When Professor Hiroyuki Sasaki retired, he wasn’t done with science. He just wanted to use it to better understand his cats.
The Japanese geneticist raised more than $73,000 from Japanese and international cat lovers and put together a team, including partners from the US. Then he began the hard work of scrutinizing feline DNA to find out why some cats are orange, and why most all-orange cats are male while virtually all calico and tortoiseshell cats, whose coats have splotches of orange, are female.
It turns out there’s no genetic instruction telling the fur to take on an orange pigment — it’s the absence of a segment of DNA, which governs pigment production, that does it.
In other words, ginger cats are mutants.
Most fully-orange cats are male because the mutation removes the DNA segment in the X chromosome. As males have X and Y chromosomes, they only need the mutation in the single X chromosome for their coats to express in that shade.
Females have an XX chromosomal arrangement, so they need the mutation in both chromosomes to turn tangerine. If the mutation only shows up in one chromosome, you get patches of the color instead of a consistent coat.
That explains why 80 percent of ginger cats are male, and why only one in 3,000 calicos and tortoiseshells are male. A male cat would need an extra X chromosome, XXY, to be born with a calico or tortoiseshell coat. One of the side effects, however, is sterility.
Scientists estimate only one in a thousand male calicos/tortoiseshells can reproduce and pass their unique mutations on.
It’s not just coat color either. The mutation impacts skin and eye color, which is why a ginger cat might have a pink nose compared to the terracotta shade of a void cat or a silver tabby.
Are orange cats really more friendly and silly?
So how does this relate to temperament, and the many people who attest to a particular personality associated with orange cats? Some people say ginger tabbies are more loyal, affectionate and social than cats of other coat colors, but they’re also more prone to doing boneheaded things.
The stereotypes have picked up steam online, where people often share memes depicting orange felines as earnestly derpy, but they may be on to something — or at least, it can’t be ruled out until we know more.
Because of the missing piece of genetic code, a specific gene, ARHGAP36, isn’t “expressed.” Like so many genes, scientists don’t fully understand everything ARHGAP36 impacts, or how alterations can lead to unexpected changes elsewhere.
“Many cat owners swear by the idea that different coat colours and patterns are linked with different personalities,” Sasaki told the BBC. “There’s no scientific evidence for this yet, but it’s an intriguing idea and one I’d love to explore further.”
Header image via Pexels
via Pain In The Bud