Roles of a Y-linked iDmrt1 paralogue and Insulin-Like Androgenic Gland Hormone in Sexual Development in the Tropical Rock Lobster, Panulirus ornatus

This study investigates the functions of the Y-linked iDmrt1 paralogue, Po-iDMY and insulin-like androgenic gland hormone (Po-IAG) in the process of sexual development in the tropical rock lobster, Panulirus ornatus (TRL). Previously, we identified that Po-iDMY, a male-specific heterogametic (Y-linked) paralogue of the autosomal Po-iDmrt1 found in TRL, is a second sex-linked iDmrt gene identified in invertebrates. Using 5’ and 3’ rapid amplification of cDNA ends and data from a draft male genome (with an assembly genome size of approximately 2.446 Gbp and 87% BUSCO completeness), we obtained the full-length Po-iDMY gene (coding for a 312 amino acids protein), which includes a 411 bp male-specific sequence located at the 3’ untranslated region of Po-iDMY mRNA used as a sex marker. Notably, this sex marker sequence is reported for the first time in our genome analysis. However, Po-iDMY is not expressed across various tissues and developmental stages across embryos, juveniles and adults. This observation suggests that Po-iDMY may not tightly regulate Po-IAG in this species, indicating that silencing Po-IAG could potentially induce sex change. Further expression analyses confirmed that Po-IAG expression is not male-specific. Despite this, Po-IAG silencing at an early juvenile stage generated two potential neo-females, implying that sexual manipulation could be a promising technique in TRL.