Noninvasive methods for collecting fresh hair tissue

Collecting genetic material noninvasively from mammals includes plucking fresh hair (Higuchi et al . 1988), collecting shed hair (Morin et al . 1993), and collecting fecal material (Hoss et al . 1992). The bulb at the end of a fresh hair provides high-quality DNA for amplification. Although shed hair is more accessible, it contains only a fraction of DNA isolated from fresh hair (Gagneux et al . 1997). Reliably amplifying DNA from fecal material can be difficult, because of DNA degradation (Golenberg et al . 1996), DNA concentration (Taberlet et al . 1996), or PCR-inhibiting compounds in the DNA extract (Constable et al . 1995). Here, we describe four novel, noninvasive methods of collecting fresh hairs from wild and captive mammals. In most cases, these methods can be used to target specific individuals, an advantage that is often absent when collecting shed hair. Method one involves shooting a rolled strip of duct tape, pressed onto the flat tip of a plastic syringe, from an airpowered dart pistol (Telinject USA, Inc.). The pistol is fitted with a barrel of variable length. Optimal shooting distance was < 15 m from subjects. Pressure from a CO 2 cartridge can be controlled so that the syringe bounces harmlessly off the subject while the tape pulls fresh hairs. The syringe may be filled partially with water as a balance. This method was developed for sampling capuchin monkeys, Cebus olivaceus , most of which are too small to dart safely or trap efficiently. The second sampling method involves making a corral by enclosing a small area with duct tape. When used on baboons, Papio hamadryas , this area was approximately 1 m 2 . Horizontal rails of tape are spaced every 30 cm for a maximum height of 1.5 m, and bait is placed inside the corral. Typically, several animals approach the corral and squeeze their bodies between tape rails to reach the bait, and thereby leave hairs. This method was designed to obtain hairs simultaneously from several baboons. Method three requires that target animals handle bait that has been wrapped with duct tape. Examples of this method include attaching bait to a tree limb by wrapping tape around it, making tape-covered food baskets, and wrapping food directly with inverted tape. Bait wraps were used successfully on capuchins and baboons of varying ages. Finally, captive animals may be sampled by wrapping inverted tape around the tip of a stick, which is then inserted into the cage to touch an animal directly so that the tape pulls hairs. Successful hair sampling with this method was carried out with carnivores ( Hyaena hyaena , Panthera leo , Felis caracal ), and baboons. The number of hairs collected varies across different methods, as presented in Table 1. Nevertheless, one to three hair bulbs yield sufficient DNA for amplification of nuclear and mitochondrial loci. DNA was isolated from one to four hairs according to Higuchi et al . (1988) or with QIAamp tissue kits (QIAGEN, Inc.). It is critical to use sufficient DNA in each PCR reaction to avoid autosomal genotyping errors resulting from disparate allelic proportions in the DNA extract (Taberlet et al . 1996). Further, the annealing temperature should be sufficiently low to enhance detection of alleles with mutations in the priming sites (Pemberton et al . 1995). Incorporating these precautions yielded consistent PCR products (Fig. 1a,b). Additionally, we found that an unexpected advantage of using nuclear DNA from hair was that it generally produced fewer artefacts during amplification than did DNA isolated from other tissues. In summary, fresh hair tissue may be collected using noninvasive methods and without the need for restraint or trauma to animals. Advantages for researchers using fresh hairs include the ability to target specific individuals and obtain high-quality DNA. The combination of the safety and success of these noninvasive methods supports their applications in genetic studies across a wide variety of mammals, including small, arboreal, or endangered taxa. The authors are grateful to the American Institute for Yemeni Studies, Cecilia and Tomás Blohm, Todd Disotell, and Clifford Jolly.