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Recent studies investigating the origins of modern Japanese populations have found a correlation between the genetic traits of Jomon hunter-gatherers and elevated body mass index (BMI) levels in individuals. This highlights how ancestral genetic factors can influence health outcomes in current populations.
Published in Nature Communications, this study provides substantial evidence for the “tripartite ancestry model.” This model indicates that the genetic diversity seen in today’s Japanese people can be attributed to the historical contributions of the ancient Jomon hunter-gatherers and two continental ethnic groups from Northeast and East Asia, who collectively shaped the genetic makeup of contemporary Japan.
The researchers analyzed genetic information from Biobank Japan, which includes data from more than 170,000 participants, as well as ancient genomes from Japan and Eurasia, along with East Asian data from the UK Biobank. In total, the study examined genetic data involving over 250,000 individuals from both ancient and modern sources.
BMI links
The team investigated links between Jomon ancestry and 80 different complex traits, such as height and BMI, making sure to account for genetic and geographic variations within the populations studied.
They discovered that the Jomon genetic signature, which contributes approximately 12.5% to an individual’s genetic profile, is linked to higher BMI levels. This connection remained significant even when they included East Asian individuals from the UK Biobank, highlighting the enduring legacy of this ancient lineage.
Shigeki Nakagome, an Assistant Professor from Trinity College Dublin’s School of Medicine and a senior author of the study, stated: “These findings imply that the genetic heritage of the ancient hunter-gatherer Jomon plays a considerable role in shaping BMI across various populations today, irrespective of geographic location, which may lead to a heightened risk of obesity.”
“This discovery emphasizes the importance of understanding ancient hunter-gatherer ancestry in relation to modern health issues. The association with increased BMI may also shed light on the obesity prevalence differences among Asian individuals living in Western countries.”
“By highlighting the relevance of Jomon ancestry in the context of BMI, this analysis serves as a vital proof-of-concept for future research that connects our historical human experience with contemporary health concerns.”
The tripartite model
A long-standing theory regarding Japanese ancestry suggests a dual-ancestry structure: the Jomon, known for their lifestyle as hunter-gatherer-fishers who occupied the archipelago for over 16,500 years, and immigrant farmers from Northeast Asia. This theory has recently evolved into the tripartite model, which adds East Asian ancestry linked to the formative Kofun period that began about 1,700 years ago.
The new study provides robust support for this tripartite model.
Prof. Nakagome noted: “Our research is the first to thoroughly characterize the tripartite ancestry across the Japanese archipelago, and it aligns more consistently with the tripartite structure than with the dual ancestry hypothesis. Additionally, it reveals significant variation in Jomon ancestry proportions, reflecting the continuum of genetic ancestry found in today’s populations.”
“The field of ancient genomics is rapidly progressing, and future studies encompassing a diverse array of ancient peoples from different periods and geographical areas will enhance our understanding of how historical factors have influenced current genetic and phenotypic variations. There is undoubtedly more to uncover, both within Japanese populations and globally.”
This research received partial support from the Wellcome Trust ISSF Award and the Japan Society for the Promotion of Science.
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