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Science. 2011 Dec 2;334(6060):1286-9. doi: 10.1126/science.1212424.

Robust crossover assurance and regulated interhomolog access maintain meiotic crossover number.

Author information

1
Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA.

Abstract

Most organisms rely on interhomolog crossovers (COs) to ensure proper meiotic chromosome segregation but make few COs per chromosome pair. By monitoring repair events at a defined double-strand break (DSB) site during Caenorhabditis elegans meiosis, we reveal mechanisms that ensure formation of the obligate CO while limiting CO number. We find that CO is the preferred DSB repair outcome in the absence of inhibitory effects of other (nascent) recombination events. Thus, a single DSB per chromosome pair is largely sufficient to ensure CO formation. Further, we show that access to the homolog as a repair template is regulated, shutting down simultaneously for both CO and noncrossover (NCO) pathways. We propose that regulation of interhomolog access limits CO number and contributes to CO interference.

PMID:
22144627
PMCID:
PMC3360972
DOI:
10.1126/science.1212424
[Indexed for MEDLINE]
Free PMC Article

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