Karyotype conservation in the fellowship of the ring

Updated: Dec 8, 2020

The ringtail, Bassariscus astutus, gets it's name from its striking black and white tail. Although known also as the ring-tailed cat or the miner's cat, the ringtail is not a true cat [1]. The ringtail is a member of the Procyonidae family alongside the raccoon and cacomistle. Ringtails are native to the south-west United States and Mexico. Although they are very common throughout these areas, they are rarely seen due to their nocturnal nature [2].

Ringtail in Phoenix, Arizona by Robertbody, [CC BY-SA 3.0], via Wikimedia Commons

Today, we share the chromosome-length assembly for the ring-tailed cat, Bassariscus astutus. We thank the San Antonio Zoo for providing the sample that made this assembly possible. This is another $1K de novo genome, with a contig n50 = 40 Kb and a scaffold n50 = 102 Mb. For assembly procedure details, check out Dudchenko et al., 2018.


In the DNA Zoo collection, we already have a close relative to the ringtail, a cacomistle Bassariscus sumichrasti genome assembly. Some studies have suggested that the sister species are quite divergent from each other, with a last common ancestor shared a full 10MYA (Koepfli et al., 2007). Karyotypically however, the two species appear to be almost identical, see the whole genome alignment between the genome assemblies below.

Whole-genome alignment plot between the cacomistle (Bassariscus_sumichrasti_HiC) and the ringtail (Bassariscus_astutus_HiC).

Interestingly, a previous study (Nash et al.,2008) suggested that ringtails may have the ancestral karyotype of all Carnivora. As such, the ringtail karyotype has been extensively studied, including with cross-species painting probes of domestic cat. The latter have suggested three major rearrangement events between the species (Nash et al.,2008), captured now in the chromosome-length genome assembly. Specifically, chromosome 1 of the ringtail corresponds to the fusion of chromosome arm A2p and chromosome C2 in the domestic cat (circled in yellow). Chromosome 3 of the ringtail corresponds to the fusion of the chromosome arms A1p and C1q of the domestic cat (circled in orange). Finally, the third fusion event of chromosome F2 and chromosome arm C1p in the domestic cat together correspond to chromosome 4 of the ringtail (circled in green).

Left: Whole-genome alignment plot between the ringtail (Bassariscus_astutus_HiC) and the domestic cat (felCat9). Right: Results of chromosome painting probes of domestic cat- (FCA) on ringtail-BAS metaphase spread (taken from Nash et al.,2008).

This is the 5th member of the Procyonidae family that we have released here on the DNAZoo blog! Check out these tails about the cacomistle, the white-nosed coati, and the kinkajou as well as the assembly page for the common raccoon and stay tuned for more!


Citations:

Koepfli, K. P., Gompper, M. E., Eizirik, E., Ho, C. C., Linden, L., Maldonado, J. E., & Wayne, R. K. (2007). Phylogeny of the Procyonidae (Mammalia: Carnivora): molecules, morphology and the Great American Interchange. Molecular phylogenetics and evolution, 43(3), 1076–1095. https://doi.org/10.1016/j.ympev.2006.10.003


Nash, W. G., Menninger, J. C., Padilla-Nash, H. M., Stone, G., Perelman, P. L., & O'Brien, S. J. (2008). The ancestral carnivore karyotype (2n = 38) lives today in ringtails. The Journal of heredity, 99(3), 241–253. https://doi.org/10.1093/jhered/esm130


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