2020-10-31

“Central Media Watches Gansu” The Lan University archaeological team found that Denisovans lived on the Qinghai-Tibet Plateau for a long time

By yqqlm yqqlm

The Lanzhou University archaeological team discovered:

Denisovans< /span>Living in the Qinghai-Tibet Plateau for a long time

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Sediment DNA sample collection

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Sample detection

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Excavation site

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Animal skeletons

“After years of hard work, the Lanzhou University environmental archaeology team has made important progress in the study of the Baishiya cave in Xiahe, Gansu, and found that the site is rich in ancient human activities from the Middle Pleistocene to the Late Pleistocene. The remains, successfully obtained the first Denisovan mitochondrial gene sequence outside Denisovan Cave, revealing that Denisovan lived on the Qinghai-Tibet Plateau for a long time in the Late Pleistocene.”

October 30 In the morning, at the latest “Archaeological China” major project important progress meeting held by the State Administration of Cultural Heritage in Beijing, the environmental archaeology team of Lanzhou University, the major breakthrough in the study of ancient human activities on the Qinghai-Tibet Plateau, was the first released project. Professor Zhang Dongju represented the research team to the industry It is solemnly released by experts and media.

Ancient humans appeared on the Qinghai-Tibet Plateau 160,000 years ago

This is the application of the most advanced ancient DNA analysis technology in the sediments of Chinese archaeological sites The first successful case of extracting genetic information from ancient humans. At the same time, the result titled”The Discovery of Denisovan Genes in Late Pleistocene Sediments from Baishiya Caves on the Qinghai-Tibet Plateau” was published online in the journal Science at 2 am Beijing time on October 30. Following the report in Nature magazine in May 2019 that the environmental archaeology team of Lanzhou University and others discovered the fossils of Denisovan mandibles on the Qinghai-Tibet Plateau at least 160,000 years ago, the focus at home and abroad once again gathered on this ancient And the mysterious ancient humans and Baishiya cave.

In 2019, the team of Lanzhou University and the Institute of Tibetan Plateau Research of the Chinese Academy of Sciences, led by academician Chen Fahu of the Chinese Academy of Sciences, reported the research results of the mandible fossil of the Xiahe Denisovan (Xiahe for short), revealing that this fossil is The first Denisovan fossil found outside the Denisovan Cave in the Altai Mountains provides the earliest evidence of human activities on the Qinghai-Tibet Plateau, extending the spatial distribution of the Denisovan from Siberia to the Tibetan Plateau for the first time. The history of human activities on the Qinghai-Tibet Plateau has been extended from 40,000 years ago to 160,000 years ago. This is the study of the Denisovans and the Qinghai-Tibet Plateauprehistoric humans Double major breakthrough in activity research. Once published, this result attracted hundreds of domestic and foreign media reports. At the end of 2019, it won multiple annual”Top Ten” selections by many domestic and foreign academic institutions:”Top Ten Archaeological Discoveries”,”Ten Scientific Breakthroughs”, and”Ten Scientific Breakthroughs”.”Big Science and Technology Progress” and”Top Ten Science and Technology News” However, because this fossil was discovered earlier and was not unearthed from an informal archaeological excavation, there is a lack of information on specific burial locations, strata and coexisting archaeological remains. Therefore, although the discovery of the Xiahe people greatly promoted prehistoric human activities on the Tibetan Plateau and the Denisovan Research, but the information it reveals is also very limited.

Use technology to release dust-covered light

In 2019, the environmental archaeology team used ancient protein analysis to identify Xiahe mandibular fossils as Denisovans , Using uranium dating methods to determine its age as at least 160,000 years ago. How did Xiahe people live in Baishiya cave? How long did it last? These questions are waiting for answers from materials unearthed from the Baishiya cave. The analysis and research of fossils and the investigation and excavation of the site are carried out simultaneously.

Academician Chen Fahu and the environmental archaeology team began to formulate a site excavation and research plan in 2016, designing a variety of dating methods to establish an age frame for the site, comprehensively collecting archaeological relics, and developing ancient DNA of sediments the study. Many research teams at home and abroad are invited to participate in some analysis work. For example, the team of researcher Fu Qiaomei from the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences is invited to conduct sediment DNA analysis, and Li Bo, Associate Professor of the University of Wollongong, Australia, is invited to jointly conduct sediment single-particle light Luminescence dating work, etc. Sediment ancient DNA analysis is a new molecular technology that can obtain information on ancient populations who have been active at the site, make up for the indispensable shortcomings of human fossils, and open a new window for the study of population activities at paleolithic archaeological sites.

“After the death of an animal or human, the genetic material in the mitochondria-mitochondrial DNA will also be degraded and broken into segments. Whether it can be preserved through tens of thousands of years of historical evolution is related to the preservation of the environment. Closely related, generally speaking, the drier and colder the place is, the more likely it is to preserve.” Zhang Dongju explained.

