Histone methyltransferase PRDM9 is not essential for meiosis in male mice

Sperm-producing Prdm9-deficient mice have a relatively high crossover rate. Black dots depict means, and error bars represent SDs. Each point represents a single mouse genetic background (data from Table 1). All mice carrying epididymal sperm (sperm count above the detection limit of a few thousands) were assigned to the “Produce Sperm” group. The MLH1 count values for the “No sperm” group were determined from genetically matched Prdm9^wt males (Supplemental Table S1). Hstx2 is not the only locus affecting crossover rate in these mice, as judged from the distribution of its alleles in the groups. The mean crossover rate in animals that “Produce Sperm” was significantly higher than that in animals that did not (P, probability, Wilcoxon test).