Researcher
研究者名
Murayama, Miho
Overview
Kyoto, Japan -- The Japanese island of Tsushima is home to the Tsushima leopard cat, a critically endangered species that can only be found on this isolated island. The most recent government survey estimated the population to be only around 150 individuals, and since domestic cats also inhabit the same landscape, introgression is a legitimate conservation concern.
That's why a team of researchers from Kyoto University became worried when, during a field survey, they spotted at least three Tsushima leopard cats with shortened tails, a trait relatively common in domestic cats but that had not yet been observed in leopard cats. The team was able to capture one of these cats for examination and discovered that its tail was half the normal length. This motivated them to investigate whether this tail abnormality reflected recent domestic cat ancestry, or a variation arising within the leopard cat population.
"An unusual phenotype can immediately raise concerns about hybridization, but we wanted to determine objectively what the genome actually tells us before drawing conclusions from appearance alone," says first author Yuki Matsumoto*.
The team analyzed the entire genome of the short-tailed Tsushima leopard cat and compared it with genome data from 15 additional leopard cats, five domestic cats sampled on Tsushima island, and four continental Amur leopard cats as an external wild reference for good measure. These analyses included principal component analysis, genome-wide inbreeding estimates, mitochondrial DNA phylogeny, ADMIXTURE, and f-statistics to assess ancestry and introgression, along with screenings of two genes associated with tail abnormalities in domestic cats.
The results fortunately revealed no evidence of domestic cat introgression in either the short-tailed Tsushima leopard cat or the 15 other leopard cats sampled. Each step of the whole-genome analysis placed the short-tailed cat firmly within the Tsushima leopard cat population, and did not detect any abnormalities.
However, the underlying cause of the tail abnormality remains a mystery for now. The team's observations of Tsushima leopard cats with short tails in different locations suggests that there may be more behind this rare phenotype. In the future, the team hopes to examine more short-tailed individuals and is developing non-invasive genetic monitoring that could help track the leopard cats without capturing them.
This study represents the first clinical and genomic characterization of a short-tailed individual in the wild cat genus Prionailurus.
"Appearance alone can be misleading when managing endangered wildlife," says Matsumoto. "By combining long-term field observations, veterinary examination, and genome-wide data, we can make conservation decisions on the basis of genetic evidence rather than phenotype alone."
*Dr Matsumoto also has affiliations with Anicom Specialty Medical Institute Inc and Azabu University.
