A joint research group of Okayama University, the University of Tokyo, and Kitasato University has clarified the diffusion route of medaka in the Japanese archipelago using comprehensive genomic sequence information of the medaka wild population.
It has been thought that the medaka fish that live in the Japanese archipelago can be broadly divided into two types: medaka fish in southern Japan and medaka fish in northern Japan.However, little has been investigated about the genetic relationships between the two groups and how each has expanded its habitat.In the Tajima and Tango regions in the northern part of Kyoto and Hyogo, it was said that there was a hybrid group formed by crossing these two groups, but the history of their formation was largely unknown.
This time, the research group comprehensively investigated the chromosomal genomes of the nationwide wild medaka strain maintenance group maintained at the University of Tokyo for more than 35 years and the wild medaka population collected in Saga Prefecture, and estimated the population structure of medaka.As a result, it was shown that the medaka group, which had been called the South Japan Group, made northern Kyushu the "hometown" and extended to Okinawa in the south and Iwate in the north.Furthermore, it was statistically shown that the Tajima-Tango region, which has been considered to be a region where a hybrid (mixed blood) of the south and the north lives, is actually likely to be the "hometown" of the northern Japanese medaka fish.From this analysis, it was concluded that the medaka fish of the Northern Japan Group, whose hometown was unknown until now, originated in the Tajima and Tango regions and spread to Aomori.
In the future, the evolutionary history of medaka may give hints to solve the evolutionary history of human populations.
Paper information:[G3: Genes, Genomes, Genetics] Medaka population genomic structure and demographic history described via genotyping-by-sequencing
