This study used molecular phylogenetic methods to attempt to resolve the taxonomic status of the federally threatened East Texas-endemic wildflower, the Neches River Rose Mallow (Hibiscus dasycalyx). Hibiscus dasycalyx co-occurs with two other closely related congeners that are currently not of conservation concern: the halberdleaf rose mallow (H. laevis); and the crimson-eyed rose mallow (H. moscheutos). This study assessed the phylogeny of these three Hibiscus species, and attempted to determine if there is possible hybridization occurring between them. To this end, Restriction Site Associated DNA Sequencing (RAD-Seq), a Next Generation Sequencing method, was used to generate genome-wide polymorphic genetic data. Two phylogenies were constructed utilizing Maximum Likelihood and Bayesian coalescence approaches. The Maximum likelihood phylogeny identified H. dasyclayx, H. laevis, and H. moscheutos as distinct monophyletic taxa. The Bayesian coalescence approach suggested H. moscheutos is a monophyletic sister clade to Hibiscus laevis, but suggested that H. dasycalyx and H. laevis are one monophyletic group and that H. dasycalyx is paraphyletic. AMOVAs did not show significant levels of admixture occurring between H. laevis, H. moscheutos, and H. dasycalyx. Bayesian clustering implemented in STRUCTURE was used determine the species relationships and gene flow between species, and revealed that H. dasycalyx clusters separately from H. laevis, and that the two species were differentiated from each other in this analysis with no evidence of admixture. The results overall do not have enough support to suggest the need, nor at the same time discredit a reclassification of H. dasycalyx. Further analysis of H. dasycalyx and H. laevis are needed to help better understand the taxonomic relationship between them.
Date of publication
Dr. Joshua Banta, Dr. Kate Hertweck, Dr. John S. Placyk Jr.
Master of Science in Biology
Norrell, Julia, "DIFFERENTIATING THE NECHES RIVER ROSE MALLOW (HIBISCUS DASYCALYX) FROM ITS CONGENERS BY MEANS OF PHYLOGENETICS AND POPULATION GENETICS" (2017). Biology Theses. Paper 43.