Shellsea Miller ’20 and Lauren Muskara ’21 presented their research on environmental DNA (eDNA), titled “A Snail out of Water: Hitting the Target on Primer Optimization for Apple Snails,” as a poster presentation at the annual meeting of the Society of Freshwater Science in Salt Lake City, Utah. Their work uses a molecular ecology application to detect the presence of nonnative apple snails. The work showcased started with SCOPE 2018 and continued through the academic year, during which both Muskara and Miller completed a number of novel experiments using the quantitative PCR thermocycler in the Keck Molecular Biology Center. This work represents part of the ongoing collaboration between Professor of Biology  Romi Burks and SU alum Matthew Barnes at Texas Tech University.

Conservation efforts increasingly rely on eDNA detection to sound an alarm for nonnative invasive species. However, successful invaders often include morphologically similar species. Detecting species with eDNA relies on understanding how amplification success varies across temperatures and how barcoding uses specific targets to identify species. To test for eDNA in water samples (250 mL), we developed primers designed to amplify a nonnative apple snail, Pomacea maculata. We used known sequences [Folmer region of cytochrome c oxidase subunit I (COI)] as the primer template to identify four candidate assays of varied amplicon length and location. All four initially worked on P. maculata, so we sought to confirm their specificity through experiments with tissue-derived DNA from other Pomacea species and other nonnative aquatic snails. We optimized our qPCR process by increasing annealing temperature in 2° increments so that our primers only amplified P. maculata at higher temperatures but other nonnative snails at lower temperatures. This work provides the first successful eDNA detection of apple snails and could help confirm the presence of one species (P. maculata), which often gets confused for a better-known invader that co-occurs across Asia (P. canaliculata).