Genetics and Environment — Why the First Cloned Cat Looked Nothing Like Her Mom and Other Stories

Photo by Cong H on Unsplash

In 2001, Texas A&M University made history with the birth of a kitten named CC.

CC was the first ever cloned cat. Her gene mother was a calico cat named Rainbow.

CC?

CC wasn’t calico. At first they thought they had an oops…how did they clone a calico cat and get a tabby and white. Genetic testing, though, confirmed that CC (short for Copy Cat) was, indeed, identical to the donor.

So, what was going on here?

X-Chromosome Inactivation, Otherwise Known as Why There Are So Few Male Tortoiseshells

Cats have a fairly compact genome. And at some point in their evolution, the color genes ended up…on the sex chromosomes.

Or rather, on the X chromosome. Yup, a cat’s coat color is determined by genes on the X chromosome.

In this specific case, we’re looking at the gene which determines whether a cat’s coat is red-based or black-based. This gene lives on the X chromosome, so female cats have two copies, but genetically normal male cats only have one (all male tortoiseshells are, in fact, intersex).