Homozygous Spider Morph

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

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Sorry, I thought you were asking a question. But what you said isn't correct either. Dominant has nothing to do with the chance of passing on the alleles, just whether or not they will be expressed. Offspring could have a 100% chance of receiving the allele if one of the parents is homozygous.

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Originally Posted by OhhWatALoser

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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A lethal form doesn't always mean it is co-dominant. It can be that the spider gene carries some "disease". This disease in a heterozygous form might be covered by the remaining normal gene. When a homozygous form is produced the normal gene is absent so the "disease" is lethal. This for example is so with yellow mice.

Actually the ball python genetics of today is way to simple. It is based on genetic laws from the simplest levels. Laws that are made in the 19 th century by Mendel. The majority of the features don't follow such a simple genetic law. This includes the colors of ball pythons.

As we see crossing over is not yet part of ball python genetics. But it is there you can be sure of that. Crossing over happens in every egg and sperm. What the ball python hobby needs are some geneticist how examine every base ball python morph to see how it inherits. A lot of crossing overs will come up togethere with some more complicated forms of gene transfer.
This will result in different chances on offspring.

For example. If crossing over is true for lets say bumblebees. This means that the 25% chance of a bumblebee crossed from a spider x pastel is not correct. The chance will be affected by the physical space between the spider and the pastel gene on a chromosome.

So far we made ball python genetic fits. But the numbers won't be correct for some ( or maybe alot) double gene morphs. Also some things can't be explained cause of this simple genetic laws we follow. So we will need an genetic expert in the hobby who can say what is going on, for example, with the homozygous spider.

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Originally Posted by Jabberwocky Dragons

Sorry, I thought you were asking a question. But what you said isn't correct either. Dominant has nothing to do with the chance of passing on the alleles, just whether or not they will be expressed. Offspring could have a 100% chance of receiving the allele if one of the parents is homozygous.

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Yes if one is homozygous. Doesnt a "het" dominant trait expressed in an animal have a 50% statistical probability for the offspring to get that trait? thats a question.

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Originally Posted by Andreass

A lethal form doesn't always mean it is co-dominant. It can be that the spider gene carries some "disease". This disease in a heterozygous form might be covered by the remaining normal gene. When a homozygous form is produced the normal gene is absent so the "disease" is lethal. This for example is so with yellow mice.

Actually the ball python genetics of today is way to simple. It is based on genetic laws from the simplest levels. Laws that are made in the 19 th century by Mendel. The majority of the features don't follow such a simple genetic law. This includes the colors of ball pythons.

As we see crossing over is not yet part of ball python genetics. But it is there you can be sure of that. Crossing over happens in every egg and sperm. What the ball python hobby needs are some geneticist how examine every base ball python morph to see how it inherits. A lot of crossing overs will come up togethere with some more complicated forms of gene transfer.
This will result in different chances on offspring.

For example. If crossing over is true for lets say bumblebees. This means that the 25% chance of a bumblebee crossed from a spider x pastel is not correct. The chance will be affected by the physical space between the spider and the pastel gene on a chromosome.

So far we made ball python genetic fits. But the numbers won't be correct for some ( or maybe alot) double gene morphs. Also some things can't be explained cause of this simple genetic laws we follow. So we will need an genetic expert in the hobby who can say what is going on, for example, with the homozygous spider.

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I prefer it simple and I dont feel there is a need to get technical with things. Most of us know what the possibilites are when we combine different morphs and that is all that needs to be known as far as I'm concerned.

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Originally Posted by Jabberwocky Dragons

Sorry, I thought you were asking a question. But what you said isn't correct either. Dominant has nothing to do with the chance of passing on the alleles, just whether or not they will be expressed. Offspring could have a 100% chance of receiving the allele if one of the parents is homozygous.

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I guess what I am saying is that with the exception with the apparent super pin from BHB I have yet to hear of another homo version of what we call dominant gene traits, therefore all the morphs we call dominant whether or not that is the correct usage will have a statistical probability for 50% of their offspring to exhibit that dominant gene trait. The gene is dominant so the offspring only need to get one of the genes for it to be expressed and its not what we call co dom/in dom because they dont make a super form that is different from the "het", in regards to how we use the term.

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Originally Posted by Domepiece

I prefer it simple and I dont feel there is a need to get technical with things. Most of us know what the possibilites are when we combine different morphs and that is all that needs to be known as far as I'm concerned.

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Ok for the chances it is not that necessary, but at least we will be able to know what is happening with those spiders.

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Originally Posted by Domepiece

Yes if one is homozygous. Doesnt a "het" dominant trait expressed in an animal have a 50% statistical probability for the offspring to get that trait? thats a question.

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yes it does. Homo = 100% Het = 50%

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Originally Posted by that_dc5

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.

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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Black pastels is co-dominant because the het and homo forms are different. If the homozygous Pin had issues, it would be different. To be dominant the trait has to be fully expressed in het and homo form. different homo = co-dom/inc. dom. black pastel it is not fully expressed, so it co-dom/inc. dom. Pin is fully expressed, so it is dominant.

Yes that what I'm saying with super pastels, I think other have explained this well enough for you.

Here the thing, I breed a pin x pin I have years of proving out before I even know ones homozygous. Pastel x pastel I know as soon as the clutch hatches, 3+ years down the road you finally prove out your homozygous pin, while the other guy has super pastel lesser black pastel. Then to get another gene with the homozygous pin more years of proving out From a pure business stand point I don't see it making sense to produce them. From a coolness factor however I would do it. Maybe I will.

