9701007 Doyle Graduate student Carl Bailey, under the direction of Professor Jeff Doyle at Cornell University, is studying the mustard-family genus Sphaerocardamum of Mexico, to improve taxonomic classification of the group, construct a phylogeny of the eight or so known species, and explore variation in floral development genes. Additional field collecting in Mexico will augment materials assembled from the field and herbarium. New molecular data from DNA sequencing of both nuclear and chloroplast genes will provide evidence for phylogenetic analyses, and these data can be combined with traditional morphological characters in delimiting species, assessing hybridization in areas of sympatry, and studying the historical biogeography of the group. Gene probes from the Arabidopsis model system, a related plant in the family, will be used to explore variation in genes affecting floral development and other features distinguishing related species. The significance of the project includes contributions to the taxonomy and phylogeny of the Brassicaceae (mustard) family, evaluation of the reliability and stability of key morphological characters in the genus Sphaerocardamum and close relatives, the development of new sources of DNA data for phylogenetic reconstruction, and the exploration of variation in genes affecting flower development, making use of probes from the Arabidopsis model system.
