Are China people from Africa?

So far, all kinds of data show that the ancestors of China people did come from the African continent, and people all over the world have a common ancestor.

Professor Li Jing from the Center for Modern Anthropology of Fudan University concluded through DNA analysis that modern China people originated in Africa! Because of the strong scientific support, his views have been endorsed by many people. But why are we so different from Africans? Where did the descendants of ancient humans discovered in China go?

How did ancient humans in China mysteriously disappear?

Scientists in China tested their DNA to explore their life experiences. Our ancestors came from Africa.

◎ How do scientists find the "migration map" of their ancestors through DNA testing?

How did the aborigines in China disappear 60,000 years ago?

How did ancient humans in China mysteriously disappear?

The research team led by Professor Li Jing from the Center for Modern Anthropology of Fudan University concluded through DNA analysis that modern China people originated in Africa! Because of the strong scientific support, his views have been endorsed by many people. However, if Professor Li Jing's conclusion is true, why are we so different from Africans? Where did the descendants of ancient humans discovered in China go? Were they killed by Africans from afar?

The ancestors of all modern people were African women 200,000 years ago?

The reporter found Tan Jingze, a teacher from the Modern Anthropology Research Center of Fudan University in Shanghai. She told reporters that Professor Li Jing's view that China people originated in Africa was published as early as 200 1. At that time, he led a research team to study the genetic molecules of China people. They want to study where China people originated. Do modern people all over the world really originate from Africa as their predecessors said? In the end, their results are consistent with their predecessors.

It is not the first time that Professor Li Jing suggested that China people originated in Africa. 1987 It was suggested that all human beings originated in Africa. Kahn and Wilson were the first scientists to infer that human beings originated in Africa.

1987 At the beginning, Kahn and Wilson proposed to trace the mitochondrial DNA of all babies forward, and finally traced it back to a woman who lived in Africa about 200,000 years ago, which is the ancestor of people all over the world today. About 6.5438+0.3 million years ago, a group of her descendants left their hometown in Africa, scattered all over the world, replaced the local aborigines, and finally settled all over the world and evolved into modern different races. So some people call this theory "Eve Theory". People think that modern people have only one origin, from Africa.

Since then, more and more genetic evidence supports that modern people all over the world, including China, originated in Africa. From 65438 to 0998, China scientist Chu Jiayou and others used 30 autosomal microsatellite loci to analyze the genetic structure of northern and southern populations, Han nationality and ethnic minorities. Microsatellite polymorphism and phylogenetic tree cluster analysis support that modern China people came from Africa and entered Chinese mainland via Southeast Asia.

Due to the high mutation rate of microsatellite loci, there are some restrictions on the study of long-standing human evolution events and population migration. Su Bing, a researcher at Kunming Institute of Zoology, Chinese Academy of Sciences, and others developed a set of research theories about Y chromosome single nucleotide polymorphism markers (SNP) to study the origin of China people. The research theory of Y-SNP is also the research theory of Li Jing and AARON Li.

This shocking conclusion comes from an ancient DNA molecule.

In 20001year, the research team led by Professor Li Jing published a paper entitled "Y chromosome genetic evidence supports that modern China people originated in Africa" in authoritative scientific journals around the world. From the perspective of DNA, this paper draws the conclusion that "modern China people originated in Africa".

In the article "Supporting Modern China People Originating in Africa" provided by Tan Jingze, the reporter learned that Professor Li Jing studied the origin of human beings through the genetic characteristics of Y chromosome in human genes. Why choose Y chromosome? Because the y chromosome is relatively simple from a genetic point of view. We know that everyone has two sets of chromosomes, one from his father and the other from his mother. Among these chromosomes, Y chromosome is a male chromosome, which is inherited only by the father, which reduces the mutation rate of the gene, so the "historical trajectory" of gene inheritance can be reflected more clearly through Y chromosome. Therefore, many geneticists, including Professor Li Jing, regard this genetic material as the best material to study the origin of modern human beings.

