| In this study, Guizhou White Goat was chosen as research object, the technologies of PCR-SSCP, direct sequencing, real-time PCR, clone and so on were utilized to the research. Meanwhile the cDNA sequence of TFAM gene was cloned to analyze the structure and physicochemical property of TFAM protein by bioinformatics. The expression level of TFAM and TFB2 M gene in different tissues and the SNPs of them was analyzed with the meat, slaughter traits of Guizhou White Goat.The study on the candidate gene of mammal meat quality and slaughter traits can improve the meat quality and shorten breeding progress of native goats. The major experimental results obtained in my study were as follows:1. The cDNA sequence of TFAM gene which we got before was utilized to analyze the structure and physicochemical property of TFAM protein by bioinformatics software. The open reading frame of TFAM protein with 741 bp could encode 246 amino acids. The theoretical isoelectric point at 9.74 showed that TFAM protein was acidic. And because there was no transmembrane helical structural, TFAM protein did not belong to membrane proteins or secreted proteins. The functional analysis of TFAM protein showed that it most likely played an important role in the cell membrane, and the value was about 13.18. The classification of gene ontology showed that it most likely played an important role in regulating internal secretion as hormone, and the value was about 17.538. Sequence analysis showed that the cDNA of TFAM gene from Guizhou White Goat had the highest homology with those of ovis(up to 98.8%).2. The SNPs of C-429 T and A17110 C were found in TFB2 M gene, but there was no SNPs in TFAM gene. There are three genotypes in the two sites, CC, CT, TT and AA, AC,CC. The genetic variation analysis had shown that both of the sites’ He were high and PIC was 0.25<PIC<0.50. The two sites accord with Hardy-Weinberg. The results of association analysis of C-429 T locus showed that, the individuals of genotype CC and CT were superior than TT in water holding, and TT were superior than CT in bone weight significantly(P<0.05), it suggested that this SNPs could have influence on meat and bone weight in Guizhou White Goat. The results of association analysis of A17110 C locus showed that, the individuals of genotype AA were superior than AC in bone weight significantly(P<0.05), and we could not obtain significant correlation in meat traits and slaughter traits in Guizhou White Goat(P>0.05), it suggested that this SNPs could have influence only on bone weight in Guizhou White Goat.3. The portfolio analysis of combination genotype combining C-429 T locus and A17110 C locus showed that genotypes AACC, CACC and CACT were significant in improving water-holding capacity, similarly, genotype CACT in improving shear force, genotypes AACC and CATT in improving bone weight, genotypes AACT, CACC and CACT in meat-bone ratio, and genotype AACC in bone percentage were also vital.4. The correlation analysis of indexes of meat quality traits indicated that water loss rate and cooked meat percentage were significantly positive correlation with marbling(P<0.01). Similarly, shear force was positive correlation with water-holding capacity, and marbling was positive correlation with water-holding capacity and cooked meat percentage too(P<0.05). The correlation analysis of indexes of meat quality traits indicated that live-weight was significantly positive correlation with carcass weight, meat weight, fur weight and lumbar muscle thickness(P<0.01), and positive correlation with bone weight(P<0.05), but negative correlation with fur percentage(P<0.05). Dressing percentage was significantly positive correlation with meat weight, lumbar muscle thickness, net meat percentage, bone percentage and meat-bone ratio(P<0.01), and positive correlation with bone weight(P<0.05), but negative correlation with fur percentage(P<0.05). Carcass weight significantly positively correlated with dressing percentage, net meat percentage, bone weight, fur weight, lumbar muscle thickness, net meat percentage and meat-bone ratio(P<0.01), and positively correlated with bone percentage and meat-bone ratio(P<0.05), but negatively correlated with fur percentage(P<0.01).5. Bioinformatics analysis of TFB2 M gene indicated that the mutation of A17110 C locus resulted in the slight change of RNA secondary structure, and the structural stability increased slightly because of its minimum free energy decreased from-529.4 kJ/mol to-529.8 kJ/mol. C-429 T locus was located in TFB2 M gene promoter which might contain two core promoter regions, and the change of C-429 T locus changed the transcription factor binding sites. Meanwhile C-429 T locus was in predicted CpG island region, but the SNPs had less effect on CpG island.6. The expression level of TFAM and TFB2 M was examined by RT-PCR in different tissues of Guizhou White Goat, and the expression rule as follows. The expression level of TFAM gene, lung ﹥ cerebellum ﹥ pituitary ﹥ heart ﹥hypothalamus﹥kidney﹥brain﹥liver﹥spleen. The expression level of TFB2 M gene, spleen ﹥ kidney ﹥ lung ﹥ pituitary ﹥ brain ﹥ heart ﹥ cerebellum ﹥ hypothalamus ﹥liver.7. The expression of TFAM gene in kidney, hypothalamus, lung and brain have significant difference positive correlation with Water loss,Shear force, Carcass weight and Meat-bone ratio(P<0.05), but, the expression in hypophysis and liver have significant difference negative correlation with Water holding and Bone weight(P<0.05). The expression of TFB2 M gene in lung, spleen, kidney, liver, spleen and spleen have significant difference positive correlation with Shear force, Water loss, Meat color, Marbling, Marbling, Thigh muscle thickness, Live-weight(P<0.05), but, the expression in liver has very significant difference negative correlation with Shear force(P<0.01). |
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