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Multiple drainage reversal episodes and glacial refugia in a Patagonian fish revealed by sequenced microsatellites

Citation

Ruzzante, Daniel et al. (2020), Multiple drainage reversal episodes and glacial refugia in a Patagonian fish revealed by sequenced microsatellites, Dryad, Dataset, https://doi.org/10.5061/dryad.n8pk0p2s5

Abstract

The rise of the southern Andes and the Quaternary glacial cycles influenced the landscape of Patagonia, affecting the phylogeographic and biogeographic patterns of its flora and fauna. Here we examine the phylogeography of the freshwater fish, Percichthys trucha, using 53 sequenced microsatellite DNA markers. Fish (N=835) were collected from 16 river systems (46 locations) spanning the species range on both sides of the Andes. Eleven watersheds drain to the Pacific, five of which are trans-Andean (headwaters east of Andes). The remaining five drainages empty into the Atlantic. Three analytical approaches (neighbour-joining tree, hierarchical AMOVAs, STRUCTURE) revealed evidence of historic drainage reversals: Fish from four of the five trans-Andean systems (Puelo, Futalaufquen/Yelcho, Baker, Pascua) exhibited greater genetic similarity with Atlantic draining systems than with Pacific systems with headwaters west of Andes. Present-day drainage (Pacific vs. Atlantic) explained only 5% of total genetic variance, while ancestral drainage explained nearly 27% of total variance. Thus, the phylogeographic structure of Percichthys trucha is consistent with episodes of drainage reversal in multiple systems and suggests a major role for deglaciation in the genetic and indeed the geographic distribution of P. trucha in Patagonia. The study emphasizes the significant role of historical processes in the current pattern of genetic diversity and differentiation in a fish from a southern temperate region.

Methods

Fish field collections by gillnetting and electrofishing, microsatellite DNA markers identified by sequencing.

Funding

Natural Sciences and Engineering Research Council of Canada, Award: Discovery Grant

National Geographic Society, Award: NGS 6799-00 & NGS 8168-07

Universidad de Concepción, Award: DIUC-PATAGONIA 205.310.042-ISP & FONDECYT 1080082

Natural Sciences and Engineering Research Council of Canada, Award: SRPJ/326493-06

National Science Foundation, Award: 2010 NSF-PIRE (OISE 05300267)