Takasu, M. | bioRxiv Science

bioRxiv2026

Left-right asymmetry of the microminipig brain.

Left-right asymmetry of the brain is well recognized in various animals including C. elegans, drosophila and zebrafish. In primates, most of the brain studies describe side of the brain. However, in spite of huge amounts of accumulating rodent studies on neuroscience, most of rodent studies do not distinguish the brain side. The pig brain is considered to occupy an intermediate position between primates and rodents in terms of structural complexity and brain function. Moreover, the numbers of studies using genetic manipulation of pigs are drastically increasing. So, we investigated microminipig (MMP) brain mesoscopic anatomy focusing on left-right differences of its morphology. Here, we show the anterior cingulate cortex, perirhinal cortex, and cerebellum of male and female MMPs, are structurally asymmetrical. The cerebellar vermis, paravermis is tilted from the midline and the consequently the cerebellar cortex exhibits asymmetrical morphology. The anterior cingulate gurus exhibited protrusion and invagination toward the midline on the right and left side, respectively. The left perirhinal lobe exhibited distinct patterns of cortical gyration between left and right side. These data demonstrate that MMPs are one of the suitable model animals for investigating cerebral and cerebellar asymmetry.

neuroscience↗

bioRxiv2018

The ability of ddRAD-Seq to estimate genetic diversity and genetic introgression in endangered native livestock

Unplanned crossbreeding between a native livestock and a specific productive breed was one of the main reasons that caused the loss of valuable genetic resources in native livestock. To avoid further loss and damage of genetic resources in the native livestock, introgressed individuals should be distinguished to eliminate them by preventing any further employment in future mating plans. In general, the genetic diversity of native livestock had already decreased and mass elimination of introgressed individuals from the population endangers their existence. To solve this problem, high-resolution markers are required to discriminate between introgressed variation and native variation. Here, we applied ddRAD-Seq markers for native Japanese horse \"Taishu\" that has undergone recent genetic introgression. Genome-wide ddRAD-Seq markers can distinguish five breeds of native Japanese horses and Anglo-Arabian introgressed breeds. We found the signatures of genetic introgression of Anglo-Arabian at only two chromosomes; however, the signatures were separated in their genome suggesting that it might not be the cause of recent introgression. The genetic diversity of Taishu was less than other Japanese breeds and the decreasing genetic diversity is an urgent issue compared to genetic introgression. Although few signatures of recent introgression were detected, a lot of shared SNPs (10% of all SNPs in Taishu) were detected between Taishu and Anglo-Arabian. To avoid misestimation of the presence and degree of introgression in native livestock, information regarding shared SNPs and population genetic approaches need to be assessed by using the large number of genome-wide markers such as ddRAD-Seq.

genomics↗