The effect of Prdm9 alleles and dosage on fertility parameters of PWK male hybrids.

Prdm9, genotype at the Prdm9 locus (maternal/paternal); −, null Prdm9 allele; +, transgenic Prdm9 allele(s); Age, male age (weeks); n, number of males; BW, average body weight (g); TW, mean weight of paired testicles in mg; rTW, relative TW (in mg per gram of BW); SC, average sperm count (millions) in paired caput epididymides (SCc) or in both entire epididymides (SCe); OFM, offspring per female per month; na, not analyzed; B6-Prdm9KO, heterozygote for Prdm9 knock-out on B6 background; B6-Prdm9C3H, congenic carrying C3H allele of Prdm9; B6-BAC21, B6 congenic carrying C3H transgene with truncated Prdm9; B6-BAC5, B6 congenic carrying Prdm9 transgene of C3H origin. See Figure 1 for a schematic view and the text of the Results section for statistical evaluations.