XVI International Botanical Congess

We have recently identified a lineage of angiosperms whose substitution rate is between 50-100 times higher than those of typical, slowly-evolving plant mitochondrial genomes. Using the cytochrome oxidase subunit I (cox1) gene we investigated rates of mutational change within the Geraniaceae and specifically within the genus Pelargonium. The analyses indicate multiple major changes in mutation rate within the family. Interestingly, two different mutational categories within Pelargonium correspond to the two intrageneric groups depicted by chromosome size and number. We have sequenced cox1 for approximately 45 taxa representing most sections within the genus. Preliminary analyses indicate that the genus is split into two clades, each having numerous closely related monophyletic subgroups. Relationships within and between these groups will be addressed.