What's Poppin' with Cross-Dressing Kittens?

A "genetically impossible" male tortoiseshell kitten is making headlines in Britain (or was last week anyway; we apologize for What's Poppin's unacceptable oversight). The 8-week-old kitten, named Eddie "after the cross-dressing comic Eddie Izzard because 'he is essentially a boy dressed in girls' clothing,' " was adopted by a vet in Harpenden after he was rescued along with his three tortoiseshell sisters.

"Male cats, like human beings, have only one X chromosome in their DNA meaning it is technically impossible for them to inherit different colours," the Daily Mail explains... which doesn't actually explain a whole lot, but suffice to say the chances of a male tortoiseshell being born are minute. "So far there are no signs of any gender confusion and he seems to be all there," his smitten new owner proclaims. Here's to a happy, hype-free life of sunspot-sleeping, tail-chasing and maybe a little Ani "I've got spots, I've got stripes, too" DiFranco–listening.

Previously > What's Poppin' with Commuting Canines?

Comments

[Elaine]

Here's the deal. Almost every tortoiseshell is a female (XX). You do need two X chromosomes in order to produce the tortie pattern - it's a sex-linked characteristic. Sometimes, though, a kitten is born with an extra chromosome (XXY). So it may present with male (XY) genitalia, but have the necessary genetic components (XX) to be tortie.

This genetic anomaly happens in humans, as well. A man might never find this out, except that the anomaly renders males sterile. So if a man is attempting to become a parent and goes the route of testing to determine why he's sterile, he might find out he's XXY.

So, anyway, there are actually three genetic possibilities for torties.

1. A normal XX female kitten - most common

2. An XXY kitten, genetically neither male nor female, but can have male or female genitalia - very rare

3. A chimera, which would look like a tortie, but not genetically be a true tortie. I'm not even going to attempt to explain this one. You can look it up, and also there was a great CSI episode about a suspect who was a chimera, and really broke it down very well. The prevalence of this is unknown, because literally anyone (or any cat) could be a chimera.