[Jack Garcia]

Is white-bellied agouti (Aw/*) dominant over regular agouti (A/*)?

What does it look like?

I know that mostly British and European fanciers have the gene, but I have reason to suspect that I have it in some of my (English-derived) stock as well, only the bellies are not actually white but rather a light creamy color...

If anybody has a picture I'd be really appreciative. I can post some tomorrow after the light comes back.

 

[Jack Garcia]

It is dominant, and from what I gather you can selectively breed it to be white and make agouti foxes, or you can breed to to be tan. I have seen a few Aw mice that haven't been bred for colour and their bellies were creamy, like the rabbit variety 'otter'.

ETA: There's some information about Aw here: http://hiiret.fi/eng/breeding/genetics/A-w.html

Sarah xxx

Thank you Sarah! That's very much what my mice look like!

I thought a whitebelllied agouti would have to be A/a^t c^h/*, although I know that the tan is is incompletely dominant over agouti...is there another gene that does that? What is A^w and where did you hear about it? Inquiring minds like mine...want to know...? I know that deer mice have white bellies and some other wild species probably do as well.

You thought incorrectly. White-bellied agouti is it's own allele on the A locus, represented as A(w) and has nothing to do with wither either a(t) or c(h), although you probably meant c(ch). You don't have it unless you got some of your agouti mice from show lines in Europe. I did, but I'm still not sure if I have it because of the frequency with which PEW and argente pop up in my agouti lines, making it hard to tell. It's also known as "light bellied agouti," and it is at play in proper show chinchillas.

I found a good picture showing the difference:

http://www.espcr.org/micemut/a005.jpg
(pic is huge, so I left it in link form)

Aw is on the left. A is on the right. But the difference is not always that clear.

There are a few other alleles on the A locus which aren't available in American petstores, like mottled (a^m) and Intermediate agouti (A^i) and Intermediate Yellow (A^iy). I'm unsure what they look like. I know of only one person who keeps mottled, though. Varieties like these aren't very common to begin with, but even if they exist in the fancy, they wouldn't make their way into the hands of people who weren't going to use them in exhibition so you won't find them in petstores or hobby breeders, mostly in laboratories and a few in serious show breeder's colonies. So that's probably why you hadn't heard of it.

It's the same with leaden: there's only one person in the US who keeps leaden.

 

[Jack Garcia]

Yeah, I hear it's much more common in Europe.

Isn't it true that fanciers in Europe let their mice go to petstores pretty often? That's how they end up in the hands of hobby breeders and such over there, but in the US it's an anathema to let properly-bred mice go to petstores because feeding live to reptiles is legal, so genes like A(w) wouldn't be as widespread over here.

 

[Jack Garcia]

It's not really as much a nightmare as you might think. The English breeding system does not use pedigrees much if at all. Keeping a detailed pedigree on each mouse is more of an American custom. Good English breeders can tell you such and such mouse is from a line of such and such mice and is related to such and such, but most that I know don't have pedigrees which go back twenty generations like some American breeders do.

 

[Jack Garcia]

Within the US, the system varies. Some clubs like the MMC (which no longer exists, but yeah) really urge you to keep rather extensive (and, in my opinion, rather useless) pedigrees.

But the ECMA requires a pedigree or a birth certificate with all mice, so if you use the English system of not keeping pedigrees, that's fine, too.

I do keep pedigrees but often I stop at generation five or six. I see no point in keeping them into the tens or hundreds of generations.

You shouldn't breed things like brindle and merle or chocolate and siamese together anyway, so it's assumed that good breeders know enough not to do that, thus eliminating the need for pedigrees.

 

[Jack Garcia]

Yeah, Sarah is right. Chocolate is not dark enough to cause adequate points in a siamese or himalayan mouse. A pointed mouse who is also chocolate is non-standard, aka ugly. :mrgreen:

most show breeders won't mix colours unless absolutely necessary anyway.

That is a very important point, and speaks to why so many good show breeders don't keep pedigrees: there is no need to!

 

[Jack Garcia]

I'm no longer keeping pedigrees on my PEWs because it became pretty obvious that it's impossible.

I've "mixed" dove with agouti before, but that was because I needed the PE dilute for argente. There's really no other way to get it, as bringing it in with silver or champagne would have potentially introduced alleles that can be problematic for agouti or argente.

When I think of people improperly "mixing" genes (and thus having to keep pedigrees so they remember who carries what), I think of things like blue and red, or angora and hairless, i.e. things that just make no sense.

 

[Jack Garcia]

I don't know. I know that carrying chocolate for sure can be wonky depending on what other alleles are present.

All good pointed mice are black (a/a) on the A-locus. So a proper siamese is a/a c(h)/c(h) and a himalayan is a/a c(h)/c.

The only thing that you can have on the A-locus other than "a" (i.e. black) is extreme black, a(e). Extreme black makes the points darker and more even, but I don't know how common it is in the UK...

 

[Jack Garcia]

That's very likely. Colder temperatures make for darker points (and larger animals).

You said the male is a good example of black? He'll be good to use in creating more pointed animals, then. The darker the black, the better the points in a siamese/himalayan litter.

 

[Jack Garcia]

Also, here are some pictures of blue-point siamese and blue-point himalayan: http://www.afrma.org/miceaocp.htm