Biology subjects

Koganebuchi, K.

Publications and source records attributed to Koganebuchi, K..

8 recordsLinked to original sources

bioRxiv2026

An iPSC-based experimental framework for investigating phenotypic variation associated with Jomon ancestry in the present-day Japanese population

Ancestry-related genomic variation may contribute to phenotypic diversity. However, its cellular consequences remain difficult to evaluate. To address this, we developed a human induced pluripotent stem cell (hiPSC)-based framework for investigating such phenotypes. We used the Japanese population as a model of Jomon-related and continental East Asian ancestry admixture. Jomon ancestry, estimated using the Jomon allele score (JAS), was associated with clinical measures, including renal-related traits and serum triglycerides in 34,152 Tohoku Medical Megabank participants. Peripheral blood mononuclear cell transcriptomics of donors from the upper and lower extremes of the JAS distribution (n = 10) suggested group-level differences in immune-related gene expression. To test whether the serum triglyceride association coincided with hepatic cellular phenotypes, we differentiated hiPSCs from these donors into hepatocyte-like cells. Neither intracellular triglycerides nor lipid-related gene expression differed between groups. These findings highlight the value of a genetically characterized hiPSC-based framework for investigating ancestry-associated phenotypes across cellular contexts.

genomics↗

bioRxiv2026

Ancient Ryukyu Jomon contributed to past and current genetic structure of Japanese populations

Characterized by the earliest use of pottery, the Jomon culture was a unique Neolithic culture that spread throughout the Japanese Archipelago. Previous archaeological evidence suggests that Jomon hunter-gatherers colonized the southernmost islands, the Ryukyu Archipelago, by approximately 7,000 years before present (YBP). However, genetic characteristics of the Ryukyu Jomon population and its contribution to the modern population have not been elucidated yet. In this study, we newly sequenced 273 modern and 25 ancient (6,700-900 YBP) whole genomes collected across the Ryukyu Archipelago. Our analysis demonstrated a genetic differentiation between the Hondo (Japanese mainland) and Ryukyu Jomon, dating back to [~]6,900 YBP. After the divergence from the Hondo Jomon, the Ryukyu Jomon experienced severe bottlenecks, with an effective population size of [~]2,000. Admixture between the Ryukyu Jomon and migrants from the historic Hondo population occurred [~]1,000 YBP, which corresponds to the widespread adoption of iron tools and agriculture in the Central Ryukyus. Different demographic histories between modern Hondo and Ryukyu populations resulted in different rates of Jomon ancestry in these populations. By providing a new perspective on the peopling of the Ryukyu Archipelago, this study significantly enhances our understanding of cultural transitions in the region.

evolutionary biology↗

bioRxiv2024

Endemic demographics of the Jomon people estimated based on complete mitogenomes reveal their regional diversity

The Jomon culture that spread across Japanese archipelago began about 16,000 years ago and lasted for over 10,000 years. The genetic diversity of the Jomon people, prehistoric hunter-gatherers bearing the Jomon culture, is of great interest in understanding prehistoric East Eurasians. Until now, their demographic history has been estimated using archaeological sites and present-day genomes, but detailed studies using Jomon genomes have been insufficient. To investigate the Jomon demography, we determined the complete mitochondrial genome (mitogenome) sequences from 13 Jomon individuals and conducted population genetic analysis on 40 Jomon genomes including previously published data. Our results revealed an effective population size increase during the Incipient - Initial phase of the Jomon period, which had not been observed in analysis of mitogenome sequences from present-day Japanese populations. This endemic demographic pattern is pronounced in the eastern part of the archipelago, under the assumption of no gene flow between the Eastern and Western Jomon.

genomics↗

bioRxiv2024

Cold adaptation in Upper Paleolithic hunter-gatherers of eastern Eurasia

Previous genomic studies understanding the dispersal of Homo sapiens have suggested that present-day East Eurasians and Native Americans can trace their ancestry to migrations from Southeast Asia. However, ineluctable adaptations during the Last Glacial Maximum (LGM) remain unclear. By analyzing 42 genomes of up to 30-fold coverage from prehistoric hunter-gatherers, Jomon, we reveal their descent from Upper Paleolithic (UP) foragers who migrated to and isolated in the Japanese archipelago during Late Pleistocene. We provide compelling evidence suggesting that these UP people underwent positive selection for cold environments, aiding their survival through the LGM facilitated by non-shivering thermogenesis and detecting it polygenically across multiple loci in the Jomon lineage. Our study pioneers the close estimation of the physiological adaptation of ancient humans by the paleogenomic approach.

evolutionary biology↗

bioRxiv2023

Collagen of ancient bones gives an indication of endogenous DNA preservation based on the next generation sequencing technology

