Recessive x Recessive

[Serpent_Nirvana]

I asked the same question and got multiple replies that many folks on here had bred visual x visual without any problems (including albino and pied).


*And now for the obligatory genetics rant .... *


... And really, as BG alludes to in the boas, there is no real reason why visual x visual should have more problems than het x het or visual x het. At the end of the day, either the snake is homozygous for the desired trait (morph) or it isn't, and it's either homozygous for the defect gene, or it isn't.

Using the albino boas as an example, if the defective recessive gene (eyelessness) is linked to the gene for the desired recessive trait (albinism), it's entirely possible to get eyeless albinos no matter what the pairing. If the defective trait (eyelessness) is actually a pleiotropic effect of the albino gene (ie, the albino gene ALSO causes eyelessness), then you really are JUST as likely to get it no matter what the pairing.

However, in albino boas I would guess it's a linkage thing simply because the rumor persists about not breeding albino x albino. Reason being, the more closely related the parents, the more likely each one is going to carry the defective gene, and the more outcrossing in the bloodline, the more likely you were able separate the two and get an animal that carries the albino gene but not the eyeless gene. (Unless the albinism gene really does cause eyelessness and the rumor was just invented by breeders to get people to continue buying albino boas ...! )

So really, I suspect the real problem was that the original albino also happened to carry a gene for eyelessness that was fairly closely linked to the albino gene, but vigilant outcrossing can separate the two -- and obviously has in a lot of animals.

It seems like it would be more important to avoid breeding closely related animals in bloodlines with known problems than to avoid visual x visual ... Then again, you also risk propagating a defective recessive gene if you don't know about it. So, then there's that.

[nickmetherd]

You get better clutch viability and larger clutches for some reason with Pied x het. Pied. Something Ralph realized a while ago is that he got better clutches and higher white clutches when he bred a Pied male to het pied females. So since then, it has spread across to other recessive genes. As well as the money factor mentioned above.

[Clear]

The only problem I have found with the albino gene is non-eaters. This year 2 of the 4 were non-eaters, one is still picky.

Pied females tend to grow slow, small females have smaller clutches.

[Big Gunns]

You get better clutch viability and larger clutches for some reason with Pied x het. Pied. Something Ralph realized a while ago is that he got better clutches and higher white clutches when he bred a Pied male to het pied females. So since then, it has spread across to other recessive genes. As well as the money factor mentioned above.

When did his Royal Heiny say this? "Higher white"? Big Gunns does not believe it for one second. "Spread across"??? What did?

[RandyRemington]

I agree with what Serpent_Nirvana said about it shouldn't matter from a genetic standpoint if the two copies of a mutation came from hets or homozygous. However, I was thinking about the rumors of problems with caramel female clutch viability. That would seem the most likely reason that het females where used. What if something about a mutation made a bad parent? Do the eyeless boas only come from albino females?

[OhhWatALoser]

When did his Royal Heiny say this? "Higher white"? Big Gunns does not believe it for one second. "Spread across"??? What did?

+1

[Serpent_Nirvana]

I really gotta wonder if there was a lot of inbreeding depression 10-15 years ago, when the pied mutation was first being established; and/or if the original founder male or females used for the original out-crosses were kinda weak animals. That rumor is so pervasive, but I don't know that it really holds true any more.

I've heard the "pieds are bad eaters" rumor for years now, and I used to speculate that it had something to do with a defect in the formation of the nervous system of the gut (similar to Lethal White Overo Syndrome in overo horses, overo being a kind of "pied" like pattern). However, lately I've asked around and it seems like pieds are just as split as other morphs as to who eats well and grows well, and my own new little pied eats like a blood python and seems to want to grow like one too ... So I'm really unconvinced that it's anything inherent to the mutation.

I don't doubt that RDR had better luck with pied x het way back when, but I question whether it's still an issue today ... I mean, can't hurt to outcross, but why outcross with a het when you can outcross with two visuals and get all visual babies?

As far as high versus low white ... I DO think you can select for it (you can do it in mammals; why not snakes??) but I doubt using hets versus visuals is gonna do you any good unless the hets come from multiple generations of high-white parents. ... Though I don't really see why you'd bother selecting for high white pieds when you can get one by crossing with half the co-dom morphs out there