View Program - 63rd Annual Drosophila Research Conference

Heterozygous inversions disrupt the meiotic crossover (CO) distribution by suppressing COs locally both within and outside of the inversion, and also triggering the interchromosomal (IC) effect, where the CO frequency on structurally normal chromosomes dramatically increases. We previously showed that these changes in the CO distribution are mediated by CO patterning mechanisms that alter the CO/NCO decision in Drosophila melanogaster. However, the exact decision making process of how the patterning mechanism exert its influence on a double-stranded break (DSB) to suppress COs outside of inversion breakpoints, as well as the pattern of suppression in terms of distance and severity, are still unknown. Traditionally, this analysis can be done by phenotypic scoring of recombinants, but we are currently analyzing the recombination mechanics of DSB repair by creating a fine-scale recombination map of the region near the breakpoints of an X chromosomal inversion dl-49 through whole genome sequencing of individual Drosophila melanogaster offspring. Our preliminary data show that from the distal breakpoint to telomere region, almost no COs were recovered. From the proximal breakpoint to centromere region, a bell-shaped pattern was observed, where the further away the location is from the breakpoint, the higher the CO frequency is (compared to the CO profile of completely wild type flies). To reduce variations in genomic background among tested flies, we are currently creating isogenized full-sibling stocks, and the experiment will be repeated using these new stocks for more robust data.

The Effect of Heterozygous Inversion on Crossover Frequency near Inversion Breakpoints by High-Res Whole Genome Sequencing