codominant or dominant spiders

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Originally Posted by bigballs

so the pastel gene is codominant and does not become dominant in the super form. the super form is just two copies of the codominant gene, right? just like mojaves and lucys? one is codom and the other is two copies of the codom gene. so what morph is truely dominant? the normal wild type?

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Pinstripe appears to be dominant other than that normal is basically the dominant expression of the various genes. Keep in mind that many morphs are not mutually exclusive. For instance a snake can be both axanthic and albino at the same time. What you see is not one Phenotype called Snow its two phenotypes albino and axanthic that are both visible at the same time.

It can get very complicated though. Look at the Labrador retriever for instance. Yellow is a recessive trait that covers up both Chocolate and Black when expressed. Black is dominant and Chocolate is recessive. This means that unless you know the underlying genetics you can get a lot of variety out of a single litter. Genetics can get very complicated and it sometimes takes years and years before the interactions of genes is understood if ever. Blood type is another interesting complicated genetic trait that turns out has many subtleties beyond just A/B, +/-.

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Originally Posted by littleindiangirl

I know, I'm terrible about explaining terminology, so usually when it gets ugly in these threads, I leave them alone from sheer exhaustion at trying to get people to understand simple inheritance VS. dominant/recessive expressions.

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Connie, I think you are great at explaining everything. And everything you have said goes along with my years of education and the last 2 months of feverish reading on how the various morph genetics work and interact.

You didn't confuse me by throwing pinstripe into the mix. I often say qualify statements with "as far as I know" or "it's my understanding" when there is not a lot of evidence to be certain. I think that it will be interesting to see if the homozygous spider turns out to be lethal or not.

I just think that being dead should count as looking different and therefor constitute a super form making spider codominant.

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Originally Posted by Egapal

I just think that being dead should count as looking different and therefor constitute a super form making spider codominant.

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But there's the problem right there, you can end up with dead hatchlings for any number of reasons. Theoretically, if you breed a spider to a spider, you'll either have 25% less eggs, or 25% dead hatchlings. It may be because noone really tries it very often, but I haven't heard of many clutches like that. I do know that lots of people also thought the pinstripe could be homozygous lethal, but as was mentioned BHB thinks he has a homozygous pinstripe right now. I do know that when we asked him about the idea of pinstripe being homozygous lethal last year, he said that he's had plenty of pinstripe x pinstripe clutches, and never noticed anything odd with the number of eggs or hatchlings that didn't make it. The guy to ask about spider x spider clutches would definitely be Kevin McCurley from NERD. He's the guy that imported the original, and I know he's the guy that probably tried the hardest to produce a super spider.

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Originally Posted by Egapal

Pinstripe appears to be dominant other than that normal is basically the dominant expression of the various genes. Keep in mind that many morphs are not mutually exclusive. For instance a snake can be both axanthic and albino at the same time. What you see is not one Phenotype called Snow its two phenotypes albino and axanthic that are both visible at the same time.

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so if the pinstripe is said to have a homozygous form that has a phenotype very similar to it's heterozygous form would the pinstripe morph still considered dominant or is it now considered codominant because the full expression of the gene requires two copies?

i understand the concept of double homozygous recessive morphs such as the snow, i think i am confusing the difference between labelling dominant and codominant morphs with dominant and codominant genes.

for example one book i read says that the pastel is a codominant form where as super pastel is the dominant form. but after reading the posts in this thread i now think that pastel is a codom gene that requires two copies of itself to be fully expressed and that a super pastel is not a dominant gene, it is just a visual expression of two copies of the codominant pastel gene but we label it as the dominant or super form.

so i think that when we talk about dominant or codominant in ball python terms we are refferring to whether or not a certain morph has a known super form or not and we are not reffering to the actual genotype of the animal.

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Originally Posted by bigballs

so if the pinstripe is said to have a homozygous form that has a phenotype very similar to it's heterozygous form would the pinstripe morph still considered dominant or is it now considered codominant because the full expression of the gene requires two copies?

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Not very similar. Its the same. The homozygous pinstripe we are talking about looks the same as the heterozegous pinstripe.

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i understand the concept of double homozygous recessive morphs such as the snow, i think i am confusing the difference between labelling dominant and codominant morphs with dominant and codominant genes

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When someone says dominant or codominant morph they are saying that the gene that causes the morph is dominant or codominant.

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for example one book i read says that the pastel is a codominant form where as super pastel is the dominant form.

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The super pastel is the homozygous phenotype (form).

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but after reading the posts in this thread i now think that pastel is a codom gene that requires two copies of itself to be fully expressed and that a super pastel is not a dominant gene, it is just a visual expression of two copies of the codominant pastel gene but we label it as the dominant or super form.

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We label it the Super form and say that its homozygous for the trait. The key is that a super pastel when bred to a normal ball python will produce all pastels. And when you breed two pastels together you get 1/4 normal, 1/2 pastels, and 1/4 super pastels.

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so i think that when we talk about dominant or codominant in ball python terms we are refferring to whether or not a certain morph has a known super form or not and we are not reffering to the actual genotype of the animal.

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Kinda, The important thing is to learn how recessive and dominant traits work. Once you got that you are left knowing that there is no way short of a genetic test or breeding the animal to tell if an animal is het for a recessive or homozygous for a dominant. Once you understand that we go a head and complicated things by saying "Oh yeah there is another way a gene can work and that's called codominant" and that's really the most intuitive. The problem is that we spend so much time understanding dominant and recessive that its hard to understand something as simple as codominant. With codom, if you have no gene you have no signs of the trait, if you have one you have some signs, if you have two you have the actual trait.

I didnt read through all of it, but I was going to suggest super spiders being a potentially lethal genotype...but Connie beat me to it a long time ago....I just searched for this thread looking for a list of codom morphs. Sorry to drag out the dead.

Where is Randy Remmington! He is usually all over the genetics questions....
But yes there is some good information in here from LittleIndianGirl and Egapal

I think Egapal and Littleindiangirl covered it.

I would vote that if spider is somehow proven homozygous lethal (very hard to prove something by its absence) that would seem to me to qualify as co-dominant due to the homozygous being different.

Also, a book that talks about the co-dominant and dominant form of the same mutation would be very unfortunate. I see enough of that terminology thrown around that I don't doubt that it's written down somewhere. As already stated, the mutation type (recessive, co-dominant, dominant) is defined by the relationship of the phenotypes (appearance) between the different genotypes (heterozygous and homozygous mutant) so it doesn't change. The pastel mutation is still a co-dominant mutation type regardless of if you are looking at a pastel or a super pastel, the difference is that the pastel is the heterozygous genotype and the super pastel is homozygous for the pastel mutation.

Cool that we finally have a ball python dominant mutation type example in pinstripe where the heterozygous pins and the homozygous pinstripe are reported to look the same (same phenotype) to fit the dominant definition. And you can see that it's the genotype that's important to know what the babies will be like with only the homozygous pinstripe producing 100% pinstripes.

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Originally Posted by RandyRemington

I think Egapal and Littleindiangirl covered it.

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Yep....Agreed. Just was surprised not to see ya on this one yet.
You always have a great way of wording your post so that most people can understand the information being presented. I enjoy reading them at least.

I heard a while back that someone actually produced the super form of a spider, but it looked the same in appearence. The only difference was that when breed to a normal, all the eggs would be spiders, but i think a lot of people just forgot about the idea, because it wasn't worth raising all of them up and proving them out as super spiders and then selling them, it wouldn't be worth it... Hmmm, you should look into it. Ill go back through my posts and try to find where i heard it and get back to you.