Origin of the unisexual lizard Gymnophthalmus underwoodi (Gymnophthalmidae) inferred from mitochondrial DNA nucleotide sequences.

Analysis of variation in nucleotide sequences in mitochondrial DNA genes among species of Gymnophthalmus supports three major conclusions. First, samples of G. underwoodi, a unisexual species of hybrid origin, have identical nucleotide sequences, supporting the hypothesis that all individuals from localities in the Guianan Region of South America and the Lesser Antilles descended from a single hybridization event. Second, G. underwoodi and G. cryptus share derived similarities in nucleotide sequences of the maternally inherited mitochondrial DNA, suggesting that the female participant in the hybridization event that produced the hybrid species was either G. cryptus or most closely related to it. Last, phylogenetic analyses recovered historical structure among population samples of G. speciosus supporting previous claims that there is unrecognized diversity under that binomial, and some analyses suggest that G. speciosus does not comprise a natural group.