Homozygous Spider Morph

Does a homozygous spider morph exist? Don't really see anyone talking about them. Seems if you had one it would bump the value a little cause you wouldn't get normals if you breed with a normal.


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Not that anyone has ever been able to prove. Which probably means they do not exist. (Homozygous Pinstripes have been proven, so Pinstripe is a dominant mutation).

While listed as dominant on many sites, Spider is probably not a dominant mutation. Instead, it may be co-dominant with a lethal super form, so that homozygous spiders never hatch.
It's not unusual for an egg or two to die during incubation, so it's unlikely it would be noticed.

That's makes sense.


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There not anymore proof of the spider mutation being dominant than it being co-dominant. We list morphs as dominant until proven otherwise.

Here is a part of a write up I did on the spider gene

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The Homozygous Spider

If the Spider is a dominant gene and I bred a Spider with another Spider, I should statistically get 25% Homozygous Spider, 50% Heterozygous Spider, 25% Normal. The homozygous Spider should look exactly like a heterozygous Spider. The only difference would be that the homozygous Spider, when bred to any other ball python, would result in offspring that are all Spiders. While the heterozygous Spider would result in offspring that would only have a 50% chance for getting the Spider gene.

Now here's the problem, the Spider was first established at NERD in 1999, and we still have yet to see a proven homozygous Spider. Now before we get into all the theories, Kevin (the owner of NERD), the guy that imported the first, and has dealt with, more Spiders than anyone else, has to say about the issue. Kevin said that he has not produced and does not believe that there is a homozygous Spider nor that Spider is homozygous lethal. From what I understand he is saying it just simply does not exist for an unknown reason and is not a simple dominant gene.

Another theory is that homozygous Spider is lethal, which is based on the fact that we haven't seen one yet. Which is a pretty weak theory in my opinion, but not entirely dismissible. I do think this theory could be put to rest by watching some Spider x Spider pairing and keeping an eye on the follicles of the females, if somewhere around 25% of them die/reabsorb/not hatch, it may strengthen this theory, but I think people would want to see a lot of eggs before we call it fact. This would be a lot of resources to waste for a big breeder to try, so don't expect it any time soon. I think the only chance of proving this, is by us small breeders trying it out and all of us putting our data together.

Another theory, there hasn't been enough Spider x Spider breedings to prove or disprove a homozygous Spider. Well here's the deal with that, you first have a breed a Spider x Spider. Every Spider offspring only has a 33% chance to be homozygous, then you have to raise up the offspring and do multiple breedings to prove it is in fact homozygous, rather than just getting really lucky on a clutch. So, yes very difficult to prove.

Not many people have the resources to do this, NERD has tired to prove it but as far as I know, they don't have any public statement about what they did to try to prove the homozygous Spider. That leaves this theory open ended. More info would sway my opinion one way or another. Though if Kevin said he did enough breedings, he most likely did enough breedings.

Now the question, "If I bred a Spider x Spider, statistically what % of Spider should I get?" Well If homozygous Spider does exist and is dodging us all these years, 25% homozygous,50% heterozygous, and 25% normal. If it's homozygous lethal then 66% heterozygous and 33% normal. If it doesn't exist for some reason, depending on how you look at it, it could either be 66% heterozygous and 33% normal or 75% heterozygous and 25% normal. So go ahead, pick one.

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I'm such a geek, cause I find the genetics to be really interesting.


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Originally Posted by WingedWolfPsion

Not that anyone has ever been able to prove. Which probably means they do not exist. (Homozygous Pinstripes have been proven, so Pinstripe is a dominant mutation).

While listed as dominant on many sites, Spider is probably not a dominant mutation. Instead, it may be co-dominant with a lethal super form, so that homozygous spiders never hatch.
It's not unusual for an egg or two to die during incubation, so it's unlikely it would be noticed.

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I was under the impression that pinstripe and spider were both dominant gene traits and that only co dominant genes and recessive genes of course could create a super form.

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Originally Posted by Domepiece

I was under the impression that pinstripe and spider were both dominant gene traits and that only co dominant genes and recessive genes of course could create a super form.

