Species Characterization and Hybrid Investigation in Juvenile Spiny Lizards (Sceloporus spp.) by Genetic Sequencing

Abstract

Identifying species accurately can be difficult. This can be especially true in groups that have many species, or multiple species that are similar in how they look or where they live. The focus of this study is on lizards in the genus (group marked by similar characteristics) Sceloporus, or spiny lizards, which is the most diverse genus in the family Phrynosomatidae. Given the number of species in the genus, and areas of range overlap, species identification can be difficult. Here I demonstrate how molecular tools can be used to identify juvenile (individuals who have not yet met sexual maturity) and hatchling Sceloporus species using different sources of molecular data, and how they can be analyzed to reliably identify unknown species and investigate possible novel hybrid individuals. I sequenced nuclear and mitochondrial DNA, and analyzed genomic-scale data to inform species identification in this group. Genetic sequencing of a mitochondrial and nuclear gene revealed the identity of the unknown species as well as the identity of a possible novel hybrid (offspring produced from parents of different species), since different species have subtle differences in their gene sequences. The most parsimonious conclusion from these results is the unknown, possible hybrid, individual is a Sagebrush lizard (S. graciosus) given that both gene trees place the unknown specimen within this group, rather than one gene from each of the two species. These methods and techniques can be used in the genus broadly to reliably identify species at stages of development when morphological features unique to each species have not yet developed. The consistent data produced indicates the usefulness of these methods in future studies where species identity is in question, and relatively inexpensive and straightforward single-gene phylogenies may be enough for reliable identification.