Journal Article

DNA capture reveals transoceanic gene flow in endangered river sharks

Straube, Nicolas, Yang, Lei, White, William T., Naylor, Gavin J. P., Harris, Mark, Li, Chenhong, Corrigan, Shannon, Hofreiter, Michael

2015

Overview

For over a hundred years, the “river sharks” of the genusGlyphiswere only known from the type specimens of species that had been collected in the 19th century. They were widely considered extinct until populations ofGlyphis-like sharks were rediscovered in remote regions of Borneo and Northern Australia at the end of the 20th century. However, the genetic affinities between the newly discoveredGlyphis-like populations and the poorly preserved, original museum-type specimens have never been established. Here, we present the first (to our knowledge) fully resolved, complete phylogeny ofGlyphisthat includes both archival-type specimens and modern material. We used a sensitive DNA hybridization capture method to obtain complete mitochondrial genomes from all of our samples and show that three of the five described river shark species are probably conspecific and widely distributed in Southeast Asia. Furthermore we show that there has been recent gene flow between locations that are separated by large oceanic expanses. Our data strongly suggest marine dispersal in these species, overturning the widely held notion that river sharks are restricted to freshwater. It seems that species in the genusGlyphisare euryhaline with an ecology similar to the bull shark, in which adult individuals live in the ocean while the young grow up in river habitats with reduced predation pressure. Finally, we discovered a previously unidentified species within the genusGlyphisthat is deeply divergent from all other lineages, underscoring the current lack of knowledge about the biodiversity and ecology of these mysterious sharks.

• Publisher: National Academy of Sciences,National Acad Sciences
• Subject: Adaptation, Biological - genetics / Animal Distribution / Animal populations / Animals / Aquatic habitats / Asia / Base Sequence / Biodiversity / Biological Sciences / Deoxyribonucleic acid / DNA / DNA, Mitochondrial - genetics / Endangered Species / Fish populations / Gene flow / Gene Flow - genetics / Glyphis / Hybridization / Likelihood Functions / Models, Genetic / Molecular Sequence Data / Northern Territory / Phylogeny / Rivers / Salinity / Sequence Analysis, DNA / Sharks / Sharks - genetics / Species Specificity