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Dom,co-dom/incomplete dom, recessive are just classifications of how the genes look in heterozygous (het) and homozygous forms (supers or visual recessives)


we don't know what the homozygous spider looks like, so we can't place it anywhere for sure. So we call it dominant until proven otherwise.

But if dominate it should be possible to have a homozygous version. One that can be breed to a normal and always produce visual spiders.


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Originally Posted by Gomojoe

But if dominate it should be possible to have a homozygous version. One that can be breed to a normal and always produce visual spiders.


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Well thats the problem lol that hasn't happened yet...that's why we are all scratching our heads. :confused:

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Originally Posted by OhhWatALoser

Dom,co-dom/incomplete dom, recessive are just classifications of how the genes look in heterozygous (het) and homozygous forms (supers or visual recessives)


we don't know what the homozygous spider looks like, so we can't place it anywhere for sure. So we call it dominant until proven otherwise.

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Thats exactly what I'm saying. I understand this however the op claimed that pin and spider are co doms or at least hinted at it and Ive never seen a homo spider or pin or have heard of anyone proving it out so wouldnt we still call them dominant?

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Originally Posted by Domepiece

I understand this however the op claimed that pin and spider are co doms and Ive never seen a homo spider or pin

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he claimed pin is dominant which it is and said spider may be co-dom. IF it is lethal it would be co-dom since het version is the spider we know and homozygous would be dead. However there is no evidence of it.

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Originally Posted by Gomojoe

But if dominate it should be possible to have a homozygous version. One that can be breed to a normal and always produce visual spiders.


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From my limited understanding if its dominant there is no homo form. But I'm sure theres probably exceptions and someone will chime in and let me know. Also from what I understand you can only get visuals from a homo form of co dom/inc. dom.

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Originally Posted by WingedWolfPsion

Homozygous Pinstripes have been proven

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I think this is where the confusion started.

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Originally Posted by Domepiece

From my limited understanding if its dominant there is no homo form. But I'm sure theres probably exceptions and someone will chime in and let me know. Also from what I understand you can only get visuals from a homo form of co dom/inc. dom.

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Your are thinking of recessive. a Pastel is a good example of a hetero Co-Dom, and the Super Pastel is the Homo version of the Co-Dom Pastel.

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Originally Posted by Domepiece

From my limited understanding if its dominant there is no homo form. But I'm sure theres probably exceptions and someone will chime in and let me know. Also from what I understand you can only get visuals from a homo form of co dom/inc. dom.

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Dominate just means that the trait is present with only 1 allele affected, and doesn't change the trait if both are affected. Huntington disease is an example where patients have predictable symptoms regardless if they are homo or het. Am I wrong?


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A homozygous spider would be desirable cause it would make visual spiders 100% of the time. Wonder if it could be a multi-allele trait?


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Originally Posted by OhhWatALoser

he claimed pin is dominant which it is and said spider may be co-dom. IF it is lethal it would be co-dom since het version is the spider we know and homozygous would be dead. However there is no evidence of it.

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He also said that pins have been proven as having a homo form so would that be claiming that pin is co dom/ in. dom? Or is that fine as long as its not visually diff from the het form?

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Originally Posted by Gomojoe

A homozygous spider would be desirable cause it would make visual spiders 100% of the time. Wonder if it could be a multi-allele trait?


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I wouldnt think it to be desirable considering the issues it has. From what Ive heard most people aviod trying for the homo and tend to out cross them.

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Originally Posted by Domepiece

I wouldnt think it to be desirable considering the issues it has. From what Ive heard most people aviod trying for the homo and tend to out cross them.

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If it were a co-Dom trait I'd agree with you that a super might have enhanced issues. Maybe that's why there is the theory the homo is fatal. But as I understand it, a homo of a dominate trait would give you 100% chance of seeing the trait in the offspring but wouldn't be any different from a het.


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Originally Posted by RobNJ

I think this is where the confusion started.

