Comparisons of the Chloroplast Genome within Pityopsis (Asteraceae)

Pityopsis includes several regionally and one federally endangered species of herbaceous perennials. Although three species are highly localized, four species are found throughout the eastern United States and the range of one extends into Mexico. Morphological studies have separated the genus into two distinct clades, but there have been few molecular studies and intrageneric relationships have not been fully resolved or understood. Additionally, all previous attempts lacked depth in sampling accepted varieties of the species. For this study, however, all seven species and their respective varieties were either collected from the wild or obtained from herbaria vouchers. After a chloroplast isolation process, chloroplast genomes were sequenced using an Illumina HiSeq Ultra Throughput Sequencing System. Sequences were aligned and compared using the MAFFT and IGV programs. In order to establish a robust phylogeny and resolve generic relationships, a phylogenetic tree was constructed and visualized using the program TREEVIEW and the Maximum Parsimony method. An additional tree using the Maximum Likelihood method was constructed to gain further insight and possible consensus. Chloroplasts are known to accumulate mutations more slowly than nuclear genomes, and therefore are considered more informative for genus-wide surveys. This study will help inform breeding and conservation practices, as well as general knowledge of ontology, hybridization, and speciation within Pityopsis.