The spindlin gene as a universal marker for molecular sex identification in different poultry species

Due to the lack of pronounced sexually dimorphic traits in many poultry species, or the presence of such traits only in adulthood, visual sexing becomes a challenging task, which can result in considerable difficulties in breeding and conservation management. This study performed laboratory sex identification analysis of eleven poultry species based on the sexing gene Spindlin (SPIN). Genomic DNA was extracted from blood or feather samples, encompassing both males and females. PCR was performed using primers SPIN319F and SPIN472R, which flanked intron 2 of SPIN. The outcomes were visualized using agarose gel electrophoresis and capillary electrophoresis plots. The length polymorphism between SPIN-W and SPIN-Z homologous genes allows for clear sex discrimination in chicken, Japanese quail, pheasant, turkey, guinea fowl, chukar partridge, mallard duck, Muscovy duck, mule duck, swan goose, and rock pigeon. The result demonstrated that SPIN was relatively conserved within the same species. We found strong support for the monophyletic grouping of all W sequences from three avian orders in one clade and of all Z sequences in the other. The research indicates that the SPIN marker is effective for genetic sex identification in the poultry species tested in this study.