#someone will post a photo and it'll be a light brown mouse

[kedreeva]

Do you think you could give your opinions on the recessive / lethal yellow genes in mice? Do you think you'd ever consider breeding recessive yellow? (If you haven't already.) I'm just super curious about your thoughts on them as I don't really know a lot about genetics. Do you think it's possible to breed a consistently healthy line of yellow mice? I'm just super curious to hear your thoughts as a breeder

Well, this is a kind of long answer and I'll warn it discusses animal death, so I'll put it behind a cut.

Personally, I wouldn't, but not because of ethics concerns; I just don't like any of the colors made with RY/AY. They're just not visually appealing to me. I had a couple RY pop up from the Taylor black line when I first got it, and they were just enh. A good, rich red, esp a satin red, can be a really perfect looking mouse... but by god that's years of work and it never ends because Red is such a hard phenotype to maintain and I'm just not that determined. I'm convinced that people breed for red because seeing it opens all the ferret cages in their brain, not because they can be normal about it. If you want good reds, it's like you dedicate your life (and mousery) to it or you don't do it, and my life's already dedicated to the peafowl. My mousery is already dedicated to blacks and tricolors.

As for the AY gene itself, it's a "lethal" gene in that homozygosity is lethal but it's lethal at the blastocyst stage so it's not really an ethical problem imo. If it was lethal as in the pups deteriorate and die post partum, or if it caused well developed pups to die/be stillborn such that it caused the dam health risks, then it would be a problem. But, it doesn't. You just get smaller litters because some cells die way early on and get reabsorbed. I don't really have any problems with that. Show breeders cull litters down to 4-6 pups (for dam and pup health reasons), so it's not like all of them would be turning into adults anyway.

As for the genetic issues with the adult mice, there are three major health issues. The first is obesity (sort of), and the major problem there is keeping them in breeding shape (meaning, capable of doing the do at all). Curiously, in at least one study I remember seeing, there's a difference between an obese mouse of X color mutation and an AY that's considered obese because of its natural body type; for example, an obese black mouse will likely have a shortened lifespan, whereas an AY mouse doesn't (at least not less than any other mouse color mutation) unless it's obese for an AY. So this isn't really a problem as long as the breeder is watching their diet and ensuring they stay fit for their body type.

The other two genetic problems actually are health issues related directly to the AY gene, and that's being prone to diabetes and to tumors. However, these are both things that (any good) breeders would notice, cull, and therefore not breed forward, in order to keep the line as free from them as possible. Which really isn't any different than any other line that develops health problems of any sort. People don't keep health problems. A good breeder should be and usually is aware of the potential health problems in the lines they are breeding, particularly if it's a genetic one that can't be avoided (like you can't avoid AY if you're breeding AY), and will know what to look for and intervene as soon as possible. Diabetic mice urinate excessively so it's REALLY noticeable, and tumors... well. Hard to miss. And tumors of various sorts is a fairly common "select away from/cull" problem in any mutation, it's just slightly higher risk in AY.

So the short answer, in my opinion, AY isn't really an unethical gene to work with. It's not one I'd choose to work with, but I don't think the people who do are doing anything wrong just for working with the gene at all. It comes down to the same ethics as any other mutation; working to maintain body condition and selecting for health.

Honestly, out of all the animals I've seen bred and bred myself, I think mouse breeders in general have proven themselves to be the most concerned with what's best for the animal, not the breeder. The show clubs like FMBA and AFRMA etc won't recognize standards for things like snub noses or manx tails or anything else that would potentially seriously impact QoL by nature of existing at all, and at least in the groups I'm in, the members are not shy about recognizing when health problems mean no breeding for a mouse regardless of how pretty or sweet. When someone newer asks what to do, I've never seen anyone support trying to breed a mouse with issues, or usually even keep one whose QoL would be poor. They are very familiar with the kindest thing you can do is let them go. It's a breath of fresh air from the goddamn chicken groups, who will limp along any bird that's still breathing regardless of what's best for the bird.

I think the only morph I've seen that I have an ethical problem with is the X-brindle gene, which is a "brindle" gene on the X chromosome that causes the mouse to be unable to absorb copper. This means that the males DO founder and die after birth (which means most people just humanely euthanize the male pups, they aren't out here letting them suffer that I've seen), and females get a strange coat color and curled whiskers from low copper absorption. Does have a second X gene that's clean so they still can, but it's really an unnecessary mutation to continue imo. It hasn't been recognized by the show clubs that I know of, but idk if they can be shown under normal brindle or if you can tell at a glance, as I don't really know as much about them or any of the AY gene specifics. I have basic knowledge but since i don't breed them myself it's very in passing knowledge. I know it's rarely bred or worked with in the first place, and I hope it stays that way or disappears entirely.