morph genetic flaws?

[myopia]

first, a random thought- anyone think about the fact that one of the super expensive morphs is basically basically a normal ball python with a defect, genetically speaking?

seriously, though, i love the morphs - something even more beautiful and special than a normal BP is. i wanted to breed my normals this season (my ladies were still a bit underweight, though), and i'm sure that eventually i'll want to buy a morph or two to make it even more exciting. since it'll be a little while before i'm working with morphs, i want to learn as much i can about them now. and i viewed a thread a few days ago that concerned me (that i can't find now). a few messages in the thread discussed some of the problems encountered with breeding the different morphs. the example i remember was the spider- the trait was expressed in the het state, being a dominant gene, but in the homozygous state it was possibly lethal to the snake. i was wondering if some breeders would share some information on this and any other problems they might have encountered in their work with the various morphs. i figure that since so many (if not all) of the different types have been inbred at sometime, there might be common problems associated with some of them.

thanks, and props to all for such an informative site.

[Adam_Wysocki]

first, a random thought- anyone think about the fact that one of the super expensive morphs is basically basically a normal ball python with a defect, genetically speaking?

no.

the example i remember was the spider- the trait was expressed in the het state, being a dominant gene, but in the homozygous state it was possibly lethal to the snake.

There is ZERO evidence of that. It's basically just wild specualtion by monday morning morph breeders. The common belief by people that are actually working with spiders is that there is simply no homozygous state for the morph.


-adam

[RandyRemington]

There is ZERO evidence of that. It's basically just wild specualtion by monday morning morph breeders.

What has had me speculating about the viability of homozygous spiders for several years is the lack of evidence that they exist. I'm not saying for sure spider is one way or the other; it's just that the proven homozygous spider is getting more and more conspicuous by its absence each year.

You could turn it around and say it's wild speculation to assume that any morph for sure isn't homozygous lethal before it's proven otherwise. There is actually a precedent for homozygous lethal in other species and perhaps even in the woma ball pythons. One breeder told me that they where taught that "homozygous lethal" would cover a pearl that wasn't healthy enough to live to breed. However now it looks like there might be another strain that might be the same thing and not have that problem. In Syrian hamsters the homozygous lethal dominant spot gene is very popular, you just don't normally pair dominant spot animals.

The common belief by people that are actually working with spiders is that there is simply no homozygous state for the morph

Please elaborate. Do you mean that you don't think the homozygous genotype is possible or that it exists and just doesn't have a visibly different phenotype? If you don't think it is possible then what is happening to the spider gene eggs that are fertilized by a spider gene sperm? Even if some how conception of the expected 1:4 homozygous spider gene babies from breeding heterozygous spider X heterozygous spider didn't happen I would think that would still fall under the classification as a "homozygous lethal" morph situation.

Maybe this year someone will prove a homozygous spider out and it’s just hasn’t been long enough to prove one before now. I have very little data on how many spider X spider breedings there have been so far and how many 33% chance homozygous spiders have been produced and bred yet. It just seems like it’s been a couple years since NERD announced that they felt they had made “enough” spider X spider crosses to feel confident that there wasn’t a visibly different looking spider so I would have expected enough of the male spider phenotype animals from those breedings to have bred by now and exposed the expected 1:3 homozygous spider.

[Adam_Wysocki]

You could turn it around and say it's wild speculation to assume that any morph for sure isn't homozygous lethal before it's proven otherwise.

You could say anything you want. I'm more concerned with what can be proven.

There is actually a precedent for homozygous lethal in other species

In 50 years of captive reptile breedings, has there ever been a documented case of a homozygous lethal anything?

What's more likely, that the first time evidence of homozygous lethal shows up in the reptile kingdom it just happens to be in a co-dominant mutation of ball pythons or that a visually different "super" spider just doesn't exist?

There's a basic principal of logic that states "one should not increase, beyond what is necessary, the number of entities required to explain anything". Obviously, I tend to agree.

