The synaptonemal complex imposes crossover interference and heterochiasmy in <i>Arabidopsis</i>
Laia Capilla-Pérez, Stéphanie Durand, Aurélie Hurel, Qichao Lian, Aurélie Chambon, Christelle Taochy, Victor Solier, Mathilde Grelon, Raphaël Mercier
Abstract
Significance Meiotic recombination promotes genetic diversity by shuffling parental chromosomes. As observed by the very first geneticists, crossovers inhibit the formation of another crossover nearby, an elusive phenomenon called crossover interference. Another intriguing observation is heterochiasmy, the marked difference in male and female crossover rates observed in many species. Here, we show that the synaptonemal complex, a structure that zips homologous chromosomes together during meiosis, is essential for crossover interference in Arabidopsis . This suggests that a signal that inhibits crossover formation nearby a first crossover propagates along this specific structure. Furthermore, in the absence of the synaptonemal complex, crossover frequencies become identical in both sexes, suggesting that heterochiasmy is due to variation of crossover interference imposed by the synaptonemal complex.