Bulk and single-cell RNA-seq reveal the role of dmrtb1 in a sequentially hermaphroditic fish, Mastacembelus armatus

Sequential hermaphroditism, whereby the sex of one individual changes during its development, has been described in many fish species. Yet, the genetic regulation of this dynamic process of sexual differentiation is not well understood. Here, we report the characterization of sequential hermaphroditism in an aquacultural fish, the zig-zag eel (Mastacembelus armatus), based on 4 years of artificial breeding. All M. armatus individuals initially developed as females, with approximately half of them then becoming males after going through an intersex phase. The ovotestes of three individual 2-year-old zig-zag eels were dissected, and mixed to a single sample of ovotestis.