Cloning and Sequence Analysis of Duck IL-18 Gene

[Objective] The research aimed to lay the foundation for deeply studying the expression of duck IL-18 gene and its biological activity and molecular adjuvant application.[Method] A pair of primers was designed according to the sequences of IL-18 gene in the duck of Hongkong on GenBank website.Total RNA from spleen lymphocyte in Guangdong teal was taken as template to make RT-PCR amplification.IL-18 gene in Guangdong teal was cloned and sequenced.[Result] The sequencing results showed that the open reading frame of IL-18 gene in Guangdong teal was 603 bp,coding 201 amino acids,with the molecular weight of 23.2 kDa.The sequence analysis showed the nucleotide homology of IL-18 gene between Guangdong teal and Hongkong duck on GenBank website was 98.2% and the amino acid homology was 100%.Its nucleotide homology with chicken and turkey were 86.9% and 87.1% resp.,the amino acid homology were 96.5% and 97.0% resp.[Conclusion] The results of phylogenetic analysis showed that duck IL-18 gene had closer evolutionary relationships with that of chicken and turkey.