Host: The Japanese Society of Toxicology
Name : The 50th Annual Meeting of the Japanese Society of Toxicology
Date : June 19, 2023 - June 21, 2023
The laboratory mouse strains, such as C57BL/6, have mosaic genomes with different subspecific origins. Their genomes are derived predominantly from Western European subspecies Mus musculus domesticus, with the remaining sequence (6-7% of the whole genome) derived mostly from Japanese subspecies M. m. molossinus. We reported that genome introgression fromJapanese fancy mice, ancestor of extant JF1/Ms strain, provided the origin of the M. m. molossinus genome in the laboratory strains, and largely contributed to their genome diversity. According to old literatures, we infer that the JF1/Ms ancestry, raised at the end of the Edo period, was transferred to Europe, where they were bred with mice from Western European subspecies. From the breeding colonie the laboratory mice were established. The admixture of different subspecies has created genomic and phenotypic diversity among the laboratory strains used in biomedical science, and this should be kept in mind when designing experiments with the laboratory mouse strains.
A similar mosaic structure is also found in genome of modern humans, in which a small portion of Neanderthal or Denisovan genome is interspersed in the genome of Homo sapiens. Interestingly, in both human and mouse, it is likely that the mosaic genome structure was not created at random, but formed under genetic constraints. The laboratory mice and JF1/Ms strain might provide unique research materials to clarify the genetic constrains, which had contributed to configuration of the mammalian mosaic genomes.
