Lost Sex in the Reptiles: Constraints and Correlations

Abstract

Reptiles are the only truly parthenogenetic vertebrates, making it especially fascinating to understand how and why some reptilian taxa have broken free of sexual reproduction. In this review we consider the evolutionary and genomic constraints, consequences, and ecological correlations of reptile parthenogenesis, and how this informs us more generally about the loss of sex in organisms. In reviewing the taxonomic distribution of parthenogenesis we find that some lineages are particularly likely to evolve parthenogenesis (e.g., teiid lizards) and others biased strongly against parthenogenesis (e.g., colubrid snakes). Moreover, all but one of the natural cases also involves hybridization. The..