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Originally Posted by dr del

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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Besides co-dom/inc dom I believe we are using the terms correctly.

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Originally Posted by Andreass

A lethal form doesn't always mean it is co-dominant. It can be that the spider gene carries some "disease". This disease in a heterozygous form might be covered by the remaining normal gene. When a homozygous form is produced the normal gene is absent so the "disease" is lethal. This for example is so with yellow mice.

Actually the ball python genetics of today is way to simple. It is based on genetic laws from the simplest levels. Laws that are made in the 19 th century by Mendel. The majority of the features don't follow such a simple genetic law. This includes the colors of ball pythons.

As we see crossing over is not yet part of ball python genetics. But it is there you can be sure of that. Crossing over happens in every egg and sperm. What the ball python hobby needs are some geneticist how examine every base ball python morph to see how it inherits. A lot of crossing overs will come up togethere with some more complicated forms of gene transfer.
This will result in different chances on offspring.

For example. If crossing over is true for lets say bumblebees. This means that the 25% chance of a bumblebee crossed from a spider x pastel is not correct. The chance will be affected by the physical space between the spider and the pastel gene on a chromosome.

So far we made ball python genetic fits. But the numbers won't be correct for some ( or maybe alot) double gene morphs. Also some things can't be explained cause of this simple genetic laws we follow. So we will need an genetic expert in the hobby who can say what is going on, for example, with the homozygous spider.

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If a single normal allele is stopping it from being lethal, that makes it inc dom (or what we call co-dom in the bp world) That fits exactly with mendel's definition, the phenotype is not fully expressed. While genetics may not be as simple as A+B=C, It's the best we can do right now and the statistics seems to follow. We still have a few weird unknowns, banana's sex linkish thing and the whiteout gene are two that come to mind. I do understand what your saying though, mendels system was pretty much made obsolete with new technology. Nothing is recessive anymore by his definition since everything is observable now with DNA analysis. But we don't have anyone working on the ball python genome that I know of, so we stick with old fashon mendel lol.

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Originally Posted by Domepiece

I guess what I am saying is that with the exception with the apparent super pin from BHB I have yet to hear of another homo version of what we call dominant gene traits, therefore all the morphs we call dominant whether or not that is the correct usage will have a statistical probability for 50% of their offspring to exhibit that dominant gene trait. The gene is dominant so the offspring only need to get one of the genes for it to be expressed and its not what we call co dom/in dom because they dont make a super form that is different from the "het", in regards to how we use the term.

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Guess you missed when I said the congo is another dominant gene according to vin russo, there are also many suspect ones, but again proving them out takes years and usually not worth the effort. Your statement would be more correct saying "all heterozygous morphs will have a statistical probability for 50% of their offspring to exhibit that heterozygous gene trait" because that how it works. Dominant co-dom are just classifications of the phenotypes in het and homo form. het and homo are where the statistics come from.


I feel as I need to repost this.

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Originally Posted by The Serpent Merchant

yes it does. Homo = 100% Het = 50%

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Exactly this is what I have been saying. One problem though, there are no homo dominant traits in ball pythons and thats what I am talking about (except for the one pin is suppose) so statistially speaking they should pass on the dominant trait to all their offspring if they are dominant but they dont exist so they dont. Its all great in theory and it works out on a punnett square but in application there are no homo dominant balls in application, except the one pin apparently.

As I understand it:
Recessive means it takes both allele at the same locus to have the mutation before the trait will express itself.
Co-dominant means there will be an expression of the trait if one allele has the mutation and an enhanced version of the trait if both allele at the same locus have the mutation.
Dominant means if either or both of the allele at the same locus have the mutation at the same locus it will express the same trait.

Heterozygous means that one allele at the same locus has said mutation.
Homozygous means that both allele at the same locus have said mutation.

To me these definitions all make sense and work within the confines of my OP. My original question was whether anyone has seen or heard of a homo-spider, to which the answer seems to be no.


Sent from my iPhone using Tapatalk

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Originally Posted by OhhWatALoser

Black pastels is co-dominant because the het and homo forms are different. If the homozygous Pin had issues, it would be different. To be dominant the trait has to be fully expressed in het and homo form. different homo = co-dom/inc. dom. black pastel it is not fully expressed, so it co-dom/inc. dom. Pin is fully expressed, so it is dominant.

Yes that what I'm saying with super pastels, I think other have explained this well enough for you.

Here the thing, I breed a pin x pin I have years of proving out before I even know ones homozygous. Pastel x pastel I know as soon as the clutch hatches, 3+ years down the road you finally prove out your homozygous pin, while the other guy has super pastel lesser black pastel. Then to get another gene with the homozygous pin more years of proving out From a pure business stand point I don't see it making sense to produce them. From a coolness factor however I would do it. Maybe I will.



Besides co-dom/inc dom I believe we are using the terms correctly.



If a single normal allele is stopping it from being lethal, that makes it inc dom (or what we call co-dom in the bp world) That fits exactly with mendel's definition, the phenotype is not fully expressed. While genetics may not be as simple as A+B=C, It's the best we can do right now and the statistics seems to follow. We still have a few weird unknowns, banana's sex linkish thing and the whiteout gene are two that come to mind. I do understand what your saying though, mendels system was pretty much made obsolete with new technology. Nothing is recessive anymore by his definition since everything is observable now with DNA analysis. But we don't have anyone working on the ball python genome that I know of, so we stick with old fashon mendel lol.



