Phylogenetics and Biogeography of Nicotiana section Suaveolentes

Suaveolentes is the largest section in the genus Nicotiana (Solanaceae), widespread in Australia, ranging from a few species in more mesic areas in northern and eastern Australia to the great majority in semi-arid and arid regions, the Eremaean Zone. The origin of Suaveolentes appears to be a result of natural allopolyploidy accompanied by genome doubling, with the allotetraploid ancestor from this section presenting 24 pairs of chromosomes. However, the modern representatives species exhibit chromosome reductions, potentially associated with speciation. Due of the putatively recent origin of Suaveolentes and rapid radiation in the arid zone of Australia, the subject of this project is species evolution and biogeography in this section. We will use next generation DNA sequencing technologies (e.g. RADseq) to develop a phylogenetic and temporal framework from which to track their genomic evolution and their ability to grow in an area in which few other groups have radiated, which will help to establish some general principles about how such phenomena progress.