442C Poster - 05. Reproduction and gametogenesis
Saturday April 09, 1:30 PM - 3:30 PM

Authors:
Joseph Terry; Savana Hadjipanteli; Nicole Crown

Affiliation: Case Western Reserve University

Keywords:
c. meiosis; n. other (DNA repair and recombination)

Meiosis is essential for the production of genetically diverse gametes in all sexually reproducing eukaryotes. During meiosis, genetic material is exchanged between chromosomes through homologous recombination, driving genetic diversity amongst gametes while simultaneously ensuring proper chromosome segregation. Recombination is initiated in response to programmed DNA double-stranded breaks (DSBs) across the genome. These DSBs are then repaired, resulting in a crossover (CO) or non-crossover (NCO).
When looking at genome-wide DNA DSB repair distribution, NCOs make up the majority of repair outcomes while a limited number of DSBs are repaired as COs. This imbalance between the total number of DSBs across the genome and the small number of those repaired as COs introduces the question: what dictates crossover patterning across the genome? Accumulating evidence has implicated three key phenomena to be involved in crossover patterning within Drosophila: crossover assurance, crossover interference, and crossover suppression. Interestingly, nearly all chromosomes are affected by these three CO patterning mechanisms, with the exception of chromosome 4 where meiotic COs never occur.
Disturbances in CO patterning, such as the attenuation of CO interference and suppression have been suggested to occur during the interchromosomal effect (IC). During the IC effect, the presence of a heterozygous inversion inhibits COs locally, while increasing CO frequency across unbalanced chromosomes. Here, we propose that CO patterning mechanisms indeed, are attenuated during the IC effect by generating a fly model that undergoes meiotic COs on chromosome 4 in the presence of a multiply inverted balancer chromosome. Using a fly model that undergoes meiotic COs on chromosome 4, we aim to generate CO distribution maps as a method to assess the impact of CO patterning mechanisms on recombination during the IC effect.