Guess you missed when I said the congo is another dominant gene according to vin russo, there are also many suspect ones, but again proving them out takes years and usually not worth the effort. Your statement would be more correct saying "all heterozygous morphs will have a statistical probability for 50% of their offspring to exhibit that heterozygous gene trait" because that how it works. Dominant co-dom are just classifications of the phenotypes in het and homo form. het and homo are where the statistics come from.


I feel as I need to repost this.

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I did miss that. By exhibit I meant show visually and I was just trying to stay on codom/indom and dominant as to not add more confusion.

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Originally Posted by Domepiece

Exactly this is what I have been saying. One problem though, there are no homo dominant traits in ball pythons and thats what I am talking about (except for the one pin is suppose) so statistially speaking they should pass on the dominant trait to all their offspring if they are dominant but they dont exist so they dont. Its all great in theory and it works out on a punnett square but in application there are no homo dominant balls in application, except the one pin apparently.

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you've missed it twice now....

*edit* ah there we go

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Originally Posted by Gomojoe

As I understand it:
Recessive means it takes both allele at the same locus to have the mutation before the trait will express itself.
Co-dominant means there will be an expression of the trait if one allele has the mutation and an enhanced version of the trait if both allele at the same locus have the mutation.
Dominant means if either or both of the allele at the same locus have the mutation at the same locus it will express the same trait.

Heterozygous means that one allele at the same locus has said mutation.
Homozygous means that both allele at the same locus have said mutation.

To me these definitions all make sense and work within the confines of my OP. My original question was whether anyone has seen or heard of a homo-spider, to which the answer seems to be no.


Sent from my iPhone using Tapatalk

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And Bingo was his namo. But no Ive never heard of a homo spider but I wish I had some homo dominant snakes it would help making combos a little easier.

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Originally Posted by OhhWatALoser

you've missed it twice now....

*edit* ah there we go

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Lol, my bad.:D

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Originally Posted by Gomojoe

As I understand it:
Recessive means it takes both allele at the same locus to have the mutation before the trait will express itself.
Co-dominant means there will be an expression of the trait if one allele has the mutation and an enhanced version of the trait if both allele at the same locus have the mutation.
Dominant means if either or both of the allele at the same locus have the mutation at the same locus it will express the same trait.

Heterozygous means that one allele at the same locus has said mutation.
Homozygous means that both allele at the same locus have said mutation.

To me these definitions all make sense and work within the confines of my OP. My original question was whether anyone has seen or heard of a homo-spider, to which the answer seems to be no.

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epic ending to the post lol

and you got it all spot on for the bp world.

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Originally Posted by OhhWatALoser

you've missed it twice now....

*edit* ah there we go

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Ok,ok, and congo.:gj:

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Originally Posted by Domepiece

Exactly this is what I have been saying. One problem though, there are no homo dominant traits in ball pythons and thats what I am talking about (except for the one pin is suppose) so statistially speaking they should pass on the dominant trait to all their offspring if they are dominant but they dont exist so they dont. Its all great in theory and it works out on a punnett square but in application there are no homo dominant balls in application, except the one pin apparently.

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I differ with this post for the following reasons:

1. The existence of one homozygous pinstripe ball python means that more can be bred.

2. The lesser pastel mutant gene is codominant to its normal allele. The mojave mutant gene is codominant to its normal allele. The lesser pastel gene and the mojave gene are alleles.

A snake with two lesser mutant genes is a blue-eyed white. A snake with a lesser mutant gene paired with a mojave mutant gene is a blue-eyed white, like the homozygous lesser snake. A snake with two mojave mutant genes is mostly white but has some pigment on its head.

Therefore, the lesser platinum mutant gene is dominant to the mojave mutant gene, and the mojave mutant gene is recessive to the lesser platinum mutant gene.

Homozygous lesser x homozygous mojave -->
100% blue-eyed white (with a lesser platinum gene paired with a mojave gene)

By the way, the royal python genetics field is a tiny ghetto compared to fruit fly or mouse genetics. Both of those species have plenty of dominant mutant genes. Also, the salmon (AKA hypo) gene in boa constrictors and the stripe gene in California king snakes are dominants.

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Originally Posted by OhhWatALoser

Besides co-dom/inc dom I believe we are using the terms correctly.

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I have been impressed with how well people have been following the standard genetics definitions in this thread. But I see many terms with incorrect definitions on the herper genetics web sites.

As for codominant vs. incomplete dominant, even the textbooks do not agree on the definitions.

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Originally Posted by paulh

As for codominant vs. incomplete dominant, even the textbooks do not agree on the definitions.

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This is how I have learned it at University. Codominant means working together. Co= together. So for example a black mouse x white mouse would give a mouse who has black and white in his coat. Incomplete dominant means when you do black mouse x white mouse you would get a grey mouse. Black is not completely dominant over white so you will get grey.

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Originally Posted by paulh

I have been impressed with how well people have been following the standard genetics definitions in this thread. But I see many terms with incorrect definitions on the herper genetics web sites.

As for codominant vs. incomplete dominant, even the textbooks do not agree on the definitions.

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I've always seen it as co-dominant means both phenotypes showing and inc. dom means combination of phenotypes showing. as in the above example. where's the disagreement at?

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Originally Posted by that_dc5

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.

