Identification of Marbling Gene Loci in Commercial Pigs in Canadian Herds

Abstract

We examined the amount of marbling and tested the genome of boars from 5 breeds of Duroc, Iberian, Lacombe, Berkshire and Pietrian that were commercially available for a swine herd in Canada. The marbling was ranked according to the amount of intramuscular fat % obtained in loin chops consisting of the longissimus dorsi muscle. The genetics were analysed by genome wide association study using 80,000 single nuclear polymorphism (SNP) microarrays. Our samples had pork that achieved > 7 % IMF from 110kg animals. Meta-analysis revealed SNP markers that were associated with the highest marbled pork chops on chromosomes 5, 7, and 16. Using the susScr 11.1 map, we determined that the nearest genes were SSNP, Rh glycoprotein and EGFLAM. We tested a sub-population of Duroc sired animals and found a different set of markers close to GRLB and KCNJ3 on chromosomes 8 and 15. Based on our sample, we can achieve pork with good marbling from animals conventionally raised to standard market weights of 110kg. The choice of a good marbling line of pig is not necessarily breed specific.