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Bingo

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Originally Posted by The Serpent Merchant

Your are thinking of recessive. a Pastel is a good example of a hetero Co-Dom, and the Super Pastel is the Homo version of the Co-Dom Pastel.

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No Im not. Im saying that the only way to get 100% visuals from a co dom trait is from a super form of that co dom/in dom. Im aware of pastels, I have several. Also a homo form of a recessive wouldnt yield any visuals unless bred to a het or another homo form of that trait, so not sure what you mean.

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Originally Posted by Domepiece

No Im not

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Ok my bad.

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Originally Posted by Gomojoe

Dominate just means that the trait is present with only 1 allele affected, and doesn't change the trait if both are affected. Huntington disease is an example where patients have predictable symptoms regardless if they are homo or het. Am I wrong?


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I dont know I'm not an expert on huntington disease or ball pythons for that matter. Im learning something everyday just like everybody else.(except those who already know it all). What I am saying is just a basic rule of thumb that I have heard, "dominants dont have homo forms only co dom/in dom/and recessive do". Just what I have always been told and have read many times here on this forum. I dont know and dont care really, I know what all my snakes are and the possibilities when I breed them together.

With all of the breedings that's been done spider X spider, Bee X spider, Bee X Bee, killerbee X spider, etc etc/ there would be a homozygous version if it existed.
Same with pinstripe...

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Originally Posted by The Serpent Merchant

Ok my bad.

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Its cool, its just difficult to convey meaning and tone while writing. Ive been told I'm not easy to understand, maybe I need to work on being more selective of how I decide to write something and choose my words more wisely.

SO just curious, are there any Homo forms of dominant traits in ball pythons. I understand that they are labled a certain way to make things easier but from the ones we call dominant is there a dominant morph that makes a homo version?

Years ago BHB reported to have an apparent homozygous pinstripe that looked like a normal (heterozygous) pinstripe but produced a large number of only pinstripe offspring. Pinstripe is the only proven dominant ball python mutation I can think of right now. It seems to me very likely that spider is homozygous lethal and hence co-dominant. Problem is it's nearly impossible to prove a homozygous lethal scenario if the homozygous babies never hatch. Sure it could still turn out that there has just been too little interest in breeding spider X spider and trying to prove the offspring homozygous to find one but with each passing year with still no public proven homozygous spider it seems less likely.

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Originally Posted by Gomojoe

But as I understand it, a homo of a dominate trait would give you 100% chance of seeing the trait in the offspring but wouldn't be any different from a het.

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You are correct. Ideally, there is no visible difference between the homozygous snake and the heterozygous snake. The only difference is that all of the homozygous snake's offspring have the gene and show the trait. While only approximately half of the heterozygous snake's offspring have the gene and show the trait.

Really good dominant mutant genes are rare in reptiles. Pigeons show several dominant mutant genes. One of those dominant genes is called spread and produces a solid black pigeon. (A normal pigeon has slate gray wings with two black bars on each wing. The head and tail are darker than the wings.)

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Originally Posted by RandyRemington

It seems to me very likely that spider is homozygous lethal and hence co-dominant. Problem is it's nearly impossible to prove a homozygous lethal scenario if the homozygous babies never hatch. Sure it could still turn out that there has just been too little interest in breeding spider X spider and trying to prove the offspring homozygous to find one but with each passing year with still no public proven homozygous spider it seems less likely.

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About the way to do prove the scenario is statistically. Produce spiders from spider x spider matings and mate them to normals. Any matings that produce normals have a heterozygous spider parent. If 20 such matings are made and all have a heterozygous spider parent, then the odds of this happening by chance are less than 0.001. This involves a lot of time and record keeping.

congo is proven dominant according to vin russo also

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Originally Posted by Domepiece

SO just curious, are there any Homo forms of dominant traits in ball pythons. I understand that they are labled a certain way to make things easier but from the ones we call dominant is there a dominant morph that makes a homo version?

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There are homo versions, they just don't look any different. If I bred a snake with dominate gene X to another snake with dominate gene X 25% on average would by homo for gene X.

It works the same way as with Co-Doms, the only difference is that there isn't a visual Difference between the het and the homo versions.

