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China.org.cn Professor Jin Li of the Research Center of Contemporary Anthropology at Shanghai Fudan University (RCCASFU) says he has proved modern Chinese people originated in Africa. 
His research, based on DNA testing techniques that have transformed the study of human evolution, supports the global scientific consensus that all modern humans are descended from people who migrated from Africa tens of thousands of years ago. The so-called "out-of-Africa" theory is the current scientific consensus and seems to be based on convincing genetic data.But archeologists have spent decades studying the fossil remains of ancient populations of hominids that lived in China long before the African migrants arrived. The question arises what happened to these early humans? Were they killed off by the newcomers? Is it possible that the two populations interbred, and would that help explain some puzzling physical differences between modern East Asians and people in Africa and elsewhere? Despite the DNA evidence, some Chinese archeologists continue to defend a multi-regional theory of human evolution in which different populations around the world evolved from local hominids independently. All modern humans are descended from a 200,000-year-old African woman Professor Jin published first his research in 2001, but he was not the first to reach essentially the similar conclusions. In 1987 the New Zealander Allan Charles Wilson and Rebecca Cann published a study of mitochondrial DNA that supported the "African Eve" theory that all human beings living today are descendents of a single woman who lived in Africa around 200,000 years ago. According to Wilson and Cann descendents of this "African Eve" migrated around the world and later evolved into the different varieties of modern humans. Since then more and more genetic evidence has accumulated, all supporting the view that modern humans, including Chinese people, originated from a single population in Africa. In 1998, Chinese scientist Chu Jiayou and his team analyzed the DNA microsatellites (also known as simple sequence repeats) of northern and southern Chinese, both those of Han and ethnic minorities. Chu concluded that the ancestors of the modern Chinese had migrated to China from Africa via South Asia. As the mutation rate of DNA microsatellites is high, it is not the best method available for researching ancient human migration and the evolution process. Su Bing and other scientists from the Kunming Institute of Zoology proposed an alternative approach using single nucleotide polymorphism (SNP) in the Y-chromosome (Y-SNP). This was the approach used by Prof. Jin Li and associate professor Li Hui. DNA molecules point to a startling conclusion Jin chose the Y-chromosome because it is relatively pure from a genetic perspective. Human beings have two sets of chromosomes, X and Y, inherited from our mothers and fathers respectively. The Y-chromosome comes from male and has a low mutation rate. It reflects how human genes are passed on from generation to generation more clearly than the X chromosome. As a result, geneticists see it as ideal material for the study of human origins. Jin and his team focused on three SNPs on the Y-chromosome M89, M130 and YAP. They are mutations of another mutated DNA molecule M168, which originated in Africa between 31,000 and 79,000 years ago. "M168 originated only in East Africans. All people outside Africa and some Africans still have it. So it is the most direct evidence to prove that modern humans came from Africa." Jin wrote in his paper. How do scientists work out the age of strand of DNA? You may ask: How do scientists work out the age of a DNA component? How do scientists know M168 existed in ancient Africa? How do they work out exactly when it originated? Associate Professor Li Hui said that non-genic DNA sequences are used in molecular anthropology because genes possess many physiological functions. If a gene mutates, a person's health may be greatly affected. There are two fundamental features of the materials Jin and his team chose: they were non-genic and genetic haploid. Mitochondrial DNA and Y-chromosomes belong to this category. Most of the Y-chromosome consists of non-genic sequences. The team analyzed two types of mutation of the non-genic sequence. The first was SNP. This type of mutation is rare and stable. It will not repeat or change back to its original form. The structural relationships of all types of Y-chromosome all over the world are based on this feature. The other type of mutation was short tandem repeats (STR). These lengthen and shorten at a constant speed. Thus the origin of each type of Y chromosome can be dated by dividing the total number of mutations by the rate of mutation. In other words analysis of SNP and SRT mutations show when the M168 mutation occurred. DNA from modern Chinese proves their African origins Jin Li and his team randomly selected 9,988 Chinese males as samples. They found that all samples of M89, M130, and YAP led to only three mutations. 9,329 samples (93.4 percent) mutated into M89T0M130C and YAP-; 370 samples (3.7 percent) mutated into M89C0M130T and YAP-. 290 samples (2.9 percent) mutated into M89C0M130C and YAP+. No new mutation was found. The results coincided with findings in other parts of the world, that is, M168 displayed no new mutations in China. The result proved that Chinese people must have come from Africa, along with all other modern humans. But Jin Li's research also supported the African origin theory from another perspective, which was beyond their original expectations. 