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What are the mutations out there that should not be bred together OR could not produce visual double homozygous mutations?

A few I've heard that could be problematic are ;

Axanthic to Caramel! Why?
Albino to Pieblad! Why?
Albino to Lavender Albino! Why?

Would be nice if you could share your insight on the reason these would not work.

THX

There are several possible complications which might fall under "incompatibility" when trying to combine mutation.

One mutation might cover up the expression of another. For example, how would you know if a leucistic was also a genetic stripe since there shouldn't be any pigment left to show the stripe. I think the term for this is epistasis. It looks like leucistic would be epistatic over most anything but albino because it would completely mask the appearance of most other mutant genes. I think this is what you might have heard about caramel and axanthic. The thinking is probably that axanthic would take away the yellow that caramel seems to put in but I'm not sure that caramel doesn't also reduce black so it might actually be a nice true ghost like combo leaving a faded gray and white snake. You just never know for sure how two genes might interact until someone tires it. Maybe caramel adds a yellow that axanthic can’t remove and caramel will largely cover up axanthic.

Another interaction might be that the combined effect of two genes might be fatal. The mutations are messing with the chemistry of the animal and even if each single mutation doesn't have an adverse effect on health it might turn out that the combined effect could. This might be what they are getting it with what you heard about albino and lavender. I think that RDR has yet to get a hatchling from trying this cross. However, it could well just be bad luck (bad clutches happen) as there can't have been too many attempts yet and I think this last year he used a het on one side so should have had the potential to get some single het babies which should not have died due to incompatible mutant genes.

It is also possible that we will find some genetic surprises once we start trying to combine more morphs. Perhaps we will find different mutations which turn out to be the same gene. For example, it might turn out that albino and caramel are alleles - different mutations of the same gene. If this is the case then when you cross an albino to a caramel you shouldn't get any normals because neither parent has a normal copy of the common gene. I crossed a couple possible hets this year and got all normals but I could well have missed on one or both parents (66% chance het caramel X 50% chance het albino). I've not heard of anyone crossing the homozygous animals but that would be the surest way to check for alleles. Maybe spider and pinstripe are alleles but without a proven homozygous of either type the way to test that would be if the spinner ever produces normals or not (same for pewter and ebony).

It is also possible that two mutations might be different genes that are linked by being close together on the same chromosome. In this scenario you can make the normal looking (if recessive, mutant looking if some type of dominant mutations) double hets just fine but it is difficult to get more than two copies total of the two genes combined into one animal. A crossover is required between the two genes to create a copy of the common chromosome with both mutations. Depending on how close together the mutations are just the right crossover might take a long time working with double hets. And if both mutations are recessive you would be hard pressed to identify the first animal with one crossover short of breeding tests. I forget how many chromosomes pythons have but the number of mutations is getting high enough that we will most likely see linkage eventually.

There is also the possibility that a combination just will not look as nice as we hoped (there have also been some that turned out better than hoped). Some speculate that an albino pied might not have enough contrast to rival a regular pied but until one is produced we just don't know and even then it will be a matter of personal preference.

that is one heck of an awesome response. Thanks Randy!

...

I love reading your posts because they hold so much information and it's flat out awesome.

Michael Ibanez

Ya'll are probably the only 3 who bother to read my LONG posts though. And I do screw up a lot in them.

Hey, the pres (the real one) was in my town this morning!

Oh, that is nice that you are humble as well Randy. I am sure many people read your long posts, I know I sure do. Keep them coming!

Ben
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Ben

I read your posts often, I have been working with reptiles (import, wholesale, recently breeding) for years now---you have some of the best info on the forum---I started my ball projects a few years ago and will finally have results hopefully this may. (hoping to produce p or a next year) every time I'm doubtful on one aspect or the other you have already answered the question within the last couple of days. I'm wondering what your background is and what morphs you work with. (did you go to daytona?)--I try to answer post's to the best of my knowledge if you see something you want to argue go ahead I invite criticism--one learns faster

I've only produced possible hets so far so my posts are mostly theoretical. Maybe next year will be my year and I'll finally have something worth going to Daytona or Chicago to sell (I can't really justify that long of a trip to window-shop).

I liked high school biology but didn't even take it in college. The genetics part is really mathematical and I'm kind of good at that. I must get it from my son, he was beating me at chess when he was 4 and now that he's 6 he is doing multi digit addition with carries in his head.