Do you know how the tabby cat gene works with siamese?

lackadaisycats:

Well….yes. More or less, cats with pointed (’Siamese’) coat colors actually have the genetic code for the usual array of cat colors and patterns. They just also happen to have an overlay of partial albinism that messes with the expression of those colors/patterns.  It’s a sort of pigmentation-creation-mutation…if you will……ahem.
It’s caused by the Himalayan gene.

When present, this gene modifies the enzyme that controls melanin (i.e. pigmentation) production, rendering it temperature sensitive. The enzyme functions as normal where the animal’s body temperature is lower, but does not fully function where the body temperature is warmer. This is what creates the characteristic point (’Siamese’) pattern. A cat’s limbs, face, tail and ears are slightly cooler than the core of its body, hence the cat’s ‘true colors’ show up only in those places, where melanin is being produced. The rest of the cat remains a paler shade (though you may notice they develop a bit more bodily pigmentation in winter, and with age).

So…

• black cat + Himalayan gene = seal point
• gray cat + Himalayan gene = blue point
• brown/gray tabby cat + Himalayan gene = lynx point
• ginger cat + Himalayan gene = flame point
• Things like a tortoise shell point and calico spots with points can occur as well because the Himalayan gene mutation, color and pattern determining factors exist at different genetic loci.

Additionally…

– Kittens are kept warm in gestation and are therefore solid white at birth
–The associated blue eyes in these cats is also caused by low pigmentation levels. The iris is highly refractive when there’s little pigmentation, and so it appears blue.
–The gene has a developmental neurological effect that commonly causes crossed eyes as well (strabismus)
–The gene is recessive, thus requires homozygous alleles to be expressed (both parents must contribute it to the mix)
–The Himalayan gene occurs in other mammals as well, like mice and rabbits.

***Some disambiguation/clarification about this coloration permutation: 
When I say ‘Siamese cats’ in this context, I’m referring to cats with pointed coat patterns and not exclusively to the formally recognized breed. Most cats we call ‘Siamese’ because of their coat coloration are not actually classified as Siamese cats in lineal terms.