Polymorphic Analysis of TLR4 Gene in Hainan Local Pig Breeds Based on Sequencing Technology

[Objective]The paper was to understand the polymorphism of TLR4 gene in Hainan local pig breeds.[Method]The TLR4 genome sequence of Wuzhishan pigs,Lingao pigs,and Tunchang pigs was cloned and sequenced by PCR.The sequence was analyzed using DNAStar and BioEdit software,and the structure of TLR4 protein was analyzed using SMART,SOPMA,and SWISS-MODEL online software.The secondary structure and tertiary structure of TLR4 protein were predicted as well.[Result]The total length of TLR4 gene in three Hainan local pig breeds were all 10435 bp which included a 2526 bp CDS(coding 841 amino acid).Intra-specific comparison showed that there was one nucleotide site with polymorphism in Wuzhishan pigs;there were six nucleotide sites with polymorphism in Tunchang pigs,two of which were located in the coding area;there were three nucleotide sites with polymorphisms in Lingao pigs,one of which was located in the coding area.When interspecific comparisons of TLR4 gene sequences from three Hainan local pig breeds were performed,there were 27 nucleotide sites with polymorphism,two of which were missense mutations,resulting in amino acid changes.The homology of TLR4 gene sequence from three pig breeds was 99.8%-99.9%,indicating that the TLR4 gene sequence was highly conservative.The predicted protein structure indicated that the G→T mutation at 7209 site and G→A mutation at 7781 site in TLR4 gene of Hainan local pig breeds caused changes in the secondary and tertiary structure of TLR4 protein.[Conclusion]TLR4 gene in Hainan local pig breeds has polymorphism.The structural changes caused by polymorphism may change the function of TLR4 gene.