Identification of Imprinted Quantitative Trait Loci (QTL) Affecting Meat Quality in Porcine Chromosomes 2, 6 and 7

Abstract

As an experimental reference population, crosses between Korean native pig and Landrace were established and information on seven meat quality traits was recorded. Animals were genotyped for 24 microsatellite markers covering chromosomes 2, 6, and 7 for partial genome scan to identify chromosomal regions that have previous known effects on meat quality. The QTL effects were estimated using interval mapping by the regression method under the line cross models with a test for imprinting effects. For test of presence of quantitative trait loci (QTL), chromosome-wide and single position significance thresholds were estimated by permutation test and normal significance thresholds for the imprinting test were derived. For tests against the Mendelian model, additive and dominance coefficients were permuted within individuals. Thresholds (5% chromosome-wide) against the no-QTL model for the analyzed traits were ranged from 4.39 to 4.89 for the Mendelian model and from 4.08 to 4.81 for the imprinting model, respectively. Partial genome scan revealed significant evidence for 7 QTL affecting meat quality traits, and 1 out of the 7 QTLs were imprinted. This study demonstrated that testing for imprinting should become a standard procedure to unravel the genetic control of multi-factorial traits. The models and tests developed in this study allowed the detection and evaluation of imprinted QTL.