Piles of scats for piles of DNA: deriving DNA of lizards from their faeces

Non-invasive genetic sampling using scats has a well established role in conservation biology, but has rarely been applied to reptiles. Using scats from captive and wild Egernia stokesii (Squamata, Scincidae) we evaluated two storage and six DNA-extraction methods and the reliability of subsequent genotype and sequence data. Accurate genotype and sequence data were obtained from frozen and dried captive lizard scat DNA extracted using a QIAamp® DNA Stool Mini Kit and a modified Gentra® Puregene® method, but success rates were reduced for wild lizard scats. Wild E. stokesii eat more plants than their captive counterparts, possibly resulting in scat DNA extracts containing plant compounds that inhibit PCR-amplifications. Notably, reliable genotypes and sequences were obtained from wild E. stokesii scat DNA extracted using a Qiagen DNeasy® Plant Mini Kit, a method designed to remove plant inhibitory compounds. Results highlight the opportunity for using scat-derived DNA in lizard studies, particularly for species that deposit scats in piles.