Testing skin swabbing for DNA sampling in dendrobatid frogs

Area of Science:

• Amphibian genetics
• Molecular ecology
• Non-invasive sampling techniques

Background:

• Minimally invasive DNA sampling is crucial for wildlife research.
• Skin swabbing has been proposed as an alternative to traditional methods like toe clipping in amphibians.
• The effectiveness of skin swabbing can vary significantly across amphibian species.

Purpose of the Study:

• To evaluate the efficacy of skin swabbing as a DNA sampling method for the dendrobatid frog Allobates femoralis.
• To compare DNA yield, quality, and genotyping success between skin swabs and toe clips.
• To assess the impact of short-term storage on DNA extracted from skin swabs.

Main Methods:

• DNA was extracted from skin swabs and toe clips of Allobates femoralis.
• DNA concentration and purity were assessed spectrophotometrically.
• Amplification success was determined using eleven polymorphic microsatellite loci.
• Skin swab samples were stored at -20°C for two months prior to DNA extraction and analysis.

Main Results:

• Skin swabs yielded significantly lower DNA quantity and quality compared to toe clips.
• Skin swabs exhibited high levels of contamination, hindering microsatellite genotyping success.
• DNA from toe clips provided sufficient quality and quantity for successful microsatellite analysis.
• Storage of skin swabs at -20°C did not improve DNA extract properties or genotyping success.

Conclusions:

• Skin swabbing is not a suitable DNA sampling method for Allobates femoralis due to low DNA yield, poor quality, and high contamination.
• The dry skin and presence of alkaloids/microbiota in dendrobatid frogs likely contribute to the failure of skin swabbing.
• Toe clipping remains the preferred method for obtaining high-quality DNA for genetic studies in this species.