Not only would breeding Spider X Spider to gather information on the possibility of a lethal homozygous form be a huge undertaking for any breeder, big or small, but what would that breeder do with all of those spider and normal babies? I'd be willing to try a few Spider X Spider pairings when my spider female grows up but I don't think it would be wise for any one breeder to devote so much time and resources to such a thing.

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Originally Posted by WingedWolfPsion

Not that anyone has ever been able to prove. Which probably means they do not exist. (Homozygous Pinstripes have been proven, so Pinstripe is a dominant mutation).

While listed as dominant on many sites, Spider is probably not a dominant mutation. Instead, it may be co-dominant with a lethal super form, so that homozygous spiders never hatch.
It's not unusual for an egg or two to die during incubation, so it's unlikely it would be noticed.

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Dominant Pin? Can you post links to this? Are there any known defects with them? Who usually has them available?

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Originally Posted by that_dc5

Dominant Pin? Can you post links to this? Are there any known defects with them? Who usually has them available?

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There are no links, just talk to brian directly, he hatched something like 27 pins from the same snake. Its the only one I know of. If there was defects it wouldn't be dominant. There are none avaliable. All it means is you have a pin looking animal that always passes a pin gene, why does everyone thing this is so different. Super pastels always pass a pastel gene, super pins always pass a pin gene. Difference is pin does look different in either form, so its classfied as dominant. Since they dont look different, its not really a project worth going after, all the work time and resources and you get an animal that looks exactly the same. Don't plan on seeing many of them

A lot of interesting concepts, unfortunately none proven true.
You can't count Brian hiding his project claiming people are giving him crap over it.
If I had a homozygous pinstripe I'd do everything I could to document and show why it's dominate.
Proof is hard to dispute, bring on the proof and more people might listen to this theory of a homozygous pinstripe or spider.

While I understand people want to prove a homo spider, as Randy says, the longer it goes the less likely there is such a thing.

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Originally Posted by OhhWatALoser

If there was defects it wouldn't be dominant.

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How does that even make sense? Super Black Pastel's (which I'd consider dominant because 100% of the offspring are Black Pastels) have a defect, duck bills. Super Pastel x Super Pastel/Pastel supposedly can be born with defects....

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Originally Posted by OhhWatALoser

All it means is you have a pin looking animal that always passes a pin gene, why does everyone thing this is so different. Super pastels always pass a pastel gene, super pins always pass a pin gene. Difference is pin does look different in either form, so its classfied as dominant.

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I understand how it works just fine, I don't need help with explaining it. I understand genetics 100%. And I understand that a super pin would still look like a regular pin. Never said it would look different.... So what you're saying is you'd consider a Super Pastel co-dominant because it looks different than the Pastel? That doesn't make sense either.

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Originally Posted by OhhWatALoser

Since they dont look different, its not really a project worth going after, all the work time and resources and you get an animal that looks exactly the same.

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That is a matter of opinion. Suppose you put a Super Lesser to a Pin. Only 50% of the offspring should have the pin gene. Where as BEL x Super Pin would = ALL Lesser Pins... Much more valuable to me. Pin x Normal = 50% normals 50% pins. Normals are pretty worthless for selling. Super Pin x Normal = all Pins, much greater return here.:gj:

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Originally Posted by that_dc5

Super Pin x Normal = all Pins, much greater return here.:gj:

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Actually a super pin or a super spider would speed up the decline in value of those morphs.
IF there was such a thing as a super pin or super spider, already two of the most produced morphs out there, the market for those two morphs would crash even further than it already has.
I would think anyone producing spider combos and pinstripe combos would not want a homozygous version proven :confused:

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Originally Posted by OhhWatALoser

There are no links, just talk to brian directly, he hatched something like 27 pins from the same snake. Its the only one I know of. If there was defects it wouldn't be dominant. There are none avaliable. All it means is you have a pin looking animal that always passes a pin gene, why does everyone thing this is so different. Super pastels always pass a pastel gene, super pins always pass a pin gene. Difference is pin does look different in either form, so its classfied as dominant. Since they dont look different, its not really a project worth going after, all the work time and resources and you get an animal that looks exactly the same. Don't plan on seeing many of them