Li Jing and his colleagues focused on three ancient Y-SNPs, namely M89, M 130 and YAP. These three Y-SNPs are all three mutation types based on M 168 mutation.

Why use the genetic molecule M 168? Li Jing and others explained in the article, "People think that M 168 is a mutant produced by African humans, and its primitive type only appears in East Africans. Modern people and some Africans except Africa have the mutation type of M 168, and M 168 is the most direct evidence that modern human common descent is in Africa. "

How do scientists infer the age of ancient humans from DNA?

Some people will wonder how scientists know the age of a DNA molecule. Why did M 168 exist in primitive Africa? How was the age of this DNA inferred?

AARON Li, an associate professor at the Center for Modern Anthropology of Fudan University, explained in an interview that molecular anthropology uses non-gene DNA sequences. Because genes have physiological functions, they cannot be changed casually. If our genes change at will, our health will be affected.

In their molecular anthropology research, the research materials and methods have two basic points, one is non-gene and the other is haploid inheritance. Mitochondrial DNA and Y chromosome DNA are haploid genetic molecules. On the Y chromosome, there are few genes, and most of them are non-gene sequences. In non-gene sequences, two types of mutations were analyzed. A mutation called single nucleotide polymorphism (SNP) is rare and stable. The same mutation, history will not repeat itself, nor will it change back. Therefore, the structural relationships of various types of Y chromosomes around the world are constructed on this basis. The other is called short tandem repeat mutation (STR), which keeps getting longer and shorter, and the change is even. Therefore, as long as the total amount of mutation is investigated and divided by the speed of mutation, the production time of various types of Y chromosomes can be obtained.

That is to say, the appearance time of mutant molecules can be inferred from the mutation law of DNA molecules called SNP and STR. The appearance time of the mutant molecule M 168 can also be inferred.

China's DNA has African genetic traces.

Li Jing and his colleagues randomly selected nearly 10000 male samples from all over China for the experiment. Through the study, it was found that all samples only had three mutations: M 168. That is to say, in these 9988 samples, only three of the oldest genetic molecules have mutated, namely M89, M 130 and YAP-. 1 mutation becomes M89T, M 130C and YAP-, and the number of individuals with this type of mutation is the largest, accounting for 93.4%. 1 mutation is M89C, M 130T and YAP-, accounting for 3.7%, with 370 cases; The final mutations were M89C, M 130C and YAP+, with 290 cases (2.9%). Except for these three mutations, no other new mutant species appeared.

This result is consistent with the genotyping results in other parts of the world except Africa, that is to say, there are no new mutations in M 168 outside Africa, only these three mutations appear. Only the emergence of new mutant samples can show that China people do not necessarily originate from Africa.

Therefore, nearly 1000 China male samples detected by Li Jing all carry "genetic traces" from Africa, which supports the theory of African origin from another angle.

This result is beyond Li Jing's expectation.

How to know the migration route of ancestors through DNA

Li Jing and others not only hope to find evidence of the independent origin of China, but also hope to study the genetic structure and distribution characteristics of China people and their genetic relationship with the people around China by investigating the distribution frequency of these three ancient Y chromosome haplotypes. How can we know the distribution and changes of human beings through these genetic molecules?

The reason is very simple, because each nation's genetic molecules have their own personality and * * *. In Li Jing's research, they can infer the distribution and migration process of various ethnic groups in China through three mutation types: M89, M 130 and YAP. For example, people with mutation types of M89T, M 130C and YAP- are most likely to appear in the Han population, and the number of Han people in the sample is also the largest, reaching 93.4%. The other two mutants are more likely to appear in ethnic minorities. According to the distribution characteristics of existing nationalities, we can roughly infer the migration and development of human beings.

