Genetics... Different Alleles for Cat Eye Color.

I picked kind of a confusing topic, so this is probably going to require a LOT of explaining... but it's pretty cool, so bear with me. :)

Cats display many different phenotypes, (the observed state of a trait) through their physical features, but certain features can be masked by dominant ones. (ex. within felines, shorthair is dominant over long hair. If a homozygous dominant short and homozygous recessive longhair cat mated, all the offspring would have short hair, but carry the long hair allele. ) The dominant genes are portrayed and the recessive ones are hidden.

Quick review: Homozygous dominant: II
                       Heterozygous: Ii   
                       Homozygous recessive: ii

The problem with isolating an allele is that they're all so closely effected by melanin... So the colour of the hair and the hair patterns relate to eachother, and the type of cat.

This here is Chloe! She's the mother of the cat below, and she's an average housecat, Felis domesticus. (Actually, she lived in the barn...) She displays a normal tuxedo pattern, which corresponds to her eye-colour, which is a yellow-ish green... almost hazel. The entire spectrum for usual cat eye colour runs from green to hazel to brown.

Now this is one of chloe's kittens. She had 4, and this was the only one that still possessed blue-colored eyes after six months. (They're all born with blue eyes.) This suggests that whoever the father figure cat was heterozygous for the blue eye allele. (Ii) Using the square, we can concur that Chloe and the father were carrying the recessive allele for blue eyes, and the rest of the kittens inherited the hazel-eye trait. This means Chloe's heterozygous... because blue eyes in cats are ALWAYS recessive. The kitten also displays the same hair pattern.

This is Annie, my indoor cat... she sleeps for 18 hours a day. She and the next cat take the most explaining. She's a ragdoll cat, but she displays codominance within her face... most ragdolls contain alleles for albinism.
Genes that affect more than one trait are called pleiotropic. Most coat genes have a pleiotropic effect on the eye colour as mentioned before. There are two alleles manipulating eyecolour on cats:
-the pointed allele for hair: c³ 
-And the sepia colouring: c^b
Both alleles are recessive to the colour allele, C but are codominant with eachother. The homozygous genotype c3c3 reduces most pigmentation (natural colour) across the animal, reducing pigment production in the eyes, resulting in bright blue, vivid eyes. Annie's eyes however, are NOT as bright a blue as they should be but she's for sure codominant.... which suggests somethings up. The next photo shows the correct eye colour.

This is Felix, my cousins ragdoll cat... he bites. This one however, is a pedigree cat, and I think it came with some kind of pedigree chart... but anyway, I'll explain: The electric blue within his eyes is what should occur within these type of cats, rather than Annie's sea-ish blue. The reduced density of the fur colour is also shown correct here: what should happen is that either pure white with 1 other colour, or beige and dark brown colouring appears, rather than black and white and all inbetween. Annie above shows that she has grey, cream and white in her face, but the rest of her body is entirely white, other than her paws. She displays a bit of a calico pattern which is odd... but also suggests again codominance with different alleles, whereas Felix is definitely a purebred. You can tell mostly with the eyes.

Because I needed a 5th picture, this is Nikki... she doesn't display anything unusual, a calico pattern with corresponding inherited brown eyes, which is the most dominant allele. She's one of my other cousins cats... we have a lot of cats in our family.

So that's that... ahah, it's a lot of typing, I'll be sure to write a bit less next time.