Biology subjects

Katsumura, T.

Publications and source records attributed to Katsumura, T..

4 recordsLinked to original sources

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↗

bioRxiv2022

Intraspecific diversity based on low temperature induced arrhythmia in embryonic heart of medaka (Oryzias latipes)

BackgroundCold tolerance during embryonic development, especially blood circulation is important for growth in poikilothermic animals. Medaka (Oryzias latipes), has cold tolerance and is distributed in the highest latitudes occupied by the genus Oryzias. Regarding cold tolerance in embryogenesis, Hd-rR strain belonging to the southern Japanese (S.JPN) group showed arrhythmia when the embryo was exposed to 15 {degrees}C in the heartbeat initiation period (st. 24), whereas the embryo of Odate medaka, which belongs to the northern Japanese (N.JPN) group, showed stable heartbeats. ResultsIn this study, to verify the sensitivity to low temperature in the medaka wild populations, heartbeat intervals of st. 24 embryos derived from three N.JPN, eight S.JPN, and two western Korean/Chinese (W.KOR) populations were investigated at an arbitrary temperature range of 12-15 {degrees}C. There was no significant difference in the mean values of the heart rates and the coefficient of variation (CV) of interbeat intervals in the N.JPN, S.JPN, and W.KOR groups. A temperature dependency of the CV within 12-15 {degrees}C was observed only in five S.JPN specimens, whereas three S.JPN, the N.JPN and the W.KOR specimens showed no alteration in CV with temperature. Temperature dependency of the heart rate was also varied in the S.JPN specimens. ConclusionsThese results suggest that the temperature dependency of the CV under 12-15 {degrees}C during the heartbeat initiation period is a variation within the S.JPN after the divergence from the N.JPN.

developmental biology↗

bioRxiv2017

Medaka population genome structure and demographic history unveiled via Genotyping-by-Sequencing

Medaka is a model organism in medicine, genetics, developmental biology and population genetics. Lab stocks composed of more than 100 local wild populations are available for research in these fields. Thus, medaka represents a potentially excellent bioresource for screening disease-risk- and adaptation-related genes in genome-wide association studies. Although the genetic population structure should be known before performing such an analysis, a comprehensive study on the genome-wide diversity of wild medaka populations has not been performed. Here, we performed genotyping-by-sequencing (GBS) for 81 and 12 medakas captured from a bioresource and the wild, respectively. Based on the GBS data, we evaluated the genetic population structure and estimated the demographic parameters using an approximate Bayesian computation (ABC) framework. The autosomal data confirmed that there were substantial differences between local populations and supported our previously proposed hypothesis on medaka dispersal based on mitochondrial genome (mtDNA) data. A new finding was that a local group that was thought to be a hybrid between the northern and the southern Japanese groups was actually a sister group of the northern Japanese group. Thus, this paper presents the first population-genomic study of medaka and reveals its population structure and history based on autosomal diversity.

evolutionary biology↗