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. 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? The history of modern humans starts with late Homo sapiens. Dr. Xing Song from the Institute of Vertebrate Paleontology and Paleoanthropology, CAS, says we must first define what we mean by the origin of modern man. It is a completely different concept from the origin of mankind. The latter refers to when and where the ancient apes evolved into people; while the origin of modern man refers to when and where people who look like modern humans originated. The academic view is that modern humans, the latest phase in the history of human evolution, i.e. late Homo sapiens, appeared in the period from around 50,000 to 10,000 years ago. Except for some particular characteristics, late Homo sapiens are basically the same as today's humans. Their fossils are widely distributed not only in Asia, Africa, and Europe but also in Australia and the Americas. Remains of late Homo sapiens dating back to between 50,000 to 37,000 years ago have been found all over China. The finds include Hetao man in Erdos, Inner Mongolia; Liujiang Man, dating back 50,000 to 30,000 years, in Liujiang County, Guangxi; the Upper cave man, dating back 30,000 years, in Zhoukoudian, near Beijing; and Ziyang man dating back 10,000 years, in Ziyang City, Sichuan. Professor Jin Li maintains that late Homo sapiens from all over the world, including China, had common ancestors, that is, migrating Africans, who arrived in China 60,000 years ago. China has been continuously settled by humans since the earliest times But despite the seemingly conclusive genetic evidence, Professor Wu Xinzhi insists the debate between "single-region evolution" and "multi-region evolution," is not settled. He maintains that Africa is not the only origin of modern humans, but that modern man evolved separately in several parts of world. He believes there is ample evidence that at least some of the ancestors of modern Chinese were native to the area. From the 1920s on, archaeologists discovered large numbers of ancient human fossils in China. According to Professor Wu, different populations of ancient humans lived in overlapping periods. Yuanmou Man in Yunnan Province dates back 1,700,000 years, Shaanxi Lantian Man 1,150,000 to 600,000 years, Peking Man 500,000 to 200,000 years, Shandong Yiyuan man 400,000 years, Anhui Hexian 300,000 to 200,000 years and Guangdong Maba Man 100,000 years. Ancient human fossils found in China Homo erectus: Yuanmou Man 1,700,000 years ago, in Yuanmou County of Yunnan Province Lantian Man 1,150,000 to 600,000 years ago, in Lantian County of Shaanxi Province No. 1 Nanjing Man 600,000 years ago, Tangshan of Nanjing Peking Man 500,000 to 200,000 years ago, Zhoukoudian of Beijing Yiyuan Man 400,000 years ago, Yiyuan of Shandong Province Early Homo sapiens: Dali Man 230,000 to 180,000 years ago, Dali of Shaanxi Province Maba Man 200,000 to 160,000 years ago, Maba of Guangdong Province Changyang Man 195,000 years ago, Changyang of Hubei Province Late Homo sapiens Upper Cave Man 30,000 years ago, Zhoukoudian of Beijing Liujiang Man 50,000 to 30,000 years ago, Liujiang County of Guangxi Province The fossil record shows that in China there have always been different populations of ancient humans. Therefore, it remains possible that today's Chinese people are directly descended from them. But there is a major problem facing the proponents of the multi-regional thesis: in China fossils from different eras are rarely found in the same location. This implies the different populations were unrelated and casts doubt on the thesis of continuity of settlement. Wu says this is because not all of the ancient human remains were fossilized and became available to later generations. Essentially he is saying there are haphazard gaps in the fossil record. Is Nanjing Man the ancestor of the modern Chinese? Xu Hankui, a researcher from the Nanjing Paleontology Institute, who discovered the fossil remains of Nanjing Man, also supports the hypothesis of multi-regional evolution. When fossilized skulls of Nanjing Man were discovered by peasants exploring an ancient lava cave, Nanjing Paleontology Institute sent several experts on a field trip. Xu was among them and participated in the study of the fossils. Later, the Institute of Vertebrate Paleontology and Paleoanthropology showed that one of the skulls was of a 21 to 35-year-old women who lived 600,000 years ago and suffered from a bone disease called periostitis. She had many of the characteristics of Beijing Homo erectus, and genetic connections with other ancient Chinese human fossils. Another skull was from a male somewhere in the transitional phase between Homo erectus to Homo sapiens. There was gap of 100,000 years between the two skulls, and the finds showed evidence of continuous evolution of ancient Chinese human populations. Xu Hankui believes that the Nanjing Man finds are evidence of multi-regional evolution. The puzzle of Chinese people's shovel-shaped front teeth One of the puzzles that the out-of-Africa theory needs to account for is the prevalence of shovel-shaped front teeth among the modern Chinese population. Dr. Xing Song says the distinctively-shaped teeth are prevalent in the Mongoloid race in East Asia. Licking