
24/05/2025
Genetic Breakthrough Reveals Why Orange Cats Are Mostly Male
Two studies published in Current Biology on May 15, 2025, have solved a 110-year-old mystery about orange cat fur.
Researchers from Stanford and Kyushu Universities identified a 5-kilobase deletion near the Arhgap36 gene on the X chromosome, which boosts gene activity in pigment cells, producing reddish-yellow fur instead of brown-black. This sex-linked mutation explains why most orange cats are male, as they need only one copy, while females, requiring two, often display tortoiseshell or calico patterns due to X-inactivation.
The mutation is unique to domestic cats, and scientists are now exploring its potential effects on health and behavior. Evidence of orange cats in ancient Egyptian art hints at the mutation’s long history, with plans to study mummified cat DNA next.