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Originally Posted by snakesRkewl

Actually a super pin or a super spider would speed up the decline in value of those morphs.
IF there was such a thing as a super pin or super spider, already two of the most produced morphs out there, the market for those two morphs would crash even further than it already has.
I would think anyone producing spider combos and pinstripe combos would not want a homozygous version proven :confused:

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I understand your theory there and it makes sense. Only thing I can say there is that since they are such a common morph, their value is already decreasing every second. So granted their value would take a big hit but that's coming regardless. So even if they end up costing what Pastels are at now, their combos are still valuable and even a $100 pin is worth more than a $30 normal. But I am not trying to change your mind, you make a great point and I respect it completely.

[QUOTE=that_dc5;1742714]How does that even make sense? Super Black Pastel's (which I'd consider dominant because 100% of the offspring are Black Pastels) have a defect, duck bills. Super Pastel x Super Pastel/Pastel supposedly can be born with defects....



I understand how it works just fine, I don't need help with explaining it. I understand genetics 100%. And I understand that a super pin would still look like a regular pin. Never said it would look different.... So what you're saying is you'd consider a Super Pastel co-dominant because it looks different than the Pastel? That doesn't make sense either.



You obviously don't understand gentetics 100%. A super Black pastel is not a Dominant gene it is a Homo versus the Black Pastel being a het. Making this by definition a co-dom gene, meaning that when two Hets(black pastels) breed they can produce a Super or Homo (super Black Pastel) version that looks differant then the hets. To be considered Dominant there can or can not be a super or Homo version, if there is it will look exactly as the het version does. Your analogy to super pastel vs pastel is flawed because you are comparing a co-dom homo to a co-dom het, just doesn't make sense. I think you are confusing the term dominant and homogezyneous, they are not one and the same.

So you're saying you'd call a Super Black Pastel a co-dominant snake, even though when paired to a normal you'd get nothing but Black Pastels? The same as if there was a homozygous Spider, you put to a normal and get nothing but Spiders. Because I wouldn't.

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Originally Posted by that_dc5

So you're saying you'd call a Super Black Pastel a co-dominant snake, even though when paired to a normal you'd get nothing but Black Pastels? .

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yes. the homozygous form of a co-dominant gene.

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Originally Posted by that_dc5

So you're saying you'd call a Super Black Pastel a co-dominant snake, even though when paired to a normal you'd get nothing but Black Pastels? The same as if there was a homozygous Spider, you put to a normal and get nothing but Spiders. Because I wouldn't.

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That is the definition of a Co-Dom animal. It is only dominate if both the het and homo are identical. The black pastel and super black pastel look different so it cannot be a dominate trait.

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Originally Posted by MrBig

You obviously don't understand gentetics 100%. A super Black pastel is not a Dominant gene it is a Homo versus the Black Pastel being a het. Making this by definition a co-dom gene, meaning that when two Hets(black pastels) breed they can produce a Super or Homo (super Black Pastel) version that looks differant then the hets. To be considered Dominant there can or can not be a super or Homo version, if there is it will look exactly as the het version does. Your analogy to super pastel vs pastel is flawed because you are comparing a co-dom homo to a co-dom het, just doesn't make sense. I think you are confusing the term dominant and homogezyneous, they are not one and the same.

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I am not trying to start a war here. I understand what you're saying, and I know that Super forms aren't considered Dominant, so believe me when I say I understand genetics...

I guess what I was trying to say is that even though Super's aren't considered Dominant, they should be. Think about it, a dominant means that when paired to a normal you get nothing but the visual het version of that snake. For example a Super Pastel x Normal would give you all Pastels. Pastels being the visual het. to Super Pastel (there being a visual difference between the two). Now consider a Super Spider. Super Spider x Normal would be all Spiders (the het. versions of the Super Spider) so even though the het version looks just like the Super, you dont get normals.

