Application of CHD1 Gene and EE0.6 Sequences to Identify Sexes of Several Protected Bird Species in Taiwan

Abstract

Many bird species, for example Crested Serpent Eagle (Spilornis cheela hoya), Collared Scops Owl (Otus bakkamoena), Tawny Fish Owl (Ketupa flavipes), Crested Goshawk (Accipiter trivirgatus), Grass Owl (Tyto longimembris), etc., are monomorphic, which is difficult to identify their sex simply by their outward appearance. Especially for those monomorphic endangered species, finding an effective tool to identify their sex beside outward appearance is needed for further captive breeding programs or other conservation plans. In this study, we collected samples of Crested Serpent Eagle, Collared Scops Owl, Tawny Fish Owl, Crested Goshawk, and Grass Owl, five protected monomorphic species in Taiwan, as well as Black Swan (Cygmus atratus) and Nicobar Pigeon (Caloenas nicobarica), two aviary introduced monomorphic species served as a control group. We used sex-specific primers of avian CHD1 (chromo-helicase-DNA-binding) gene and EE0.6 (EcoRI 0.6-kb fragment) sequences to identify the sex of these birds. The results showed that CHD1 gene primers could be used to correctly identify the sex of Black Swans, Nicobar Pigeons and Crested Serpent Eagles, but it could not be used to correctly identify sex in Collared Scops Owls, Tawny Fish Owls, and Crested Goshawks. In the sex identification using EE0.6 sequence fragments, A, C, D and E primer sets could be used for sexing Black Swans; A, B, C, and D primer sets could be used for sexing Crested Serpent Eagles; and E primer set could be used for sexing Nicobar Pigeons and the two owl species. Correct determination of sex is the first step if a captive breeding measure is required. We have demonstrated that several of the existing primer sets can be used for sex determination of several captive breeding and indigenous bird species.