Meiotic Chromosome Pairing in Drosophila

Meiosis is geared towards ensuring the segregation of homologous chromosomes at the reductional division by forming links between the homologs. The homologs are brought together in an elaborate pairing process that may begin with chromosomes aligned at a distance. This process culminates in a more intimate association where the homologs are held together along their entire length by the synaptonemal complex (sc). During this time meiotic recombination occurs, probably initiated with a double strand break (DSB). The repair and resolution of the repair process is believed to occur within a sc-associated, the recombination nodule (RN). Through our analysis of meiosis in Drosophila melanogaster females it has been shown that a key component of machinery that initiates meiotic recombination is conserved. In contrast, it has also been shown that the relationship between meiotic recombination and sc formation is not conserved. Long-term goals are to understand the mechanism and regulation of meiotic recombination and homolog pairing. Genetic and cytological techniques will be used to test the model that sc forms before recombination is initiated and genetic and chromosomal factors that regulate DSB formation will be identified and characterized. Specific aims are: To test the model that recombination initiates after sc formation. To identify genetic factors regulating double strand break formation. To identify chromosomal factors regulating double strand break formation.

Knowledge of the mechanisms resulting in chromosome pairing is critical to an understanding of inheritance. The results of this study will result in greater insight into phenomena central to a complete understanding of genetic mechanisms utilized by eukaryotic cells.