Marker-assisted selection of YY supermales from a genetically improved farmed tilapia-derived strain

DEAR EDITOR, Genetically improved farmed tilapia (GIFT)and GIFT-derived strains account for the majority of farmed tilapia worldwide.As male tilapias grow much faster than females,they are often considered more desirable in the aquacultural industry.Sex reversal of females to males using the male sex hormone 17-α-methyltestosterone (MT)is generally used to induce phenotypic males during large-scale production of all male fingerlings.However,the widespread use of large quantities of sex reversal hormone in hatcheries may pose a health risk to workers and ecological threats to surrounding environments. Breeding procedures to produce genetically all-male tilapia with limited or no use of sex hormones are therefore urgently needed.