https://www.science.org/content/article/gene-behind-orange-fur-cats-found-last
It would be pretty easy to guess that Garfield was a tomcat even if you didn’t know his name—or didn’t want to peek under his tail. Most orange cats are boys, a quirk of feline genetics that also explains why almost all calicos and tortoiseshells are girls.

Scientists curious about those sex differences—or perhaps just cat lovers—have spent more than 60 years unsuccessfully seeking the gene that causes orange fur and the striking patchwork of colors in calicos and tortoiseshells. Now, two teams have independently found the long-awaited mutation and discovered a protein that influences hair color in a way never seen before in any animal.