So, here’s a fun story about mouse genetics.
I am currently breeding seal point siamese mice. Genetically, SPS mice are mice with a double dose of the Himalayan gene c^h. Seal point x Seal Point mice should produce all SPS babies. When SPS mice are born, their first coat of fur is a warm, pale brown/tan color, and as they get older, depending largely on the temperature they’re kept in, the “points” of their body (nose, ears, feet, tail) that are coldest will fur in seal brown and the warmest part of their bodies will fur in a creamy white that gets a little darker on the rump.
Except, a few litters ago, one of my pairings threw a bunch of white babies.
Now, a Himalayan mouse genetically has one c^h and one albino gene, so I thought maybe the person I bought them from had mistakenly sold me a Himalayan (I’m still learning, so I wouldn’t have recognized it at the time) instead of an SPS mouse, and that I was getting albinos. In order to test this theory, I set aside a breeding pair of the white mice, to see if they stayed white.
Well, MOST of them stayed white, but their points all turned a pale, toasted-marshmallow tan color, like the big mouse above.
I have... NO idea what that means. I called the breeder back, since I know he knows a lot about show mouse genetics, and he ALSO has no idea what the hell that is. I’ve sent him a bunch of photos, he doesn’t recognize this coloration or know what it would be, genetically, if it popped out of two seal points. Even if it popped out of Himalayans.
Alright, I said. Okay. Fine. This is fine. I’ll breed them to each other and see what they produce. If they are himalayan based, then they should produce babies in 3 different colors; a double gene, a single gene, and a no gene color combo. The first litter (the one above) was born 4/10, and they all look the same as each other--- but they look nothing like their parents did at that age. Their parents were white from the get-go. These guys look like toasted marshmallows all over.
So now I have a second unexplained litter. I’m still waiting to hear back from the breeder to see if THIS answers any questions for him, but I am beginning to suspect not. I’ve also sent an inquiry to a mouse breeding association to ask if they know what might be going on. Guess we’ll see what they have to say about it!