Phylogeny of Tetraploid Catostomid Fishes Based on the Loss of Duplicate Gene Expression

Abstract

Ferris, S. D. and G. S. Whitt (Department of Genetics and Development, University of Illinois, Urbana, Illinois 61801) 1978. Phylogeny oftetraploid catostomid fishes based on the loss of duplicate gene expression. Syst. Zool. 27:189–206.—A distinctive property of polyploids, the loss of duplicate gene expression over time, allows phylogenetic inferences to be drawn from multilocus isozyme data. Once the “loss” of a duplicate gene expression has begun, soon after polyploidization, primitive and derived character states are clearly defined, though not immune to errors in coding. Even with a relatively small number of characters, cladistic, and phenetic trees may be constructed which are similar to each other and to those based on morphology. The Wagner method is shown to be a particularly appropriate method of analysis for handling gene duplication data. Comparison of patristic and phenetic distances has revealed little homoplasy for species in closely related genera of catostomid fishes, but increasing homoplasy for comparisons between more divergent taxa. With increasing employment of isozyme technology, and the concomitant increase in the number of characters it should be possible to analyze many other polyploid taxa with this cladistic technique.