A Comparison of Random Genetic Variation in Bisexual and Unisexual Lizards

JOHNSON, G.W. *; JOHNSON, J.D.; IRWIN, L. N.: A Comparison of Random Genetic Variation in Bisexual and Unisexual Lizards.

We analyzed genomic variation in three sympatric species of Teiid lizards of the genus Cnemidophorus that differ in reproductive structure and karyotype, to test the hypothesis that genetic variation is greater in parthenoforms than in sexually reproducing sister taxa. Genetic diversity within local populations of C. tigris (bisexual, 2N), C. tesselatus (unisexual, 2N), and C. exsanguis (unisexual, 3N) was analyzed by the randomly amplified polymorphic DNA (RAPD) technique. Using four different primers, Nei’s index of similarity ranged from 54% to 87% in the bisexual species and from 37% to 72% in the unisexual species. However, the differences were not statistically significant. The similarity index for Cophosaurus texanus, a bisexual sympatric lizard from a different family (Phrynosomatidae), ranged from 29% to 79%, and was also statistically indistinguishable from the three Teiids. Our results do not yet support the theoretical expectation that genomic variation increases with the evolution of parthenogenesis, at least over the relatively brief history of the hybrid species in this study. 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.

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