CUNYUS, V.L.; GOMEZ, A. L.; JOHNSON, G. W.; JOHNSON, J.D.; IRWIN, L.N.*: Taxonomic Utility of Random Genetic Variation in Lizards
We have used the randomly amplified polymorphic DNA (RAPD) technique to assess the utility of random genomic variation as a taxonomic trait at the Family level and below. We hypothesized that genomic similarity as measured by RAPDs would be greater within families than across families, and that the variation observed would predict phylogenetic relationships in agreement with traditional assumptions. DNA was extracted from members of the families Crotaphytidae (Crotaphytus collaris), Phrynosomatidae (Phrynosoma modestum, Sceloporus poinsetti, Urosaurus ornatus, and Uta stansburiana), Teiidae (Cnemidophorus tigris, C. tesselatus, and C. exsanguis), and Eublepharidae (Coleonyx brevis), amplified by PCR, and analyzed by agarose gel electrophoresis. Nei’s index of similarity was 33+15% for 7 pairwise comparisons within families, and 14+11% for 19 pairwise comparisons across families, a highly significant (U = 18.5, p = 0.003) difference. Using a similarity matrix based on the RAPD data, a phenogram was constructed that conforms to traditional assumptions about phylogenetic relationships among and within these families, except that Crotaphytus collaris clustered among the Phrynosomatidae. These results support the validity of random genomic variation as a useful taxonomic trait at the Family level and below, and suggest that the RAPD technique may disclose some relationships different from those based on other characteristics. Supported by grants from the RCMI (G12-RR0814) and Bridges to the Future programs of NIH. We thank Dr. Elizabeth Walsh for significant help and advice.