The Origin and Evolution of Parthenogenesis in Heteronotia binoei (Gekkonidae): Genetic Diversity among Bisexual Populations

Abstract

Variation in chromosomes and allozymes was assayed among bisexual populations of the genus Heteronotia. Three major cytotypes of H. binoei, A6, A6-2, and SM6, are recognized on the basis of variation in the morphology of chromosome 6. The A6 and A6-2 cytotypes can be further subdivided into a series of karyomorphs by polytypic variation in the distribution of C-band heterochromatin. Allozyme comparisons revealed little differentiation, with few fixed differences and many shared polymorphisms among the chromosome groups. In a phenetic analysis, geographically widespread samples from the SM6 cytotype clustered together, as did CA6 karyomorph samples. Karyotypes and allozymes were also assayed from representatives of H. spelea and an undescribed form of Heteronotia. Phylogenetic analysis of chromosome data supported monophyly of the SM6 cytotype, but suggested that the A6-2 cytotype, and thus H. binoei as currently defined, is paraphyletic. At least five groups, most of which should be considered as species, can be delineated within Heteronotia: H. spelea, an undescribed form, SM6 H. binoei, A6-2 H. binoei, and other H. binoei. The genetic data are consistent with Heteronotia being a relatively recent member of the Australian herpetofauna, but indicate greater diversity than has been recognized previously.