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Dominant is not defined as "when paired to a normal you get nothing but the visual het version of that snake." That's the definition of Homozygous. Homozygous means having two copies of the same gene. If that gene is dominant then you get nothing but visual hets that are the same phenotype as the homozygous parent. If the gene in question is co-dominant then you get nothing but visual hets but that visual het has a different phenotype. That means that they don't look like homozygous parent.

Oh and as for homozygous spider being lethal. Absence of evidence is not evidence except when evidence would be expected. Basically that means that since basic genetics tells us we should see pairings of spider to spider produce 25% homozygous, we would have many of these animals in the population and thus should see a homozygous spider prove out. Since we don't see that we have to ask the question of where those animals are. Its pretty common to have a lethal gene so this theory is not without precedent. It won't be proven conclusively without a proper scientific test. Ideally this would include genetic testing. So not seeing a homozygous spider is evidence for the lethal theory but its far from conclusive. Not seeing a homoyzgous spider could also be evidence for aliens teleporting them out of the mother before the eggs are layed. Again the reason we are conjecturing its lethal is because we have proof of this phenomena in other species.

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Originally Posted by Egapal

Oh and as for homozygous spider being lethal. Absence of evidence is not evidence except when evidence would be expected. Basically that means that since basic genetics tells us we should see pairings of spider to spider produce 25% homozygous, we would have many of these animals in the population and thus should see a homozygous spider prove out. Since we don't see that we have to ask the question of where those animals are. Its pretty common to have a lethal gene so this theory is not without precedent. It won't be proven conclusively without a proper scientific test. Ideally this would include genetic testing. So not seeing a homozygous spider is evidence for the lethal theory but its far from conclusive. Not seeing a homoyzgous spider could also be evidence for aliens teleporting them out of the mother before the eggs are layed. Again the reason we are conjecturing its lethal is because we have proof of this phenomena in other species.

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LOL, Im going with the alien hypothesis.

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Originally Posted by Domepiece

LOL, Im going with the alien hypothesis.

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Me too, aliens are stealing our homozygous spiders, AHHHHHHHHHHHHHHH :rofl:

For what its worth, Kevin from NERD says they do the spider x spider crosses all the time and there's no such thing as a lethal homozygous spider mutation. He states this ~1 minute in on the Lethal Combinations Part 2 video (not sure if links are allowed).

Assuming there's no lethal combination, sometimes the simplest explanation is correct (Occam's Razor). There are several unnoticed homozygous spiders spread out amongst the sea of ball python keepers. Their offspring are quickly turned to het spiders by spider x non-spider crosses. Over the past half year, I have read several posts (not a lot but some) by people saying they have spiders or know of people whose spiders produce only spiders but they are quickly drowned out by dissenters. That may be all you get, not some grand coming out by a large breeder with 3 generations of documented records, but just regular people who hit the odds by chance.

I'm not saying I believe this but I just wanted to throw it out as something to consider along with Kevin's take on the lethal combination hypothesis. Personally, I'm leaning towards the alien abduction theory :)

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Originally Posted by OhhWatALoser

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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Actually, there is. NERD did a show recently on lethal gene combinations, and pointed out that champagne appears to interact with the spider gene, and the resulting offspring usually die in the egg, or shortly after hatchling. Those that survive have severe wobbles. That a similar pattern-affecting gene proves lethal when combined with spider suggests that double spider is most likely homozygous lethal. "Proven"? No, perhaps not...but readily inferred, and certainly logical.

I do not recollect them stating that there was no evidence that spider was homozygous lethal.
If spider is highly homozygous lethal, the eggs would die early in incubation, and would be discounted as simply 'bad eggs'. Unless every bad egg from a spider X spider clutch were to be opened and inspected under a microscope to check for abnormalities or a dead spider embryo, and nothing was found, there is no reason to believe that spider is NOT homozygous lethal.

Spider is not dominant, regardless, because if it were, homozygous spiders would be produced. They would look like normal spiders, and when bred to a normal, would produce 100% spiders. This has never happened, so homozygous spiders are different from heterozygous spiders (if they weren't different, they would exist, you see). Therefore, whatever the spider mutation is, it is definitely not dominant.

I do recall hearing that homozygous pinstripes, identical to heterozygous pinstripes, have been produced. That makes pinstripe dominant.

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Originally Posted by WingedWolfPsion

Actually, there is. NERD did a show recently on lethal gene combinations, and pointed out that champagne appears to interact with the spider gene, and the resulting offspring usually die in the egg, or shortly after hatchling. Those that survive have severe wobbles. That a similar pattern-affecting gene proves lethal when combined with spider suggests that double spider is most likely homozygous lethal. "Proven"? No, perhaps not...but readily inferred, and certainly logical.

I do not recollect them stating that there was no evidence that spider was homozygous lethal.
If spider is highly homozygous lethal, the eggs would die early in incubation, and would be discounted as simply 'bad eggs'. Unless every bad egg from a spider X spider clutch were to be opened and inspected under a microscope to check for abnormalities or a dead spider embryo, and nothing was found, there is no reason to believe that spider is NOT homozygous lethal.

Spider is not dominant, regardless, because if it were, homozygous spiders would be produced. They would look like normal spiders, and when bred to a normal, would produce 100% spiders. This has never happened, so homozygous spiders are different from heterozygous spiders (if they weren't different, they would exist, you see). Therefore, whatever the spider mutation is, it is definitely not dominant.

I do recall hearing that homozygous pinstripes, identical to heterozygous pinstripes, have been produced. That makes pinstripe dominant.

