Fine scale recombination variation in Drosophila melanogaster

The study of natural variation is a principle component of biology. One process that affects levels of natural variation is meiotic recombination—the process by which homologous chromosomes break and interchange genetic information with one another during the formation of gametes. Surprisingly, this factor that shapes levels of natural variation across the genome itself presents with a great deal of variation. That variation manifests itself at many levels: within genomes, between individual organisms, across populations, and among species. The factors and mechanisms responsible for the non-random patterning of recombination events across the genome remain particularly elusive in most cases. Herein, I utilize a combination of bioinformatic and molecular genetic approaches to better explain recombination patterning. I explore several factors that are now known to contribute to the distribution of recombination events across genomes. In particular, I demonstrate that transcriptional activity during meiosis is associated with, and partially predictive of crossing over events in Drosophila melanogaster. Additionally, I present a model which is capable of accounting for approximately 40% of the variation in crossover rates in Drosophila based on the localization of several previously identified DNA motifs. Lastly, I present preliminary data describing how recombination patterns are altered under naturally stressful conditions, a key insight that is necessary for uniting our findings at one level of variation with the many others. These findings support a multifactorial model for crossover distribution that includes both genetic and epigenetic factors and will further progress the field in developing a comprehensive understanding of recombination localization.