-adam

[Joe_Compel]

first, a random thought- anyone think about the fact that one of the super expensive morphs is basically basically a normal ball python with a defect, genetically speaking?

Yeah...I think about it all the time. Except, I don't think of them as "defects"; I think of them as mutants I often wonder if any of the mutants I have would make it out in the wild.......I know most would not. Lucky to have me.....who knows????? But I do think about it often.
I often wonder if the climate or environment were to change in Africa, which of the mutants would be best suited for survival. I think brown backs or spiders or axanthics would make it out in the wild and who knows.......if the environment were to change in such a way as to favor their survival.......they might become the norm. Albinos don't stand a chance
There is one thing that irks me though......"non snake" people tend to think of mutations, or "defects" as you put it, as a bad thing. But the truth is that mutation is the key to life and one of the key prinicples to evolution. Mutation is a good thing.

[Joe_Compel]

Originally Posted by myopia
i wanted to breed my normals this season (my ladies were still a bit underweight, though), and i'm sure that eventually i'll want to buy a morph or two to make it even more exciting. since it'll be a little while before i'm working with morphs, i want to learn as much i can about them now.

Good for you....that is the way to get things done. Do your homework first. Good luck in your future projects

Originally Posted by myopia
the example i remember was the spider- the trait was expressed in the het state, being a dominant gene, but in the homozygous state it was possibly lethal to the snake.

I don't think this is the case.....I don't think there is much evidence to suport this idea. I suppose that a homozygous spider can be produced.....will it or does it look different than a spider with just one copy of the mutant gene.....I don't know. The fact of the matter is that I have yet to breed or produce a single spider. Most keepers and enthusiasts are in the same boat. Very few have bred a spider to another spider. You would have to ask keepers with real experience on the subject (Kevin or Kara at NERD) to get an answer based on real trials.
I love spiders. It would be awesome if a super spider could be produced (one that was phenotypically different from a spider). But even if one can't be produced or the homozygous version looks no different than regular spider.......it's all good by me. Spiders are killer!


Incidentally, I do think it is possible that we will see a lethal mutation in ball pythons. We are just scratching the surface.......our breedings and understanding on ball python genetics are limited. To say something like that is impossible would be foolish.

[RandyRemington]

I guess we are coming up on about 50 years since the albino corn snake was first bred but the first cb ball python morph (also albino) is only about 12 or 13 years old. Morph breeding in snakes has really increased exponentially in the last few years and we have hardly had time to try anything yet.

If there where a homozygous lethal gene in snakes I think it would take a very long time to prove it. The only proof might be the absence of the homozygous and people could say for years that it just hadn't been long enough yet to prove one. I suspect that lots of spider phenotype animals from spider X spider have been bred by now but such numbers are hard to get. We should be seeing 1/3 of these potential homozygous spiders proving out by only producing spiders when bred to a normal but I'm not aware of one of them proving yet. If there have only been a handful of these bred so far then maybe it is just too early to call one way or the other but if dozens of potential homozygous spiders have been bred by now and all of them have proven only heterozygous spider then the evidence is mounting. Just because homozygous lethal is difficult to prove doesn't make it extremely improbable. In fact, I think we as snake breeders tend to sweep the difficult genetic questions under the rug and that might explain why we haven't documented more cases of hard to explain things like multiple morph alleles or mutations being linked by being on the same chromosome.

[Adam_Wysocki]

I guess we are coming up on about 50 years since the albino corn snake was first bred but the first cb ball python morph (also albino) is only about 12 or 13 years old. Morph breeding in snakes has really increased exponentially in the last few years and we have hardly had time to try anything yet.

If you consider the number of corn, burn, boa, and retic morph breedings and offspring over the last 50 years, ball pythons are just a drop in the bucket. Even though albino balls were proven 12 years ago, ball pythons didn't get hot until 99 or so when Pete proved out pieds.

If there where a homozygous lethal gene in snakes I think it would take a very long time to prove it.

