Isolation of new alleles of the swine <I>TLR4</I> gene and analysis of its genetic variation

Abstract

Using the PCR-SSCP method, the genetic variation in exon 1 of the TLR4 gene was detected among 893 animals, including Asian wild boars, 3 imported commercial and 10 Chinese indigenous swine breeds. This was conducted to analyze the polymorphisms of exon 1 of TLR4 gene in native and foreign pig breeds and aimed at providing a theoretical foundation for further research on the role that TLR4 gene played in immune and defense system. New alleles were isolated for exon 1 of the swine TLR4 gene for the first time, There were 6 genotypes and 3 alleles, in which the Duroc appeared AA, BB, CC, AB, AC and BC genotypes; Sutai pig, which has Duroc pig origin, were detected to be BB, CC, and BC genotypes; Yorkshire and Landrace were detected to be CC and BC genotypes. Wild boar and all 10 Chinese native pig breeds appeared highly conserved in exon 1 of TLR4 gene, with only CC genotype. Among the 3 homozygous genotypes, the CC genotype matches the sequence in GenBank, while a G93C synonymous mutation and a G194A nonsense mutation were found in the BB and AA genotypes, respectively. The correlation between these two mutation points of TLR4 gene with resistance to stress and disease is worthy of further study.