Multiple mechanisms limit meiotic crossovers: TOP3α and two BLM homologs antagonize crossovers in parallel to FANCM
Abstract
During meiosis, crossovers (COs) reshuffle homologous chromosomes, generating genetic diversity on which natural or human selection can act. However, CO numbers typically are very low, raising questions about the evolutionary forces that impose this constraint and limiting the efficiency of breeding programs. Here, we identified anti-CO factors in Arabidopsis and showed that several mechanisms actively antagonize CO formation in parallel. Disrupting these anti-CO factors provokes a large increase in CO frequency without affecting meiotic progression. These results suggest that COs are restrained not because a high number would impair chromosome segregation but because excessive recombination could break favorable genetic combinations built by past selection. These findings hold great promise for improving the efficiency of plant breeding programs.
- Publication:
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Proceedings of the National Academy of Science
- Pub Date:
- April 2015
- DOI:
- 10.1073/pnas.1423107112
- Bibcode:
- 2015PNAS..112.4713S