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talk to kevin directly if you want to hear him say it. I would also disagree that that it would make it a most likely scenario, just because something looks similar doesn't make it the same. your using another gene to make the comparison, I don't see that as evidence at all... by your logic how can spider + hidden gene woma be fine? looks like champ has a better chance of being the issue.
champ + spider = not good
spider + hidden gene woma = good
champ + hidden gene woma = not good
the evidence is no more of a stretch, than its completely normal gene and we just haven't had one proved out publicly.

anything else I have to say has already been said, this argument goes round and round. want to skip to the bottom line there is no proof of any theory, so why not wait until there is something worth talking about to come out? you use words like definitely when there is nothing definite about this entire subject......

I said it was logical and likely that spider was co-dominant, and homozygous lethal, and I believe that.

I did say it was definite that spider isn't dominant, because, by definition, there is no difference in phenotype between a heterozygous and homozygous animal, with a dominant gene. The very absence of homozygous spiders means that the homozygous animals cannot be identical to the heterozygous animals--something is different, or they would exist.

Now, this is simplistic, as there quite simply are more options than just recessive, incomplete dominant, and dominant, but without getting incredibly complicated, spider simply can't fit into the definition of a dominant gene, so it has to be something else.

Now, I'm personally unaware of any scenario that would prevent 2 copies of a gene from ever winding up in the same animal, and I'm unaware of any scenario that would enable a snake with two copies of a gene to pass on a normal gene. That doesn't mean no such scenarios exist, but do you know of any such instances? That would, logically, seem to be the only alternative to the idea that homozygous spiders die before hatching.
Obviously, either homozygous animals are created, but don't live, or they are not created. If you believe there are other options, I would be curious to hear what else you think it might be.

I do not think either of the two above scenarios could be said to be present in any normal case of dominance, though.

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Originally Posted by WingedWolfPsion

I said it was logical and likely that spider was co-dominant, and homozygous lethal, and I believe that.

I did say it was definite that spider isn't dominant, because, by definition, there is no difference in phenotype between a heterozygous and homozygous animal, with a dominant gene. The very absence of homozygous spiders means that the homozygous animals cannot be identical to the heterozygous animals--something is different, or they would exist.

Now, this is simplistic, as there quite simply are more options than just recessive, incomplete dominant, and dominant, but without getting incredibly complicated, spider simply can't fit into the definition of a dominant gene, so it has to be something else.

Now, I'm personally unaware of any scenario that would prevent 2 copies of a gene from ever winding up in the same animal, and I'm unaware of any scenario that would enable a snake with two copies of a gene to pass on a normal gene. That doesn't mean no such scenarios exist, but do you know of any such instances? That would, logically, seem to be the only alternative to the idea that homozygous spiders die before hatching.
Obviously, either homozygous animals are created, but don't live, or they are not created. If you believe there are other options, I would be curious to hear what else you think it might be.

I do not think either of the two above scenarios could be said to be present in any normal case of dominance, though.

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how bout the case where its a completely normal gene and we haven't had one prove out publicly? There has only been one public pin and only one public congo. You do realize what It takes to "prove" out a homozygous dominant animal, correct? It's not out of the realm of possibilities that there just isn't one publicly. The absence means nothing, since there could be homozygous spiders out there, just not proven publicly.

there no more proof of a lethal spider than the scenario above, you keep saying absence is proof..... it's not, i'm sorry.

know what else we haven't seen homozygous of? Avalanche, Banana, Black Belly, Black Head, Black Lace, Calico, Champagne, Coral Glow, Daddy Gene, Desert, Ember, Epic, Fader, Granite, Het Highway, Spark, Josie, Marble, Napalm, Orange Glow, Philistine, Reaper, Shatter, Spector, Sugar, Whirlwind, Whitesmoke, Woma. Are they all co-dominant also since there is an absence of homozygous forms of them, or maybe it's just not proven yet.....

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Originally Posted by Jabberwocky Dragons

For what its worth, Kevin from NERD says they do the spider x spider crosses all the time and there's no such thing as a lethal homozygous spider mutation. He states this ~1 minute in on the Lethal Combinations Part 2 video (not sure if links are allowed).

Assuming there's no lethal combination, sometimes the simplest explanation is correct (Occam's Razor). There are several unnoticed homozygous spiders spread out amongst the sea of ball python keepers. Their offspring are quickly turned to het spiders by spider x non-spider crosses. Over the past half year, I have read several posts (not a lot but some) by people saying they have spiders or know of people whose spiders produce only spiders but they are quickly drowned out by dissenters. That may be all you get, not some grand coming out by a large breeder with 3 generations of documented records, but just regular people who hit the odds by chance.

I'm not saying I believe this but I just wanted to throw it out as something to consider along with Kevin's take on the lethal combination hypothesis. Personally, I'm leaning towards the alien abduction theory :)

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I do not know if links are allowed either. Please try to post the link. If it gets deleted, please send it to me by personal message. I really want to know what evidence Kevin has for that statement. If he has made many spider x spider matings, then he should be able to do breeding tests to find homozygous spiders. Or could he be just be saying that that such matings produce plenty of spider offspring without specifying whether these spiders are heterozygous or homozygous? Even if all the homozygous spiders die early in egg, spider x spider matings would produce plenty of heterozygous spiders.

"All" is a pretty slippery term. I'd like to see numbers. "All" = 30 means more than "all" = 3.

I'd think the worst thing that could happen is it is proven homozygous(doubt).

