Study On Cloning And Expression Of Baixi Pig Meat Quality Related Gene And Their Relationship With Intramuscular Fat Content

Baixi pig is an excellent local breed in Guizhou Province with superior meat quality, slow growth and low lean percentage, which becomes an important breakthrough point for the futher study. Till now, more researches are still necessary regardless of achievements obtained about the development and utilization of germplasm resources. Aimed at exploring genetic mechanism of those genes which were ralated to meat quality traits of Baixi pig at the molecular level, providing reference for utilization and cultivation new varieties of germplasm resources for Baixi pig, F1 generation of Baixi pig crossed with Duroc was treated as research object, of which Baixi pig acted as the female parent, and germplasm performance measurement was conducting on DBF1 generation. PID1 and LYRM1, two meat quality related genes, used as the candidate genes. The technology of gene cloning and qPCR was applied to detect polymorphism of two genes before and after hybridization, mRNA expression and its relationship with the IMF deposition. Research results were as follows:Haln gene wasn't found in Baixi pig. The body remained moderate in size after hybridization.loin eye area(28.33±7.09cm2), fleshcolor, marbling(3.50±0.50) and pH(pH1=6.39±0.03,pH24=6.06±0.05) were still maintained a good level. Unsaturated fatty acids(64.33±0.21%),muscle fiber diameter(32.11±1.31 ?m) and density(860.23±25.31 beam/mm2) were all kept a high level. IMF content(4.08±0.89%) and leg-to-buttock percentage(31.32±3.13%) showed an upward trend. What's more, average backfat thickness(24.69±3.91%), delicious amino acids(48.46±0.35%)and total amino acid content(73.85±1.46%) were significant down-regulated, with muscle tenderness and water holding capacity decreasing significantly.The PID1 and LYRM1 genes were highly conserved among many species and none of polymorphisms were found in Baixi pig. A hydrophilic protein was encoded by the PID1 gene,which was composed of 217 AA, localized in the cytoplasm, and a special PTB domain was found at C terminal. The pig LYRM1 gene was cloned for the first time. The LYRM1 gene encoded a hydrophilic protein composed of 122 AA with the subcellular localization in mitochondria, no special domains were found either. Two genes were totally expressed in all 9 organizations, no matter whether hybridization or not, appearing differential expression. Before hybridization, PID1 gene was significantly higher expressed in liver and lower expressed in heart; LYRM1 gene was significantly higher expressed in spleen and lower expressed in the lung. The two expression rules were inconsistent. After hybridization, both PID1 and LYRM1 genes were significantly higher expressed in heart and lower expressed in muscle, and the two expression rules were relatively consistent. IMF was up-regulated after Baixi Pig crossing with Duroc; no significant difference expression was indicated on PID1 gene. However, the highly significant down-regulated expression was existed on LYRM1 gene and presented extremely significant negative correlation with intramuscular fat deposition.