Fishes are not only one of major groups with highest species diversity among vertebrates,but also one of important parts for studying vertebrate evolutionary processes. Based on available information from whole-genome sequencing of representative fish species,in order to understand changes in genomes or genes that occurred during vertebrate evolutionary processes from Agnatha to Chondrichthyes and to Osteichthyes,this paper reviews genome duplication,evolution of important genes,and evolution of immune syst...