The role of the DNA double-strand break response network in meiosis

Organisms with sexual reproduction have two homologous Copies of each chromosome. Meiosis is characterized by two successive cell divisions that result in four haploid sperms or eggs, each carrying a single copy of homologous chromosome. This process requires a coordinated reorganization of chromatin and a complex network of meiotic-specific signaling cascades. At the beginning of meiosis, each chromosome must recognize its homolog, then the two become intimately aligned along their entire lengths which allows the exchange of DNA strands between homologous sequences to generate genetic diversity. DNA double-strand breaks (DSBs) initiate meiotic recombination in a variety of organisms. Numerous studies have identified both the genomic loci of the initiating DSBs and the proteins involved in their formation. This review will summarize the activation and signaling networks required for the DSB response in meiosis. (C) 2004 Elsevier B.V. All rights reserved.