Investigation of a QTL region for loin eye area and fatness on pig Chromosome 1

Previously, quantitative trait loci (QTL) for tenth-rib backfat (TENTHRIB) and loin eye area (LEA) were identified on pig Chromosome 1 (SSC 1) near microsatellite S0008 from a three-generation Berkshire × Yorkshire cross (BY). This work attempted to refine these QTL positions and identify genes associated with these QTL. Genotypes of BY (n = 555) were determined by PCR-RFLP or PCR tests for 13 polymorphisms identified in BY F₀ individuals for candidate genes, BAC end sequences, and genomic clones. Using least-squares regression interval mapping, the LEA QTL was estimated at S0008; the TENTHRIB QTL position was shifted approximately 1 cM downstream from S0008. Of the genes/sequences mapped in the QTL region, CL349415 was significantly associated with TENTHRIB (p = 0.02) and solute carrier family 2, member 12 (SLC2A12) was significantly associated with LEA (p = 0.02). These results suggest that the gene(s) responsible for the LEA and TENTHRIB QTL effects are tightly linked to S0008 or that the high informativeness of S0008 relative to surrounding markers is influencing the QTL position estimates. In addition, janus kinase 2 (JAK2) was mapped to a suggestive LEA QTL region and showed association with LEA (p = 0.009), fatness, color, and pH traits in BY.