What causes a misshapen pupil in your eye?

Why does my cat have a blue right eye? She has an average yellowish left eye. Her right pupil is more akin to a human, and blue. She was born as such, she is a forth generation cat, and she is a white domestic shorthair. What causes this?

• Answer:

  An odd-eyed cat is a cat with one blue eye and one green, yellow or brown eye. It is a feline form of complete heterochromia, a condition which occurs in some other animals. The condition most commonly affects white colored cats but can be found in a cat of any color, as long is it possesses the white spotting gene. 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) or the white spotting gene (which is the gene responsible for bicolor and tuxedo cats)prevents melanin (pigment) granules from reaching one eye during development, resulting in a cat with one blue eye and one green, yellow or brown eye. It only rarely occurs in cats that lack both the dominant white and the white spotting gene.