Testing skin swabbing for DNA sampling in dendrobatid frogs

Skin swabbing, a minimally invasive DNA sampling method recently proposed for adult amphibians, was tested on the dendrobatid frog Allobates femoralis. I compared DNA yield from skin swabs and toe clips by evaluating obtained DNA concentrations and purity of extracts, as well as amplification success using eleven polymorphic microsatellite loci. I also tested whether storing skin swabs for two months at -20°C affected the properties of the extract or microsatellite analysis. Results show that skin swabs of adult A. femoralis suffered from high contamination and yielded significantly lower DNA quality and quantity, resulting in insufficient genotyping success, than DNA obtained from toe clips. The relatively dry skin in dendrobatid frogs may have impeded the collection of sufficient viable cells, and the presence of skin alkaloids and microbiota in the frog mucus may lead to high contamination load of skin swabs.