Identification of Caspase-6 and Caspase-7 from miiuy croaker and evolution analysis in fish

Apoptosis is a basic biological phenomenon of cells, which is an important component in the evolution of organisms, the stabilization of the internal environment and the development of multiple systems. In addition, the caspase protein family plays an important role in these pathways of apoptosis. Among them, apoptotic executors can directly act on specific substrates to complete the apoptotic response. In this study, we identified the Caspase-6 and Caspase-7 genes of miiuy croaker, and then analyzed the evolution of the whole Caspase family, furthermore described the evolutionary selection sites of the caspase-6 and caspase-7 genes in fish. The results showed that Caspase-6 gene appeared earlier than Caspase-7 in species evolution and gene duplication in teleost fish. Moreover, we also found that caspase-6 gene had no potential positive selection sites in the evolution of fish. Unlike the caspase-6 gene, the caspase-7 gene did not appear to be missed or replicated during the evolution of the species, while, it to be found two potential positive selection sites.