My Silver Foxes all carry chocolate. A few carry blues but the blues are back at the Greg-grandparents. For one of my does, only one great-grandparent carries blue. My bucks have more blue in their genes. How do I determine the chances of getting a blue from a mating? Heck, I don't even know if I'd be able to tell the color difference! LOL
Recessive Blues
- Thread starter ollitos
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The blue color doesn't come from "blue" gene. It comes for a black B gene, combined with "dd" dilute. Since the "d" is recessive it can "hide" for MANY generations. The best way to find out if your animal carries the "d dilute is to breed to a dilute mate. I don't know all the colors in silver fox, I only raise Rex, but the colors that ARE dilute are
Lynx A_bb C_ dd
lilac aa bb C_ dd
Opal A_B_ C_ dd
Blue aa B_ C_ dd
If you breed to one of these, and have a blue kit, then you know your rabbit carries the dilute. You can assume that if you NEVER get a blue from one of those breedings, it doesn't carry the dilute gene. But it would be possible for it to carry it, and just not have enough kits in its lifetime to have it show up.
Lynx A_bb C_ dd
lilac aa bb C_ dd
Opal A_B_ C_ dd
Blue aa B_ C_ dd
If you breed to one of these, and have a blue kit, then you know your rabbit carries the dilute. You can assume that if you NEVER get a blue from one of those breedings, it doesn't carry the dilute gene. But it would be possible for it to carry it, and just not have enough kits in its lifetime to have it show up.
Calculating probabilities is no fun. If I remember statistics class correctly (loooong time ago), for each generation back you multiply by 50%. If the ancestor actually was a blue, then it definitely gave a copy of dilute to the kit. If the ancestor was a black known for certain to be carrying dilute, then the chances it gave it to the the kit are 50/50. And after that, the chances are 50/50 for each generation.
So, great-grand blue, grand carrier, parent unknown, kit unknown = 100% x 50% x 50% = 25% chance
If the great-grand was just a carrier, then the chance goes down to 12.5%
What I can't remember is, if you cross those two together, do you add or multiply the chances? One way gives and answer of 37.5%, the other gives an answer of just 3.125% It was just too long ago, that class I had to take, but I think you're supposed to multiply. So that would be a 3% chance, pretty depressing. If everybody is carrying chocolate, that means you also have a 3% chance of lilac.
Hope that helps you plan your strategy!
So, great-grand blue, grand carrier, parent unknown, kit unknown = 100% x 50% x 50% = 25% chance
If the great-grand was just a carrier, then the chance goes down to 12.5%
What I can't remember is, if you cross those two together, do you add or multiply the chances? One way gives and answer of 37.5%, the other gives an answer of just 3.125% It was just too long ago, that class I had to take, but I think you're supposed to multiply. So that would be a 3% chance, pretty depressing. If everybody is carrying chocolate, that means you also have a 3% chance of lilac.
Hope that helps you plan your strategy!
Figuring out the exact odds is way too much of a pain and it doesn't really help you any. Anywhere along the line the gene could have just not been inherited and calculating the exact percent chance isn't going to change that. If you want to know if your rabbit carries dilute then go breed it to a dilute. It doesn't have to be a silver fox or a blue even since getting any of the other colors mentioned would prove dilute so long as you have something to do with the mutt offspring. Also if silver fox can produce chocolate and blue someone is getting some lilacs in there even if they aren't recognized.