their inside front teeth, Chinese people will find that there's a dent in their upper teeth while the surfaces of the lower ones are even. From the inside, the upper teeth look like shovels. According to Xing, these peculiarly shaped teeth were inherited in a continuous line from early Chinese hominids. About 80 percent of Chinese have such upper front teeth in contrast to only 5 percent of Europeans and 10 percent of Africans. Xing says this is strong evidence of the continuity of human evolution in China. Moreover, hominid fossils in China share the same facial features: comparatively flat faces, a larger angle between the nose and the forehead, a flat nose bridge, rectangular eye sockets and forward-projecting cheekbones. All these features are absent in Africans. Early Chinese lacked advanced stone technology seen in Africa. The stone artifacts unearthed in China also present difficulties for the out-of-Africa theory. In Palestine, archaeologists discovered stone artifacts from 100,000 years ago. These artifacts, very sophisticated and skillfully made, belong to the third phase of stone artifacts, much more advanced than the first and second phases. Palestine is an obvious route for African hominids to travel to the Eurasian Continent. If the geneticists are right, the African ancestors of the modern Chinese left Africa about 100,000 years ago, and passed through Palestine before reaching China some 60,000 years ago. Logically, the trekking Africans should have had the skills to make third phase stone artifacts when they arrived in China, and we would expect to find such artifacts. But the fact is that the most basic stone artifacts, dating back 1.7 million years ago, were still in use on the Chinese mainland 30,000 years ago. About 98 percent of stone artifacts used by Chinese hominids belong to the "first phase." If migrating Africans were the ancestors of modern Chinese, why didn't they carry their advanced stone-working skills to China? Huang Wanbo, a research fellow of the Institute of Vertebrate Paleontology and Paleoanthropology of Chinese Academy of Sciences, has been conducting paleoanthropological research for more than 20 years in the Three Gorges area. He says that just as the physical characteristics of East Asian hominid fossils can be traced back to a single origin, so can the artifacts of ancient East Asian cultures. For example, the "hand-axe" was one of the important African stone artifacts, dating back 1.7 million years. Most were made of obsidian formed by volcanic eruptions. In contrast, the ancient Chinese mostly used choppers and crushers made of quartz. Gao Xing, another research fellow, echoed his colleague's opinion, saying that Chinese culture had developed continuously without interruption since remote antiquity and there was no sign that it had ever been replaced by foreign cultures. Chinese may be "hybrid" descendants of "natives" and African migrants Wu doesn't rule out that Chinese people interbred with African or European migrants but maintains this was relatively rare. There is evidence of genetic exchanges between ancient Chinese and Europeans and Southeast Asians. Unlike the rectangular eye sockets of most Chinese hominid fossils, the Maba skulls unearthed in south China's Guangdong Province had round orbits, which may have come from interbreeding with Europeans. Another example is the bulging occipital bone in skulls discovered in Guangxi. Similar skulls were also discovered in Sichuan and Yunnan. The characteristics are also typical of Europeans. Moreover, some ancient Chinese skulls also exhibit high nose bridges, which could come from either European or African ancestors. Xu Hankui says the similarities between the skulls of Nanjing Man and European and African Homo erectus and Homo sapiens prove that hybridization took place during the evolution of the modern Chinese. Wu says hybridization became more frequent as human travels covered a wider area. Foreign genes gradually changed the original Chinese type. As a result some modern Chinese have rectangular eye sockets and some have round ones. Can human history be inferred from fossil DNA? According to Xu, inferring human history from tests on modern human DNA is an uncertain approach. But why can't we use DNA from fossils? As early as 1974, scientists successfully collected mitochondrial DNA from 60,000-year-old remains in southeast Australia. They concluded the DNA had no connection with other DNA discovered in specimens of early Man known to have originated in Africa. At the time, the result cast doubt on the idea that modern humans originated in Africa. But Xu said DNA collected from fossils is unreliable because after being buried for millions of years it could be polluted by other materials, especially water. He says only DNA collected from the insects preserved in amber can reliably be used in genetic research. Wu cites an article by Chinese American, Wen-hsiung Li, who argues that the genetic research done so far is relatively limited in scope and that much more evidence needs to be gathered before final conclusions can be drawn. So while the genetic evidence points strongly to the African origin of all modern humans, including the Chinese, dissenting archeologists maintain the fossil record supports some version of the multi-regional hypothesis and suggest DNA evidence alone is inconclusive. Obviously, this complex debate is set to continue.
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