Mongoose on the loose
The small Indian mongoose (Urva auropunctata) may be a small carnivorous species, but it has managed to have an incredibly large ecological impact! The Indian mongoose's native habitat is widespread across South Asia, from Iraq to Myanmar. However, in the late 19th and early 20th century, the small Indian mongoose was introduced into Hawaii, the Caribbean, the Adriatic, and Japan to serve as a predator against rats and snakes. Unfortunately, the Indian mongoose's ability to thrive in a variety of environments and opportunistic hunting style lead to massive devastation on the introduced habitats.
Today, we release the chromosome-length assembly for the small Indian mongoose. This is a short-read genome assembly, with a contig N50 = 80 Kb and a scaffold N50 = 133 Mb. The sample used to generate this assembly was a primary fibroblast cell line provided to us by the T.C. Hsu CryoZoo from the M.D. Anderson Cancer Center. Thank you to Drs. Asha Multani, Sen Pathak, and Richard Behringer in the Department of Genetics at the MD Anderson Cancer Center as well as Dr. Liesl Nel-Themaat and Arisa Furuta for their help with this sample!
Interestingly, in initial studies of the eutherian small Indian mongoose the Y chromosome could not be identified in somatic cells. The male chromosome number is uniquely odd, 2n = 35, whereas that of females is 2n = 36. Further studies suggested that this unique karyotype resulted from a translocation of the ancestral Y chromosome to an autosome (Murata et al., 2016)!
We now confirm this finding and identify the autosome of interest (luckily our fibroblasts turned out to be male). The last chromosome in our assembly (HiC_scaffold_18) appears in two versions. One of these version reported in the default fasta (Urva_auropunctata_HiC.fasta) is the canonical autosomal version. Each female Indian mongoose would have two of these. Males, on the other hand, would have only one of these. The other copy, reported separately in our assembly as Urva_auropunctata_Y.fasta, has a completely different sequence on it's q-tip. Check out the full release page for links to the relevant files, and check out the the contact map below showing 18 'canonical' chromosomes of the small Indian mongoose Urva auropunctata.