# rex coat genetics



## *Lisa* (Oct 27, 2009)

Here's my young rex buck Dumpling.

Is the rex coat completely dominant to normal coat? Will all his offspring be curly coated?

What would happen if I bred him with a rex doe? I've heard rex x rex makes hairless.


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## moustress (Sep 25, 2009)

Yes it is dominant; I know nothing about hairless genetics. You could try the search function of this forum. I know there are several members who could help with this. Your mousie is also long haired in addition to being rex (otherwise called Texel)? That's one very, very hairy little beastie!


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## *Lisa* (Oct 27, 2009)

He sure is a fuzzball


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## Jack Garcia (Oct 9, 2009)

You're misinformed on a few counts... Rex (Re/*) X Rex (Re/*) does not create hairless in mice or anything resembling hairless. It creates a version of hairless in _rats_, but the rex gene that rat people work with is slightly different from the Rex gene in mice. In mice a homozygous Rex is simply a Rex who has slightly tighter curl that lasts longer into adulthood. 

Rex is completely dominant over standard coat but that does not mean all his babies will be rex. Here you're confusing complete dominance with homozygosity. If he is homozygous, all his babies will be Rex. This has nothing to do with the type of dominance of the allele that causes Rex fur, though.

Also, fuzzy (fz/fz), when homozygous and selectively bred over the course of many generations, can produce somewhat hairless mice (known as "fuzzy hairless"). You might be confusing Rex with fuzzy, but they are separate alleles of separate genes with different modes of inheritance (one is dominant, one is recessive).

There are a lot of mutations of coat in mice, so it's easy to get confused if you're new. Feel free to ask any further questions you have!


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## *Lisa* (Oct 27, 2009)

Thanks for your help Jack.

His mum had the same kind of curly coat with long guard hairs, but I'm not sure about his dad. If his dad wasn't carrying the rex gene, then he's heterozygous for rex, I guess. Will he therefore have a 50% chance of passing the coat on to his offspring (assuming he is put to does not carrying the rex gene)?

How about the longhaired aspect, assuming Moustress is correct and he is a Texel? I only have short haired self coloured does at present, so I'm wondering what he'll throw out. He looks just black and white in this pic, but he actually has a tan patch underneath.


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## Jack Garcia (Oct 9, 2009)

Well it's complicated because you're working with two different mutations here, one recessive and one dominant and they just so happen to be combined in one mouse.

So no matter who he is bred to, statistically speaking* half of his babies will be rex.

If the mother isn't longhair or doesn't carry it, then 0-50% of the babies will also be longhair.

If you want more just like him the best bet is to breed him to one of his daughters or breed one of his sons and daughters together.

*In smaller litters you may have different results due to chance.


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## *Lisa* (Oct 27, 2009)

Jack Garcia said:


> If you want more just like him the best bet is to breed him to one of his daughters or breed one of his sons and daughters together.


I will do that, I think. He is rather cute!


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## *Lisa* (Oct 27, 2009)

put him to a pink eyed white doe and have got these, which I expected - all like him in colour and 50/50 rex/normal










also put him to my breeding group of 4 girls (2 black, 1 fawn and 1 agouti) and have got this lot - there's a right hotch potch in there!


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