$15 spider males, $40 spider females...:snake:

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Originally Posted by Andreass

This is how I have learned it at University. Codominant means working together. Co= together. So for example a black mouse x white mouse would give a mouse who has black and white in his coat. Incomplete dominant means when you do black mouse x white mouse you would get a grey mouse. Black is not completely dominant over white so you will get grey.

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Here are definitions taken from three genetics texts. They differ in definitions and how they classify the various examples. How the sickle cell gene is classified depends on the test used.

How would each text classify the spider mutant gene (assuming spider is not dominant to normal)?

For what it's worth, I follow Miller because that definition is the simplest for a breeder to use.

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Atherly, et al. (1999):
codominance -- a form of dominance relationship between two alleles of one gene in which the heterozygote shows the phenotypes of both alleles. Example -- A, B, and AB human blood types; sickle cell trait in humans.

incomplete dominance -- progeny that possess a phenotype that is approximately intermediate between the homozygous parents. Example -- red, white, and pink flowers; sickle cell trait in humans; Siamese, Burmese, and Tonkinese cat coat colors.

overdominance -- a dominance relationship in which the heterozygote has a greater or more extreme phenotype than individuals homozygous for either allele. Example -- a heterozygous plant that is larger than either homozygous parental type; sickle cell trait in humans.
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Zubey (1987):
codominance -- A situation in which the phenotype is the additive function of two alleles. Both alleles are expressed. Example -- A, B, and AB human blood types; sickle cell trait in humans; Siamese, Burmese, and Tonkinese cat coat colors.

incomplete dominance -- A situation in which only one allele is expressed, and the amount of expression is directly proportional to gene dosage. Example -- red, white, and pink flowers.

overdominance -- the situation in which the heterozygote a more extreme form of a trait than either homozygote. Example -- a heterozygous plant that is larger than either homozygous parental type; sickle cell trait in humans.
------------------------
Miller (1991):
Codominance -- the heterozygote's phenotype can be distinguished from either homozygote's phenotype. This allows each of the three genotypes to be inferred from its phenotype. Synonyms -- incomplete dominance, overdominance, many others. Examples -- A, B, and AB human blood types; sickle cell trait in humans; red, white, and pink flowers; Siamese, Burmese, and Tonkinese cat coat colors; a heterozygous plant that is larger than either homozygous parental type.
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References:
Atherly, Alan G., Jack R. Girton, and John F. McDonald. The Science of Genetics. Saunders College Publishing, Fort Worth, TX. 1999, 704 pp.

Miller, Wilmer J. A Survey of Genetics. Ginn Press, Needham Heights, MA. 2nd ed., 1991, 328 pp.

Zubay, Geoffrey. 1987. Genetics. The Benjamin/Cummings Publishing Co., Menlo Park, CA. 1987, 973 pp.

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Originally Posted by paulh

Here are definitions taken from three genetics texts. They differ in definitions and how they classify the various examples. How the sickle cell gene is classified depends on the test used.

How would each text classify the spider mutant gene (assuming spider is not dominant to normal)?

For what it's worth, I follow Miller because that definition is the simplest for a breeder to use.

------------------------

Atherly, et al. (1999):
codominance -- a form of dominance relationship between two alleles of one gene in which the heterozygote shows the phenotypes of both alleles. Example -- A, B, and AB human blood types; sickle cell trait in humans.

incomplete dominance -- progeny that possess a phenotype that is approximately intermediate between the homozygous parents. Example -- red, white, and pink flowers; sickle cell trait in humans; Siamese, Burmese, and Tonkinese cat coat colors.

overdominance -- a dominance relationship in which the heterozygote has a greater or more extreme phenotype than individuals homozygous for either allele. Example -- a heterozygous plant that is larger than either homozygous parental type; sickle cell trait in humans.
------------------------
Zubey (1987):
codominance -- A situation in which the phenotype is the additive function of two alleles. Both alleles are expressed. Example -- A, B, and AB human blood types; sickle cell trait in humans; Siamese, Burmese, and Tonkinese cat coat colors.

incomplete dominance -- A situation in which only one allele is expressed, and the amount of expression is directly proportional to gene dosage. Example -- red, white, and pink flowers.

overdominance -- the situation in which the heterozygote a more extreme form of a trait than either homozygote. Example -- a heterozygous plant that is larger than either homozygous parental type; sickle cell trait in humans.
------------------------
Miller (1991):
Codominance -- the heterozygote's phenotype can be distinguished from either homozygote's phenotype. This allows each of the three genotypes to be inferred from its phenotype. Synonyms -- incomplete dominance, overdominance, many others. Examples -- A, B, and AB human blood types; sickle cell trait in humans; red, white, and pink flowers; Siamese, Burmese, and Tonkinese cat coat colors; a heterozygous plant that is larger than either homozygous parental type.
------------------------
References:
Atherly, Alan G., Jack R. Girton, and John F. McDonald. The Science of Genetics. Saunders College Publishing, Fort Worth, TX. 1999, 704 pp.

Miller, Wilmer J. A Survey of Genetics. Ginn Press, Needham Heights, MA. 2nd ed., 1991, 328 pp.

Zubay, Geoffrey. 1987. Genetics. The Benjamin/Cummings Publishing Co., Menlo Park, CA. 1987, 973 pp.

