Whats 66% het?

I’m just getting into reptiles. Trying to learn all the terms and lingo. Im trying to understand the genetics world of it and im getting confused on 66% het. You have 100% het if you know for sure they carry the gene. 50% het if your not sure they carry. Whats 66%?

The same thing as 50%, but with a higher chance of them carrying it.

How do you determine between 50 and 66 though?

If you breed 2 100% hets and get a normal, then that animal is 66% het. I recommend using the MM genetic calculator to learn how hets work in combos.


Alright thank you

And I do want to add, even at rare occurrences 100% het may not prove out. It’s not a guarantee but usually if you buy from a honest breeder, 100% hets will prove out.


This video from @mutation_creation will help you out a lot.


If you breed one 100% het to a non het animal, each of their offspring will have a 50/50 chance of also getting the one parent’s het. Pair two with the same 100% het het recessive and you will get some visual morphs but all the ones not showing the recessive gene, will have a 66% chance of carrying it. I admit that I suck at math and 66% has always seemed an odd number to me but that’s what it breaks down to, since they have the chance of getting it from either of the parents.

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You have to go back and think about your high school bio class when you learned about genetics, Gregor Mendel’s pea plants and recessive vs dominant traits. If you have a snake that is a “het” it is heterozygous for a specific trait, which means it has one copy of gene that makes that trait, and one normal/wild type copy (two copies of each gene in total because chromosomes come in pairs). You will only see that specific trait if there are two copies of it in the same animal, because it is recessive.

If you cross two hets, each with one copy of the normal/wild type and one copy of the trait you want (such as piebald), you can draw a basic punnett square (like the one I quickly whipped up below) to figure out what the offspring will be. 1/4 will have two copies of the piebald gene, 1/2 will be hets, and 1/4 will be normals. However you cannot visually tell the difference between the hets and the normals, so each offspring that looks normal has a 66% chance of being a “het”


Awesome thanks guys it makes sense now