Identification and Evolution Analysis of the Genes Involved in the 20-Hydroxyecdysone Metabolism in the Mud Crab, : A Preliminary Study.

Background: 20-Hydroxyecdysone (20E) is the most ubiquitous ecdysteroid (Ecd) and plays critical roles during the life cycle of arthropods. To elucidate the metabolism pathway of 20E in the economically important species, , we conducted a comprehensive exploration of the genes involved in the 20E metabolism pathway.

Methods: A comprehensive exploration of genes involved in the 20E metabolism pathway was conducted, including gene annotation, local blast using the ortholog as query, and TreeFam ortholog genes identification. Bioinformatics and expression profiling of the identified genes were performed to assess their roles in the 20E metabolism of green mud crabs.

Results: This experiment indicated that, except for and , all other ortholog genes involved in the 20E metabolism can be found in the mud crab, suggesting that the function of these two genes might be replaced by other genes or the "active" Ecd in mud crabs was not the 20E. All genes had the typical features of each gene family, clustered with the specific clade in the phylogenetic trees. In addition, all the identified genes had the highest expression level in the Y-organ, and sex-biased gene expression was observed in these genes.

Conclusions: This study provided some valuable insights into the metabolism and diversity of ecdysteroids in crustaceans.