Male/Female segregating single nucleotide polymorphism (SNP) density in selected linkage groups. SNPs segregating with gender in 3 female and 2 male genomes were plotted. A 5 cM sliding window was used to determine the density of segregating SNPs per 100 kb and this was plotted as a red line next to the linkage group. LG12 contains the only region of high density segregating SNPs in the genome, suggesting it is indeed the sex chromosome. Localization of the sex determination region to a portion of the chromosome suggests the rest of the chromosome is still freely recombining.