Why are orange cats usually male while calicos, which have orange patches, generally female?

Question

If the orange color is sex regulated, how does it also appear on the females?

In: Biology

Answer 1

The genes that determine fur color in cats is in the X chromosome.

For male cats they only have 1 copy of those genes, so whichever version of the gene they get determines their hair color. Be it black, orange, tuxedo, grey, tabby, etc

For female cats they have 2 copies of those genes.

Cats actually have 2 versions of the orange haired gene, a dominant gene O and a non-dominant o.

For a female cat to be orange they need two copies of the O gene. If they have 2 copies of the o gene they up end up black. If they have O/o then they are a tortie. If the are O and another hair color they end up a calico.

This is because the O gene is isn’t fully suppressed by the other hair color gene. So as cells divide they have to pick one of the other resulting it splotches of different colors all over the cat.

The dominant A gene however tends to override any other hair color gene, which is why Tabby’s are so prominent. Tabby patterns are also the natural hair pigmentation of the African bush cat that domestic cats descend from.

Male calico’s do exist but they are very rare and are often hermaphrodites.