Right, this is starting to get confusing, lol. Okay, Indeed alleles are variants of a locus. So, if there is a mutation from one allelic state to another, it is no longer the same allele, it is a new allele. Hence, there cannot be a mutation on the same allele, there are mutations of the same locus, i.e. variant alleles. Now, to get more confusing, theoretically one allele can mutate to another, already existing, allelic state. This is known as a homoplastic mutation, where the alleles are similar in structure, but not in origin. This, however, is unlikely to result in the phenotypic variation that exists between, for example, butters, platty's, Mojaves, etc.

Warren

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Dr Warren Booth
North Carolina State University
Department of Entomology
3309 Gardner Hall
Raleigh, NC 27695-7613

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