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I have been reading The Complete Ball Python trying to brush up on my morphs & genetics. While reading it, I thought about something that didn't make sense. This is probably a dumb question, but here it goes:

Both Spiders and Super Pastels are listed as dominant genes. When you breed a Super P to a normal, you get all Pastels. When you breed a spider to normal, you only get 1/2 spiders though, right? Why are spiders not considered co-dom? Because there is no super form?

>>I have been reading The Complete Ball Python trying to brush up on my morphs & genetics. While reading it, I thought about something that didn't make sense. This is probably a dumb question, but here it goes:
>>
>>Both Spiders and Super Pastels are listed as dominant genes. When you breed a Super P to a normal, you get all Pastels. When you breed a spider to normal, you only get 1/2 spiders though, right? Why are spiders not considered co-dom? Because there is no super form?

Exactly,because there is no super form....The term super is sort of a breeder slang for a "complete dominant",whereas a regular pastel(one allele)is actually an "incomplete dominant".
So the spider kind of threw a monkey wrench into the slang terms,since no super spider was produced.
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Charles Glaspie

Spiders are considered a Dominant Gene.
Spider X Normal =
1/2 normals and half spiders.
Spider X Spider does not make any super...at least not a visual super. And I have seen no evidence yet of a non-visual super either.
(Co-dom Boa morphs like the Hypos and Super-Hypos can be "non-visual" Homozygeous traits. You can't easily tell which one is the super...without raising it up and breeding it out.)

Super Pastels are the Homozygeous/Super form of the co-dominant
Pastel trait.

Super Pastel X normal ALL PASTELS.

does that help answer your question?

Harlin Wall - WALL TO WALL REPTILES!
970-245-7611

Should have read:

Super Pastel X normal = All Pastels.

I'm sure someone has a homozygous spider -cough-NERD-cough- and just hasn't said anything yet.
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"What is man without the beasts?
If all the beasts were gone,
men would die from great loneliness of spirit.
For what happens to the beasts,
soon happens to men.
All things are connected."

-Chief Seattle (Duwamish Tribe)

"Both Spiders and Super Pastels are listed as dominant genes."

That maybe using "dominant" to mean anything that isn't recessive; as in “it could be either co-dominant or completely dominant but at least it's some type of dominant".

"When you breed a Super P to a normal, you get all Pastels. When you breed a spider to normal, you only get 1/2 spiders though, right? Why are spiders not considered co-dom? Because there is no super form?"

You might be falling into a common confusion where dominant/co-dominant are used where homozygous and heterozygous should be.

A super pastel X normal produces all pastels because a super pastel is homozygous for the pastel mutation. Homozygous means that it has two of the same versions of the pastel gene – in this case the mutant version. So a homozygous pastel passes the pastel mutation to 100% of its offspring because it has no other version to give.

A “normal” pastel is heterozygous for the pastel mutation. Heterozygous means it has an unmatched pair of versions of the pastel gene, one mutant and one normal in this case. For this reason each offspring of a pastel has a 50/50 chance of getting the mutant version. The pastel randomly selects which of it’s two versions to give each offspring and about half get the normal for pastel version.

The pastel mutation is classified as co-dominant because both the heterozygous and the homozygous mutant versions are morphs but look different from each other. It doesn't mater if you are looking at a normal pastel (heterozygous for the pastel mutation) or a super pastel (homozygous for the pastel mutation); the mutation type is co-dominant. It's actually the relationship between the two that defines it as co-dominant. The mutation type does not change with the animal like the heterozygous/homozygous status can from one pastel line animal to the next.

Spiders are heterozygous for the spider mutation of the spider gene. They have one spider mutant version and one normal for spider version so when bred to normals produce eggs with 50% odds of hatching spiders. If a homozygous spider was ever produced and proven to be homozygous by breeding and turned out to be in all ways except breeding results the same as a heterozygous spider then spider would be classified as a completely dominant mutation. Again, it would be the relationship between the heterozygous and the homozygous mutant animals that would define the dominant mutation type. It would be incorrect to call a homozygous spider the dominant form and the heterozygous spider the co-dominant form as those are terms for mutation type and that doesn't change from animal to animal.