Recombination rate itself is a sexually dimorphic trait, with overall higher rates in female germ cells in humans, except at the telomeres of chromosomes where male recombination rates exceed those of females80,81. A recent genome-wide association study of recombination rates in 1887 Icelandic men and 1702 Icelandic women identified a locus that showed significant sex-specific effects78. Three SNPs in a block of LD spanning 200 kb on chromosome 4p16.3 showed genome-wide significant evidence of association in men (P<10−10) and two of those SNPs were also genome-wide significant in women (P<10−7). Surprisingly, the combination of alleles associated with low recombination rates in men (allele C at rs3796619 and allele T at rs1670533) were associated with high recombination rates in women. The opposite effect of these SNPs on male versus female recombination was replicated in a second sample of 3135 men and 3365 women from Iceland (P<10−8 in men and P<10−4 in women). Relative to the average recombination rate in the population, each copy of rs3796619 decreased recombination rate by 2.62% in men whereas each copy of the rs1670533 T allele increased
