Factors affecting DNA quality in feathers used for non-invasive sampling

The development of genetic methods broadens the scope of non-invasive sample types. Large shed feathers are good material for genetic analyses, since they are easy to collect and a single feather can provide a sufficient amount of DNA for PCR-based methods. Previous studies have demonstrated that feather quality and type affect the DNA quality extracted from the feather tips. Besides the tip, the superior umbilicus part of the shaft is also proposed as an appropriate source of DNA. In our study, we examined whether some feather parameters (physical condition, type and size) and storage time affect amplification success of DNA extracted from the superior umbilicus of shed Eastern Imperial Eagle (Aquila heliaca) feathers. We also tested the effects of sunlight, temperature and humidity on DNA extracted from Domestic Goose (Anser anser domesticus) feathers with amplification of fragments of various sizes, modelling the environmental conditions of the moulting season. While good quality feathers usually provided sufficient DNA, the usability of the DNA extracted from moderate quality feathers were affected by feather type. DNA quality was influenced in order of importance by humidity, direct sunlight and heat. Our findings support the usability of DNA samples derived from the superior umbilicus of shed feathers, and help to schedule field work by careful consideration of our results about feather quality and environmental factors.