A comparison of plucked feathers versus blood samples as DNA sources for molecular sexing

ABSTRACT

ABSTRACT.  Feathers are increasingly collected as a nondestructive source of DNA for avian genetic research. Although feather samples are not optimal in some important ways than more robust blood or tissue samples, feather sampling requires less training for field workers, results in shorter handling times for the organism, generates no hazardous wastes, and requires simpler storage procedures. Along with these largely positive attributes comes a set of challenges, particularly the relatively low copy number of DNA present in feather samples. We compared the utility and reliability of feathers to the more traditional blood samples as sources of DNA for polymerase chain reaction (PCR)-based molecular sexing of Black-capped Chickadees (Poecile atricapilla). DNA from 102 individuals was extracted separately from both single rectrices and from blood samples, and the sex of each bird was then determined using standard PCR-based methods. We found complete agreement between sex determinations based on feather versus blood DNA extractions. Slight variations in lab protocols were necessary to obtain consistent results from these two DNA sources; and we briefly discuss other sources of error that could occur in feather-based molecular sexing studies. This controlled comparison of feather versus blood samples demonstrates that plucked rectrices provide a highly reliable source of DNA for molecular sexing of wild birds.