Ancient genome analysis has become an indispensable tool in studies of human population history and evolution after the breakthrough of whole genome sequencing technology. Meanwhile, the problem has been not resolved that ancient genome cannot be analyzed without crushing non-small pieces of precious specimens; in spite of that, in many cases, there is no DNA remaining sufficiently in the piece of samples for obtaining the whole genome sequences. In previous studies, therefore, a couple of indicators (e.g., racemization ratios) have been proposed to estimate the endogenous DNA in ancient samples. However, these studies have used polymerase chain reaction (PCR) to test whether endogenous DNA is remaining, which has been inadequate because the success or failure of PCR amplification does not necessarily reflect DNA remaining. To assess the amount of endogenous DNA, we use the ratios of reads generated by the next-generation sequencer (NGS) mapped to the human reference genome sequence. We investigate 40 Jomon remains and find a significant association between the collagen residual ratios (CRRs) in rib bones and the mapping ratios (MRs). Because the weight of bone required to measure collagen residual is much less than that required to obtain DNA needed for NGS analysis, which is always necessary for dating, the collagen in ribs can be a good indicator for successful ancient genome analyses.

genomics↗

bioRxiv2019

Jomon genome sheds light on East Asian population history

Anatomical modern humans reached East Asia by >40,000 years ago (kya). However, key questions still remain elusive with regard to the route(s) and the number of wave(s) in the dispersal into East Eurasia. Ancient genomes at the edge of East Eurasia may shed light on the detail picture of peopling to East Eurasia. Here, we analyze the whole-genome sequence of a 2.5 kya individual (IK002) characterized with a typical Jomon culture that started in the Japanese archipelago >16 kya. The phylogenetic analyses support multiple waves of migration, with IK002 forming a lineage basal to the rest of the ancient/present-day East Eurasians examined, likely to represent some of the earliest-wave migrants who went north toward East Asia from Southeast Asia. Furthermore, IK002 has the extra genetic affinity with the indigenous Taiwan aborigines, which may support a coastal route of the Jomon-ancestry migration from Southeast Asia to the Japanese archipelago. This study highlight the power of ancient genomics with the isolated population to provide new insights into complex history in East Eurasia.

genomics↗

bioRxiv2018

A new targeted capture method using bacterial artificial chromosome (BAC) libraries as baits for sequencing relatively large genes

To analyze a specific genome region using next-generation sequencing technologies, the enrichment of DNA libraries with targeted capture methods has been standardized. For enrichment of mitochondrial genome, a previous study developed an original targeted capture method that use baits constructed from long-range polymerase chain reaction (PCR) amplicons, common laboratory reagents, and equipment. In this study, a new targeted capture method is presented, that of bacterial artificial chromosome (BAC) double capture (BDC), modifying the previous method, but using BAC libraries as baits for sequencing a relatively large gene. We applied the BDC approach for the 214 kb autosomal region, ring finger protein 213, which is the susceptibility gene of moyamoya disease (MMD). To evaluate the reliability of BDC, cost and data quality were compared with those of a commercial kit. While the ratio of duplicate reads was higher, the cost was less than that of the commercial kit. The data quality was sufficiently the same as that of the kit. Thus, BDC can be an easy, low-cost, and useful method for analyzing individual genome region with substantial length.

genomics↗

bioRxiv2017

Analysis of ancient human mitochondrial DNA from Verteba Cave, Ukraine: insights into the origins and expansions of the Late Neolithic-Chalcolithic Cututeni-Tripolye Culture

BackgroundThe Eneolithic (~ 5,500 yrBP) site of Verteba Cave in Western Ukraine contains the largest collection of human skeletal remains associated with the archaeological Cucuteni-Tripolye Culture. Their subsistence economy is based largely on agro-pastoralism and had some of the largest and most dense settlement sites during the Middle Neolithic in all of Europe. To help understand the evolutionary history of the Tripolye people, we performed mtDNA analyses on ancient human remains excavated from several chambers within the cave.\n\nResultsBurials at Verteba Cave are largely commingled and secondary in nature. A total of 68 individual bone specimens were analyzed. Most of these specimens were found in association with well-defined Tripolye artifacts. We determined 28 mtDNA D-Loop (368 bp) sequences and defined 8 sequence types, belonging to haplogroups H, HV, W, K, and T. These results do not suggest continuity with local pre-Eneolithic peoples, but rather complete population replacement. We constructed maximum parsimonious networks from the data and generated population genetic statistics. Nucleotide diversity ({pi}) is low among all sequence types and our network analysis indicates highly similar mtDNA sequence types for samples in chamber G3. Using different sample sizes due to the uncertainly in number of individuals (11, 28, or 15), we found Tajimas D statistic to vary. When all sequence types are included (11 or 28), we do not find a trend for demographic expansion (negative but not significantly different from zero); however, when only samples from Site 7 (peak occupation) are included, we find a significantly negative value, indicative of demographic expansion.\n\nConclusionsOur results suggest individuals buried at Verteba Cave had overall low mtDNA diversity, most likely due to increased conflict among sedentary farmers and nomadic pastoralists to the East and North. Early Farmers tend to show demographic expansion. We find different signatures of demographic expansion for the Tripolye people that may be caused by existing population structure or the spatiotemporal nature of ancient data. Regardless, peoples of the Tripolye Culture are more closely related to early European farmers and lack genetic continuity with Mesolithic hunter-gatherers or pre-Eneolithic groups in Ukraine.

evolutionary biology↗