So what exactly is the rush? Personally, I'd rather bet on the obvious until that possibility is completely exhausted before I start fantasizing about alternatives. A theory means nothing until it can be proven.

Just because homozygous lethal is difficult to prove doesn't make it extremely improbable.

I agree, but logic dictates that all obvious probabilities should be thoroughly exhausted before considering new precedent. I think the lack of known prior occurrence in any reptilian species is what sets the bar for skepticism. Do you have enough data to conclude that we will never see a homozygous spider and we should be looking for alternative explanations? I don't think anyone does yet.

In fact, I think we as snake breeders tend to sweep the difficult genetic questions under the rug and that might explain why we haven't documented more cases of hard to explain things like multiple morph alleles or mutations being linked by being on the same chromosome.

I don't agree at all. I think snake breeders are passionate about finding the truth and promoting their love for snakes. I don't think there is anything that a true breeder would not at least consider if it meant understanding their animals better. We've come a long way in only a handful of years and breeders are working very hard to take care of their animals, clean rodents, promote their business, work on sales, educate customers, ship snakes, etc. In that time, people focus on what they can prove. The hobby/business is growing and moving so fast that I don't think people have the luxury of focusing on speculation. For now, people are focusing on what they can prove for certain. I think you'll find that once those avenues are exhausted, the search for answers will take different people in different directions and hopefully lead to some definitive explanations. I think it's unrealistic to expect that to have happened by now, or tomorrow, or next week. Like Joe said above, we are only now scratching the surface.

-adam

[RandyRemington]

So what exactly is the rush? Personally, I'd rather bet on the obvious until that possibility is completely exhausted before I start fantasizing about alternatives. A theory means nothing until it can be proven.

It just seems to me that many are banking on the "obvious" that there will be a homozygous spider without any proof that there will be one. I'm certainly not saying that spider is definitely homozygous lethal, I'm just pointing out the possibility. With very little data on what spider X spider breedings and more importantly breedings of the possible homozygous spiders have been done I can only speculate that it seems like a proven homozygous spider is overdue.

If spider (or any dominant type morph) is homozygous lethal it will likely take years for the public to gather enough indirect evidence to come to a consensus that it is "proven" homozygous lethal. I think the people who work on the project for those years should at least be aware of the possibility so they can make informed decisions and be on the lookout for evidence either supporting or refuting the theory.

If a theory where proven it would be a fact. Theories are useful for comparing to the data along the way to get to the facts eventually. Unfortunately some theories are difficult to prove.

If sickly potential super spiders where regularly hatched (like with Pearl) or about 1/4 of the spider X spider eggs went bad then we would have some direct evidence to support this theory. However, I did see a post by NERD once indicating that spider X spider eggs don't have an abnormally high rate of bad eggs so that is evidence against the homozygous lethal theory. If some how the lethal effect happens early enough to not only prevent sickly homozygous hatchlings or even bad eggs then there would be no direct evidence, just the never ending wait for a proven homozygous spider. This is how the nature of the homozygous lethal dominant spot gene in Syrian hamsters was eventually proven. The hamster breeders had the advantage of much quicker generation times and inexpensive animals to work with so they didn’t have to wait as long for an answer and the stakes and passions probably weren’t as high.

[Adam_Wysocki]

I think the people who work on the project for those years should at least be aware of the possibility so they can make informed decisions and be on the lookout for evidence either supporting or refuting the theory.

Why would you assume that they aren't already aware of the possibility? Believe it or not, there are some pretty intelligent people out there that actually own and produce spiders, and every year they are getting closer to an answer to this question. I think it's pretty arrogant to assume that you're the only person that can think outside the box and feel the need to educate the rest of the world.

If sickly potential super spiders where regularly hatched (like with Pearl) or about 1/4 of the spider X spider eggs went bad then we would have some direct evidence to support this theory.

So how many sickly potential super spiders have you documented?

-adam