Pronounced genetic separation among varieties of the Primula cusickiana species complex, a Great Basin endemic

Distinguishing between populations with strong genetic structure and unique species is a common challenge in systematics, especially for taxa occurring in fragmented habitats where allopatric speciation may be widespread and distinct groups may be morphologically similar. Such is often the case with species complexes across sky island environments. In these scenarios, biogeography may help to explain the taxonomic relations between species complex members, and restriction site-associated DNA (RAD) sequencing methods are commonly used to compare closely related species across thousands of loci. Here we use RADseq to clarify the boundaries separating the geographically distinct but morphologically similar varieties of the Primula cusickiana species complex, and to contextualize past findings of strong genetic structure among populations within varieties. Our genetic analyses demonstrate pronounced separation between isolated populations of this Great Basin endemic, indicating that the cur...