Image courtesy Ari Kankainen

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 cat owners 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 this distinctive look. 

A striking new coat pattern 

Back in 2007, cats with a unique fur pattern initially termed “the Finnish mutation” were observed in the local feral domestic cat population in the central Finland region. These cats were black and black-and-white colored, or “tuxedo” patterned, except with the addition of color gradation of the black hairs. This resulted in a color pattern 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 likely descend from the same wild population, and only non-pedigreed cats are known to have this coat pattern. Since all cats with this coat pattern brought in from the streets were neutered, no one knew if the pattern was heritable. 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 with genetic samples in hand, researchers at the University of Helsinki reached out to Dr. Heidi Anderson of the Wisdom Panel™ team for help investigating the genetics of this coat color. 

Digging into the genetics 

The study began by genotyping the cat for known coat color variants using MyCatDNA™ (the European equivalent to Optimal Selection™ Feline) testing. This effort revealed that a part of the coloration—all the white hairs in this cat—had no known genetic explanation. 

Further intrigued by this unique color pattern, the researchers at the University of Helsinki reached out to the public through a national newspaper, seeking sightings of cats with a similar pattern. This successful outreach led to the discovery of additional cats with this coat pattern. However, the pattern was not only found on solid black cats, but also blue, brown tabby, and tortoiseshell cats. 

Genotyping with the MyCatDNA™ panel test confirmed that their atypical white patterning had a novel genetic background.  Usually, white patterning 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). For example, the appearance of breed-defining white paws in Birman cats is associated with another variant in the KIT gene. Dr. Anderson 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, the color was named "salmiak,” after the popular Finnish salty licorice.

To continue the collaborative investigation with University of Helsinki, two salmiak-colored cats were whole-genome sequenced, and further explored the region of the KIT gene. Initially, no unique variants were discovered within the coding region of the KIT gene. However, visual inspections of the sequence region revealed a large deletion near the KIT gene of both salmiak cats that could impact gene expression. Genotyping additional Finnish domestic cats for the newly discovered variant confirmed the novel KIT variant was fully concordant with salmiak appearance.  

Findings & Inheritance  

The salmiak color 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-colored cats. Both karpati and salmiak may be described as being similar to roan coloring in other domestic species. 

Final Thoughts 

The discovery of the salmiak variant enriches our understanding of feline coat color genetics, and the many genes that contribute to white color patterns in cats. These "salty licorice" 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