A selective genotypingapproach identifies singlenucleotide polymorphismsin porcine chromosome2 genes associated withproduction and carcass traitsin Italian heavy pigs

摘要

Several studies have shown that porcinechromosome 2 (SSC2) harbors importantquantitative trait loci (QTL) for productiontraits. In particular, an imprinted QTL for musclemass production is determined by a mutationin the IGF2 gene (intron3-g.3072G>A).We recently identified and analysed singlenucleotide polymorphisms (SNPs) in genes(cathepsin D, CTSD g.70G>A; cathepsin F,CTSF g.22G>C; lactate dehydrogenase A, LDHAg.46G>T) localized on SSC2 (including theIGF2 intron3-g.3072G>A SNP) showing associationwith production traits in Italian LargeWhite pigs and/or localizing them on QTLregions. Here we analysed these markersapplying a selective genotyping approachbased on estimated breeding values (EBVs).Three groups of Italian Large White pigs eachmade by animals with the most positive (n. 50)and most negative (n. 50) EBVs for averagedaily gain (ADG), backfat thickness (BFT) orweight of lean cuts (LC) and one group ofItalian Duroc pigs made by 50 animals withmost positive and 50 animals with most negativeEBV for visible intermuscular fat (VIF)were genotyped. In Italian Large White pigs,allele frequency differences for the IGF2intron3-g.3072G>A SNP between the twoextreme tails for all groups were highly significant(considering all analysed animals:P=9.53E-20 for LC; P=3.16E-15 for BFT; P=4.41E-6 for ADG). Significant allele frequencydifferences were also observed for the CTSDg.70G>A (P=0.0002 for ADG; P=0.00068) andLDHA g.46G>T (P=2.32E-5 for ADG) polymorphisms.These results provide further supporton the effects of these polymorphisms or geneswhose application on marker assisted selectionprograms could be envisaged.