Mechanisms of meiotic recombination

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The goal of my research program is to further our understanding of the molecular mechanisms of meiosis. In the current proposal I will determine gene functions involved in the establishment of the meiotic recombination pattern in Caenorhabditis elegans. C. elegans provides many unique advantages for my research program. There is normally only one crossover per autosome making it possible to determine where that crossover occurred and how frequently in a population of events. The pattern is eliminated in the mutant, Rec-1, and altered in mutants in chromatin modifiers. A large body of research exists on the molecular components of meiosis; however the basis of the meiotic recombination pattern is not understood. Although meiotic crossing over can happen between any two nucleotide pairs, there are regions of the chromosome where it occurs preferentially. Thus, the frequency of crossing over per length of DNA differs from region to region, as much as ten-fold for certain regions of the C. elegans autosomes. Distribution of meiotic exchange results in an apparent clustering of meiotic markers. The Rec-1 mutant, which eliminates the pattern, demonstrates that it is subject to evolutionary selection, and responds to molecular determinants encoded genetically. In collaboration with Dr. Steven Jones of the Michael Smith BC Genome Sequencing Center, we have the entire genomic sequence of Rec-1. Using the genomic sequence we can identify the molecular change responsible for the phenotype and characterize the nature of the pathways involved.