Four new single nucleotide polymorphisms (SNPs) of toll-like receptor 7 gene discovered in Chinese ducks

Abstract

In order to reveal the single nucleotide polymorphisms (SNPs), genotypes and allelic frequencies of each mutation site of TLR7 gene in Chinese native duck breeds, SNPs of duck TLR7 gene were detected by DNA sequencing. The genotypes of 465 native ducks from eight key protected duck breeds were determined by polymerase chain reaction ligase detection reaction (PCR-LDR) method. The results show that four new SNPs (T2606C, T2739C, C2820T and A3284G) were discovered and three genotypes were all found in each mutation site. The first and the fourth SNPs resulted in two amino acid changes of Methionine (M) → Threonine (T) and Glutamine (Q) → Arginine (R), respectively. Allele C frequency of TLR7 T2606C mutation site in Gaoyou (GY) duck breed was significantly higher than the corresponding allelic frequency in the other duck populations, and allele T frequency of TLR7 C2820T mutation site in GY duck breed was also significantly higher than the corresponding allelic frequency in the other duck populations except Putian (PT) duck breed. In conclusion, the four new SNPs and the genetic differences among different duck breeds will promote duck disease resistance research. Key words : TLR7, duck, single nucleotide polymorphism (SNP), polymerase chain reaction ligase detection reaction (PCR-LDR).