Depending on how cat mad you are, you’ve probably never seen a Selkirk rex kitty, let alone seen or held one. They’re not a popular breed — far less than the Persian (b, in the picture above) or the Scottish fold (c) — but their main feature is a curly coat (a, left). The curly trait is dominant, so about a quarter of any Selkirk rex litter will be the less-wanted straight-hair variety (a, right).
The Selkirk rex is a very new breed, having been developed after a curly-coated (aka rex) mutation arose in a cat in 1987. There have been about 8.4 generations of these kitties, which have been outbred to British shorthairs, exotic shorthairs and Persians to establish the breed (without too much inbreeding).
Though scientists (and breeders) have known that the curly trait is dominant, they hadn’t been able to find the responsible gene. The latest — and successful — attempt comes from a team led by Barbara Gandolfi at the University of California Davis. They published their results in Scientific Reports.
The team looked at the genes of nine curly coated Selkirk rex cats and 29 control kitties, a group that included Persians, British shorthairs and straight-haired Selkirk rex cats. The cats may look different, but they all belong to a big group of related kitties known as the “Persian family.” Gandolfi’s team eventually traced the curly trait to a gene KRT71 — they’re not sure exactly what the gene does, but they know it has something to do with the development of the hair follicle (not exactly surprising).
KRT71 had been ruled out as the curly coat gene in the Selkirk rex in an earlier study that looked at curly-coated cats of several breeds, but it seems that the Selkirk rex in that study was a straight-haired cat, so the researchers would have never been able to find a curly coat gene in it. That study did find, though, that various mutations in KRT71 produced curly hair in the Devon rex breed and the naked look of the sphinx cat.
Photos by Barbara Gandolfi, via Creative Commons license: Gandolfi, B. et al. A splice variant in KRT71 is associated with curly coat phenotype of Selkirk Rex cats. Sci. Rep. 3, 2000; DOI:10.1038/srep02000 (2013).