The phylogeography of the southeastern species of the genus Dalea L. (Fabaceae) using a molecular approach.

Abstract

The genus Dalea (Fabaceae) consists of approximately 160 species with a few species being geographically widespread, and most of the genus being endemic to restricted areas with calcareous substrates. A previous study (McMahon and Hufford, 2004) looked at the phylogeny of the tribe which Dalea belongs to, Amorpheae, and one other phylogenetic study (Diggs, 2013) has been conducted on several species in the genus itself, mainly from the mid-west and coastal plains of Alabama. This study focuses on the phylogeny and phylogeography of Dalea species from the Gulf Coastal Plain, including D. carnea, D. floridana, D. feayi, D. pinnata var. pinnata,D. pinnata var. trifoliata, D. adenopoda, D. mountjoyae, and D. albida compared to two species in the genus Amporpha (Fabaceae) a closely related genus. Phylogeny for Dalea will be determined by DNA sequences taken from the plastid trnK/matK intron, and the nuclear ribosomal ITS1, 5.8S, and ITS2, and compared to sequences obtained from previous phylogenetic studies of Dalea. DNA sequences from all specimens have been obtained for the nuclear loci ITS1 and a majority for matK. Bayesian analysis was performed using MrBayes, and the species we studied grouped with other east coast species. D. floridana falls out as a sister group to D. carthagenesis as it should since D. floridana was once a variety of D. carthagenesis. Both varieties of D. pinnata fall out as separate taxa with 100% probability. D. feayi & D. albida form a polytomy with the D. pinnata group, and warrants further study.