“…Several germ cell markers have been investigated and used in reproductive biological and biotechnological studies on vertebrates, including DEAD (Asp-Glu-Ala-Asp) box polypeptide 4 ( ddx4 ; previously known as vasa ), microRNA-mediated repression inhibitor 1 ( dnd1; previously known as dnd ), nanos protein ( nanos3 ; previously known as nanos ), piwi-like RNA-mediated gene silencing 1 ( piwil1 ; previously known as piwi ), sry-box transcription factor sox-3 ( sox3 ), and deleted in azoospermia-like ( dazl ) [ 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 ]. Specifically, ddx4 and dnd have been extensively used as DNA markers for germline and gonad development, sex determination, and sex differentiation in fish [ 9 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ].…”