The long term goal of our research is to understand mechanisms underlying homologous chromosome pairing and genetic recombination during meiosis. We have developed the basidiomycete fungus Coprinus cinereus as a model system for analysis of meiosis, because many features of the C. cinereus life cycle facilitate such studies. C. cinereus chromosomes can be visualized easily using both light and electron microscopy. Meiosis occurs synchronously in this species, and gram quantities of meiotic cells can be harvested at any desired state. The induction and genetic analysis of mutations is straightforward, and the small genome can also be manipulated by DNA-mediated transformation.

In current projects, we are analyzing the genetic controls of chromosome pairing, with particular emphasis on how homologues are recognized. We have assembled a collection of meiotic mutants, and we are cloning the genes that complement these defects using cosmid libraries. We have found that prior to meiosis, a genome-wide homology search occurs in C. cinereus that results in the methylation of duplicated sequences. We are currently asking if the same genes control premeiotic and meiotic homology searches. We are also analyzing chromosomal sites that act autonomously to initiate synapsis. Since the essential features of meiosis are highly conserved, we expect that our results will be relevant to understanding meiosis in less tractable eukaryotes.