Mitochondrial and chloroplast DNA-based phylogeny of Pelarogonium (Geraniaceae)

Overall phylogenetic relationships within the genus Pelargonium (Geraniacea e) were inferred based on DNA sequences from mitochondrial(mt)-encoded nad1 b/c exons and from chloroplast(cp)-encoded trnL (UAA) 5' exon-trnF (GAA) e xon legions using two species of Geranium and Sarcocaulon vanderetiae as ou tgroups. The group II intron between nad1 exons b and c was found to be abs ent from the Pelargonium Geranium, and Sarcocaulon sequences presented here as well as from Erodium, which is the first recorded loss of this intron i n angiosperms. Separate phylogenetic analyses of the mtDNA and cpDNA data s ets produced largely congruent topologies, indicating linkage between mitoc hondrial and chloroplast genome inheritance. Simultaneous analysis of the c ombined data sets yielded a well-resolved topology with high clade support exhibiting a basic split into small and large chromosome species, the fil s r group containing two lineages and the latter three. One large chromosome lineage (x = 11) comprises species from sections Myrrhidium and Chorisma an d is sister to a lineage comprising P. mutans (x = 11) and species item sec tion Jenkinsonia (x = 9). Sister to these two lineages is a lineage compris ing species from sections Ciconium (x = 9) and Subsucculentia (x = 10). Cla distic evaluation of this pattern suggests that x = 11 is the ancestral bas ic chromosome number for the genus.