Kunming Institute of Zoology The research results published in Current Biology have aroused heated discussion. Chinese scientists recently sequenced the protein genome of a late Pleistocene human excavated from Malu Cave. The results showed that this genome represents the early diversified lineage of East Asia.
What's more remarkable is that this genome is closely related to the first people to arrive in the Americas.
Was the Chinese the first to reach the American continent?
In 2002, retired British naval officer Gavin Menziesty proposed in his book "1421: China Discovered America" that Zheng He's fleet had sailed to the Americas as early as 1421. This view, which is 70 years earlier than and Columbus , has aroused strong repercussions around the world.
And in 2005, at the international academic symposium commemorating the 600th anniversary of Zheng He 's voyages to the Western Ocean, Menzies' assistant reiterated this view and showed a world navigation map, believing that this map was probably from Zheng He. hand. But he didn't have enough evidence to support this idea, and no experts had dated the ink on the map, so the guess was unconfirmed.
However, scientists from the Kunming Institute of Zoology sequenced genes from 14,000 years ago and showed that the first people to arrive in the Americas might really have come from China.
Malu Cave Man is an early modern human
In 1989, quarry workers discovered a cave that had long been naturally closed in Mengzi, Yunnan. After identification, experts confirmed that it was an ancient human site. After rescue excavation, more than 30 fossils were unearthed from this site, including skulls, mandibles, femurs, and fossils of mammals such as red deer, macaques, and black bears. In 2008, it was determined that the age of the entire Malu Cave site ranged from 17,830±240 to 13,290±125 years ago.
Archaeological excavations in southern my country have unearthed many late Paleolithic sites. After carbon 14 determination, it was confirmed that the oldest thin slice tools came from Yunnan Province, my country. Among these sites are the Mengzi people from Malu Cave, Yunnan, and the Longlin people from Laomaocao Cave, Guangxi. According to modern characteristics, they all have mosaic characteristics of modern humans and ancient humans.
At first, researchers believed that Mengzi Man might be a branch of late in human evolution, belonging to a "minority among the people at that time" and possibly representing an unknown, extinct ancient population in East Asia. Early research on it found that although the Mengzi Man is within the variation range of modern humans, it is close to the boundary of the variation range of and Homo erectus , and has a relatively unique human phenotype.
But this time the skull (MLDG1704) that was genetically sequenced by the Kunming Institute of Zoology was unearthed with strata dating to about 14,000 years ago. After conducting genetic analysis of ancient DNA on this skull, it was proved that this skull of the Mengzi Man is not an ancient human, but comes from an early modern Asian female.
and her mitochondrial DNA belongs to the extinct basal lineage of the M9 haplogroup, which indicates that there was obvious genetic stratification in the ancient southern populations of East Asia and Southeast Asia during the Late Pleistocene, as well as a certain degree of north-south differences.
Glacier Extinction in the Late Pleistocene
You may be confused by a term in the above text. What is the Late Pleistocene?
The late Pleistocene is also called the Pleistocene, which is the final stage of the Pleistocene in the Quaternary Epoch , from 126,000 (±5,000) to 10,000 years ago. Most of the late Pleistocene was dominated by glaciers, and many large animals such as the saber-toothed tiger, jaguar, and wolf became extinct during this period.
However, the modern human species survived the cold ice age, eliminated other human species, not only survived, but also spread its footprints to places other than Antarctica.
The Mengzi people have Southeast Asian genetic components
After it was determined that the Mengzi people were actually modern humans, scientists began to use Africans as a control group to conduct tests in order to evaluate the level of genetic introgression of ancient humans.The results show that in the Mengzi genome, the level of ancient human gene introgression is about 1.29% in the Denisovan ancestry, and about 1.27% in the Neanderthal ancestry, which is the same as that of current East Asians. Similar levels of introgression were reported.
However, due to the low coverage of the sequenced Mongolian genome, it cannot be completely ruled out that there may be ancient alleles in the genomes of Denisovans or Neanderthals and Mongolians. However, what is certain is that the nuclear genome of the Mengzi Man contains very different ancestors of modern humans in Asia. The main genetic components of her and my country's Fujian Qihedong No. Ⅲ belong to Southeast Asians, while Amur River (Heilongjiang ) and Bianbianhe sites mainly contain and Northeast Asian components.
Genetic variants that make skin whiter
Scientists used time-series aDNA data sources to track the emergence and spread patterns of sequence variants, thereby reconstructing the spatiotemporal distribution of East Asian specific variants. The results showed that this variant, which helps skin whitening, appeared for the first time on two islands off the coast of southern China, mainly distributed in the coastal areas of East Asia. It then spread to northern East Asia about 3,500 years ago, eventually becoming dominant (about 60%) among today's East Asians. This mutation causes the skin of East Asians to lighten in response to the relatively low ultraviolet radiation at high latitudes.
The genetic affinity test between the Mongolian people and global populations shows that the Mongolian people have the closest affinity to ancient Siberians and the first Americans, even closer than the Amur River samples. The examination also showed some relationship between the Mongolians, or ancient Siberians, and the Mongolians, or Amur peoples, and the first Americans, suggesting that East Asian contributions to Native Americans may have originated in South and Northeast Asia. before differentiation.
It is worth noting that all ancient Siberians who lived during the Last Glacial Maximum contained a considerable proportion of Native Americans, which confirms that Siberia was the earliest outpost of migration to the Americas.
Japan was just a midway stop for the Mongzi people's migration
In addition, the affinity between the first Americans and the Mongolian people was higher than that of the Hὸabìnhian population in late Southeast Asia, the Jomon population in Japan, and several other populations in the late Pleistocene. Several samples from the Amur region and Far East Siberia, identified as post-Last Glacial Maximum, all show a close relationship with the first Americans.
Based on this, scientists speculate that during the Late Pleistocene, modern humans rapidly expanded northward, starting from southern East Asia, passing through the coastal areas of China, the Korean Peninsula and the Japanese Islands, then expanding northward, reaching Siberia, and finally Pass through Bering Strait and reach America.
However, the higher affinity of Mongolians to Americans may reflect that the Japanese Jomon population does not represent the early post-Last Glacial Maximum humans who settled in the Japanese archipelago. Recently discovered Paleolithic sites in western Idaho, USA, have discovered a technology of non-fluted handle projectiles before the emergence of ancient Indian traditions. This technology shows early cultural connections with Japan's Paleolithic unfluted projectile points, and the natives of northern Japan and the Russian island of Sakhalin, have closer affinities with northeastern Siberians than central Siberians, so , the Japanese archipelago can be regarded as a way station in the migration route of the Mongolian people.
Yunnan is not only a global biodiversity hotspot, but also one of the ice age refuge areas. The fossil sedimentary basins owned by Yunnan not only record the evolutionary history of biodiversity, but also provide clues for the exploration project of the origin of Chinese civilization.
A community with a shared future for mankind may not be just a concept that has been proposed in contemporary times. Various archaeological studies in ancient times have shown that in the long history of human development, some kind of cause and effect has already been destined.
Reference article
Xiaoming Zhang,Xueping Ji,Chunmei Li,Yanyi Huang,Yaoxi He,Bing Su.A Late Pleistocene human genome from Southwest China[J/OL].Current Biology,2022,7(14)
Yang Mo.Ma Lu Cave people - ethnic minorities 10,000 years ago. Encyclopedia knowledge .2012, (11)
