Approximately 80% of orange cats are male. But why?
Rebecca Ramirez/NPR
hide caption
toggle caption
Rebecca Ramirez/NPR
Approximately 80% of orange cats are male. But why?
Rebecca Ramirez/NPR
About 80% of orange cats are males, including the four orange cats owned by the Short Wave team: Zuko, Benny, Tang and Dorito.
Scientists have long suspected that their orange color was a sex-linked trait — hiding somewhere on the X chromosome of domestic cats.
Male cats – just like male humans – have an X and a Y chromosome, so any male cat with this mutation ends up orange. Due to X chromosome inactivation, female cats require the mutation on both X chromosomes to be fully orange, which is statistically less likely.
Two independent teams have located and characterized the mutation responsible for this fur color. One was led by Hiro Sasaki at Kyushu University in Japan and another was led by Christopher Bryan Kaelin at Stanford University.
Both groups published their results in the journal Current Biology Thursday.
They found that the mutation responsible for orange coloration increases the activity of a nearby gene, known as Arhgap36. This gene is normally expressed in neuroendocrine tissues. However, the orange mutation in cats appears to cause this gene to express in pigment cells.
The Orange Cats of Short Wave
No orange cats were harmed in the pursuit of this genetic mystery.
In fact, study author Greg Barsh says the Stanford team partnered with cat lovers and community scientists to gather DNA samples from dozens of different orange cats.
“It’s an example of how scientists and the public can work together to not only uncover cool things, but also learn important aspects about biology,” Barsh says.
And there are some other important aspects to feline biology for your consideration, cat lovers. For instance, calico and tortoiseshell cats carry this mutation as well. Another fun fact: Nearly all calico and tortoiseshell cats are female because this orange mutation is found on only one of their X chromosomes. Finally, any male calico or male tortoiseshell cat is extra rare, and the result of having an additional X chromosome.
Read the Toh, Hidehiro et al. paper here and the Kaelin, Christopher B. et al. paper here.
Have a question about the animals all around us? Email us at shortwave@npr.org — we’d love to hear from you!
Listen to Short Wave on Spotify and Apple Podcasts.
Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave.
Today’s episode was produced by Rachel Carlson and Elena Burnett. It was edited by Rebecca Ramirez and Christopher Intagliata. Tyler Jones checked the facts. Kwesi Lee and Ted Mebane were the audio engineers.
