title: The evolutionary history of Xiphophorus fish and their sexually selected sword: a genome-wide approach using restriction site-associated DNA sequencing.
abstract: Next-generation sequencing (NGS) techniques are now key tools in the detection of population genomic and gene expression differences in a large array of organisms. However, so far few studies have utilized such data for phylogenetic estimations. Here, we use NGS data obtained from genome-wide restriction site-associated DNA (RAD) (∼66000 SNPs) to estimate the phylogenetic relationships among all 26 species of swordtail and platyfish (genus Xiphophorus) from Central America. Past studies, both sequence and morphology-based, have differed in their inferences of the evolutionary relationships within this genus, particularly at the species-level and among monophyletic groupings. We show that using a large number of markers throughout the genome, we are able to infer the phylogenetic relationships with unparalleled resolution for this genus. The relationships among all three major clades and species within each of them are highly resolved and consistent under maximum likelihood, Bayesian inference and maximum parsimony. However, we also highlight the current cautions with this data type and analyses. This genus exhibits a particularly interesting evolutionary history where at least two species may have arisen through hybridization events. Here, we are able to infer the paternal lineages of these putative hybrid species. Using the RAD-marker-based tree we reconstruct the evolutionary history of the sexually selected sword trait and show that it may have been present in the common ancestor of the genus. Together our results highlight the outstanding capacity that RAD sequencing data has for resolving previously problematic phylogenetic relationships, particularly among relatively closely related species.
authors.affiliation: Lehrstuhl für Zoologie und Evolutionsbiologie, Department of Biology, University of Konstanz, Universitätsstrasße 10, 78457, Konstanz, Germany.
authors.forename: Julia C
authors.initials: JC
authors.lastname: Jones
authors.forename: Shaohua
authors.initials: S
authors.lastname: Fan
authors.forename: Paolo
authors.initials: P
authors.lastname: Franchini
authors.forename: Manfred
authors.initials: M
authors.lastname: Schartl
authors.forename: Axel
authors.initials: A
authors.lastname: Meyer
mesh_terms: D000818:Animals; D001483:Base Sequence; D005075:Biological Evolution; D002489:Central America; D003532:Cyprinodontiformes / Q000145:classification / Q000235:genetics*; D019143:Evolution, Molecular; D005819:Genetic Markers; D049810:Genetic Speciation; D014644:Genetic Variation; D059014:High-Throughput Nucleotide Sequencing; D052586:Mating Preference, Animal; D010802:Phylogeny; D020641:Polymorphism, Single Nucleotide; D017422:Sequence Analysis, DNA
chemical_list: D005819:Genetic Markers