I thought I'd better make more of an effort to write these posts. You never know, someone might be interested one day!
Ok, so we've looked at how there is one colour gene for cats. We've looked at how this gene can express itself in different ways, brown, chocolate and cinnamon (not in the Tonkinese) And we know that the orange gene can mask this colour gene and make a cat orange.
Added to this, there's a gene called 'dilute'. It does exactly what it says on the tin- makes the colour of the coat less intense. Thus black ('brown') is diluted to a grey colour cat fanciers call 'blue', chocolate is diluted to a paler browny- pinky- grey called 'lilac' and cinnamon is diluted to 'fawn'- a light beige shade.
Which starts to explain some of my cats, doesn't it? Ava and Theo are blue cats- they have the brown allele plus dilute. Indigo is a lilac, she has the chocolate allele plus the dilute. All three have other 'bits' going on as well... tabby and colourpoint, but we haven't got to them yet.
Cats can have zero, one or two copies of the dilute gene. Dilute is recessive, in order to express itself there needs to be two copies present. A cat with full colour/ dilute will be full colour, but as ever, will still be able to pass on the dilute gene genetically.
What happens when the cat's colour is masked by the orange 'red' gene? The dilute gene still has an effect, lightening the cat from orange to a buff colour called 'cream'
Cream eh? Don't know about feeling blue, all these cat colour names are making me feel hungry...