# What kind of gene . . ?



## Rhasputin (Feb 21, 2010)

Okay, I'm going to try and explain this as best as my dyslexia will allow. :lol:

I have mice, with some kind of recessive trait. But it doesn't behave like your standard recessive trait.

Lets say we have 2 mice. Mouse A (is the mouse displaying the recessive) and mouse B (who is standard).

Now if you breed mouse A, to mouse B, you'd assume you'd get carriers. So if you bred their offspring back to mouse A, you should get more like mouse A, right?

Well no.

Mouse A in person, is nearly hairless (not Fuzzy hairless. She has legitimately bald patches of skin, not peach fuzz). When any of the line is crossed with standard, you get rex babies, and sometimes you get fuzzy babies if you cross the offspring.
But you never get more nearly naked mice.
Some of the fuzzies that I've gotten from crossing to standard, will remain FH for months and months, and then suddenly grow a full coat of rex fur.

But when you cross a nearly naked mouse with another nearly naked mouse, you get more nearly naked mice. You also get some that are less naked, and some that are somewhere in between naked and furred.

What kind of gene is this nearly naked buisness? It's some kind of recessive trait, right? :?


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## Stina (Sep 24, 2010)

the coat you get can vary wildly with fuzzy and rex genes at play and my guess would be that you have both and that's all that's going on. It could be something else...but fuzzy and rex interactions are probably most likely.


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## Rhasputin (Feb 21, 2010)

Well yes. But shouldn't there be some kind of 'return' of the baldness outside of just the family?

Maybe not. :lol:


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## Wight Isle Stud (May 19, 2010)

think along these lines, Recessive to what ? one recessive can act as dominant to another recessive............... notwithstanding combination genes that give rise to one single effect. Bit of a mine field to predict.


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## Rhasputin (Feb 21, 2010)

I seee. . .

So I guess it's just a matter of a lot of genes all combining at once. Maybe if I did enough generations of crossing out, I'd get another nearly naked mouse eventually. Hmm. . .


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## moustress (Sep 25, 2009)

Aren't there a number of 'unusual' types of meeces that have unstable genetic content? Like tailless and others? Merle and roan are unpredictable as well, I think. Not to mention the tris.


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## Rhasputin (Feb 21, 2010)

That's true! Maybe it's a bit like Tris then, where many things have to be at work at one time, to create the desired effect!


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## moustress (Sep 25, 2009)

I've also noticed that there are features of curliness that seem unpredictable, as well as long hair. Satin meeces have odd changes too, like the 'greasy' looking satin, a throwback to an intermediate stage of satin development some decades ago.

I wish someone would do a more comprehensive accounting of odd coat types that can occur but are not recognized as standard. You know how I feel about standards in general, they're useful but hardly all encompassing. There are so many coat types, like the shaggy ones that look like little merino sheep, for instance, and the feathered ones, and the ones with hair shirts or shirts or chaps.


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## Rhasputin (Feb 21, 2010)

They're mostly pretty well documented on JAX, but there are hardly any photographs there for identification. :|


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## WillowDragon (Jan 7, 2009)

Maybe technically the mouse is hairy, but the hair is so brittle it is rubbing off and breaking in patches? You know like on double rex rats?


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## Jack Garcia (Oct 9, 2009)

I think you're dealing with poor, inconsistent examples of fuzzy. If these mice are related to the folks I think they are, this makes sense since they do this quite a lot: they breed for fuzzy and fuzzy hairless in the same litters, which is a bad idea for both varieties! Think of dove and silver, which are often both caused by the same allele as well. Now imagine trying to make doves both darker and lighter at the same time, and all the variants you would get. It's the same principle here, so it makes sense that breeding nearly hairless (or very pale silver) to nearly hairless (or very pale silver) will give you mostly or all nearly hairless (or very pale silver) as this is the nature of selective breeding. If you're aiming for hairless ("fuzzy hairless"), don't breed any except the most hairless, and stick to that regimen.

Unfortunately, I think what you're seeing can be chalked up to poor breeding in the past, and fuzzy mice show poor breeding choices (not on your part, I mean going back a few years) very well. But on the flip side, a really nice fuzzy mouse (or fuzzy hairless mouse) shows good breeding very well.

Breeding nearly hairless to furred mice and backcrossing will give all kinds of variants, as you've seen. The same is true with any outcross and subsequent backcross--the F2 generation always varies more phenotypically than the F1 because more genotype combinations are possible. That's why inbreeding selectively is so important: you have to "set in" those traits you want to keep and very deliberately breed _against_ those you don't. You can't do both at the same time.

And I can't edit a post and eat greasy pizza at the same time...


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## moustress (Sep 25, 2009)

Yeah, I've tried to harvest little bits of info from Jax. It's slow going.


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