Amphioxus Development Of Several Related Genes And Misaki The Stigma Insect's Morphology Was Observed

Amphioxus, a cephalochordate, widely considered as the closest living invertebrate relatives of the vertebrates. It is a key organism for understanding evolution of developmental mechanism because its body structure is simple than that of vertebrates but resembles the common ancestor of amphioxus and vertebrate, Furthermore, amphioxus has its idiographic evolution history. Although the genome of amphioxus is not duplicated extensively, the duplication or lost of some independent genes shouldn't be disregarded. So amphioxus is an ideal organism for the research of animal developmental mechanism as well as origin and evolution of vertebrates. The research of amphioxus on molecular level has progressed greatly in recent years. A lot of genes have been cloned from amphioxus, which includes transcription factors, growth factors, signal molecules, and so on. Now we have gained more knowledge of the developmental mechanism in amphioxus, and the research on the genome of amphioxus will complete soon. The study of amphioxus will be certainly helpful to elucidate the mechanism of development and evolution of vertebrate. Because of the difficulty in the acquirement of this kind of material, which is caused by amphioxus's extremely limited distribution, the work on the research of amphioxus is still not enough.Acorn worm, a special Notoneuron, is regarded as another important animal model for phylogenetic analyses. As one of the basic steps necessary for extending and clarifying information of phylogenetic analyses, the systemic morphologic observation on acorn worm is performed.Here, four genes (Thymosin-β4, AmphiRACK1, AmphiHMGB and Toll-like) have been cloned from amphioxus, and the expression patterns and the phylogenetic analysis have been performed. These data give insight into the development mechanism and evolution of the amphioxus and vertebrates. The systemic morphologic observation on acorn worm is also reported in this dissertation.