extracted DNA information from the bones and teeth of 166 ancient people and used genome sequencing to finely analyze the formation history of East Asian populations.
Author丨Gan Xiao
"With black eyes, black hair, and yellow skin, you will always be the descendant of the dragon." We Chinese are often proud of our "descendants of the dragon" lineage.
Tracing back to our roots, as East Asians, who are our ancestors and how did they get here? What is the relationship between various ethnic groups?
On February 22, the academic journal Nature published a research paper jointly conducted by Professor Wang Chuanchao’s research group at the Institute of Anthropology of Xiamen University and Professor David Reich’s team at Harvard Medical School. This study, together with 85 co-authors from 43 units around the world, extracted DNA information from the bones and teeth of 166 ancient people and used genome sequencing to finely analyze the formation history of East Asian populations.
Screenshot of the thesis web page
"Snowballing" "questioning"
"Who am I? Where do I come from?" Plato's ultimate philosophical proposition still confuses mankind to this day. In recent years, anthropologists have used advanced life science technologies to try to answer this question from an evolutionary perspective.
Around 2015, Wang Chuanchao, who was very curious about the origins of East Asians, led his team to launch this scientific research project. "At the beginning, our plan was to find ancient bones, teeth and other samples from archaeological remains across the country, extract DNA, sequence them, and reveal the genetic relationship between them." Wang Chuanchao told "China Science Journal" introduce. The
research team has successively obtained a large number of ancient samples from archaeological sites in Shaanxi, China, and Taiwan, China. However, the ancient stories told by these samples did not satisfy researchers.
As a result, they focused on a broader geographical space, expanding from China to the surrounding Russian Far East, Japan and other places, and the number of teams joining the research continued to increase. "For example, if you want to know where a certain group of people came from 5,000 years ago, you may have to trace it back to 6,000 years ago or even longer, and you also need information about the people around them." Wang Chuanchao said.
's analysis of samples from the Russian Far East found that these samples were relatively closely related to ancient humans near Lake Baikal, which inspired them to pursue further inquiries.
"From a geographical point of view, the Russian Far East is almost the end point of human migration, and further north and east are the Bering Strait and the Pacific Ocean, which are not suitable for survival." Wang Chuanchao and researchers analyzed. Based on this, they speculated that these ancient humans may have come from the Mongolian Plateau west of Lake Baikal, and this group of people was most likely to span the entire Mongolian Plateau and connect with the Eurasian steppe.
In 2019, Wang Chuanchao invited scientific researchers from Mongolia to join the team and obtained samples from local archaeological sites to verify this hypothesis.
In this 6-year study, it was precisely because of the continuous questioning of scientific questions that the scientific research team continued to expand like a "snowball". In the end, 85 co-authors from 43 units around the world completed this work.
The largest-scale "East Asian" archeology
This research has obtained important conclusions such as "Sino-Tibetan origins" and "Southern Island and Zhuang and Dong origins". "DNA research results show that the ancestors of the Yellow River Basin about 5,000 years ago have a homologous relationship with the people in the Central Plains and the Tibetan Plateau. This shows that they are the ancestors of both the Han people in the Central Plains and the Tibeto-Burman people." Wang Chuanchao explain. This conclusion also verifies the theory of "sino-Tibetan homology" in linguistics.
At the same time, the research also provides direct evidence for the hypothesis that the Austronesian people originated from the southern region of mainland China, that is, "Austronesian and Zhuang Dong have the same origin." Researchers believe that the ancestors who originated from the southern region of mainland China most likely reached Taiwan via the southeast coast, and then migrated and expanded to Southeast Asia and Far Oceania.
In addition, questioning about Lake Baikal and the Mongolian Plateau refutes the linguistic hypothesis that "the expansion of agricultural people in the Western Liao River contributed to the spread of the original Pan-Eurasian language (Transeurasian)." This is because experimental analysis of ancient DNA found that about 8,000 years ago, the gathering and hunting people on the vast land from the Mongolian Plateau, Lake Baikal to the Heilongjiang River Basin were indeed the ancestors of the Mongolian and Tungus-speaking people, but in 2000 There was no significant genetic influence from agricultural populations many years ago.
It is understood that this is the largest archaeological genomics study in East Asia currently conducted in China. "The number of ancient genome samples from East Asia reported by this study is twice the total number of samples published by domestic research institutions in the past. We hope to change the long-term lag in archaeological genomics research in East Asia, especially in China," said Wang Chuanchao.
Second-generation sequencing meritorious service
In the opinion of the researchers, the success of this study directly benefited from the rapid development of second-generation sequencing technology.
Wang Chuanchao has deep feelings. Around 2000, each genetic site cost about 1 US dollar to sequence. The cost of testing the entire human genome was as high as 2 to 3 billion US dollars. Now it only costs 3,000 RMB.
The high-throughput sequencing technology developed around 2010 has greatly improved efficiency and reduced costs, opening the door to a new world for ancient human genomics research.
"You can imagine that ancient humans were buried in the soil after their death. Their DNA continued to degrade and corrode, and there were many microorganisms and pathogenic bacteria in the soil." Wang Chuanchao pointed out, "When we excavated them today, in fact To restore this person's DNA information from a pile of degraded and contaminated bones, new sequencing technology helps us obtain useful information from a large amount of data. "
In addition, ultra-clean laboratories are also used for ancient human genomics research." Standard configuration", the Institute of Anthropology of Xiamen University established this "sharp tool" in 2017. Researchers need to put on protective clothing, goggles, masks, gloves, and headgear, and go through an air shower before entering this "time and space tunnel" and encountering ancient humans.
Wang Chuanchao and others work in the ancient DNA ultra-clean laboratory (photo provided by the research team)
Regarding this research result, Yang Yimin, a professor at the School of Humanities, University of Chinese Academy of Sciences, commented: "This is only the beginning of the story. As more ancient genome results are published, , I believe that the face of human migration in China over the past 10,000 years will become increasingly clear."
Paper link: https://www.nature.com/articles/s41586-021-03336-2
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