Associations between pig adiponectin (ADIPOQ) genotype and serum lipid levels are modulated by age-specific modifiers

The adiponectin (ADIPOQ) locus is a positional and functional candidate gene for 2 porcine chromosome 13 (SSC13) QTL influencing cholesterol (CHOL) and low-density lipoprotein (LDL) concentrations in 190-d-old pigs. By sequencing 2.37 kb of the pig ADIPOQ cDNA, we have identified 1 c.*1512G > T 3′ untranslated region polymorphism that has been genotyped in a Duroc pig commercial population with records for serum lipid levels at 45 and 190 d of age. Statistical analysis of the data have revealed significant associations between the ADIPOQ genotype and CHOL (P = 0.0040) and LDL (P = 0.0011) concentrations at 190 d but not at 45 d. In family 3, most of the SSC13 QTL effects on LDL levels at 190 d were explained by the ADIPOQ genotype. We also found an association with triglyceride levels at 45 d (P = 0.0060) but not at 190 d. Measurement of allelic mRNA imbalance demonstrated that the G and T alleles are expressed at very similar levels at muscle and fat tissues, indicating that the c.*1512G > T polymorphism does not affect transcript abundance. As a whole, results obtained in the current work as well as previous data gathered in humans and pigs provide[AU: please confirm change] evidence that the magnitude of associations between blood lipid phenotypes and candidate loci genotypes may vary depending on the age of the individual, therefore suggesting the existence of dynamic genotype × environment interactions changing on a temporal scaleThis work has been funded by grants AGL2007-66707-C02, AGL2010- 22208-C02-01, and AGL2010-22208-C02-02 (Ministerio de Ciencia e Innovación) and CSD 2007-00036 (Ministerio de Ciencia e Innovación, Consolider Ingenio 2010 Program). The authors are indebted to Selección Batallé S.A. for providing the animal material and for their cooperation in the experimental protocol. D. Gallardo and C. Melo were funded with fellowships from the Universitat Autònoma de Barcelona and the Instituto Agronómico Mediterráneo, respectively. A. Zidi received a contractual grant under the framework of CSD 2007-0003