Mystery Solved! Scientists Discover the Gene Behind Orange Cat Fur

For decades, the striking orange coat of domestic cats has been a charming, yet perplexing, genetic puzzle. Scientists knew the trait was somehow tied to sex, but the exact gene responsible remained elusive. Now, groundbreaking research has finally unraveled this long-standing mystery.

Recent studies published in the journal Current Biology, conducted independently by teams at Stanford University in the U.S. and Kyushu University in Japan, have pinpointed the specific genetic mutation that gives orange cats their fiery hue. This is a major step forward in understanding feline coat color genetics.

The studies identified a deletion mutation in a region near theARHGAP36 gene on the X chromosome as the key factor. Unlike many genetic mutations that inactivate a gene, this particular deletion appears to increase the activity of theARHGAP36 gene specifically within the cat's pigment-producing cells, known as melanocytes.

How does this lead to orange fur? Cat coat color is determined by two main pigments: eumelanin (responsible for black, brown, and grey) and pheomelanin (responsible for red, yellow, and orange). The researchers believe that the increased activity of ARHGAP36 protein interferes with the signaling pathway that normally leads to eumelanin production. This interference causes the melanocytes to primarily produce pheomelanin, resulting in the characteristic orange color.

This genetic discovery also definitively explains why approximately 80% of orange cats are male. The gene responsible for orange coloration is located on the X chromosome.

• Male Cats: Have one X chromosome and one Y chromosome (XY). If their single X chromosome carries the orange mutation, they will be orange.
• Female Cats: Have two X chromosomes (XX). To be fully orange, a female cat must inherit the orange mutation on both of her X chromosomes (one from each parent). Inheriting the mutation on only one X chromosome, alongside a non-orange gene on the other, typically results in a tortoiseshell or calico coat, where patches of orange are mixed with other colors due to random X-chromosome inactivation in different cells during development.

Because females need two copies of the relatively less common orange mutation, they are statistically much less likely to be solidly orange compared to males.

It's a common misconception that "Orange Tabby" is a specific cat breed. In reality, "orange" refers to the coat color and "tabby" refers to the pattern of stripes, swirls, or spots that is always present on an orange cat's coat. The gene for orange coloration actually ensures the tabby pattern is visible.

The orange color can appear in many different cat breeds, including:

• Domestic Shorthair/Longhair
• Maine Coon
• British Shorthair
• Persian
• Abyssinian (often as 'ruddy' or 'sorrel' which are shades of orange/red)
• American Bobtail
• Egyptian Mau
• Turkish Van

So, while your orange cat might have the distinctive color, their actual breed (or mix of breeds) will determine other physical and temperamental traits.

Many cat owners and enthusiasts share anecdotes about orange cats having distinct personalities – often described as friendly, outgoing, sometimes a bit goofy, or having a single shared brain cell! While these stereotypes are popular and often endearing, scientific studies to date have not found a definitive link between coat color and personality.

A cat's behavior and personality are primarily shaped by a combination of genetics (related to breed, not just color), early socialization, environment, and individual experiences. While the ARHGAP36 gene is active in other tissues, including those related to the nervous system, the current research hasn't established that the orange-causing mutation directly impacts behavior.

So, while your orange cat might indeed be a lovable goofball, it's more likely due to their unique individual nature than the color of their fur!