Methods to maximize environmental DNA (eDNA) for detection the presence of Alligator Gar (Atractosteus spatula)

Abstract

Introduction of alligator gar (Atractosteus spatula) into a new range of its distribution has been reported in several freshwater ecosystems. The presence of alligator gar in Indonesia has been recorded in Jakarta during big flood in 2007. The concern about introducing this species is because of its predatory behavior and can impact the trophic system in freshwater ecosystem in its non-native range. Here, we demonstrated two methods, conventional and kit method, to maximize eDNA concentration in addition to detect the presence of alligator gar in freshwater ecosystem. We used mesocosm study to mimic the real condition of freshwater system in tropic region. We found that both methods can extract eDNA from water samples. The kit showed better yield of eDNA with average concentration 62.28 ± 22.27 ng/μL than conventional method with average concentration 19.35 ± 9.89 ng/μL. Another advantage of the kit method was better purity of eDNA, with average purity 1.92 ± 0.05 compared to conventional method with average purity 2.23 ± 0.42. The better concentration and purity of eDNA could be advantageous for further analyses such as PCR and DNA sequencing.