title: Label free molecular sexing of monomorphic birds using infrared spectroscopic imaging.
abstract: The absence of sexual dimorphism in many birds often makes sex determination difficult. In particular immature birds and adults of monomorphic species show no external sex characteristics. Molecular techniques based on DNA hybridization or polymerase chain reaction (PCR) are standard methods for sex identification. However, these methods are expensive and time consuming procedures and require special sample preparation. Noninvasive methods for a rapid determination of bird's gender are of increasing importance for ornithologists, breeders as well as for successful captive-breeding programs. Fourier transform infrared (FT-IR) spectroscopy is one such technique that can provide gender specific information. In this study, using the example of domestic pigeons (Columba livia f. dom.) we demonstrate that only a small amount of the feather pulp is needed to determine the gender. FT-IR spectroscopic images of feather pulp suspensions were recorded in transmission mode. Principal component analysis (PCA) and linear discriminant analysis (LDA) were performed to identify the sex. The gender related information are described by 2nd and 4th principal component principle component (PC). The 2nd PC represents different amounts of proteins while the 4th PC shows variations within the amide I and amide II bands as well as in the region of phosphate vibrations of nucleic acids. Blood cells of male pigeons exhibit a significantly higher amount of proteins and nucleic acids than those of female pigeons. Feather pulp samples of male species were assigned with 100% accuracy. Seven from eight female samples were assigned correctly while one sample could not be classified. This study demonstrates that the sex of domestic pigeons can be accurately and and rapidly identified by infrared spectroscopic imaging.
authors.affiliation: Dresden University of Technology, Faculty of Medicine Carl Gustav Carus, Clinical Sensoring and Monitoring, Fetscherstr. 13, 01307 Dresden, Germany; University of Vilnius, Faculty of Physics, Department of General Physics and Spectroscopy, 9 Saulėtekio, 10222 Vilnius, Lithuania. Electronic address: gerald.steiner@tu-dresden.de.
authors.forename: Gerald
authors.initials: G
authors.lastname: Steiner
authors.affiliation: Dresden University of Technology, Faculty of Medicine Carl Gustav Carus, Clinical Sensoring and Monitoring, Fetscherstr. 13, 01307 Dresden, Germany.
authors.forename: Grit
authors.initials: G
authors.lastname: Preusse
authors.affiliation: Leibniz-Institut für Polymerforschung Dresden, Hohe Straße 6, 01069 Dresden, Germany.
authors.forename: Cordelia
authors.initials: C
authors.lastname: Zimmerer
authors.affiliation: University of Leipzig, Faculty of Veterinary Medicine, Clinic for Birds and Reptiles, An den Tierkliniken 17, 04103 Leipzig, Germany.
authors.forename: Maria-Elisabeth
authors.initials: ME
authors.lastname: Krautwald-Junghanns
authors.affiliation: University of Vilnius, Faculty of Physics, Department of General Physics and Spectroscopy, 9 Saulėtekio, 10222 Vilnius, Lithuania.
authors.forename: Valdas
authors.initials: V
authors.lastname: Sablinskas
authors.affiliation: University of Leipzig, Faculty of Veterinary Medicine, Institute of Physiological Chemistry, An den Tierkliniken 1, 04103 Leipzig, Germany.
authors.forename: Herbert
authors.initials: H
authors.lastname: Fuhrmann
authors.affiliation: Dresden University of Technology, Faculty of Medicine Carl Gustav Carus, Clinical Sensoring and Monitoring, Fetscherstr. 13, 01307 Dresden, Germany.
authors.forename: Edmund
authors.initials: E
authors.lastname: Koch
authors.affiliation: University of Leipzig, Faculty of Veterinary Medicine, Clinic for Birds and Reptiles, An den Tierkliniken 17, 04103 Leipzig, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Bartels
mesh_terms: D000818:Animals; D010856:Columbidae / Q000235:genetics; D005241:Feathers / Q000737:chemistry; D005260:Female; D023281:Genomics; D008297:Male; D057054:Molecular Imaging; D012727:Sex Characteristics; D012732:Sex Determination Analysis / Q000379:methods*; D017550:Spectroscopy, Fourier Transform Infrared
keywords: FT-IR spectroscopic imaging; Molecular sexing; Monomorphic birds; Multivariate data analysis