Introduction
The freshwater prawn Macrobrachium rosenbergii bears the WZ/ZZ system of sexual heritability, in which females are heterogametic (WZ) and males are homogametic (ZZ)[1]. The insulin-like androgenic gland (IAG) hormone is a universal master switch in decapod crustacean sex differentiation, in which IAG expression induces masculinization and its absence results in feminization thus termed the “IAG-switch” [2]. Manipulations of the IAG-switch afforded cases of functional WZ males, ZZ females, and even WW males and females, enabling the production of monosex homogametic M. rosenbergii populations [1, 3, 4

General aim
Identifying sexually biased W and Z-associated genes in early developmental stages upstream to the IAG-switch and elucidating their role in sexual differentiation.

Scientific approach
Screening an early developmental stages transcriptomic library of WW females and ZZ males and identify differentially expressed candidate genes that are located on W and Z associated scaffolds in M. rosenbergii phased genome. Characterization of candidate genes in-silico using bioinformatics tools for target gene selection and in-vitro validation by quantitative (q) PCR. The function of the selected gene (gene 9946) was studied using in-vivo RNAi loss of function experiments in early post-larval stage. The procedure relevance was further studied by the effect on IAG expression level.

conclusions
Reduction and refinement of the list of candidates were achieved resulting with identification of 6 candidate genes from the early developmental stages transcriptomic library of WW female and ZZ male

*Gene 9946 was found to be homolog to a family of cytochrome P450 proteins

Silencing of the 9946 gene resulted in a decrease in MrIAG expression but without statistical significance