Calico Cats and Kleinfelters
http://aebrain.blogspot.com/2008/05/calico-cats-and-kleinfelters.html5/6/2008
"As for the male calico in question, Gould had to look to the X
chromosome, where the cat's gene for coat color resides. A cat, she
tells us, can have either the "O" gene, for orange, or the "o" gene
for black (or, strictly speaking, non-orange). Orange in this case is
only partially dominant over non-orange, and a hybrid, "Oo," has a
coat with a little bit of orange, a little black—in other words,
calico. And since the color gene is on the X chromosome, you can't
have a male hybrid, any more than you can have a male carrier of
sex-linked diseases like hemophilia, because males have only a single
X."
