title: Recombination patterns in maize reveal limits to crossover homeostasis.
abstract: During meiotic recombination, double-strand breaks (DSBs) are formed in chromosomal DNA and then repaired as either crossovers (COs) or non-crossovers (NCOs). In most taxa, the number of DSBs vastly exceeds the number of COs. COs are required for generating genetic diversity in the progeny, as well as proper chromosome segregation. Their formation is tightly controlled so that there is at least one CO per pair of homologous chromosomes whereas the maximum number of COs per chromosome pair is fairly limited. One of the main mechanisms controlling the number of recombination events per meiosis is CO homeostasis, which maintains a stable CO number even when the DSB number is dramatically altered. The existence of CO homeostasis has been reported in several species, including mouse, yeast, and Caenorhabditis elegans. However, it is not known whether homeostasis exists in the same form in all species. In addition, the studies of homeostasis have been conducted using mutants and/or transgenic lines exhibiting fairly severe meiotic phenotypes, and it is unclear how important homeostasis is under normal physiological conditions. We found that, in maize, CO control is robust only to ensure one CO per chromosome pair. However, once this limit is reached, the CO number is linearly related to the DSB number. We propose that CO control is a multifaceted process whose different aspects have a varying degree of importance in different species.
authors.affiliation: Section of Plant Biology, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853;
authors.forename: Gaganpreet K
authors.initials: GK
authors.lastname: Sidhu
authors.affiliation: Section of Plant Biology, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853;
authors.forename: Celestia
authors.initials: C
authors.lastname: Fang
authors.affiliation: Section of Plant Biology, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853;
authors.forename: Mischa A
authors.initials: MA
authors.lastname: Olson
authors.affiliation: Génétique Quantitative et Evolution-Le Moulon, Institut National de la Recherche Agronomique/Université Paris-Sud/CNRS/AgroParisTech, Université Paris-Saclay, F-91190 Gif-sur-Yvette, France.
authors.forename: Matthieu
authors.initials: M
authors.lastname: Falque
authors.affiliation: Génétique Quantitative et Evolution-Le Moulon, Institut National de la Recherche Agronomique/Université Paris-Sud/CNRS/AgroParisTech, Université Paris-Saclay, F-91190 Gif-sur-Yvette, France.
authors.forename: Olivier C
authors.initials: OC
authors.lastname: Martin
authors.affiliation: Section of Plant Biology, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853; wp45@cornell.edu.
authors.forename: Wojciech P
authors.initials: WP
authors.lastname: Pawlowski
mesh_terms: D000818:Animals; D002843:Chromatin / Q000235:genetics / Q000378:metabolism; D032461:Chromosomes, Plant / Q000235:genetics / Q000378:metabolism; D003434:Crossing Over, Genetic; D053903:DNA Breaks, Double-Stranded; D006706:Homeostasis / Q000235:genetics*; D059765:Homologous Recombination; D008540:Meiosis / Q000235:genetics; D051379:Mice; D008856:Microscopy, Fluorescence; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D051135:Rad51 Recombinase / Q000235:genetics / Q000378:metabolism; D003313:Zea mays / Q000235:genetics*
chemical_list: D002843:Chromatin; D010940:Plant Proteins; D051135:Rad51 Recombinase
keywords: crossing-over; crossover homeostasis; double-strand breaks; meiosis; recombination