Preliminary Study About The Porcine TXNIP,CKM And ACTC Gene

Based on the study using suppression subtractive hybridization (SSH), this study was aimed at laying groundwork for isolating and identifying genes related to heterosis as well as exploring the molecular mechanism of heterosis at the level of gene expression, generated the forward- and reverse- subtractive cDNA libraries containing some differentially expressed fragments between Longissimus Dorsi of Largewhite and F₁ of Meishan×Largewhitepigs. In order to understand the structure and function of the differentially expressed genes, association study and genetic effect analyses between the polymorphisms of the two differential expressed genes from the cDNA libraries and important production traits in pig were carried out, as well as the general study on the promoter of the genes. The results are as follows:1. The full genomic sequence of porcine TXNIP gene were cloned and sequenced using Largewhite and Landrace and Meishan pigs DNA. By comparing DNA sequences among the three pig breeds, 8 SNPs were detected within genomic sequence, Long DNA fragment missing and insertion mutation were not found in these introns. The spliting sites conform to GT/AG rules in all these introns.2. A C126T polymorphism was detected in intron 4 of pig TXNIP gene, and detected by the PCR-Mae I -RFLP genotype method. Studies in Meishan, Large White and Landrace breeds and Large White x Meishan reference family showed that:(1) In 40 Meishan, 33 Large White and 16 Landrace pigs, Meishan and Large White pigs were almost BB genotypes with B frequency 98% above; while Landrace pigs were mainly AA genotypes, with A frequency 97%. It could be concluded that in those three pig populations, allele A and B frequencies appear to be significantly different between Meishan and Landrace pig breeds.(2)Association analysis in 181 (Yorkshire×Meishan) F2 resource families showed that: for carcass traits, significant associations were found between genotypes and DP, TFT, while no associations detected for meat quality traits.(3) REG procedure analysis showed that, this locus seemed to be additive; for CL1 and CL2, the additive effects were significant (P < 0.05), while for TFT and LEA, it is highly significant (P < 0.01). Compared with BB genotypes, AA genotypes have thinner TFT and higher DP.3. The intron5, intron6, intron7 and promoter of CKM gene from the Largewhite, Landrace and Meishan were cloned and sequenced. The mutation number, including single mutations and missing mutations in intron5, intron6, intron7 and promoter are 2, 4, 2 and 9 respectively. The spliting sites conform to GT/AG rules in all these introns. The sequence length of pig CKM gene intron5, intron6, intron7 and promoter are 1770bp, 1200bp, 1210bp...