Genes generally come in pairs, one from each parent. Then when the animal breeds it passes on one of each of its pairs to each of its offspring. For any given gene pair about half of the offspring get one copy and the rest get the other copy.



Heterozygous means having an unmatched pair of genes. We are mainly interested in mutations which are unusual versions of a particular gene. A heterozygous for albino ball python has an unmatched pair of genes at the albino gene location. It inherited a normal for albino gene from one of its parents but from the other parent it inherited a copy with the albino mutation. Most ball pythons have a matched set of normal for albino genes at that location so would have the homozygous normal for albino genotype.



However, the albino mutation is recessive. That means that even just one normal for albino copy can compensate for one albino mutant copy and cause the heterozygous for albino snakes to look normal. The only visible albino phenotype animals are the ones that are homozygous for albino (having a matched set of genes at the albino location both with the albino mutation).



So, if you breed a heterozygous for albino snake to a homozygous normal for albino all the babies will get the normal for albino version of the gene from the homozygous normal parent because that's the only version that parent has to give. The heterozygous parent will randomly give the albino mutant copy to about half the offspring and its normal for albino copy to the other half. So, on average about half the offspring from het albino X normal for albino will be het albino and the other half will be completely normal for albino. Because albino is recessive the het offspring will look normal just like the het parent so as a group the babies will be referred to as 50% chance hets although in reality each will either be a het or not it's just that you can't tell short of breeding them which are which.



There will not be any visible albinos produced because that would require two copies of the albino mutant version of the gene and it's only available to inherit from one parent. Because the albino gene is not sex linked it doesn't mater which parent is the het albino and which the normal for albino.

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