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) and works cooperatively with MER3 to promote crossovers. Interacts with HEI10 and SHOC1. Detected in punctuate foci onto the chromosomes in prophase I meiocytes. Complete loss of fertility due to defect in meiosis. Extended N-terminus. Extended N-terminus.