© Ari KankainenA cat showing the double-recessive coat pattern dubbed 'salty licorice'
There's always something new to uncover in the world of feline genetics. When that discovery is an eye-catching coat pattern, it draws the attention of geneticists and pet parents alike. That's exactly what happened when a distinctive fur color — now called salmiak — was first identified. Read on to learn about this coat color variant and how the Wisdom Panel team contributed to the understanding of the genetics behind the distinctive look.
A striking new coat pattern
Back in 2007, cats with a unique fur pattern were observed in domestic cats in the central Finland region. These cats, typically found in a feral cat population consisting of black and black-and-white colored cats, displayed a normal black-and-white "tuxedo" coloration with additional gradation of color within hairs on its colored areas. This resulted in hair with a colored base and white hair tips.
Since first observed, cats with this color pattern have remained a rare sight in central Finland. They descend from the same wild population, and only non-pedigreed cats are known to have this coat pattern. And since all cats brought in from the streets were neutered, no one knew if they could reproduce. That is, until recent evidence showed a cat with this coat pattern giving birth to a litter of four kittens.
Captivated by the look of these cats and in possession of a genetic sample, researchers at the University of Helsinki, reached out to the Wisdom Panel team for help investigating the genetics of this coat color. And we were happy to lend a hand!
Digging into the genetics
Our study began by genotyping known coat color variants using the MyCatDNA™ panel screening test. This effort revealed that a part of the coloration — all the white hairs in this cat — had no known genetic explanation.
© Heidi Anderson, Milla Salonen, et al./Animal GeneticsSalmiak coloring in cats. Prominent features of the coloring are: “tuxedo” (a.k.a. bicolor) white spotting in the absence of white spotting alleles (Ws, g), and additional gradation of the pigment within hairs of primary color toward no pigmentation at the tips in the body, legs and tail. Additionally, there is primary colored spotting in the white areas of the front legs and chest, more intense coloring in the scapular region, and a very pale tip of the tail. (a) Salmiak solid black cat (aa/wsalwsal), (b) salmiak solid blue cat (diluted black, aa/dd/wsalwsal), (c) salmiak brown mackerel tabby (wsalwsal) (right) and his normal-colored brother heterozygous for salmiak (wsalw), (d) salmiak phenotype on a long-haired solid black cat (not genotyped), (e) salmiak solid black cat (aa/wsalwsal) and (f) salmiak phenotype on a tortoiseshell cat (not genotyped). Cat a was sequenced, and cats b, c and e were genotyped for salmiak. Photo credits: (a) Ari Kankainen and (b–e) courtesy of the cat owners.
Genotyping with the MyCatDNA panel test confirmed that their atypical white patterning had a novel genetic background. Given that around the world, the white patternings and full white color, in both pedigree and non-pedigree cats, are largely explained by two common variants of the KIT gene (also known as White, or W locus). Additionally, the appearance of breed-defining white paws in the Birman cats is associated with another variant in the KIT gene. We considered the KIT gene as the most likely candidate locus for this newly discovered white fur pattern, due to its Finnish origin and its close resemblance to the local salty sweet, we named this color "salmiak" (salty licorice in Finnish).
A bowl of salty licorice candy on a wooden board.
Findings & Inheritance
The salmiak colour pattern was found to be recessively inherited, meaning it requires one copy of the salmiak variant from both parents in order for the trait to be visible. Although white spotting patterns can lead to hearing impairment in cats as well as dogs, researchers did not note any signs of deafness. However, they recommended BAER (brainstem auditory evoked response) testing in the future to rule out this possibility. The allele appears to be quite rare, with only 5 cats found to be positive for the pattern, and another 3 carriers for it, out of 183 Finnish domestic cats screened. The variant has not yet been found in other domestic cat populations.
Two additional domestic cats were also genotyped, one domestic cat from Romania and one from the UK, which manifested a similar type of white patterning referred to as "karpati," of yet-unknown molecular cause. This pattern has been used as the basis of the creation of a new breed, called the "Transylvanian." The term karpati is related to "Carpathian," the region where local cats were noted to have this pattern. Researchers confirmed that the salmiak allele was absent in both of the karpati-coloured cats. Both karpati and salmiak may be described as being similar to roan colouring in other domestic species.
Final Thoughts
The discovery of the salmiak variant enriches our understanding of feline coat colour genetics, and the many genes that contribute to white colour patterns in cats. These "salty liquorice" cats are a beautiful testament to nature's boundless creativity and the rich genetic diversity of non-pedigreed local cats yet to be discovered. It is Wisdom Panel's hope that with future updates to MyCatDNA™, this variant may be made available as a commercial test, potentially contributing to the preservation of this rare trait in our feline companions.
References:
Heidi Anderson, Milla Salonen, Sari Toivola, Matthew Blades, Leslie A. Lyons, Oliver P. Forman, Marjo K. Hytönen, Hannes Lohi (2024). A new Finnish flavor of feline coat coloration, "salmiak," is associated with a 95-kb deletion downstream of the KIT gene. Animal Genetics, 55(4), 676-680. DOI: https://doi.org/10.1111/age.13438
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