Reptile & Amphibian Forums

Hello again all,

Since I'm new to snakes, I'm really not following all the breeding threads, but I'm interested. I don't mean to say that I'm interested in doing any breeding myself, but I would like to understand what you are all talking about when you say, for instance "double het" and what that means in terms of what the hatchlings will / may look like.

I wonder if anyone would mind giving me a brief layman's rundown or posting I link so I can bring myself up to speed?

Thanks in advance,
ITD

In simple mendalin genetics - a trait is governed by a particular gene pair.

The gene pair is said to be homozygous (or homo) if both genes in the gene pair are the same. The gene pair is said to be heterozygous (or het) if the two genes in the gene pair are different.

Most of the traits for which the terms are used have a dominant/recessive relationship. Usually the "normal" gene is dominant and the "morph" gene is recessive.

What this means - if both genes in the gene pair are the same and "normal" - the snake has the "normal" trait.

If the gene pair is heterozygous with a "normal" and "morph" gene - the snake displays the "normal" trait because it is dominant.

If both genes in that pair are the "morph" gene - then the snake displays the morph.

This snake of mine is heterozygous for amel albinism:

It looks like a normal banded california kingsnake, and the only way I know it is het for amel is because it has an amel mother, so it had to get an amel gene from the mother. It got a normal gene at that gene pair from the father, which is dominant - and that's why she looks normal. But she carries the amel gene and could produce some amel babies if mated with another snake that carries the ame; gene.

Double Het is a snake that has two gene pairs that are heterozgous. For example - the gene that causes ghost is a different gene pair than the gene that causes amel.

So if you bred a ghost with an amel, the hatchlings would be normal looking (not express ghost or amel) but carry both genes.

Not all traits are simple dominant/recessive - but many are.
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3.6 L. getula californiae (Cal. King)
1.1 L. getula nigrita (MBK)
1.0 Pantherophis guttatus guttatus (Corn)
1.0 Thamnophis sirtalis fitchi (Valley Garter)
1.0 Boa constrictor constrictor (suriname, fostering/rescue)
3.3 Elgaria multicarinata multicarinata (Cal. Alligator Lizard)

Sooooooooo... If I have this right, when the quadruple hets that Kerby is breeding for arrive mostly they'll be pretty normal looking, a few of them will display a recesive trait, a very few of them will display one or two recessive traits and if all goes well there exists a possibility that a very, very few of them will display four recessive traits.

Is that about right?

Actually I don't have a clue what they will look like.
There's some weird stuff.

Some guy in southern california bred two different lavender lines and got normals that were slightly hypo. The single hets for those lines looked normal but the double hets (het for both strains of lavender) were visibly different from normals. Not by much, but they were lighter.

I think it was NewAgeReptiles but I might be wrong.

It seems that not everything is simple.

There's also cases where two different mutations are from the same gene pair. Both are recessive to normal, but are codom or dom/rec to each other.

I *think* the PB brooksi and amel brooksi are that way - same gene pair. Both recessive to normal, but when bred together - they are codom. Bluerosy knows more about that. In that case though even though it is two different traits, since it is same gene pair it is only single het - but I assume single hets that can throw either PB or amel offspring (IE breed a jelly to jelly results in 25% amel, 25% PB, 50% jelly, no normals) - has that pairing been done? What happened?

Anyway - it's hard to say what they'll look like - I expect normal but it might not be.
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3.6 L. getula californiae (Cal. King)
1.1 L. getula nigrita (MBK)
1.0 Pantherophis guttatus guttatus (Corn)
1.0 Thamnophis sirtalis fitchi (Valley Garter)
1.0 Boa constrictor constrictor (suriname, fostering/rescue)
3.3 Elgaria multicarinata multicarinata (Cal. Alligator Lizard)