中文摘要：

为比较干扰素调节因子（IRF）4、IRF8、IRF9和IRF10在硬骨鱼类中的进化和分化情况，构建系统进化树，并采用非同义替代（Ka）与同义替代（Ks）的比值计算这几种基因在硬骨鱼类中进化率。结果表明：IRF4、IRF8、IRF9和IRF10在进化树上各成一支，硬骨鱼类IRF4进一步分化为IRF4a和IRF4b。4个基因的Ka／Ks值均小于1，说明这些基因在硬骨鱼类进化过程中是负选择，提示在不同物种中这些基因保持原有的功能并趋于稳定。尽管如此，不同基因进化速率存在明显差异。IRF9、IRF10、IRF4a、IRF4b和IRF8进化率分别为0．50、0．30、0．20、0．25和0．15。充分表明在硬骨鱼类进化过程中IRF8、IRF4a和IRF10分化程度低，而IRF46和IRF9分化程度高。

英文摘要：

IRF4, IRF8, IRF9 and IRF10 belong to IRF4 subfamily in interferon regulatory factor family. The phylogenetic tree and evolutionary rate of IRF4, IRF8, IRF9 and IRF10 were compared in the study, which would elucidate the conservation and diversification in evolution about the four genes in bony fishes. Evolutionary rate was calculated with the ratio of nonsynonymous to synonymous substitution rates （Ka/Ks）. The results showed that IRF4, IRF8, IRF9 and IRFIO clustered to a group respectively and IRF4 genes were consisted of IRF4a and IRF4b. The average Ka/Ks ratios of four genes in IRF4 subfamily among different bony fishes were all less than 1, indicating they were under purifying selection. However, evolutionary rate between them was different. The Ka/Ks ratio was about 0.50, 0.30, 0.20, 0.25 and 0.15 for IRF9, IRF10, IRF4a, IRF4b and IRF8, respectively. All these data proved that IRF8, IRF4a and IRF10 showed higher conservation while IRF4b and IRF9 presented higher diversification in bony fish.