Well, I'll stick my oar in.

There is no such thing as het for Miami for the same reason there is no such thing as het for snow.

A heterozygous creature has different alleles at one or more corresponding chromosomal loci. A locus is heterozygous if the two alleles present at the locus are different.

The definition of "het for snow" requires two things - 1) two different alleles at 2) the locus where the "snow" mutant gene resides. A locus containing a normal gene paired with the snow mutant gene would be het for snow. But there is no mutant gene named "snow" and, therefore, no locus for it.

A corn snake can be heterozygous at the amelanistic locus or heterozygous at the anerythristic locus or even heterozygous at both the amelanistic locus and the anerythristic locus. But it can't be heterozygous at the snow locus because there is neither a snow mutant gene nor a snow locus.

I know that a lot of people use "het for snow" when they mean a snake that is heterozygous at both the amelanistic locus and the anerythristic locus. But that is slang and is technically incorrect.

Corns from a Miami x normal mating are probably heterozygous at one or more of the unknown number of loci involved in producing the Miami phenotype. But we have not been able to assign the Miami phenotype to a single mutant gene at a single locus. That's why there is no "het for Miami".

Paul Hollander

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