DNA helicase required for crossover formation, complete synapsis of homologous chromosomes and bivalent formation during meiosis. Is specific to recombination events resulting in interference-sensitive crossovers (class I meiotic crossover). ATP + H2O = ADP + H(+) + phosphate ATP + H2O = ADP + H(+) + phosphate Expressed in meiocytes during meiosis. Low levels of fertility due to a significant decrease of meiotic crossovers. Belongs to the DExH box helicase family.