東アジア初期人類の一部はデニソワ人と遭遇していなかった(Some Early East Asians Did Not Meet Denisovans)

2025-11-07

2025-11-04 マックス・プランク研究所

マックス・プランク進化人類学研究所の国際研究チームは、ユーラシア各地の100超の古代ゲノムを解析し、デニソワ人との交雑史を時空間的に再構築した。約4万年前の中国・田園人など初期東アジア人は最も高いデニソワ人由来DNA(約0.2%)を保持していたが、その後の遺伝的混合で希釈された。一方、日本列島の縄文人はほぼ交雑の痕跡がなく、東アジア集団の中でも独自の系統を維持していた。デニソワ人DNAは東ユーラシアから西方へも僅かに拡散し、人類拡散史の再構築に新たな手がかりを与える。成果はCurrent Biology誌に掲載。

Ancient individuals included in this study. The ages are indicated by colors, and the number of individuals at each site is indicated by heights.© Jiaqi Yang et al., Current Biology (2025)

<関連情報>

デニソワ人の祖先が予想外に少ない、初期の東アジア系譜 An early East Asian lineage with unexpectedly low Denisovan ancestry

Jiaqi Yang (杨家琦) ∙ Leonardo N.M. Iasi ∙ Qiaomei Fu (付巧妹) ∙ … ∙ Janet Kelso ∙ Stéphane Peyrégne (裴思凡) ∙ Benjamin M. Peter
Current Biology Published:October 20, 2025
DOI:https://doi.org/10.1016/j.cub.2025.08.051

Highlights

DNA segments introgressed from Denisovans were detected in ancient humans
Denisovan ancestry is shared across diverse Eurasian lineages
The ancestors of the Jomon did not participate in major contact(s) with Denisovans

Summary

Denisovan ancestry in present-day humans is heterogeneously distributed and comes from genetically distinct Denisovan groups. Understanding the origin of this heterogeneity could provide insights into the early population history of modern humans in Eurasia. However, population movements and admixture after the initial dispersals of modern humans have obscured the origin of this heterogeneity. To address this, we investigated how Denisovan ancestry in early modern humans relates to that in present-day humans. We found that varying levels of Denisovan ancestry in Eurasians were shaped by admixture between diverse early modern human lineages. In particular, ancient Japanese individuals from the Jomon period have the least Denisovan ancestry among individuals from Eastern Eurasia, providing evidence for an ancient East Asian lineage with little to no Denisovan ancestry. By contrast, the earliest mainland East Asians harbor the most Denisovan ancestry in Eastern Eurasia, including ancestry from multiple divergent Denisovan groups, already before the last glacial maximum. Together with evidence of Denisovan ancestry sharing among ancient and present-day genomes, these patterns show how Denisovan ancestry in Eurasia spread through gene flow from early East Asians. Our study provides the first systematic investigation of Denisovan admixture across time and extends our understanding of human population history in Eurasia.