Dom x Normal

Dom x Normal = 50% showing morph

What my question is if you breed a dominant form to a normal and you get 50% showing are the others het for that morph or are they just normal?
Is it the same with codom and dom.
Ex: Spider x normal = 50% spider 25% het spider 25% normal
Pastel x normal = 50% pastel 50% het pastel
Ive heard spider is a codom morph but if I am wrong please correct me.
Is this correct or am I way off?

Spider is dominant. There is no such thing as a het spider.

When you breed doms by normals, the ODDS* are that you will be get 50% morphs and 50% normals.

The normals are normals and will never be anything but normals. They are not het for anything.

*Remember, this is a game of chance, just like flipping a coin. You could just as easily get all normals or all morphs. Pray to the morph gods!

There is also no such thing as a het pastel.

It either is or isn't visual when you are talking about co-dom mutations.

Thats what I thought but wasnt 100% sure. Thanks for clearing that up for me

one other questions. So there are no het codoms but are there het dominants or just het recessives?

Just het recessive....... FYI..I had 5 eggs from a spider x normal and all 5 were normal :( but the 5 babies are hotttttttt

Just het recessives.

Ok I think my confusion is gone now, thanx for clearing everything up for me

Well let's see if I can't get you confused again, lol.

All pastels and probably all spiders are heterozygous for their respective mutant genes. There are still a lot of ball python keepers who use the terminology from the previous posts but I believe this is more technically correct and in the long run will be less confusing. If you haven’t already learned it the other way you might as well learn this way. I think those who have learned it the other way will eventually need to switch as combinations get more complicated.

You asked about a mutation type (Dom). Here are the definitions of the mutation types.

Recessive, co-dominant, and dominant just tell you what the heterozygous animals look like in relation to the homozygous normal and the homozygous mutant.

Recessive: The hets look normal and only the homozygous mutant are visable morphs. Example - albino, the hets look normal and the only albino looking ones are homosygous for albino.

Co-dominant: Both the hets and the homozygous are visable morphs but look different from each other. Example - pastel, the hets have the pastel apperence and the homozygous have the super pastel apperence.

Dominant: Both the hets and the homzoygous are visable mutants but they look the same. No publicly proven ball python examples yet but there are suspicions that pinstripe and/or spider might be dominant. Will a homozygous proven through breeding results to be sure.

IMHO a better way to predict what something will produce is to break it down to its genotype because the same inheritance rules for genotypes work regardless of the mutation type. As the combinations get more complicated working with genotypes will be much easier to keep straight.

Here are the definitions of the genotypes.

Heterozygous: Having an unmatched pair of whatever gene you are talking about. It just happens to work out with recessive mutations that the hets look normal but if you understand that the pastel phenotype has the heterozygous for pastel genotype than you see why it has a 50% chance of passing the pastel mutant copy of the gene to its offspring and a 50% of passing the normal for pastel version. It has both versions and randomly picks one to pass to each offspring.

Homozygous: Having a matched pair of whatever gene you are talking about. Since both copies of a super pastel's genes at the pastel location have the pastel mutation you can see why it can only give that version - it doesn't have a normal for pastel version to give.

Once you understand genotypes it's easy to figure the offspring of crosses like pewter X killer bee in you head. Start out by breaking each parent down to its genotypes:

pewter = het pastel and het cinnamon
killer bee = homozygous pastel and het spider

Then you can apply the same basic genotype rules to each gene independently:

het X normal for that gene = 50% het and 50% normal
homozygous X normal for that gene = 100% het
het X het = 25% homzoygous, 50% het, 25% normal for that gene
hozygous X het = 50% homozygous and 50% het

So from a pastel perspective this is a het X homozygous breeding so 50% homozygous pastel and 50% heterozygous pastel.

From a cinnamon perspective this is het X normal (for cinnamon) so 50% het cinnamon and 50% normal for cinnamon.

From a spider perspective this is het X normal so 50% het spider and 50% normal for spider.

