ALLOZYME CLADISTICS IN MALACOLOGY - WHY AND HOW

A hypothetical but plausible data set is introduced for which Mickevic h and Mitter's (1981, 1983) qualitative-coding, minimum-turnover cladi stic (= discrete parsimony) method accurately reconstructs phylogeny, whether rare alleles are detected or not, but for which both the UPGMA distance method and a hand-calculated application of Swofford and Ber locher's (1987) frequency-parsimony method give incorrect phylogenies. Mickevich and Mitter's (1981, 1983) method is outlined and demonstrat ed. When applying this method to 20 polygyrid genera using Hennig86 (F arris, 1988), two problems arose and were circumvented. First, allelic combinations occurred in complexly interrelated sets (interim solutio n: treat such sets as single character-states); and second, alternativ e character-state trees existed for each locus (solution: binary-code each alternative, then weight by the reciprocal of the number of alter natives). Cladistic analysis of the polygyrid-genera allozyme data (Em berton, 1994) ordered yielded the same topology as, but higher resolut ion than, when run unordered.