USING MONOCLONAL-ANTIBODIES FOR PHYLOGENETIC ANALYSIS - AN EXAMPLE FROM THE HELIOTHINAE (LEPIDOPTERA, NOCTUIDAE)

Vertebrate antisera have been used for phylogenetic analysis for > 85 yr by raising them against molecules from one taxon and reacting them with homologous molecules from other taxa in the groups under consideration. The reactions are evaluated quantitatively and are used to estimate immunological distances between taxa. The strength of these reactions reflects the summation of interactions between the individual antibodies making up the antiserum and the antigenic determinants they recognize on the molecule. The availability of monoclonal antibodies makes possible a new approach for immunological phylogenetic analysis because they recognize individual antigenic determinants that are either present or absent, thus qualifying as character states. We illustrate this approach with monoclonal antibodies to determinants on two larval plasma proteins from Helicoverpa zea (Boddie). The distribution of these two determinants is consistent with current thinking on the close relationship of H. zea and Heliothis armigera (Hubner), and supports the monophyly of those heliothines that we have tested. Immunoblotting may be used with this approach to support the homology of determinants in different taxa by confirming the identity of the molecules on which they reside, after the molecules have been characterized by such assays as native PAGE and isoelectric focusing.