Resumen de Biogeographic relationships between the mediterranean and north american floras: insights from molecular data
Molecular phylogenetic analysis has proven to be a powerful tool for inferring the evolutionary history of organisms. These methods can also be used to examine the origins and relationships of plant taxa that are disjunctly distributed between the Mediterranean region and North America. Examples are given from studies of Pinus (Pinaceae), Datisca (Datiscaceae), Astragalus (Fabaceae), and Senecio (Asteraceae). In Pinus subgenus Pima and Datisca, Old World I New World disjunctions can be explained by vicariance dating back to the Late Cretaceous and Eocene, respectively, The intercontinental disjunct species pair Senecio flavus subsp. breve ores and S. mohavensis probably originated through Holocene long-distance dispersal. The previously unsuspected relationship between the Mediterranean species Astragalus echinatus and the New World aneuploid Astragalus Glade is supported by two independent data sets; however, its biogeographic origin remains unresolved. These examples illustrate the range of biogeographic questions that molecular phylogenetic methods can address.
