%A WANG Ting-Ting, Hao You-Jin, He Zheng-Bo, Mei-Ting, Chen-Bin %T Characteristics and classification position of the ionotropic receptor genes IR8a and IR25a in four vector mosquito species of medical importance %0 Journal Article %D 2017 %J Acta Entomologica Sinica %R 10.16380/j.kcxb.2017.04.003 %P 379-399 %V 60 %N 4 %U {http://www.insect.org.cn/CN/abstract/article_5997.shtml} %8 2017-04-20 %X 【Aim】 To identify the ionotropic receptor genes IR8a and IR25a , and the representative iGluRs and IRs genes in four vector mosquito species of medical importance, Anopheles sinensisAnopheles gambiaeAedes aegypti and Culex quinquefasciatus, and to investigate the characteristics and phylogenetic relationships of these genes, so as to determine the classification position of the IR8a and IR25a genes in the group of ionotropic glutamate receptor genes. 【Methods】 By using BLASTP and BLASTN searching against the genomes of these four mosquito species with the iGluRs and IRs gene sequences of Drosophila melanogaster as query sequences, the sequences of iGluRs and IRs genes of these four mosquito species were identified. The characteristics of the amino acid sequences of IR8a and IR25a and the representative iGluRs and IRs genes identified were predicted and comparatively analyzed by bioinformatics methods. The phylogenetic relationships of these genes in the five species were deduced and discussed by using maximum likelihood, Bayesian and maximum parsimony methods based on amino acid sequences, and the selection pressures of these genes were analyzed with the dN/dS(ω) values calculated by using PAML software. 【Results】 The sequences of IR8a and IR25a, 24 representative traditional iGluRs genes and 30 representative IRs genes in mosquitoes An. sinensisAn. gambiaeAn. aegypti and Cx. quinquefasciatus were identified by bioinformatics methods. The comparative analyses of characteristics and phylogenetic relationships of these genes showed that the amino acid sequence lengths of IR8a and IR25a in the four mosquito species and D. melanogaster are closer to those of iGluRs, and their mean values are significantly longer than those of other IRs. IR25a has the aminoterminal domain (ATD) that is the characteristic of traditional iGluRs, and IR8a also has a region similar to ATD, although it is not conservative, while IRs have no ATD. IR8a and IR25 also have the conserved S1 and S2 ligand-binding domain (LBD), the characteristics of iGluRs, but IRs do not have it. The dN/dS(ω) values of all these genes were far less than 1, suggesting the purifying selection in evolution, while the dN/dS(ω) values of IR8a and IR25a were closer to those of iGluRs. In addition, like non-NMDA, IR8a and IR25a have specific sites which do not exit in IRs. IR8a and IR25a cluster together with non-NMDA to form a sister group, with the genetic distance between the sequences within the group less than that of any other pairs of sequences in this study. Based on these results, IR8a and IR25a were classified into the non-NMDA receptors in iGluRs, and named as Putative receptors. 【Conclusion】 This study developed the information frame of iGluRs and IRs genes of mosquito species and determined the classification position of IR8a and IR25a genes, which is of significance for further functional study of these genes.