440A Poster - 05. Reproduction and gametogenesis
Thursday April 07, 2:00 PM - 4:00 PM

Investigating chromosome-specific differences during meiosis


Authors:
Katherine Billmyre 1; R. Blake Billmyre 1; R. Scott Hawley 1,2

Affiliations:
1) Stowers Institute for Medical Research, Kansas City, MO, United States of America; 2) Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS, United States of America

Keywords:
c. meiosis; j. pairing/transvection

Inheritance of a complete set of chromosomes is critical for fertility and production of viable offspring. However, all chromosomes are not the same. Cells face the challenge of building a system that can accurately segregate chromosomes with vast structural and size differences (as much as 5x in humans and 46x in Drosophila). However, the mechanisms underlying recombination and segregation of specific chromosomes are not understood. In Drosophila melanogaster, a set of partial loss-of-function synaptonemal complex (SC) mutants exhibit chromosome-specific defects in recombination and pairing during meiosis. The SC is a conserved meiotic structure that holds homologous chromosomes together and is necessary for the repair of double-strand breaks (DSBs) into crossovers. We are currently using a two-pronged approach of super-resolution imaging and genomics to examine the relationship between the SC, DSBs, and recombination on different chromosomes both in wildtype flies and those that exhibit chromosome-specific defects. Using next generation sequencing, we have found in a partial loss of SC background, that DSBs are able to be repaired as non-crossover gene conversions, even when they are unable to be repaired as crossovers. To further examine the importance of synapsis, pairing, DSB placement, and crossovers on the behavior of different chromosomes, we are combining the LacO/LacI system with super-resolution imaging and chromosome tracing to assess the meiotic landscape on individual chromosomes. Together these approaches will provide a one-of-a-kind map to elucidate the role of the SC in regulating meiosis.