# Rex and Fuzzy Genetics



## MythsNTails (May 2, 2013)

Is Fuzzy Hairless a recessive gene? I have a male fuzzy hairless and two of his daughters. One is Rex, one is not. I purchased them from a breeder but I can't recall what the mother-doe was.

If I were to cross the Fuzzy Buck with both of the young does, what types/percentages would the offspring be?

Also, starting with just one Fuzzy how could I start producing fuzzy in my own mousery? Fuzzy are extremely rare here--I only know of two breeders "near" (ha) where I am located so breeding mice are extremely difficult to find. I've only ever worked with Standard coat before but Fuzzy has always been my dream!


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## Laigaie (Mar 7, 2011)

Rex is dominant; fuzzy is recessive. A rex bred to a non-rex will produce either half rexes (if the rex has one copy of the gene) or all rexes (if the mouse has two copies of the gene). A rex bred to another rex could have 75% rex babies if they each have only one copy of the gene, or all rex if one or both of the parents has two copies. A line could be made to breed true eventually by selecting against mice that produce non-rexes. A fuzzy bred to a fuzzy carrier (meaning a non-fuzzy mouse who had a fuzzy parent, or other ancestor from which they got the gene), will have half fuzzies and half carriers. A fuzzy bred to another fuzzy would have all fuzzies. They always breed true.

Do you have both rex and fuzzy? They do seem to be bred together fairly often, but are visually distinct enough when you don't have both genes on one mouse.


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## MythsNTails (May 2, 2013)

Thank you so much! *feeling more hopeful*
The three (Fuzzy Buck + His two daughters 1 Rex/1 Standard) are the only Fuzzy/Rex I have at the moment. I'm just starting out with them =)

Curiosity arisen from reading your post: What would happen/would anything happen if I bred two non-showing Fuzzy carriers together?


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## Laigaie (Mar 7, 2011)

Breeding carriers together gets you a 25% chance of fuzzy, 50% chance of carriers, and 25% chance of non-carriers.

Those numbers hold true for any recessive. Have you read about Punnitt squares? They're kinda awesome for visualizing how genes are inherited.

Could you post photos of the FH and the Rex girl? It would be helpful to you to know for sure that both genes are present. Since FH dad isn't Rex, the Rex girl's mom must have been. If you're sure, though, and you're wanting more fuzzies, you'll want to breed the FH dad to his non-rex daughter. Breeding the rex girl to dad will give you both rex and fuzzy AND some that are both, which makes things difficult to sort out. I don't know enough about the breeding of FH to know whether it's easier to get all the fuzz off the fuzzy when you add another fur-kinking gene. It makes sense that it might, but I honestly don't know. Fuzzy is one of those genes that has a huge range of expression. Everything from a poofy sheep mouse to a nearly hairless mouse all due to the same fz/fz, just with different modifiers.


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## MythsNTails (May 2, 2013)

This is the rex doe--she's also long-haired so technically a "texel" I guess. 









The other doe. I thought she was going to be long-haired too but she is losing it as she ages









Fuzzy Hairless Buck---Their Father









I'm planning on breeding him to both his daughters in a couple months--but also thought about breeding him to my other standard does and then breeding their offspring together to try and get genetic diversity starting with such a small fuzzy gene pool.


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## Laigaie (Mar 7, 2011)

Sounds like a good plan! The second doe does look poor longhaired. Her guard hairs are way long, though the rest of the coat is losing some length. That's also recessive too, so Dad must either be longhaired (hard to tell with fuzzy), or carry it. If you do outcross to the standard-coated does, you could just keep the does and breed them back to him for a larger proportion of fuzzies in the litters.


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