Chapter 9 - Meiotic and mitotic recombination: First in flies

Abstract

In this chapter, we examine landmark discoveries made in mitotic and meiotic recombination using Drosophila as a model organism. Mitotic recombination is detrimental to cell viability, causing loss of heterozygosity and genome rearrangements, and unrepaired double-strand breaks (DSBs) can result in cell death. To avoid these outcomes, cells utilize multiple pathways to ensure that mitotic DSBs are repaired into non-crossover products. Here we discuss the major mitotic DSB repair pathways homologous recombination repair (especially synthesis-dependent strand annealing) and end joining. In contrast to mitotic cells, crossovers are beneficial during meiosis. Meiotic recombination is important to ensure proper chromosome segregation during gametogenesis and defects in crossover formation result in aneuploidy and sterility. Accordingly, we discuss key regulatory mechanisms of meiotic recombination that promote repair of meiotic DSBs as crossovers and distribution of crossovers along chromosomes.