A simplified protocol for molecular sexing in the emu (Dromaius novaehollandiae)

Male and female emus are nearly identical both as chicks and as adults. Although morphological differences of the internal genital tract can be used to distinguish the sexes, a high degree of diagnostic skill is required for accurate sexing. DNA-based sexing methods are highly accurate and can be used to diagnose sex without requiring a high degree of technical skill. However, conventional PCR-RFLP is time consuming and costly, requiring the digestion of PCR products. In this study, we simplified the protocol for sexing the emu by using multiplex PCR without restriction enzyme treatment. Multiplex PCR based on a W-specific primer, with the commonly designed primer set on both Z and W chromosomes, amplified both 197-bp and 272-bp bands in the female, and only the 272-bp band in the male. Sexing results obtained in this way were completely concordant with results obtained using the conventional PCR-RFLP method. Thus, we succeeded in simplifying the protocol for sexing the emu, and suggest that our protocol improves production efficiency by facilitating rapid pairing and selection of individuals to establish high-quality pedigrees.