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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. [ABSTRACT FROM AUTHOR]

The swine fatty acid binding protein gene ( FABP3) has been screened with 4 primer sets for 270 purebred Yorkshire pigs from National Institute of Animal Science. The selection of primers was based on the swine cDNA sequence (AJ416019), and primer sets ( FABP3- 2 and FABP3- 3) amplified target segments in real time PCR to analyze expression levels at growth stages, producing 235 and 224 bp of fragments, respectively. Relative expression of the swine FABP3 gene for back and intramuscular fat was continuously increased from day 0 to 150, and decreased at day 210, showing the highest expression levels at day 150 compared with day 0. The results may be caused by requirements of high physiological activities with more gene expressions for growth around day 150. Nucleotide variations were observed at nucleotide positions 80 (A/G), 167 (A/G), 260 (A/G), 295 (A/G), 394 (T/C), and 440 (A/G), showing substitutions of amino acids at positions 80 (S to G), 167 (T to A), and 260 (S to G). FABP3 genotypes at positioned nt167 have been associated with carcass back fat thickness (BFT), and dominance genetic effects were observed for BFT with nt167 and intramuscular fat (IMF) contents with nt80. Our results concluded that the FABP3 polymorphisms can be used as genetic markers in breeding programs for IMF content as well as carcass BFT. [ABSTRACT FROM AUTHOR]

Relationships of the calpain system with meat tenderness and carcass traits were examined for 94 purebred Angus bulls with genotypes of the calpain classified by RFLP (restriction fragment length polymorphism) and SSCP (Single strand conformation polymorphism) analysis. Designing of primers based on the calpain regulatory subunit (CAPNS) and u-calpian (CAPN1) genes. Bulls from 15 months of age were slaughtered, and carcass traits, including fat thickness (FAT); longissimus muscle area (LMA); percentage of kidney, pelvic, and heart fat (KPH); hot carcass weight (HCW); marbling score (MAR); and quality grade (QUL), were analyzed. Measurements regarding meat tenderness involved activities of calpastatin (CAC), u-calpain (UAC), m-calpain (MAC), Warner-Bratzler Shear Force (WBS) and myofibril fragmentation index (MFI). Statistical significances of the calpain genotypes accounted for variations in MAR and QUL at CAPNS locus, and both loci explained variations of UAC and MAC. Significant mean differences in genotypes of CAPNS locus were found for MAR (BB > AB > AA) and QUL (AB > BB > AA). UAC showed significant correlations with MAC, CAC, MFI, FAT, and MAR, and we found that MAC correlated with WBS, FAT, HCW, MAR, and QUL. Strong positive correlation detected between LMA and HCW, and MAR and QUL, and a negative correlation between MFI and MAR was estimated. From the result it may be possible to use the calpain genotypes classified by RFLP and SSCP analysis in marker assisted selection programs to estimate UAC and MAC precisely regardless meat tenderness and to improve MAR and QUL of beef cattle.