Ancient human genomes shed new light on East Asia's history
First large-scale ancient genome analyses from China chart migrations of early farmers.
An 8,400-year-old skeleton from the Qihe cave archaeological site in Fujian, China.Credit: Xiujie Wu/Institute of Vertebrate Paleontology and Paleoanthropology
Os estudos também revelam conexões entre humanos antigos que se estendem do sul da China ao Pacífico Sul, e um elo entre habitantes costeiros que poderia oferecer pistas sobre como os humanos se estabeleceram no leste da Ásia.
Os resultados são de um estudo de 14 de maio na Science que analisou os genomas de duas dúzias de chineses antigos1 e uma pré-impressão de março que analisou quase 200 genomas antigos de todo o leste asiático2.
Os asiáticos orientais contemporâneos descendem, em geral, de humanos que deixaram a África entre 50.000 e 100.000 anos atrás.
Mas os pesquisadores sabem pouco sobre as antigas mudanças populacionais que moldaram os genomas dos 1,7 bilhão de habitantes atuais da região. Apenas um punhado de genomas humanos antigos do Leste da Ásia foi publicado, e não está claro como eventos importantes, como a disseminação da agricultura - que alterou drasticamente a composição genética dos eurasianos ocidentais - afetaram essa parte do mundo.
Uma equipe liderada por Qiaomei Fu, geneticista populacional do Instituto de Paleontologia e Paleoantropologia de Vertebrados em Pequim, analisou os genomas de 24 indivíduos que viviam no leste da Ásia, incluindo o que é hoje a China, entre 9.500 e 300 anos atrás. A maioria dos genomas veio de sítios arqueológicos na Bacia do Rio Amarelo, no nordeste da China, ou a mais de 1.000 quilômetros de distância, na província de Fujian, no sudeste da China.
This suggests that farming in East Asia could have spread through mixing of farmers and hunter-gatherers, says Ling Qin, an archaeologist at Peking University in Beijing. That’s different from what ancient-genome studies have found in western Eurasia, where farmers with Middle Eastern ancestry largely replaced hunter-gatherers in Europe3.
Farmers in the Yellow River Basin also moved west. A team led by David Reich, a population geneticist at Harvard Medical School in Boston, Massachusetts, who is a co-author of Fu’s study, analysed the genomes of 20 5,000-year-old individuals from this region and found connections with contemporary Tibetans. Their results are part of a study of 191 ancient individuals from East Asia that was posted to the bioRxiv preprint server on 25 March.
Ancestry from southeastern China stretched even farther afield. Neolithic individuals from Fujian and islands in the Taiwan Strait were closely related to ancient islanders from Vanuatu in remote Oceania, Fu’s team found. Previous ancient-genome studies had recorded the spread of this ancestry from East Asia to Oceania4, and Fu’s study suggests that this group originated in southern China.
This conclusion makes sense, says Matthew Spriggs, an archaeologist at Australian National University in Canberra. Archaeological and genetic evidence has linked the South Pacific migration to ancient humans in Taiwan, whose Neolithic inhabitants probably came from southern parts of the mainland. “I am very pleased to see this paper,” he says of Fu’s study.
Qin says that the ancient southern Chinese people in Fu’s study lived in an isolated pocket that might not be representative of the wider area. A priority should be sequencing DNA from early farmers from the Yangtze River Basin in southern China, a centre for rice domestication and a potential source of other migrations, she adds.
The studies give researchers hope that ancient genomics will help them delve even deeper into East Asia’s early history. Pontus Skoglund, a population geneticist at the Francis Crick Institute in London, would love to know whether the first Homo sapiens to settle in the region interbred with Denisovans, an extinct group of hominins. “I think one of the most exciting open big questions of the region relates to the pre-Neolithic settlement — who were the earliest modern humans in the region?” adds Martin Sikora, a geneticist at the University of Copenhagen.
Uma equipe liderada por Qiaomei Fu, geneticista populacional do Instituto de Paleontologia e Paleoantropologia de Vertebrados em Pequim, analisou os genomas de 24 indivíduos que viviam no leste da Ásia, incluindo o que é hoje a China, entre 9.500 e 300 anos atrás. A maioria dos genomas veio de sítios arqueológicos na Bacia do Rio Amarelo, no nordeste da China, ou a mais de 1.000 quilômetros de distância, na província de Fujian, no sudeste da China.
North–South divide
Durante o período neolítico inicial, cerca de 10.000 a 6.000 anos atrás, as pessoas dessas duas regiões geográficas eram geneticamente distintas, concluiu a equipe de Fu. Mas, com o tempo, começaram a se misturar: os chineses contemporâneos traçam grande parte de seus ancestrais aos grupos do norte, mas também estão relacionados ao antigo povo Fujian em graus variados (os do sul da China tendem a ser os mais próximos). A equipe de Fu não sabe exatamente quando os dois grupos começaram a se cruzar, mas viu sinais de que a assinatura genética do norte havia começado a se espalhar para o sudeste da China na época do final do neolítico de 5.000 a 4.000 anos atrás.This suggests that farming in East Asia could have spread through mixing of farmers and hunter-gatherers, says Ling Qin, an archaeologist at Peking University in Beijing. That’s different from what ancient-genome studies have found in western Eurasia, where farmers with Middle Eastern ancestry largely replaced hunter-gatherers in Europe3.
Farmers in the Yellow River Basin also moved west. A team led by David Reich, a population geneticist at Harvard Medical School in Boston, Massachusetts, who is a co-author of Fu’s study, analysed the genomes of 20 5,000-year-old individuals from this region and found connections with contemporary Tibetans. Their results are part of a study of 191 ancient individuals from East Asia that was posted to the bioRxiv preprint server on 25 March.
Distant relatives
The studies also revealed some surprising long-distance connections. Neolithic people who lived near China’s coast, whether in the northeast or southeast, shared some ancestry with ancient individuals from coastal sites in southeast Asia and Japan. “That means the entire coast of East Asia is a really important place for people to migrate,” says Fu. Reich and his team found a similar connection, which they say could be evidence that modern humans first settled in East Asia along a coastal route.Ancestry from southeastern China stretched even farther afield. Neolithic individuals from Fujian and islands in the Taiwan Strait were closely related to ancient islanders from Vanuatu in remote Oceania, Fu’s team found. Previous ancient-genome studies had recorded the spread of this ancestry from East Asia to Oceania4, and Fu’s study suggests that this group originated in southern China.
This conclusion makes sense, says Matthew Spriggs, an archaeologist at Australian National University in Canberra. Archaeological and genetic evidence has linked the South Pacific migration to ancient humans in Taiwan, whose Neolithic inhabitants probably came from southern parts of the mainland. “I am very pleased to see this paper,” he says of Fu’s study.
Qin says that the ancient southern Chinese people in Fu’s study lived in an isolated pocket that might not be representative of the wider area. A priority should be sequencing DNA from early farmers from the Yangtze River Basin in southern China, a centre for rice domestication and a potential source of other migrations, she adds.
The studies give researchers hope that ancient genomics will help them delve even deeper into East Asia’s early history. Pontus Skoglund, a population geneticist at the Francis Crick Institute in London, would love to know whether the first Homo sapiens to settle in the region interbred with Denisovans, an extinct group of hominins. “I think one of the most exciting open big questions of the region relates to the pre-Neolithic settlement — who were the earliest modern humans in the region?” adds Martin Sikora, a geneticist at the University of Copenhagen.
doi: 10.1038/d41586-020-01456-9
References
- 1.M. A. Yang et al. Science https://doi.org/10.1126/science.aba0909 (2020).
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