Found this remarkable feline at an adoption fair in Berkeley a couple weekends ago. Lucky I got there early, because I bet someone adopted her really quick: total sweetheart, and amazing appearance.
Cat coat color genetics. Pretty fascinating stuff.
Look at the funky little spots on the ears.
Tortoiseshell kitty!! I have had a calico and a tortoiseshell and both were amazing girls (almost always girls). Little crazy, but wonderful! As it happens, they both had ‘half and half’ face colouring – maybe it is part of the genetic code?
Bingo! It’s something called ‘partial X inactivation’. It can only happen to females: since girls have two X chromosomes, their bodies have to decide which one to take orders from when choosing coat color, etc. The other X chromosome is ‘inactivated.’ This is what you get when one X chromosome is active in some places and a different one is active in different places.
This doesn’t happen to dogs, because dog coat color genes aren’t on the sex chromosomes. Cats’ are, which is in turn why you get almost no male tortoiseshell cats: it’s a color combo that’s only possible with a double-X chromosome. (Usually. Mostly. Ish.)
Amazing the things you pick up when running a blog like this. I had no idea about any of this stuff five years ago.