Association between promoter polymorphisms in a key cytoskeletal gene (Ankyrin 1) and intramuscular fat and water-holding capacity in porcine muscle.

Ankyrin 1 (ANK1) is a positional and functional candidate gene for both bovine and porcine meat quality. The objectives of this study were: (1) to determine if the gene expression levels of ANK1 are associated with pig meat quality traits; (2) to examine polymorphisms in the promoter region of the porcine ANK1 gene for association with meat quality in diverse breeds; and (3) to search for putative transcription factor binding sites predicted to be altered by such polymorphisms. ANK1 gene expression was positively correlated with drip loss (%) in the Large White breed. Twelve novel SNPs were discovered in a 761 bp region of the ANK1 promoter in three phenotypically diverse F1 cross populations. Five were subsequently selected for association analysis with meat quality traits and genotyped in three pure pig breeds (Pietrain n = 98, Duroc n = 99 and Large White n = 98). Two of these five SNPs were associated with meat quality traits at the Bonferroni significance threshold: g.-606G>A with drip loss % in the Pietrain breed and g.-272G>A with intramuscular fat (IMF) in the LTL and SM. Following haplotype construction from SNP genotypes, Haplotype 3 was found to be associated with drip loss % at the Bonferroni level of significance in the Pietrain breed and Haplotype 5 was associated at the Bonferroni level with IMF in two muscles in the Large White breed. Further associations were observed at the nominal significance threshold. Our conclusion from this study is that SNPs in the ANK1 gene promoter could potentially contribute to genome-assisted selection SNP panels to improve IMF and water holding capacity on a breed basis.