title: Evidence of positive selection at signal peptide region of interferon gamma.
abstract: Interferon gamma (IFNG) is a major cytokine and plays crucial roles in pathogen clearance. About the course of evolution of IFNG, it has been reported that IFNG is being subjected to adaptive selection, which is proved at the level of gene. Neighbor-joining method was used to reconstruct the phylogenetic tree of all IFNG protein-coding sequences. The pair-wise computation of Ka/Ks between every exon homologs, branch-specific model, and site-specific model of the likelihood method were performed to detect positive selection of IFNG. We reported, for the first time, that the signal peptide region of IFNG is under significant positive selection, evolving faster than other parts. We provide evidence at the level of individual exon and individual amino acid site that IFNG is under adaptive evolution, which establishes the basis for further researches about IFNG.
authors.affiliation: a Department of General Surgery, Ren Ji Hospital, School of Medicine , Shanghai Jiao Tong University , Shanghai , China.
authors.forename: Zhengshi
authors.initials: Z
authors.lastname: Wang
authors.forename: Ming
authors.initials: M
authors.lastname: Zhong
authors.forename: Maobin
authors.initials: M
authors.lastname: Fu
authors.forename: Tonghai
authors.initials: T
authors.lastname: Dou
authors.forename: Zhengqian
authors.initials: Z
authors.lastname: Bian
mesh_terms: D000818:Animals; D001499:Bayes Theorem; D019143:Evolution, Molecular; D005091:Exons / Q000235:genetics; D006801:Humans; D007371:Interferon-gamma / Q000737:chemistry* / Q000235:genetics*; D016013:Likelihood Functions; D010802:Phylogeny; D021382:Protein Sorting Signals; D012641:Selection, Genetic; D012984:Software
chemical_list: D021382:Protein Sorting Signals; D007371:Interferon-gamma
keywords: Ka/Ks; adaptive evolution; interferon gamma (IFNG); site model