Massive crossover elevation via combination of HEI10 and recq4a recq4b during Arabidopsis meiosis

During meiosis homologous chromosomes undergo reciprocal crossovers, which generates genetic diversity and underpins classical crop improvement. Meiotic recombination initiates from DNA double strand breaks, which are processed into single-stranded DNA that can invade a homologous chromosome. The re...

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Published inbioRxiv
Main Authors Serra, Heidi, Lambing, Christophe, Griffin, Catherine H, Topp, Stephanie D, Seguela-Arnaud, Mathilde, Fernandes, Joiselle, Mercier, Raphael, Henderson, Ian R
Format Paper
LanguageEnglish
Published Cold Spring Harbor Cold Spring Harbor Laboratory Press 06.07.2017
Subjects
Centromeres
Chromosomes
Crop improvement
DNA damage
DNA helicase
Genetic diversity
Genetic recombination
Genomes
Heterochromatin
Meiosis
Recombination
Single-stranded DNA
Telomeres
Ubiquitin-protein ligase
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Summary:During meiosis homologous chromosomes undergo reciprocal crossovers, which generates genetic diversity and underpins classical crop improvement. Meiotic recombination initiates from DNA double strand breaks, which are processed into single-stranded DNA that can invade a homologous chromosome. The resulting joint molecules can ultimately be resolved as crossovers. In Arabidopsis competing pathways balance the repair of ~100-200 meiotic DSBs into ~10 crossovers per meiosis, with the excess DSBs repaired as non-crossovers. In order to bias DSB repair towards crossovers, we simultaneously increased dosage of the pro-crossover E3 ligase gene HEI10 and introduced mutations in the anti-crossover helicase genes RECQ4A and RECQ4B. As HEI10 and recq4a recq4b increase interfering and non-interfering crossover pathways respectively, they combine additively to yield a massive meiotic recombination increase. Interestingly, we also show that increased HEI10 dosage increases crossover coincidence, which indicates an effect of HEI10 on interference. We also show that patterns of interhomolog polymorphism and heterochromatin drive recombination increases towards the sub-telomeres in both HEI10 and recq4a recq4b backgrounds, while the centromeres remain crossover-suppressed. These results provide a genetic framework for engineering meiotic recombination landscapes in plant genomes.
DOI:10.1101/159764