Mouse strains.

The relevant genotype of the mouse strains used in this study are indicated. At the Prdm9 locus, strains carry the b allele (from b haplotype, present in strains such as B6) and/or the wm7 allele (from wm7 haplotype, from the M. musculus molossinus derived strain B10. MOL(SGR)). The Prdm9 transgenes carry the zinc finger array either from the b or wm7 alleles (see Materials and Methods). At the Psmb9 hotspot, alleles are from b, a (from the B10.A strain), wm7, or the recombinant wm7-a haplotype. The relevant single nucleotide polymorphisms (SNPs) at the center of the hotspot are shown.