The Genes That Give Tabby Cats Their Stripe Patterns

Have you ever wondered how tabby cats get their stripes? Or why all cats don't have the same stripe patterns? Along a cat's nineteen pairs of chromosomes, there are genes, which make up the genome. Each breed of cat has its own dominant genes, and different genotypes and phenotypes that determine the pigments in its fur, the texture of its fur, the pattern of its fur, and there are different genes for cats that grow no fur at all. All cats have genes that affect the way they look, but one of the most distinct is the striped and blotched pattern look that tabby cats have in their fur. There have also been recent discoveries made in why all stripes are not created equal.

An example of how genes can affect the patterns in cat fur is a pattern known as Agouti. Some cats have different colored bands along the shafts of their tails, and the gene that causes this pattern is the “Agouti Signaling Protein,” and a mutation or change in this gene can have drastic affects on the pattern in a cat's fur. The banding is based on the dominance of the Agouti gene and occurs when a cat carries one or two copies of the gene. When the banded fur and solid fur alternate, it is called tabbying, which is common in many cats. If a cat has two copies of the non-agouti gene, then the fur will be solid. In most tabby cats, the stripes are defined and evenly spaced. There is also the tabby gene, as well, that affect the pattern. There are three different stripe patterns which are inherited through the tabby gene: Mackerel, Classic, and Abyssinian. A mutation in any of these genes can cause variations of those patterns.
In a recent study, there was a discovery of a mutation in the genomes in domestic tabbies which may even explain further into how cats get blotches instead of stripes. The gene mutation is called the “Taqpep mutation.” Researchers found that blotched tabbies had mutations in their copies of the gene, whereas striped tabbies had at least one copy with no mutation. Also, the mutated gene is one that blotched tabbies share with wild cheetahs whose fur went from spotted to striped. This mutation explains the pattern, but makes no distinction as to the color of the fur in cheetahs. A gene called the Edn3 decides the colors in the fur patterns.  

Tabby patterns only show up when cats begin to grow hair, which is within their first seven weeks of gestation, carried out while the embryo develops, by changing levels of Edn3. During gestation, levels of Taqpep increase. The Taqpep mutation happening earlier on in a cat's life may determine why spots and stripes don't change as the cat grows older. The main researcher in the study speculated that the gene has other functions, and may do more for the cats than simply change their patterns, such as helping boost immunity against disease and infections.


http://news.sciencemag.org/sciencenow/2012/09/how-the-tabby-got-its-blotches.html?ref=hp
http://www.nytimes.com/2012/09/25/science/the-gene-behind-cheetahs-spots-and-tabbies-stripes.html
http://news.discovery.com/animals/tabby-cat-stripes-gene-120921.html
http://www.livescience.com/23348-how-the-tabby-cat-got-its-stripes.html