Real-time DNA barcoding in a remote rainforest using nanopore sequencing

Abstract

Advancements in portable scientific instruments provide promising avenues to expedite field work in order to understand the diverse array of organisms that inhabit our planet. Here we tested the feasibility for in situ molecular analyses of endemic fauna using a portable laboratory fitting within a single backpack, in one of the worlds most imperiled biodiversity hotspots: the Ecuadorian Choco rainforest. We utilized portable equipment, including the MinION DNA sequencer (Oxford Nanopore Technologies) and miniPCR (miniPCR), to perform DNA extraction, PCR amplification and real-time DNA barcode sequencing of reptile specimens in the field. We demonstrate that nanopore sequencing can be implemented in a remote tropical forest to quickly and accurately identify species using DNA barcoding, as we generated consensus sequences for species resolution with an accuracy of >99% in less than 24 hours after collecting specimens. In addition, we generated sequence information at Universidad Tecnologica Indoamerica in Quito for the recently re-discovered Jambato toad Atelopus ignescens, which was thought to be extinct for 28 years, a rare species of blind snake Trilepida guayaquilensis, and two undescribed species of Dipsas snakes. In this study we establish how mobile laboratories and nanopore sequencing can help to accelerate species identification in remote areas (especially for species that are difficult to diagnose based on characters of external morphology), be applied to local research facilities in developing countries, and rapidly generate information for species that are rare, endangered and undescribed, which can potentially aid in conservation efforts.