Effects of SNPs using differentially expressed serum proteins at growth stages on average daily gain in pig.

This study was aimed to search SNPs, which have been generated from differentially expressed proteins at growth stages, to use as molecular or biological markers accounting for variation of average daily gain (ADG). A total of 40 purebred Yorkshire pigs in half-sib pedigree were used to detect differentially expressed blood serum proteins at growth stages (12, 18, 24, and 30 weeks of age) using two-dimensional electrophoresis (2-DE). Differentially expressed spots between growth stages have been identified by MS/MS analysis resulting in nine genes (Immunoglobulin Kappa, Lambda, and Gamma, Retinol-Binding Protein, Albumin, Fibrinogen Alpha and Gamma, Antithrombin, and Alpha-1-Antitrypsin). Expression patterns by growth stages have been defined to four types depending on expression levels. PCR analysis showed 12 successful amplified products, and the sequence alignment for 270 individuals revealed 49 SNPs for the segments of SSP7107, SSP4410, SSP5112F, SSP5112R, and SSP4004. A total of 27 SNPs revealed substitutions of amino acids by SNPs in four genes (Gamma fibrinogen, Immunoglobulin G, Retinol-Binding Protein, and Immunoglobulin K), and the newly identified sequences have been submitted to GenBank with accession numbers. The genotypes from SNPs (positions at 306 of SSP4410; 280 of SSP5211F; 411 of SSP7107) were significantly associated with ADG showing additive and dominance allele effects. The identified SNPs may be helpful to understand different expression profiles of proteins at various growth stages as well as to explain genetic variations associated with ADG in pig industry.