Homozygous Spider Morph

[Jabberwocky Dragons]

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

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.

[Andreass]

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.

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.

[Domepiece]

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.

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.

[Domepiece]

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.

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.

[Domepiece]

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.

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.

[Andreass]

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.

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

[The Serpent Merchant]

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.

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

[OhhWatALoser]

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.

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.

Heh heh,

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


dr del

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

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.

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.

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.

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.

[Domepiece]

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

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.

[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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