Physical distance versus linkage distance and SNP number for female-specific SSCX. a) Distribution of genetic (cM) against physical (Mb) distances for female-specific SSCX according to Sscrofa10.2. A, B, C, D and E boxes frame cold and hot recombination spots. b) Distribution of the SNPs contained in PorcineSNP60 BeadChip and mapped on SSCX according to Sscrofa10.2. c) Distribution of the SNPs retained in the current dataset and mapped on SSCX.