“…Along with rapid advances of molecular genetics and genomic sequencing, numerous sex-specific or sex chromosome-linked DNA markers have been successfully screened and identified from a wide range of more than 100 aquatic species including fish, testudines, amphibia, echinodermata, decapod, and shellfish (Table 1) by different genetic and genomic methods, such as restriction fragment length polymorphism (RFLP) (Devlin et al, 1991), random amplified polymorphic DNA (RAPD) (Chen et al, 2009), suppression subtractive hybridization (SSH) (Chen et al, 2010), microsatellite or simple sequence repeats (SSR) (Sakamoto et al, 2000), amplified fragment length polymorphism (AFLP) (Dan et al, 2013;Ezaz et al, 2004;Griffiths et al, 2000;Ma et al, 2010;Olmstead et al, 2011;Pan et al, 2015;Wang et al, 2009a;Wang et al, 2009b), fine and linkage mapping of sex quantitative trait locus (QTL) or sex determination (SD) locus (Kamiya et al, 2012;Liu et al, 2020;Sun et al, 2014;Viñas et al, 2012;Yu et al, 2017;Zhang et al, 2019b), putative sex-linked and sexrelated gene sequence comparison or next-generation sequencing (NGS)-based and high-resolution melting (HRM) typing system (Gao et al, 2020;Ou et al, 2017;Perez-Enriquez et al, 2020;Yang et al, 2020), genome sequencing and re-sequencing (Han et al, 2020;Lin et al, 2017a;Liu et al, 2018;Xiao et al, 2020;Zhang et al, 2017a), comparative transcriptome and RNA sequencing (RNA-seq) (Lamatsch et al, 2015;Sun et al, 2018), restriction-site associated DNA sequencing (RAD-seq) (Fang et al, 2020;Lange et al, 2020;…”