You know that in the cat fancy grey cats are called blue cats. The best known is the ‘Blue British Shorthair’. This is a grey-furred cat. Grey fur is caused by the presence of the dilution gene. It causes the melanin pigment clumps in each hair strand to be dispersed with gaps as shown in the infographic. Incidentally, I have relied on a drawing by Sarah Hartwell for the image of a dilute hair shaft. Thanks Sarah. She is the world expert of cat genetics in my view.
The infographic explains my theory as to why grey makes blue in the cat fancy! It is a bit confusing to some. But then the grey fur of domestic cats does have a bluish tinge so the description by cat breeders is accurate. It is just that we are not looking at bright blue or navy blue!
The coat colour is a dilute black which is gray with a hint of blue. Comments are welcome to support of disprove the theory. As long as they are not too rude. The theory is based on the known physics as to why the sky is blue. The particles in the sky scatter blue light more than the other colours which make up white light.
I have used that theory to explain blue cats. The hair shaft when devoid of pigment is semi-opaque which is why all-white cats have hair shafts without pigment. White cats DO NOT have hair shafts that contain white pigmentation. The hair is has a milky appearance.
The same theory if blue light scattering is behind blue kitten eyes as they have no melanin pigmentation in their irises.
Here is a microscopic photo of a hairs haft showing the melanin pigment granules.
The weakness in my theory is that white cats should have a slight blue tinge. Do they? If not, it may be because the keratin of the hair shaft has a slight yellow colour which counters the blue light. If that was the case the same would be happening in blue cats.
Below are some more pages on the dilution gene.
