After reading over most of the posts below, I thought of a possibility that does not seem to have been suggested.

What if there are three possible alleles for the amel locus? Let's call the three alleles normal, amel, and extreme.

If so, the gene pairs and their possible appearance could be as follows:
normal//normal = normal
normal//amel = looks normal
normal//extreme = looks normal
extreme//extreme = extreme to dark extreme
amel//amel = amel
extreme//amel = extreme to light extreme

Testing this idea would include mating an extreme to a relatively unrelated amel. The expectation would be either all extreme or 1/2 extreme and 1/2 amel. If any normals hatch out, then the idea can be rejected.

Disclaimer: This is not a new idea. This sort of thing has already been suggested for cases in the black rat snake, corn snake, and boa constrictor. Multiple alleles have been known for a century in mammals.

Paul Hollander

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