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I dont think that anyone is really doubting the way genetics actually work technically speaking, only that for the purposes of ball pythons we use them pretty basically to make things more simple. Its more application and trial and error, many of morphs out there havnt really been explored or combined with every different morph so nothing is known until proven many times over. The example of mice isnt really the same thing, ball python patterns and color mutations are a little harder to predict than a black and white mouse makes grey or a black and white mouse, any person with any sense could resonably asume that would be the case, and mice can breed months after they are born and balls can take up to 3 years which makes it a little more difficult to prove out genetics. Only time will tell. But for the mean time the misnomers for the names we label genetic traits seems to work for its purpose. Essentially too many morphs, not all have been combined, lack of extensive genetic experimentation, this gene usually does this, we havent seen that gene do that yet=just call it this trait for now and if its proven something else later, change it.

Hi,

I'm sure we've seen super forms of the black head and the granite. Both from Ralph Davis iirc.


dr del

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Originally Posted by OhhWatALoser

talk to kevin directly if you want to hear him say it. I would also disagree that that it would make it a most likely scenario, just because something looks similar doesn't make it the same. your using another gene to make the comparison, I don't see that as evidence at all... by your logic how can spider + hidden gene woma be fine? looks like champ has a better chance of being the issue.
champ + spider = not good
spider + hidden gene woma = good
champ + hidden gene woma = not good
the evidence is no more of a stretch, than its completely normal gene and we just haven't had one proved out publicly.

anything else I have to say has already been said, this argument goes round and round. want to skip to the bottom line there is no proof of any theory, so why not wait until there is something worth talking about to come out? you use words like definitely when there is nothing definite about this entire subject......

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Absence is not proof but it is evidence as we would expect to see homozygous spiders. The long the absence persists the stronger that evidence becomes. As for woma hidden and champain, are these allelic? That would explain alot. Regardless the reason we continue to talk about this instead of waiting for proof is the community has members who are considering a spider x spider pairing. If this gene is lethal then a clutch of 6 viable eggs could have been 8 if bred to normals with the same odds at 4 spider hatchlings either way. What if a homozygous spider has a much worse wobble. A spider x spider pairing could result in selling a problem animal as a pet. Not everyone has no vested interest in this topic.

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Originally Posted by dr del

Hi,

I'm sure we've seen super forms of the black head and the granite. Both from Ralph Davis iirc.


dr del

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i see, he hasn't updated his website, right now it says both of them are unknown. However I found pictures of both a with a little google search. thanks

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Originally Posted by Domepiece

we havent seen that gene do that yet=just call it this trait for now and if its proven something else later, change it.

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isn't that how science in general pretty much works? lol

Quote:

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Originally Posted by Egapal

Absence is not proof but it is evidence as we would expect to see homozygous spiders. The long the absence persists the stronger that evidence becomes. As for woma hidden and champain, are these allelic?

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I would hardly call it evidence, all we know is that spider x spider pairings have been done. We have no numbers, what exactly was tired with how many offspring after that.... we got nothing publicly. people claim to do spider x spider pairings, but wheres the record keeping which is pretty much needed to prove these things out? absence of information is what we have, I don't see that as evidence. also I don't think your going to ever find out if they lay on the same locus, train wreak combo.

I believe HG Woma is technically an example of a homozygous lethal ball python mutation. The pearls hatch but apparently don't live to maturity.

NERD has been consistently opposed to any label with the word "lethal". I can understand because you can't get much more negative but as I've regularly pointed out "homozygous lethal" doesn't really say anything negative about heterozygous spiders and their many beautiful combos. Still people jump to incorrect conclusions when you talk about spider possibly being homozygous lethal like that spider X spider can't produce any viable offspring (3/4 of the clutch should still be good) or that you would have to see the problem homozygous spiders (they might not hatch) so maybe that's why NERD is saying spider can't be homozygous lethal.

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Originally Posted by OhhWatALoser

...know what else we haven't seen homozygous of? Avalanche, Banana, Black Belly, Black Head, Black Lace, Calico, Champagne, Coral Glow, Daddy Gene, Desert, Ember, Epic, Fader, Granite, Het Highway, Spark, Josie, Marble, Napalm, Orange Glow, Philistine, Reaper, Shatter, Spector, Sugar, Whirlwind, Whitesmoke, Woma. Are they all co-dominant also since there is an absence of homozygous forms of them, or maybe it's just not proven yet.....

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I've not followed all of these but I do remember RDR doing a platy X platy breeding and producing a female normal looking that should have been a super daddy gene (aka hidden). Didn't hear if it grew up ok and bred to prove its expected genetics. Should have been able to breed it to a homozygous lesser and produce 100% platy.

At this point I sort of take a negative agnostic view. I would say that any morph without a proven viable homozygous example is potentially homozygous lethal and unknown if it's dominant or co-dominant (on a like subject I would say any morph without a proven producing female is potentially female sterile). How likely it's just a case of not enough time to prove one out versus an actual homozygous lethal situation depends on how long the morph has been out and how many people are working with it. I understand the first spider was imported over 20 years ago and many many people are breeding spiders so the lack of a public proven homozygous spider is conspicuous.

I've also heard the occasional claim of a potential homozygous spider having produced a string of only spiders. Most of these are 3rd party reports but of course I'd love to hear more info on them rather than just assuming when they don't come back with updated info that the string was eventually broken.

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Originally Posted by RandyRemington

I believe HG Woma is technically an example of a homozygous lethal ball python mutation. The pearls hatch but apparently don't live to maturity.

