Mechanisms of meiotic recombination

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Mechanisms of Meiotic Recombination The processes of meiosis, homolog pairing, recombination and chromosome segregation are fundamental to sexual reproduction and faithful inheritance of genetic information.  Pairing is essential for recombination, and meiotic exchange determines segregation patterns.  Thus crossing over is an essential process in meiosis.  It is well known that genetic linkage as determined by crossover events is proportional to DNA length.  However, the number of crossovers per unit length of DNA varies for different regions of the chromosome, and generates the 'meiotic pattern' of crossing over.  Meiotic patterns are highly conserved within phyla and between species.  The conservation suggests that the pattern is of fundamental biological importance, and several hypotheses have been put forward to explain why the frequency of crossing over is higher or lower for certain regions.   In Caenorhabditis elegans, the meiotic pattern has been extensively characterized, and the number of crossovers per million base pairs can vary as much as ten-fold across the chromosome.  A mutation in the rec-1 gene eliminates the meiotic pattern, generating a genetic map similar to the physical map.   The existence of this mutation proves that the meiotic pattern is under genetic control, and provides the potential to examine the molecular basis of the pattern.   In this proposal, I am requesting funding to characterize the rec-1 gene product.  In order to determine the mechanism by which the rec-1 gene product functions, we will generate additional alleles in order to extend our phenotypic characterization of the gene, investigate gene interactions, determine the cellular localization of the gene product, and examine possible alterations in chromosome architecture.  The long-term goal of my research program is to understand more fully the fundamental genetic and molecular processes controlling meiosis, and the evolutionary significance of meiotic patterning.