关键词: 中华按蚊, HPX家族, 全基因组鉴定, 特征, 系统发育, 进化

Abstract: 【Aim】 To identify genes of the heme peroxidase (HPX) family of Anopheles sinensis at the whole-genome level, to predict the basic features of these HPX members, and to explore the phylogenetics and evolution of the HPX members of five representativedipterans. 【Methods】 The amino acid sequences encoded by HPX genes in Drosophila melanogaster, Bombyx mori and other insects were downloaded from NCBI databases and used as queries to search for the HPX genes in An. sinensis genome using the local Blast program. The HPX genes in Anopheles gambiae, Aedes aegypti and Culex quinquefasciatus on the whole genome were also identified by using the same method. The HPX genes identified in An. sinensis were named following the nomenclature system established for An. gambiae HPX genes. The characteristics of these HPX genes in An. sinensis, including the structure and scaffold location of these genes, the substitution rate and conserved domain of their amino acids, and the 3D structure of their proteins, were predicted using bioinformatics analysis. These An. sinensis HPX genes were also located on chromosome through the synteny analysis with An. gambiae HPX genes. The phylogenetic relationships of the HPX genes of five representative species of Diptera were constructed based on nucleotide sequences using maximum likelihood method with PAUP 4.0 and MEGA 6.0. 【Results】 The An. sinensis genome contains 20 HPX genes, while those of An. gambiae, Ae. aegypti and Cx. quinquefasciatus contain 18, 14 and 12 HPX genes, respectively. The HPX proteins of the four mosquito species were all classified into Peroxinectin, Peroxidasin, DBLPX and DUOX subfamilies, with the molecular weights of their amino acids ranging from 61.6-186.6 kD, except AsHPX8 (29.6 kD). The 20 HPX genes of An. sinensis contain 98 exons and 75 introns, and the distribution patterns of their exons and introns are quite diverse among different genes. These HPX genes of An. sinensis are mapped on 10 scaffolds, and syntenied to the chromosomes 2R, 3R, 2L, 3L and X in reference of An. gambiae genome. All the amino acid sequences of HPX genes in An. sinensis (except DUOX) each has one heme and five Ca²⁺ binding sites, and contains two cysteine sites in each of N-terminus and C-terminus, which define two disulfide bonds. The ω values of An. sinensis and An. gambiae orthologousgene pairs were all less than 1, suggesting that HPX genes has no obvious environmental selective pressure during their evolution. The HPX genes of the five representative dipteran species were divided into 16 groups on the phylogenetic tree, 11 of which showed to be monophyletic with ＞83% bootstrap support and homologous genes clustered together. 【Conclusion】 This study provides the basic information frame for the HPX genes of An. sinensis. The HPX proteins in different mosquito species have similar molecular weights, and this is associated with a high degree of structure conservation of the HPX family proteins. The DUOX of mosquitoes gradually lost its function with their deletion of the main functional loci, and this is related to its specific environmental adaptation. The peroxidase domain in the DBLPX subfamily is the most conserved in all subfamilies of the HPX family. 

Key words: Anopheles sinensis; HPX family, genome-wide identification, characteristics, phylogeny, evolution