Weird Problem for Breeders and Genetics Experts

[Die Fledermaus]

I got three lovely fancy mice on Dec. 13th from an award-winning breeder.

To my shock, on Jan. 5th, two had babies within hours of each other! One never was pregnant.

Note that this is 23 days since I got them, and mice gestation is usually supposed to be 19-21 days.

I cannot imagine any possibility that a "wild mouse" loose in my place exists or that he could have gotten in with them if he does exist. But how can I be 100% certain?

Here are the babies today, eight days after birth:

MICE BABIES

They are almost without doubt the result of two separate litters from these mothers:

Vita


and Kori



The babies are described as "agouti" by the breeder.

So, are such colored babies possible from a "wild mouse", and would his agouti genes dominate over those of the mothers (as they clearly do)?

Is it conceivable that a mouse gestation could indeed last 23 days, meaning I got them pregnant from the breeder?

I am puzzled about all of this especially as I can recall no way a "wild mouse" allegedly somewhere in my house could have done this in mid-December a day or two after I got them. They've always been in a My First Home cage that I don't believe any mouse could squeeze out of (or in). :huh:

Comments?

[megs]

OKay, I know this topic is a little old now, but I think it's a very interesting story!

How troubling not knowing the origin of these surprise litters! You're right, the mothers are absolutely lovely! But the babies are all so identical and you're right, they really don't look like their mothers do they!

I'm an undergraduate biochemist, and have some background in genetics but very little. Mostly microbial genetics. Very different from mammals. But I would imagine that deep in their genome, the fancy mice might also carry agouti genes that have continued to have been passed down generation to generation. There are always two copies of each gene, one from mom, one from dad. So, when mom and "wild-dad" got together in this case, every baby was guaranteed to get agouti genes from dad. Alot of babies may have also received agouti genes from mom. And because the agouti "wild-type" (that's genetic talk for all-natural or non-mutant) is a dominant gene, these babies are all made up of agouti genes having been expressed, with very little influence from mom's fancy genes. Expression of the agouti genes gives them the coat colour and patterns, and traits of wild mice.

This is only a guess-timation. Mouse genetics is not my specialty. But my guess is that because dad was wild, and combined with chances of agouti genes from mom's side as well, all these babies express agouti genes only? The babies still carry some fancy genes from mom, but they remain "repressed" (unexpressed).

But I repeat, I am no expert. But it got me thinking.

One more thing, I talked to a friend that has a stronger genetics background and she says that you can control a female mouse's reproductive cycle but just adding some used bedding from a male mouse. Females kept together will synchronize their cycles when a male is around, but apparently this takes a few days of the male (or bedding) being around. So this could explain why they gave birth the same day. But she thinks that because this synchronization thing takes a few days that this likely occured before you brought them home, (maybe they got pregnant the night before?) Just more speculation

Best of luck with all of them!

[Die Fledermaus]

I know the agouti gene is dominant. And they are NUTS to control!

>> But she thinks that because this synchronization thing takes a few days that this likely occured before you brought them home <<

Me too. There was a LONG thread on this in the Mouse forum on petshub.com in mid January including with comments from the breeder. If interested check it out.

I have established that for a number of reasons getting mice on Dec. 13 and having them give birth early on the 5th of January is not impossible at all. Even though a few days beyond the established gestation period. I am sure I GOT them preggers from the breeder.

[megs]

I think you probably did as well. And if that person is breeding, I would imagine they keep alot of mice. Probably more likely a little wild one is lurking around that place, (Lots of females in one area), than your place. Especially if you've had no trouble before!

[Die Fledermaus]

Exactly. But he will never admit it. Again, read that petshub thread if you wish. It got heated at one point.

[megs]

I hunted down the thread and read the whole thing, including the other one that had been linked. My goodness, that took longer than I thought it would!

But I'm glad I read it

I loved your little story about how Harry (it's Harry right?) just maybe escaped and got in there. Sure did make me laugh. Oh and the Don Juan ladies man wild mouse that loves them and leaves them. cute.

I understand the whole story alot better now. And I still think it was a wild mouse, based on how "wild" and out of control they are. (Or is this normal for all mice?) And also if the wild mouse was at your place, I think you would see (or have seen) more of him.

Hope all the little ones are doing well. Even if the boys are right out of control!! How are the girls?

[Die Fledermaus]

Glad you found the thread and found it interesting.

The girls are calmer; maybe that is typical of females, or maybe their nearly tame moms gve a good example for them.

The male agoutis I have to clean tonight. Ugh.

A different batch of fancy mice female had pinkies a day ago. That is no big deal.