Dating the origins of polyploidy events
Products have included the development of methods and techniques of molecular systematics and genomics, and the development of a battery of simple sequence repeat loci in relatives of soybean. TARGET AUDIENCES: Target audiences: scientists, graduate students, undergraduate students, high school teachers.
Findings include massive invasion of transposable elements into a region duplicated by polyploidy; partitioning of disease resistance genes between homoeologous segments; unequal rates of nuclear genes across these taxa. Around 75 low copy nuclear genes have been assayed for utility in phylogeny reconstruction for the subgenus, and two microsatellite libraries have been constructed and tested.These include sequencing of specific nuclear, mitochondrial, and chloroplast genes, restriction endonuclease mapping of chloroplast genomes, and polymerase chain reaction-based surveys of structiual variation in all three plant genomes.Methods of analysis include determination of rates of sequence evolution and phylogenetic reconstruction using standard methods, mainly parsimony.Pediomelum is a genus endemic to North America comprising about 26 species, including the megalanthum complex, which consists of Pediomelummegalanthum and its varieties retrorsum and megalanthum, Pediomelummephiticum, and the recently described Pediomelumverdiense and Pediomelumpauperitense.Historically, species of the megalanthum complex have been variably recognized at the species or variety levels, dependent upon the relative importance of morphological characters as diagnostic of species.