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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: BACKGROUND, RESULTS. Meshes: Animals, Crossing Over, Genetic, Drosophila, Female, Male, Meiosis, Mutation, Synaptonemal Complex.
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Does the Synaptonemal complex component C ( 2 ) M regulate meiotic crossing over in Drosophila? Context: The synaptonemal complex (SC) is a proteinaceous structure that forms between homologously paired meiotic chromosomes. Previous studies have suggested that the SC is required for meiotic crossing over in Drosophila. However, only one component of this structure, C(3)G, has been identified in Drosophila. Mutations in c(2)M cause a reduced frequency of meiotic crossing over due, in part, to how recombination events are resolved. Cytological evidence suggests that C(2)M is a component of the SC and is required for the assembly of C(3)G (a putative transverse filament of the SC) along the chromosomes. Additionally, C(2)M localizes along the chromosomes in the absence of C(3)G. Despite having a defect in C(3)G localization, c(2)M mutants unexpectedly affect crossing over less severely than a c(3)G mutant. There is virtually no crossing over in a c(3)G mutant, but c(2)M or c(2)M; c(3)G double mutants produce a substantial number of crossovers. The appearance of C(3)G-independent crossovers in c(2)M mutants suggests that C(2)M prevents recombination in the absence of complete SC formation.
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We have identified a new Drosophila SC component, C(2)M, that promotes the formation of crossovers. Furthermore, the appearance of C(3)G-independent crossovers in c(2)M mutants suggests a novel role in preventing recombination in the absence of complete SC. Final Decision: yes