AARON Li once studied his own DNA molecules to infer where his ancestors might have come from. He saw from his Y chromosome that his Y chromosome is O 1 type, and its roots are in the coastal area of Beibu Gulf and the west part of Hainan. The discovery of O 1 can be traced back to more than 20,000 years ago, and it spread to Guangdong, Taiwan Province and Fujian about 1 10,000 years ago. It began to reach the coastal areas of Jiangsu and Zhejiang today 8,000 years ago. The Y chromosome of O 1 is the type of this group of people who arrived in the coastal areas of Jiangsu and Zhejiang about seven or eight thousand years ago, and it is an indigenous type here, so he inferred that the history of his ancestors was in Guangdong more than 10,000 years ago and arrived in Zhejiang and Shanghai 8,000 years ago.

Similarly, scientists can infer how Africans migrated to different parts of the world, including China. But how did Africans overcome all kinds of obstacles along the way and come to China thousands of miles away? For example, how did they cross mountains and rivers, and how did they survive under different climatic conditions in different regions? On this issue, Li Shilin, a teacher from the Modern Anthropology Research Center of Fudan University, said that human ancestors had no purpose in the process of migration, mainly depending on where the environment was suitable for survival.

According to the geographical conditions at that time, Africans should be scattered all over the world along the coastline, because the coastline can get food from land and sea at the same time, which is convenient for their survival and development, and the team will become bigger and bigger, thus extending to the whole world, including China.

Why do we say that our ancestors were pure Africans?

But even if ancient Africans overcame the obstacles of the natural environment and came to all parts of the world, including China, why did Africans living alone become our ancestors, and where did all the human groups living in their native land go? Why can genetic scientists say with such certainty that modern people are descendants of Africans? Not the descendants of indigenous people or the descendants of indigenous and African hybrids?

For this problem, Li Jing and others explained it like this. At the beginning of their experiment, they also did it with doubts about the origin of Africa. They also considered the possibility of indigenous people staying. After all, many primitive hominid fossils have been unearthed in Asia, especially in China, and these hominid fossils have shown good continuity and inheritance in time and form. Why did modern people finally become descendants of people who migrated from Africa? Is it possible that there is protohuman inheritance?

This is why Li Jing and his team took so many original experiments from China, trying to find out the difference from the samples found in the past, that is, the mutant M 168 has a new mutation, but the result is still not. Therefore, Li Jing and others finally reached the same conclusion as before. China people also come from Africa.

How did indigenous people disappear?

Where did the protozoan go? After carefully studying the fossil evidence unearthed in China, Li Jing found that there was a fault between ancient humans and modern humans. All fossils belonging to ancient humans have a history of more than 6.5438+million years, while those of modern humans are less than 40,000 years (mostly between 6.5438+million and 30,000 years), which means that no fossils from 50,000 to 6.5438+million years have been found so far. After analysis, Li Jing and others think that it is no accident that faults appear on this fossil, because most biological species on the East Asian continent became extinct during this period.

The human fossil faults 50,000 ~ 6,543.8+10,000 years ago are roughly consistent with the existence time of Quaternary glaciers in this area. Due to the existence of Quaternary glaciers, most biological species in East Asia and other regions, including Chinese mainland, could not survive during this period, including indigenous people. In Africa, because it is close to the equator and the temperature is relatively high, the ancients there can survive. Teacher Kong Xinggong from the School of Geography of Nanjing Normal University told the reporter that during the ice age, the average temperature in the equatorial region dropped by about 1-2℃, and the more the temperature went to the poles, the more it dropped.

Perhaps it is for this reason that this part of Africans living near the equator survived, while the ancients in most other areas disappeared. Nyante, known as the origin of Europeans, should have died out about 20,000 years ago, because it was the peak of the Ice Age.

About 60,000 years ago, just after the end of the Ice Age, Africans began to enter Chinese mainland from south to north in Southeast Asia, thus replacing the pre-Ice Age hominids in Chinese mainland and becoming the ancestors of modern China people.

From Professor Li Jing's point of view, it seems certain that China people originated from Africa. But people still have many questions about it. The biggest question is, can we see the whole process of human migration and development from only a few genetic molecules? Therefore, some scientists are still skeptical about this. They believe that the theory of DNA genetics and molecules cannot completely rule out the possibility that protozoa may also stay and reproduce.