Particle.news
Download on the App Store
5 ARTICLES
·
yesterday

Genetic Mutation Behind Orange Cat Fur Pinpointed After Century-Long Search

Scientists confirm a 5.1-kb deletion in the X-linked ARHGAP36 gene as the cause of orange pigmentation, with implications for broader biological research.

A ginger domestic cat is resting lying on a gray sofa
Since ARHGAP36 is active in many areas of the body, including in areas of the brain and hormonal glands, it’s possible that the orange variant may cause shifts in gene activity elsewhere, influencing more than just coat color. Credit: Neuroscience News
Image
The sex-linked orange mutation in domestic cats causes variegated patches of reddish/yellow hair and is a defining signature of random X inactivation in female tortoiseshell and calico cats; unlike the situation for most coat color genes, there is no apparent homolog for sex-linked orange in other mammals; Kaelin et al. show that sex-linked orange is caused by a 5-kb deletion that leads to ectopic and melanocyte-specific expression of the Arhgap36 gene. Image credit: Kaelin et al., doi: 10.1016/j.cub.2025.04.055.

Overview

  • Researchers from Kyushu University and Stanford University independently identified a 5.1-kb deletion in the ARHGAP36 gene as the genetic basis for orange fur in domestic cats.
  • The mutation is X-linked, explaining why most orange cats are male and why female carriers display calico or tortoiseshell patterns due to random X-chromosome inactivation.
  • The deletion alters gene regulation in melanocytes, shifting pigment production from dark eumelanin to lighter pheomelanin, resulting in orange coloration.
  • The findings, published simultaneously in *Current Biology*, suggest the mutation originated from a single ancestral event in domestic cat populations.
  • ARHGAP36’s activity in brain and hormonal tissues raises questions about potential effects beyond coat color, with researchers exploring its broader physiological and evolutionary roles.