# Genetics on Black Self



## fuzzymom (Nov 28, 2009)

I bred a black self doe to an agouti buck. She had five babies and they are all a week old. I can tell they are all agouti. So with the color they are displaying, what does this mean for their genetics. Black self is on the A isn't it? Isn't black self a/a or something like that (from what I remember from my other thread). I do not know the genetic history of any of these mice (as I breed for feeders and got them from the feeder bin. I really need to get some good quality mice). Its safe to say they do not carry any angora or satin like my other group, though I think it would be really neat to breed for agouti long haired mice. Is it possible the agouti male carries no other carried genetics? I think agouti is like the wild type, isn't it? Oy, I'm always so confused with mouse genetics but slowly I will learn.


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## Jack Garcia (Oct 9, 2009)

Agouti is wild-type. Some wild mice are also Aw/Aw, particularly in eastern North America. Good (show) blacks are usually ae/ae. Common (petstore-derived) blacks are a/a. If your mouse had all agouti babies, it's likely that she is A/A and passed on one copy of A to each baby. It could also be that she is A/a and it just so happened that there were only A/a babies born, especially with a litter as small as 5.


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## fuzzymom (Nov 28, 2009)

So A is the dominant wild type and a is the recessive black, right? So the babies are all A/a. If the mother is a black self though isn't she a/a and not A/a? What does the w mean in Aw/Aw? I do not believe she is a quality show black as she came from a feeder bin.

Thanks for helping me.


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## Jack Garcia (Oct 9, 2009)

Aw/Aw is white-bellied agouti. It's a kind of agouti with a creamy belly. Most of the wild mice in the world are A/A, but some are Aw/Aw. Technically "A/A" is what most people mean when they say wild-type.

If the mother is black self, then she is a/a, yes. I got the buck and doe mixed up, sorry.


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## fuzzymom (Nov 28, 2009)

The agouti buck and the agouti doe have bellies that are lighter than the fur on their backs but I wouldn't consider it white. Its like a shade or two lighter, so I think they are just A/A.

Thanks for the info on these genetics. I like to map out the genetics of my mice like I did with the other group. So is it possible these agouti mice don't carry anything? There were no albinos in this litter, so they might not carry albino.


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## Jack Garcia (Oct 9, 2009)

Yeah, it's possible, but not very likely. You'd have to breed them to their siblings over and over for a couple years to know for sure. Recessives of coat and color can "lurk" in the background for a very long time without popping up. That's why they're hard to get rid of.


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## fuzzymom (Nov 28, 2009)

Is it ok to breed related mice together like that? I know with reptiles its common practice, but I've never done it with mammals before. If so, should I breed the females from the litter back to their father and the males back to their mother (not all at once of course) or would it be better to breed siblings together?


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## Jack Garcia (Oct 9, 2009)

Different people will give you different answers. It also depends on what you're breeding for. Inbreeding depression is a very serious concern if you aren't very knowledgeable and careful, and even if you are it can still happen.

All that said, the majority of inbred strains of laboratory rats and mice currently in existance have been bred brother x sister for hundreds of generations or more, to the point that they're genetically identical. Some of these strains have been bred brother x sister since the early part of the 1900s so that's _a lot_ of generations.


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## fuzzymom (Nov 28, 2009)

So if I were to breed a few generations of related mice, and then add new blood in every few generations, would that vary the genetics enough to keep inbreeding problems away? What would be the best way of going about finding hidden genetics but keeping my colony healthy?


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## Jack Garcia (Oct 9, 2009)

The best bet is to secure some pedigreed show mice who breed true. That way you know for certain what they carry, their background, and have a guarantee of health. There is a mouse show and rodent gathering in Pennsylvania coming up on 01 May. Depending on how much time and money you're willing to spend, though, that's not always possible.

Otherwise, it's a trade-off. If you bred brother x sister for a few generations and then crossed another mouse in, you're basically starting over with that new mouse so I don't personally see the point in that.

A lot of people will tell you that inbreeding is dangerous, and it can be so there's a lot of truth in that, but it's not always. As long as you're prepared to euthanize any mice who develop serious problems and discontinue breeding them, I don't see a problem with it. They're your animals and you have final say in their care.


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## fuzzymom (Nov 28, 2009)

I would love to get my hands on some show mice, but seeing as I breed for feeders, and don't show, show quality mice might not be the best option for me, and traveling like that is out of the question right now seeing as I don't have a job. Although, it would be a good idea to get some mice from breeders so I know I'm starting off with healthy stock. Genetic health is important in any feeder colony and it would be a good idea to make sure my colony is healthy in that aspect. I might have to look into getting some mice from a breeder. Maybe not show quality but definitely good strong healthy individuals. And as a bonus I would know their genetic history and breeding for colors would be more fun.

Thanks for all your help. Something I see often when people are showing pictures of their new mice or mice they have bred is type. What exactly does type mean? Is it the body structure of the mouse? What makes up a good quality mouse as far as body structure, ear structure and placement, etc.


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## Jack Garcia (Oct 9, 2009)

In its very basic meaning, type is the over-all appearance or construction of an animal, that is, how it conforms to the show standards. It's subtle but there's a world of difference between a petstore-derived animal and a line of animals who have been bred toward the standard for 50 years. There's an example of the ideal mouse here: viewtopic.php?f=42&t=2600

(And it just so happens that I wrote it, haha.)


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## fuzzymom (Nov 28, 2009)

Thanks. I'll have to compare my store bought mice to that and see how hard they fail. :lol:


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