi-regional evolution, have yet been found in China. Jin Li believes this gap is not accidental. During that 50,000 year period, the majority of biological species on the East Asian mainland became extinct.
That fossil gap corresponds to the Quaternary ice age, which killed off the majority of species, including indigenous humans, in East Asia, as well as other parts of the world. But in Africa, near the equator, where the temperature remained relatively high, ancient human beings were able to survive and reproduce. Kong Xinggong from the School of Geographical Sciences of Nanjing Normal University, said that during the ice age, the average temperature in the equatorial regions was only 1-2 ℃ lower than now, while closer to the poles, the temperature dropped dramatically.
This explains why equatorial Africans survived, while the ancient human populations from other parts of world disappeared. The Neanderthals became extinct in Europe about 20,000 years ago, at the height of the ice age there. After the ice age, Africans migrated from Southeast Asia into Chinese mainland, replaced ancient pre-glacial man there, and became the ancestors of the modern Chinese.
Professor Jin Li sees the African origin of the Chinese people as a hard fact, but not everyone agrees. Some scientists say it is wrong to rely solely on genetics to establish the origins of modern humans.
Academician Wu Xinzhi from Institute of Vertebrate Paleontology and Paleoanthropology at the Chinese Academy of Sciences, believes that the ancient human population on the Chinese mainland did not die out, but evolved into modern Chinese. In other words, modern Chinese people have a direct lineal descent from the original hominid inhabitants. On what does Wu base his argument and can it stand up to scrutiny?
Go to Forum >>0 Comments