NERD has been consistently opposed to any label with the word "lethal". I can understand because you can't get much more negative but as I've regularly pointed out "homozygous lethal" doesn't really say anything negative about heterozygous spiders and their many beautiful combos. Still people jump to incorrect conclusions when you talk about spider possibly being homozygous lethal like that spider X spider can't produce any viable offspring (3/4 of the clutch should still be good) or that you would have to see the problem homozygous spiders (they might not hatch) so maybe that's why NERD is saying spider can't be homozygous lethal.

I've not followed all of these but I do remember RDR doing a platy X platy breeding and producing a female normal looking that should have been a super daddy gene (aka hidden). Didn't hear if it grew up ok and bred to prove its expected genetics. Should have been able to breed it to a homozygous lesser and produce 100% platy.

At this point I sort of take a negative agnostic view. I would say that any morph without a proven viable homozygous example is potentially homozygous lethal and unknown if it's dominant or co-dominant (on a like subject I would say any morph without a proven producing female is potentially female sterile). How likely it's just a case of not enough time to prove one out versus an actual homozygous lethal situation depends on how long the morph has been out and how many people are working with it. I understand the first spider was imported over 20 years ago and many many people are breeding spiders so the lack of a public proven homozygous spider is conspicuous.

I've also heard the occasional claim of a potential homozygous spider having produced a string of only spiders. Most of these are 3rd party reports but of course I'd love to hear more info on them rather than just assuming when they don't come back with updated info that the string was eventually broken.

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Would have to ask kevin what he means. The platty x platty rumor has been going around for a while, its not true. Ralph is attempting it this year however. I figure that gene and the yellow belly stuff could easily be proven out that way, yay for complexes. Apparently first spiders were produced in 1999 so that makes 13 years of babies, but length of time doesn't mean much since I see claims of spider x spider pairings, but never any follow ups on the clutches let alone the spider offspring after. We have the same lack of information every year.

RDR's first platy X platy breeding was 2007 clutch 76:

http://ralphdavisreptiles.com/birthi...thons_8_07.asp

The story I heard was that the original spider was imported by CalZoo and sold by Randy Buck of Super Pets in Orange County CA to NERD in 1989 and that was the same year VPI got the clown from the same seller. I think I've read that it took a while for the clown project to get going and might be the same for the spider but at any rate it's been a while. I picked up my founder Garcia line chocolate at a pet store in 2001 and didn’t hatch my first homozygous until 2011 so I know how that goes.

TSK did some spider to spider in 2007 and 2 of the 8 eggs where small and didn't hatch. All of the spider babies where females but they hoped to breed them this last year, I just haven't checked back to ask if they went. In 2008 they did another spider X spider breeding and report 6 good eggs and 1 slug hatching 1.4 spiders so maybe that 2008 possible homozygous spider male has bred by now too.

Quote:

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Originally Posted by RandyRemington

RDR's first platy X platy breeding was 2007 clutch 76:

http://ralphdavisreptiles.com/birthi...thons_8_07.asp

The story I heard was that the original spider was imported by CalZoo and sold by Randy Buck of Super Pets in Orange County CA to NERD in 1989 and that was the same year VPI got the clown from the same seller. I think I've read that it took a while for the clown project to get going and might be the same for the spider but at any rate it's been a while. I picked up my founder Garcia line chocolate at a pet store in 2001 and didn’t hatch my first homozygous until 2011 so I know how that goes.

TSK did some spider to spider in 2007 and 2 of the 8 eggs where small and didn't hatch. All of the spider babies where females but they hoped to breed them this last year, I just haven't checked back to ask if they went. In 2008 they did another spider X spider breeding and report 6 good eggs and 1 slug hatching 1.4 spiders so maybe that 2008 possible homozygous spider male has bred by now too.

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never seen that link before thanks for clearing that up, interesting because i sent this to ralph

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I was curious how much Christmas money I need to save up to purchase a het platty daddy male or female from you?

I also had a question about the het platty daddy, I herd you bred a platty to a platty and produced a normal looking animal (it would have to be a homozygous/super het platty daddy), can you confirm this? If not have you attempted to produced a homozygous het platty daddy?

thx and hoping to hear back form you
-matt

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this is the email i got from ralph.

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Hi,

I sell het platties for $1750 each.

I have not gotten that far with the platty gene. I do know that any normal offspring from a platty are “het”………the lessers are not I’m trying platty x platty this season.

Thanks,
Ralph

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maybe he ment he hasn't proved out that homzoygous animal.... but sounded to me like he never made anything.

Hopefully they keep us updated.

I did hear that someone produced a homozygous woma (NOT hg woma), which proved woma to be dominant.
No clue who, though.
Maybe I'll try it next year.

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Originally Posted by OhhWatALoser

I would hardly call it evidence, all we know is that spider x spider pairings have been done. We have no numbers, what exactly was tired with how many offspring after that.... we got nothing publicly. people claim to do spider x spider pairings, but wheres the record keeping which is pretty much needed to prove these things out? absence of information is what we have, I don't see that as evidence. also I don't think your going to ever find out if they lay on the same locus, train wreak combo.

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You are free to decide for yourself the strength of the evidence but I would still say that the absence of something when it's expected is evidence. Its certainly far from conclusive. We could very easily prove these things if we cared enough to put the money down for the proper genetic testing. I plan on living for a quite a while yet so unless you know something about my life span that I don't or have some insight into the future of at home genetic testing I don't see any evidence for your assumption that I will never find out if they lay on the same locus.