Since the genes are all independent you can just overlay the results:

12.5% super pastel cinnamon spider
12.5% super pastel cinnamon
12.5% super pastel spider
12.5% super pastel
12.5% pastel cinnamon spider
12.5% pastel cinnamon (aka pewter)
12.5% pastel spider (aka bumble bee)
12.5% pastel

for the general case of a dominant x normal I believe you have two possible cases:

pure morph x normal = 75% showing, and 25% normal. More specifically, you'd get 25% "pure", 50% het, and 25% normal. But, since its a dominant morph, 75% with show the trait.

het morph x normal = 25% het, 75% normal. For a dominant gene, you would have 25% showing the trait.

Correct?

nope... now that I read Randy's post in more detail I realize I made a mistake.

homozygous x normal = 100% het. all would show the trait for a dominant gene.

Quote:

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Originally Posted by ladywhipple02

Spider is dominant. There is no such thing as a het spider.
When you breed doms by normals, the ODDS* are that you will be get 50% morphs and 50% normals.

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How can this be true? I can see that there would be no outward difference between a pure and het dominant. However, the snake can still carry either one or two copies of the morphed gene, right?

so if 25% are normal and 50% HET how do you tell the difference.

Quote:

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Originally Posted by bearhart

for the general case of a dominant x normal I believe you have two possible cases:

pure morph x normal = 75% showing, and 25% normal. More specifically, you'd get 25% "pure", 50% het, and 25% normal. But, since its a dominant morph, 75% with show the trait.

het morph x normal = 25% het, 75% normal. For a dominant gene, you would have 25% showing the trait.

Correct?

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By "pure" do you mean homozygous? In which case, per your later posts homozygous X normal does produce 100% hets just looking at the genotypes for the breeding results. You can then come along afterward and apply the mutation type and figure out that for a dominant mutation the hets look like their homozygous parent but have a different genotype so will have different breeding results when they are grown up and bred.

Het X normal would however produce eggs with a 50% chance of being hets and a 50% chance of being normal regardless of the mutation type but being a dominant type the hets would show.

The belief that "het" only applies to normal looking recessive hets I think goes back to the recessive snake morphs being where most of us first learned the term het. Outside of snakes, het is understood to mean having an unmatched pair of genes and doesn't necessarily tell you what the animal looks like (without knowing the mutation type) but is very useful in understanding its breeding results. By knowing that it has two different types to choose from you can see that each offspring has a 50/50 chance as to which version of the gene (in our case mutant or normal) it gets.

Quote:

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Originally Posted by RandyRemington

By "pure" do you mean homozygous? In which case, per your later posts homozygous X normal does produce 100% hets just looking at the genotypes for the breeding results. You can then come along afterward and apply the mutation type and figure out that for a dominant mutation the hets look like their homozygous parent but have a different genotype so will have different breeding results when they are grown up and bred.

Het X normal would however produce eggs with a 50% chance of being hets and a 50% chance of being normal regardless of the mutation type but being a dominant type the hets would show.

The belief that "het" only applies to normal looking recessive hets I think goes back to the recessive snake morphs being where most of us first learned the term het. Outside of snakes, het is understood to mean having an unmatched pair of genes and doesn't necessarily tell you what the animal looks like (without knowing the mutation type) but is very useful in understanding its breeding results. By knowing that it has two different types to choose from you can see that each offspring has a 50/50 chance as to which version of the gene (in our case mutant or normal) it gets.

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yea by "pure" I mean homozygous. I want to abbreviate like "het" but I can't bring myself to use "homo" since that's pretty much taken. :rolleyes:

But, yes I see my error now which is really the same as my original mistake. I was applying an even 25% chance to each gene, forgetting that the offspring has to have one from each parent.

Quote:

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Originally Posted by NateDogg13

Dom x Normal = 50% showing morph

What my question is if you breed a dominant form to a normal and you get 50% showing are the others het for that morph or are they just normal?
Is it the same with codom and dom.
Ex: Spider x normal = 50% spider 25% het spider 25% normal
Pastel x normal = 50% pastel 50% het pastel
Ive heard spider is a codom morph but if I am wrong please correct me.
Is this correct or am I way off?

