The blue eyes of Atlas and Trico crackle and sparkle. There is almost a texture in them. I am not sure why these eyes have this ‘texture’ as I have described it. A lack of pigmentation in the iris of eyes makes them blue because of white light refraction. This is why the eyes of kittens are blue. Both for Trico and Atlas the eyes lack pigmentation because Trico is all-white and has the dominant white gene which removes melanin leaving the hair strands and eyes without pigment. Atlas has the piebald or white spotting gene which does the same thing to the eyes and leaves the coat with white sections. Calicos are tortoiseshell-and-white cats. “Calico” is an American term.
I believe that what we are seeing in these eyes is the muscle of the irises. It is a little mystifying but it is also beautiful. The light helps too as the bright light has caused the pupils to become very small which shows us to see more of the iris. Great eyes.
I am reliant upon their owner for his decription of the cats. It is all but impossible to claim that a cat is a Siamese Mix or Turkish Angora Mix unless you know the pedigree. Visually a cat might have the correct appearance but in claiming that a cat is a “Mix” you are claiming that there is some purebred DNA in the cat and you can only know that if you know the pedigree. Great cats though.
Some more about the dominant white gene and the piebald gene
The completely white cat which has two blue eyes and often odd-eye colour is due to a dominant white gene which is symbolised by a W. Visually it is impossible to tell whether other genes are present in the genotype because the all white coat prevents it. In other words the dominant white gene is epistatic to other colour mutants masking the effect of all other colour genes.
The W gene affects both coat and eye colour in various ways. You might know that it is also linked to deafness. The gene, as mentioned, prevents melanin being deposited in the hair shaft. This is because it also stops melanocytes being present in the skin. These are the cells that produce melanin. In kittens there might be a small spot of colour on the head but this disappears at adulthood. The deafness is due to degenerative changes in the cochlea and succule.
The white spotting gene or piebald gene is very common in domestic cats. It can occur in conjunction with any colour coat. The effect may be limited to small tufts of white hair on the breast or belly (tuxedo cat) or it might render a cat almost completely white with the areas of pigment being confined to the tail or to small spots on the head or body. When the white is extensive it is referred to as “high-grade spotting”. The opposite is referred to as “low-grade spotting”.
Medium-grade spotting is the reason why we have bicolour cats found in many breeds and high-grade spotting is a characteristic of the Turkish Van cat, both for purebred, pedigree cats when created by a breeder or street cats in the Van area of Turkey.
Here are some more pages on eyes.