what does it mean when a cat has one blue eye and one green eye
Odd-eyed cat The odd-eyed coloring is caused when either the epistatic (dominant) white gene (which masks any other color genes and turns a cat completely white)[4] or the white spotting gene (which is the gene responsible for bicolor and tuxedo cats)[5] prevents melanin (pigment) granules from reaching one eye during development,[3] resulting in a cat with one blue eye and one green, yellow, or brown eye. The condition only rarely occurs in cats that lack both the dominant white and the white spotting gene.[4]
Tortoiseshell cat "Tortoiseshell" is typically reserved for particolored cats with relatively small or no white markings. Those that are largely white with tortoiseshell patches are described as tricolor,[2] tortoiseshell-and-white (in the United Kingdom), or calico (in Canada and the United States).[7]