So again, even though that is how the reptile industry has labeled things, I don't think we should separate the terms because the het. version of a Super Pastel looks different where the het. version of the "Super Spider" looks the same as it. You get me? When it comes to trying to explain through words, I suck lol. If you heard me trying to explain it you'd understand.

Heh heh,

The problem is the snake breeding community uses several of the terms incorrectly from a geneticists point of view.


dr del

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Originally Posted by that_dc5

I am not trying to start a war here. I understand what you're saying, and I know that Super forms aren't considered Dominant, so believe me when I say I understand genetics...

I guess what I was trying to say is that even though Super's aren't considered Dominant, they should be. Think about it, a dominant means that when paired to a normal you get nothing but the visual het version of that snake. For example a Super Pastel x Normal would give you all Pastels. Pastels being the visual het. to Super Pastel (there being a visual difference between the two). Now consider a Super Spider. Super Spider x Normal would be all Spiders (the het. versions of the Super Spider) so even though the het version looks just like the Super, you dont get normals.

So again, even though that is how the reptile industry has labeled things, I don't think we should separate the terms because the het. version of a Super Pastel looks different where the het. version of the "Super Spider" looks the same as it. You get me? When it comes to trying to explain through words, I suck lol. If you heard me trying to explain it you'd understand.

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But that's what we use the term Co-Dominate for. Dominate means that there isn't a difference between the het and homo, and Co-Dom means that the het looks different than a normal and the homo looks different than the normal or the het. So why do you want to call that dominate?

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Originally Posted by The Serpent Merchant

There are homo versions, they just don't look any different. If I bred a snake with dominate gene X to another snake with dominate gene X 25% on average would by homo for gene X.

It works the same way as with Co-Doms, the only difference is that there isn't a visual Difference between the het and the homo versions.

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I get the odds but I was under the impression that there werent any homo versions of a dominant trait and Ive never heard of a homo dominant snake that thows all dominant babies, it would be sweet though.

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Originally Posted by that_dc5

So you're saying you'd call a Super Black Pastel a co-dominant snake, even though when paired to a normal you'd get nothing but Black Pastels? The same as if there was a homozygous Spider, you put to a normal and get nothing but Spiders. Because I wouldn't.

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Im pretty sure black pastel is co dominant as well. Just because the super form makes all black pastel babies doesnt make it a dominant trait.

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Originally Posted by that_dc5

I am not trying to start a war here. I understand what you're saying, and I know that Super forms aren't considered Dominant, so believe me when I say I understand genetics...

I guess what I was trying to say is that even though Super's aren't considered Dominant, they should be. Think about it, a dominant means that when paired to a normal you get nothing but the visual het version of that snake. For example a Super Pastel x Normal would give you all Pastels. Pastels being the visual het. to Super Pastel (there being a visual difference between the two). Now consider a Super Spider. Super Spider x Normal would be all Spiders (the het. versions of the Super Spider) so even though the het version looks just like the Super, you dont get normals.

So again, even though that is how the reptile industry has labeled things, I don't think we should separate the terms because the het. version of a Super Pastel looks different where the het. version of the "Super Spider" looks the same as it. You get me? When it comes to trying to explain through words, I suck lol. If you heard me trying to explain it you'd understand.

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Doesnt dominant mean that the offspring have a 50% chance of getting the dominant gene.

No, dominant means the allele is fully expressed in a heterozygous animal. The animal can be either heterozygous or homozygous, it has no bearing on the expression. A heterozygous animal will have a 50% chance of passing a gene on while a homozygous animal has a 100% chance.

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Originally Posted by Jabberwocky Dragons

No, dominant means the allele is fully expressed in a heterozygous animal. The animal can be either heterozygous or homozygous, it has no bearing on the expression. A heterozygous animal will have a 50% chance of passing a gene on while a homozygous animal has a 100% chance.

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I know, thats what I said. I think that people are just looking at this from different points of view. Also if it is a co dom/in dom or dominant I'm pretty sure it does have a bearing on expression with ball pythons, if it passes those genes to its offspring and they are dominant or co dom that snake will be a visual.