Currently, there is no simple, unambiguous, nontraumatic method of establishing the sex of monomorphic birds, those whose sex is not apparent from external appearence. Surgical identification, the method most frequently used, requires a skilled veterinarian and is not applicable until the bird reaches sexual maturity. Even with mature birds, identification of the sex organs can be difficult, ambiguous or impossible. Because of the dangers from anesthesia and surgery, most managers of captive breeding programs choose karyotyping to identify the sexes. This method, though less dangerous than surgical sexing, requires about a milliliter of blood and is such a specialized procedure that only a handful of people/labs have been able to do it successfully. The goal of this project is to develop a DNA probe which can be used in a standard DNA hybridization technique, to sex a bird using DNA from a drop of blood or from cells from the pulp of a feather. Such sex-specific DNA sequences have been found in a variety of species. The investigators have created a genomic library representing approximately 6000 random DNA fragments and are in the process of identifying those DNA clones which hybridize to female but not male DNA. If successful in isolating a probe from whooping cranes, the investigators will attempt to develop sex- specific probes for members of other endangered species. Although the project is primarily concerned with sexing birds, the results are also expected to shed light upon molecular evolution of sex-specific DNA and, in the long tern the phylogeny of birds.
