Identification, Evolution and Expression Analysis of Dmrt Genes in Polychaetes

Abstract The doublesex-mab3-related transcription factor (Dmrt) gene family is a class of crucial transcription factors characterized by one or several DM domains. Dmrt family genes play important roles in sex determination/differentiation. Polychaete annelids are critically important in most marine ecosystems. However, to date, the genome-wide characterization and analysis of Dmrt genes in polychaetes have not been investigated. In this study, the identification and analysis of Dmrt genes were performed in three representative polychaetes, including Capitella teleta, Dimorphilus gyrociliatus, and Owenia fusiformis. A total of 12 Dmrt genes have been found, and the number of Dmrt genes in different polychaetes ranges from 3 to 5. The phylogenetic tree showed that all identified Dmrt genes were classified into 4 classes: Dmrt2/11E, Dmrt3/93B, Dmrt4/5/99B, and DSX. Furthermore, the selection pressure analysis suggested that all the Dmrt genes underwent strong purifying selection pressure. The spatiotemporal expression profile in O. fusiformis suggested that Dmrt genes have diverse functions, and the Dmrt2/11E-like gene may play an important role in the sex determination/differentiation of polychaetes. In general, this study provides a molecular basis for polychaete Dmrt genes and may serve as a reference for in-depth phylogenomics.