The genome sequences of the Okinawa island spiny rat, Tokudaia muenninki

The Okinawa island spiny rat, Tokudaia muenninki, has highly unique sex chromosomes. The diploid chromosome number of T. muenninki is 44 with XX/XY sex chromosome constitution, and both sex chromosomes are uncommonly large. The euchromatic regions of the X and Y chromosomes occupy 8% and 4% of the haploid genome, indicating that autosomal fusions have occurred. T. muenninki has multiple SRY copies on the large Y chromosome. Therefore, we conducted whole genome sequencing and de novo assembly analysis for two aims: first, to utilize the information for the research of the evolution of the sex chromosomes, and second, to reserve the information as an important resource.