ABSTRACT
Single-nucleotide polymorphisms of the MyoG gene were tested using PCR-SSCP from 73 Landrace pigs, 68 Large White pigs, 57 Yimeng pigs and 83 Laiwu pigs. The effects of the MyoG gene on the birth weight, the average daily gain, the meat tenderness, and the backfat thickness were also analyzed. On the basis of the DNA sequence (M14331) of the porcine MyoG gene, primers were designed to amplify MyoG gene. One polymorphism was found in the amplified region of intron 1, in which two alleles ( A, and B) and three genotypes (AA, AB, and BB ) were examined. A G→ C transition was detected at 2 943 locus by sequencing the homozygotes. The results show that: ( 1 ) The Large White breed differed significantly ( P ＜0.05) in genotype distribution from the Landrace, the Laiwu and the Yimeng breeds;and the Laiwu breed differed significantly( P ＜ 0.05) in genotype distribution from the Landrace and the Yimeng breeds; whereas no significant differences( P ＞ 0.05) were found in genotype distribution between the Landrace and the Yimeng breeds. (2) On the basis of the fixed effect model, significant differences ( P ＜ 0.05) were found in the birth weight and the tenderness among the different MyoG genotypes, whereas no significant differences ( P ＞ 0.05)existed in the average daily gain and the backfat thickness. (3) Using least square analysis, it was seen that significant differences ( P ＜ 0.05) exist in the meat tenderness between the individuals of the BB genotypes and those of the AA genotypes; and significant differences ( P ＜ 0.05 ) were found in the backfat thickness compared the pigs of the AA genotypes with the pigs of the AB, BB genotypes. These results suggest that the MyoG genotype has significant effects on the meat quality, the growth rate, and the backfat thickness,therefore MyoG gene can be used in marker-assisted selection to improve meat quality and growth rate, and to accelerate the breeding progress.
ABSTRACT
Objective To achieve the fusion expression of the entire human beta-defensin-3(hBD-3) gene. Method We synthesized two oligonucleotide primers accor ding to the codon preference of Escherichia coli. The gene was cloned into p GEX -4T-2 to establish the pGEX-4T-2-hBD-3 as the fusion expression vector by PCR. Transformed into E.coli strain DH5α, the express vector was induced an d ex pressed by IPTG. The fusion protein GST-hBD-3 was obtained by repeated cycles of freezing and thawing, cut by thrombin to attain the recombinant hBD-3 protei n. Result The result of the antibacterial peptide agarose diffu sion assay shows the antibacterial activity of the rhBD-3 against the S.aureu s exists, and it reaches 0.843U. Conclusion The fusion expr ession of the hBD-3 gene is successful.