Before the excavation of the site, the archaeologists were”fully armed”, wearing protective clothing to extract samples into sterile bags to minimize contact and ensure that samples were not exposed to modern human DNA during the collection and transportation process. Pollution. Just like using magnets to suck out iron nuggets from a pile of mixed metals, Fu Qiaomei’s team captured and fished the mitochondrial DNA of 242 mammals and humans in the sample through experiments. Analysis shows that the ancient DNA of animals in the sediments includes extinct animals such as rhinos and hyenas, which are consistent with the remains of animal bones found at the site, verifying the reliability of sediment DNA analysis. At the same time, the ancient human mitochondrial DNA was successfully obtained. Further comparative analysis showed that this is the DNA of the Denisovan.

Another big problem is dating. When did the Denisovans live here? The source and transportation of cave sediments are more complicated, so accurate dating is more difficult. The research team selected 14 animal bones on the first 1-6 layers of the T2, and conducted pre-processing and AMS14C tests at Lanzhou University, Peking University and Oxford University. It was found that the bones on the 4th-6th floors have exceeded the carbon fourteen date. The upper limit is 50,000 years. At the same time, 12 optical luminescence samples were collected on the 2nd-10th floors. The team of the 2018 Ph.D. student Sheng Ting and Li Bo of Lanzhou University jointly carried out single-particle optical luminescence dating analysis.

“When quartz or feldspar particles are buried in the environment, it starts to accumulate radiant energy like a timer. One day we dig it out and use light to excite its energy. The signal coming out will tell us how long it has been silent there. This is the optical luminescence dating method.” Zhang Dongju said. Combining the results of carbon fourteen and optical luminescence dating, the team established a Bayesian age model, which established a reliable age frame for the site about 190-30,000 years ago, and advanced the earliest history of prehistoric human activity on the Qinghai-Tibet Plateau by another 30,000 years. It also provides more conclusive evidence for the conclusion that the fossils were unearthed in the Baishiya cave and that the Xiahe mandibles belonged to the Denisovans.

Opening a new chapter in the study of human evolution in East Asia

The Denisovans are a newly discovered group of ancient humans, and have been widely distributed Neanderthals in Europe are a sister group. His human bone fossils are rarely found, but the genetic characteristics are very significant, and they have genetic contributions to the indigenous populations of modern Oceania, East Asia, South Asia and the Americas. His research was twice selected in the annual selection of Science magazine in 2012 and 2019. Top Ten Scientific Breakthroughs in the World”.

“The known archaeological evidence supports that modern humans originated from the African continent and from there to the world. The discovery of the Denisovans and their different genetic contributions to some living populations paint a picture for us. A more complicated picture of human evolution and migration.” Zhang Dongju said. As the highest and largest plateau in the world, the Qinghai-Tibet Plateau has a unique natural geographical environment:the main body is above 4000 meters above sea level, oxygen is thin, ultraviolet radiation is strong, and animal and plant resources are single. The harsh environment poses a major challenge to human survival and reproduction in this area. Xiahe County, located in the northeastern part of the Qinghai-Tibet Plateau, has historically been at the junction of the plateau ethnic groups and the Central Plains regime. The special geographical environment has also injected more historical and cultural features into Xiahe County. Therefore, studying the origin and source of Tibetans also appears to be extremely meaningful.

Due to the sensational effect generated by the release of academic results and media reports in 2019, the environmental archaeology team of Lanzhou University has improved a lot at the Baishiya site. Not only the local government and the cultural relics protection department are very supportive, but the people nearby also realize the scientific value of the”sacred cave”. In the winter of the same year, the team continued to excavate in the cold wind at the end of the year for more than 20 days. Based on the exploration in 2018, the team successively excavated an exploration of the same size and obtained more abundant archaeological remains.

Zhang Dongju introduced at the important progress work meeting of the”Archaeological China” major project, Baishiya Cave is the earliest known Paleolithic archaeological site on the Qinghai-Tibet Plateau, and its rich cultural heritage is for further understanding of the early Qinghai-Tibet Plateau Human activities provide important information and fill the gaps in the identification of specific species of ancient populations between Homo erectus and modern humans in East Asia. It is of great significance to reconstruct the history of ancient human activities on the Qinghai-Tibet Plateau and even clarify the evolution history of ancient humans in East Asia. The international leading level of Chinese paleolitic archaeology research.

Previously, the environmental archaeology team has achieved important results in the study of agricultural population settlement on the Qinghai-Tibet Plateau. The team’s follow-up research will further reveal the early human history of the Qinghai-Tibet Plateau, especially providing more scientific evidence and information on the physical morphology, genetic characteristics and cultural connotation of the Denisovans on the Qinghai-Tibet Plateau.

“Our current work is only the beginning of the study of the Denisovans on the Qinghai-Tibet Plateau. The Xiahe people lived during the two coldest glacial periods. They should have successfully adapted to the alpine and hypoxic environment. They How to adapt, how to make fires to keep warm, make stone tools, and hunt for fruit is all necessary for human survival. Archaeological work is an important work to show and build the history of the Chinese nation and the treasures of Chinese civilization. Our research has just begun and has unlimited potential.” Zhang Dongju said.

According to Xinhua News Agency