Click the "Meow!" button (or press space) to generate a cat genotype. For an explanation of what each pair of letters means for your cat's appearance, click the corresponding button to read about it. To make the info go away, click anywhere on it. Unfortunately, I don't have the space to go into much detail about how each gene works, so each info box just summarizes the basics. For each locus, it doesn't matter what order the letters show up in. Dominant genes are always dominant no matter how they're written.
I sometimes use my own symbols for simplicity's sake, or because I couldn't find an official symbol. Some of the genes have not been confirmed to work a certain way, but I treat them as if they all do, to make things easier when trying to figure out genetics for characters in stories. Most of the genetic information came from the Messybeast website and the book Legacy of the Cat. If you want more detailed information about feline genetics, I highly recommend checking out those resources. At this point in time, I'm not sure if I'll be updating this with more genes, but if I do, I will be adding Barrington brown and Lykoi.