Cats Are Not Peas: 12/06/07

Cats Are Not Peas by Laura Gould is the best explanation of calico cat genetics I have ever read. It is also one of the best science books for non-scientists I have ever read. Heck, it is one of my all time favorite books.

Cats Are Not Peas is a memoir of Laura Gould's journey to discover why her calico cat was different. She like the rest of us had always heard that calico cats are always female but she had a male calico cat (George). She wanted to know why her cat was male.

The reason, she learns, is that orange and black genes are carried on the X chromosome. White is a color that isn't carried on a sex chromosome. So if you have an orange, black and white cat (a calico) or an orange and black cat (a tortoiseshell) then you have to have a cat with two X chromosomes. In other words, you have to have a female cat.

So where does George fit into the equation? Laura had him genetically profiled. Turns out George was a chimera. He was the result of two or more fertilized eggs blending together into one individual. So he had at least two X and at least one Y chromosome. And that's how you get a rare boy calico.

Comments (2)

Comment #1: Thursday, December, 6, 2007 at 21:23:50

Cereal Girl

That is a fascinating tail... I first heard about chimeras by watching C.S.I. but I thought they were so rare I'd never hear of one outside of fiction."

Comment #2: Friday, December, 7, 2007 at 07:21:03

gautami tripathy

I like the title!

reading room"