Inbreeding question: what about the doe?

I've always wondered, but now it's extremely relevant to me. I inbreed, breeding daughter back to the same buck. So far so good, now weaning F3. I understand this brings out undesirable recessives. However, would this method bring out the doe's recessives or just the buck?

I am looking at an astrex doe that would be quite a hassle to access but would be amazing to bring into Ontario. However, I'm talking to the breeder and she wrote this:

"This litter's great grandma and great great grandma were albino lab mice. They had a genetically predisposed condition called necrotizing dermatitis of the pinna, unique to their strain - the ears rot off as the mice age. Thankfully this is recessive and none of the offspring who were crossed with pet and exotic mouse strains have ever showed signs."

So...obviously it's carried. Is the outcrossing preventing it from showing up? Would I likely run into problems if I continued to breed daughters back to my (healthy) buck using this doe?

The further away from the breeding with the recessive you don't want...the less likely it will appear. Just keep inbreeding. If it starts showing up then you can stop that inbreeding line.

I wouldn't stop inbreeding if it shows up...inbreeding would become even more important if it showed up in order to remove it from the line. I would inbreed specifically to test if it is present personally...and then to get rid of it if it was

Thank you both! I've literally drawn out Punnett square and flow charts of possible routes to take here.

Very handy to learn the further away one gets from an occurrence, the less likely it'll show up. So very worst case scenario, the ear issue pops up. In which case, could I select the babies that didn't exhibit the condition and breed them? Or would it be irresponsible to continue?

So inbreeding with my presumed non-carrier buck would be okay? But is this because he isn't (likely) a carrier? I ask because down the line, say a year from now, I'd like to keep a buck from the line to inbreed to, so he too could possibly carry it in which case I'd be breeding carrier to carrier. <- This is where my brain starts to hurt...looking at the big picture.

I'm guessing that keeping the gene hidden means losing the coat which is okay, I was just curious if there was a way to maintain it without likely producing sick mice.



Thank you both so much. I love the members of this forum!

Personally I'd inbreed immediately...fish out if the gene is in the mice you got....if it is, breed offspring back to one that exhibits the trait to see if they carry it...you can quickly find out who is least likely to carry it (if you have 1 or 2 litters out of one that exhibits the trait where none of the offspring exhibit it, the other parent is very unlikely to carry it)

I also choose to inbreed immediately. Why waste time and lives?

Well she does have a brother. By inbreeding immediately do you mean after I cross the new doe with my buck? aka keep a son of hers and breed back to her? One person suggested that I just breed back to my buck and the gene will always be hidden if I don't use a buck with the carrier gene. What do you think?

If you outcross repeatedly you could be hiding the gene for many generations and end up giving mice carrying it to other breeders... I would do what you suggested there and breed a son back to the doe...

Sounds good to me! I'll definitely need a little coaching re: prepping CO2 if it does show up...I have watched some YouTube videos but none of active baking soda/vinegar application (other than in a bag).

This is true, I wouldn't be able to rehome mice anymore (though I've only done it twice). So far, my adopters are wonderful pet owners but I don't know if I'll be so lucky and someone might breed them. There aren't any breeders around here (online, anyway) but "one time" litters might end up in pet shops and boom.

Should I grab the brother? Or is a son more effective? I'm a bit hazy on COI. Just wondering if there's a reason I should outcross first, then inbreed. I prefer to keep the buck number low.

as tight of inbreeding as possible would be ideal...IF it does pop up....keep one or two back to test breed others...b/c that is the only way you will really be able to weed it out to prevent more being produced.

What is this CO2 chamber you are talking about?

@Dino, just a culling method for adults. I'm not sure if I'm allowed to discuss it outside of a culling thread though! As far as I know, if done properly, it seems like a humane way to euthanize.

The breeder just sent me photos:

Does:




Buck:


Am I insane or...are they possibly pied and not splashed?

I did see curls on them as babies so I guess they just lost the rex look.

They are pied. Not splashed. And at least two of them still look rex. They lose the tight curl as adults and just look ummm fluffy! LOL!

*heart breaks* Bugger. Thank you!

Now to rethink this whole thing!

No promises that they carry merle either really. It is a recessive...but it would surprise me if she had merle when she thought pied was splash.

I think you're right! Perhaps she's thinking of variegated (trying to think of something patchy-looking that's not uncommon). Looks like I'll be working with astrex and anything else will be a bonus! Their father is a himi so maybe I can work with that as well. It'll be nice to have a litter and have that true element of surprise again.

That said, black pied x black pied = black pied right? : P Maybe the first breeding should be to a buck of mine (ce/c), then breed a son back to her like Stina was suggesting.

black pied x black pied = ANYTHING! LOL! It is all in what they carry!
For example..I bred a blue to a blue and got 3 blue and 3 PEW! recessives are always a fun surprise!

That's excellent news! Because I really don't like black pied, lol! I mean, I'll deal with it if I must, but I'd be breeding away from it for sure! They carry himalayan, blue, champagne at least. The breeder said variegated and banded are the great great grandparents so that's interesting...I'm more set on a good astrex.

While I have the experts attention, can I ask if there's hope of seeing RY? My own buck's great grandmother and great aunts are RY but worry I accidentally bred it out as I was selecting type and behaviour above coat colour and just weaned F3 (bone x PEW). RY astrex would be amazing.

Thanks so much for these posts!

Variegated and Banded are both dom...so if you don't see it...you don't have it. Those genes cant be carried. BUT if they carry blue and champagne...then they carry dilute and pink eye and chocolate...so you can get dove, sliver, blue, lilac, champagne, chocolate, and black all in pied or not. So yeah...almost ANYTHING!

Anything is possible if you don't know exactly what they carry...and genes that are very buried CAN come out, but the further you get from a visible RY the less likely you will be to get it.

0.0!

Silver? Really? Oh I'd be over the moon. I hoped to see silver with F2 but no dice. Chocolate would be amazing. Oh this is looking good. : D

To add more confusion to the situation, my unrelated RY doe, diagnosed with a hernia, doesn't appear to have one anymore. o.0 I didn't think that could just...disappear. I've emailed the vet just in case there's the slightest chance she can breed (if it's not actually a hernia).

Well, I'm okay with no variegated or banded.

Good to note that the further I am from the RY, the less likely it is! I'm sure that's genetics 101 but I missed it. ; ) So with that logic, does that mean the further we are from an occurrence of the ear condition, the less likely it is to pop up? In other words, would it be beneficial for the doe to be paired with my non-carrier buck, then use a daughter of hers to breed back to the brother? I'm flip flopping between bringing it out by crossing brother and sister (if it's there) and hiding it. : / I just wonder if I should inbreed a generation later to lessen the likelihood.

Thank you so much!