Understanding How Chromosome Structure Influences Recombination

Abstract

Meiotic recombination results in the exchange of DNA between homologous chromosomes, creating allelic diversity while at the same time ensuring correct segregation of chromosomes during the meiotic divisions. Most maize COs are found in the distal regions of chromosomes, whereas the highly repetitive centromeric and pericentromeric regions are often devoid of COs. However double-strand breaks (DSBs), whose formation initiates the recombination pathway, do not follow the same pattern of CO distribution. Instead, maize DSB hotspots occur along the entire length of chromosomes, with no preference for distal or proximal regions. In this study, I tracked the dynamics of the DSB repair protein RAD51 between euchromatin and heterochromatin through the stages of early prophase I. By comparing the spatiotemporal localization of RAD51 between inbred lines with difference CO patterns, I found that the eventual CO pattern in each inbred likely reflects the distribution of early DSB repair.