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pastel is a co-dominant gene but can be considered "het for super pastel" because breeding pastel x pastel may give you the dominant gene super pastel. if a pastel is bred to a normal then you will get 50% chance of pastels and 50% chance of normals. the normals are not het for anything.

spider is considered a dominant gene because there is no super form when spider x spider are bred. if a spider is bred to a normal then you will get 50% chance of spiders and 50% chance of normals. the normals are not het for anything.

[QUOTE=bigballs;662850]pastel is a co-dominant gene but can be considered "het for super pastel" because breeding pastel x pastel may give you the dominant gene super pastel. QUOTE]

Sorry to nitpick but the pastel mutation doesn't change from the co-dominant type to the dominant type when you are looking at a super pastel. The mutation type stays the same - co-dominant. It's the genotype that changes from heterozygous when looking at a pastel to homozygous when looking at a super pastel. The misuse of "dominant" for homozygous is very common and I believe may have even been published but adds to the confusion.

I know this has come up before...but isn't it kind of weird that there is no homozygous form of Spider? How is this possible, genetically speaking? The mother and father each give one copy of a gene to the child. If both parents were spiders (had one copy of the spider gene) then isn't there a 25% chance the offspring should inherit both copies? Is it the case that the homozygous form is lethal/ends up in slugs or is the gene located in such a way that two copies aren't possible??

If two copies were possible, then theoretically these homozygous spiders should produce ALL spider offspring when bread to a normal, and I know of no such spider existing.

JonV

Quote:

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Originally Posted by nevohraalnavnoj

I know this has come up before...but isn't it kind of weird that there is no homozygous form of Spider? How is this possible, genetically speaking? The mother and father each give one copy of a gene to the child. If both parents were spiders (had one copy of the spider gene) then isn't there a 25% chance the offspring should inherit both copies? Is it the case that the homozygous form is lethal/ends up in slugs or is the gene located in such a way that two copies aren't possible??

If two copies were possible, then theoretically these homozygous spiders should produce ALL spider offspring when bread to a normal, and I know of no such spider existing.

JonV

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This is pretty much what was just said. A homozygous morph bred with a normal with produce 100% hets. In the case of a dominant gene, all of the offspring will show the mutation.

this helps out a lot...

http://www.ballpythons.ca/what_get/co_dominant.html


http://www.ballpythons.ca/what_get/dominant.html


http://www.ballpythons.ca/what_get/recessive.html

Good luck!

Why there isn't a public proven homozygous spider 8 years into the project is a mystery. Possibilities I can think of include:

1. Just not enough interest in producing and proving one. When a stunning super spider wasn't produced quickly and so many nice spider combos where I suppose it's natural that not many (any?) spider X spider crosses are done any more. I just got my first pair of spiders this year (I decided to buy the female from myself for what I'd have to mark her down to sell) but was just thinking about if I'd breed her to the male to try to get a possibly disappointing answer or to a pastel and go for known stunning bees. I've got a year at least to decide but it will be hard to breed her to the male spider.

2a. The 25% chance homozygous spiders from spider X spider don't hatch. If homozygous spider is a lethal genotype then hard to say if it could happen early enough to even prevent shelling so as not to produce a noticeable 25% bad eggs ratio (which would actually be pretty hard to notice in a small number of ball python clutches anyway).

2b. The 25% chance homozygous spiders from spider X spider are not breedable and/or in some way not publicly presentable. In this scenario, maybe they look just like normal spiders but are infertile so can't be proven. Alternatively, maybe they are a train wreak chalked up to a birth defect and not talked about or perhaps they even breed but again aren't shown for some reason of appearance or behavior.

I'm sure there are other valid theories (a conspiracy to prevent homozygous spiders from being produced and flooding the market quicker) but the odds seem lower and lower down the list. Maybe we'll have an answer by the 2009 season and the 10th anniversary of the cb spider.