Polymerase chain reaction-single strand conformation polymorphism applied to sex identification of Accipiter cooperii

Determination of sex in birds is valuable for studying population dynamics and structure, habitat use, behavior and mating systems. The purpose of the present study was to optimize a DNA-based methodology to allow the sex identification in Accipiter cooperii nestlings. Chromo-helicase-DNA-binding (CHD1) gene was used in this work as a marker for sex identification. CHD-W and CHD-Z sequences should present length and/or sequence differences providing a way to identify gender. We used a non-invasive method for DNA extraction from feathers and performed polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) method. The length difference between CHD-W and CHD-Z amplified fragments observed by electrophoresis in conventional agarose gel was not enough to provide a clear differentiation between males and females. However, patterns obtained by PCR-SSCP differentiated undoubtedly males and females in A. cooperii. This tool provides a precise gender identification assay and will be applied to confirm and refine morphometrically based sexing techniques used in the field.