Silver & Smoke
Wednesday, January 30th, 2008Rangashrii requested some educational reading and Michelle just wants to read my ramblings.
Hope you’re feeling better today, Michelle! As requested, here’s some info about silver and smoke coloring in NFCs.
I don’t think I ever wrote anything about basic color genetics in cats. So starting off… All cats are black. Uh huh. Yep. Look around. All black. Okay, well, some are red. Red is sex related and carried on another chromosome. But when I start talking about the modifying genes that change how a cat looks (instead of just being black), they apply to the red as well.
So we start with a solid black cat. Then we add in other things like tabby markings, pattern to the markings, and color modifiers. Silver and smoke are the result of a gene that you will often see called the “inhibitor” gene because it’s action is to inhibit the placement of pigment on the hair shaft. It is a dominant gene, meaning that if a cat has it, they will show it. You cannot get a silver or smoke cat from two non-silver/smoke parents. However, a silver (and for ease in writing I’m going to from now on refer to it simply as silver rather than silver/smoke) cat can have offspring that are not silver if the cat “carries” the non-silver gene and is bred with a non-silver cat or a silver who also is carrying non-silver.
Silver is variably expressed, meaning that the degree to which it inhibits the placement of pigment can be different from cat to cat. You may see a silver who has only the very base of his/her fur that is white, pale blue, or pale beige. You may also see cats — like Kefira, for example — who have color only on the tips of their fur. The rest of the hair shift is white. In any case, the color is inhibited from the root towards the end of the hair. In other words, you won’t see a cat with white tips and dark roots. Unless someone got a little crazy with the dye. (Just kidding!) Depending on the breed and the registry, the expressions of the gene may also have different color description names even though the base color is the same.
The difference between silver and smoke is that silver is what we call the gene’s expression in a tabby. So you’ll see silver mackerel and classic tabbies, or blue silver, or red-silver (cameo), etc. A silver tabby is genetically a brown tabby with the inhibitor gene. Kefira is a silver patch mackerel tabby, meaning she’s a brown patch mackerel tabby (genetically) with the inhibitor gene. Smoke is the expression in a solid colored cat. That is, a smoke is a black cat with the inhibitor gene. Blue-smoke is a solid blue cat with the gene and so on. Keep in mind that whenever I’m talking about a tabby or a solid color cat, I’m also talking about those same colors on cats who have white. A blue smoke cat with white areas would be registered as a blue smoke & white.
So that’s your mini color genetics lesson for the evening. I’m sorry I was so late getting it posted. Sometimes I get distracted with other things. Now that I’m thinking about color genetics, though, I may post some more on the subject tomorrow.