Exploring the utility of "next-generation" sequence data on inferring the phylogeny of the South American Valeriana (Valerianaceae)

Abstract

This study aimed to investigate the phylogenetic utility of genotyping-by-sequencing (GBS) data in the southern South American subclade of Valerianaceae (Dipsacales). The variety of forms that has arisen in this clade, presumably over the past 5-10 million years, has all the signatures of an adaptive and rapid radiation. While the phylogeny of Valerianaceae has received a great deal of attention in the last decade, species relationships have been hard to resolve using traditional phylogenetic markers. Here, we collected high-throughput genomic sequence data from reduced-representation libraries obtained through GBS protocols. Putative orthologs were identified using within- and among-sample clustering using the computer software pyRAD. We recovered over 3000 loci for 14 species of southern South AmericanValeriana,with 140 loci present across all samples.We analyzed a set of phylogenetic trees generated from each locus using maximum likelihood methods, as well as multispecies coalescent (∗BEAST) methods. For comparative purposes, we also used a supermatrix approach to infer the phylogeny for these taxa. Across different methods and data sets, we recovered consistent relationships for the southern South American valerians that we sampled with varying degrees of support.

Keywords: GBS; Multispecies coalescent; Rapid radiation; Valeriana; Valerianaceae.