Phylogenetics of the Borage Family: Delimiting Boraginales and Assessing Closest Relatives

Abstract

The placement of Boraginales, and relationships within the family have remained elusive in modern, broad phylogenetic studies. In order to assess the phylogeny of Boraginales, and specifically to test the sister lineage of the order, a data matrix of the chloroplast markers rbcL, ndhF, and trnL-trnF was assembled fromGenBank and de novo sequences (representing 132 newGenBank accessions). Phylogenies inferred using Maximum Likelihood and Bayesian frameworks resulted in identical topologies. Tests for alternative topologies were used to assess whether any of the candidates for sister (Solanales, Gentianales, Lamiales, or Vahlia) to Boraginales could be ruled out with this dataset. Gentianales was eliminated as the possible closest relative to Boraginales. Additionally, SH tests were used to test topological results within Boraginales: monophyly of Hydrophyllaceae cannot be rejected and paraphyly of Ehretiaceae with respect to the parasitic Lennoaceae is supported. Taxonomic implications are discussed within the context of these phylogenetic results.