Protein and RNA extraction from mucosal swabs: a minimally invasive source of ecological data for studies of natural populations

1.Mucosal swabs have long been used to study various physiological processes in humans. In contrast, systematic sampling of mucosae is rare for wild animals, and except for its use as a source of DNA for population genetics, its potential as a tool to study physiologically-relevant processes of natural populations has not been explored fully. 2.We collected swabs from the rectal, genital, nasal and oral mucosae of California sea lion pups and investigated differences in RNA and protein yield, quality, and integrity between storage times and mucosal types. Downstream applications were tested on the extracted products to determine the potential value of mucosal sampling in free-ranging mammals. 3.For most samples, RNA yield was stable regardless of storage time, and RNA quality and integrity was equal for all mucosal types. Ribosomal fragments of sizes expected for mammals, yeast and bacteria were observable in genital and rectal samples, but in nasal and oral samples only bacterial ribosomal fragments were observable. Amplification of selected transcripts was successful for all samples. The protein profile was distinct between mucosae, and samples with high protein yields were useful for antibody detection. 4.Our study demonstrates that mucosal swabbing is a minimally-invasive tool that yields useful physiological data for free ranging wildlife. Minimum experience is needed to collect samples, processing is inexpensive and downstream applications for ecological studies are realistic. This article is protected by copyright. All rights reserved.