Employing hypothesis testing and data from multiple genomic compartments to resolve recalcitrant backbone nodes in itGoodenia/it s.l. (Goodeniaceae)

摘要

Goodeniaceae is a primarily Australian flowering plant family with a complex taxonomy and evolutionary history. Previous phylogenetic analyses have successfully resolved the backbone topology of the largest Glade in the family, Goodenia s.l., but have failed to clarify relationships within the species-rich and enigmatic Goodenia Glade C, a prerequisite for taxonomic revision of the group. We used genome skimming to retrieve sequences for chloroplast, mitochondrial, and nuclear markers for 24 taxa representing Goodenia s.l., with a particular focus on Goodenia Glade C. We performed extensive hypothesis tests to explore incongruence in Glade C and evaluate statistical support for clades within this group, using datasets from all three genomic compartments. The mitochondrial dataset is comparable to the chloroplast dataset in providing resolution within Goodenia Glade C, though backbone support values within this Glade remain low. The hypothesis tests provided an additional, complementary means of evaluating support for clades. We propose that the major subclades of Goodenia Glade C (C1-C3 + Verreauxia) are the result of a rapid radiation, and each represents a distinct lineage.