A Polymorphism in the 5′-Untranslated Region of the Porcine Cholecystokinin Type A Receptor Gene Affects Feed Intake and Growth

The location and utilization of quantitative trait loci (QTL) and candidate genes with significant effects on economically important traits are becoming increasingly important in livestock breeding programs. The porcine cholecystokinin type A receptor (CCKAR) is a candidate gene for performance traits, due to its known role in the physiological control of feed intake, satiety, and obesity. We investigated the association of CCKAR polymorphisms with feeding, growth, and efficiency traits in an F2 population derived from a cross between Meishan and Large White founder animals and in lines of Large White pigs that had been divergently selected on the basis of lean growth efficiency traits. In the F2 population, CCKAR genotype was significantly associated with daily feed intake and average daily gain. The effects of the polymorphisms were then assessed in a larger-scale analysis of segregating commercial lines. A newly discovered single-nucleotide polymorphism (SNP) within the 5′-untranslated region (5′-UTR) had highly significant effects on feed intake, average daily gain, and days to 110 kg, which were not seen for a previously reported SNP within the CCKAR gene. Furthermore, we provide evidence that the novel SNP disrupts the binding of the YY1 transcription factor, which raises the possibility that it is the causal variant. The 5′-UTR SNP could be utilized as a molecular genetic test for increased feed intake, faster lean growth, and reduced days to market weight in segregating commercial lines.