Acknowledgements:
NIH Grant #1R01GM60766-01
"Disease on New Hosts..."

NSF Grant #0075654
"Consequences of Intra-Tetrad Selfing..."

NSF Grant #9972650
"DIG: Evolution of Virulence..."

NSF Grant #0074483
"PRF in Bio-Informatics..."

Research:
Intra-tetrad mating and genomic organization -- We are focusing on an intriguing mating system we have discovered in the fungus causing anther-smut disease, Microbotryum violaceum. This fungus mates among the products of a single meiosis. This occurs in other fungi, in mosses, and is similar to meiotic parthenogenesis in plants and animals. Our fungal system has the advantage that we can isolate the linear tetrads by micro-manipulation for use in molecular analysis. We are testing the prediction that intra-tetrad mating can maintain heterozygosity with a consequent build-up of alleles that may be deleterious in the haploid stage, but may have benefits in the diploid stage by altering disease expression.

Evolution of sex chromosome dimorphism in haploids -- While several very cogent mechanisms have been proposed for the evolution of sex chromosome dimorphism in diploids, there is little a priori reason to expect such dimorphism when sex determination is in the haploid stage of the life-cycle. Microbotryum exhibits large variation in chromosome size, and we have evidence from saturated AFLP mapping and electrophoretic karyotyping that such differences probably exist between the sex-chromosomes (mating-type chromosomes). We are currently establishing the molecular basis of these differences with a view to better understand the mechanisms of sex chromosome evolution in haploids.