Abstract: Vitellogenins, cyclorraphan yolk polypeptides and lepidopteran minor yolk proteins are main three classes of yolk proteins in insects, and evolutionary relationships among them are always the key problems for study. This paper explored the molecular evolution relationships within and among three yolk proteins based on their sequence data retrieved from the NCBI protein database through alignment and phylogenetic analysis. Combined with what have been achieved for their evolutionary relationships, we concluded that vitellogenins are well conserved in insects, showing similarity to the vertebrate apolipoprotein B; yolk polypeptides are related to vertebrate hepatic and pancreatic lipases but lost their functions in phylogenesis, while minor yolk proteins are related to a family of lipases containing vertebrate gastric lipases and lingual lipases. In addition, molecular characteristics of three yolk proteins were also summarized.

Key words: Vitellogenin, yolk polypeptides, minor yolk protein, molecular evolution, phylogenetic analysis