Vouchering of Forensically Important Fly Specimens by Nondestructive DNA Extraction

DNA extraction frequently requires destruction of whole samples. However, when the sample is very rare or has taxonomic importance, nondestructive DNA extraction is required for preservation of voucher specimens. In the case of arthropod specimens, minor anatomical structures such as a single leg or a single wing are often sacrificed instead of the whole body for DNA extraction. In an attempt to save the entire anatomical structure of specimens, several authors tried to brew the whole specimen in a lysis buffer and to extract DNA from the “soup.” We applied this nondestructive DNA extraction technique to a forensically important blowfly species, Phaenicia sericata. With nondestructive DNA extraction, a satisfactory quantity and quality of DNA for PCR amplification was obtained with only minimal anatomical disruptions that do not alter the morphologic identification. This nondestructive method may be applicable to DNA extraction of rare samples as well as vouchering of regular fly samples. 1. Introduction Most DNA extraction methods inevitably consume at least a small portion of biological specimens. Of course, minor damages to samples do not matter in many instances and many small insect samples are even totally grinded for DNA extraction [1–4]. However, because photographic records prior to sample destruction do not always preserve all the important morphologic features, saving voucher specimens is advisable for specimens with taxonomic importance. In the case of forensically important fly species, many authors have utilized small portions of the body such as legs, wings, thoracic muscle, and entire thorax [5–9]. However, preserving the entirety of the specimen is often preferred, and dissection of specific anatomical parts such as the thoracic muscle is often complex and time consuming. In 1995, Phillips and Simon tried to extract DNA from unimpaired arthropod specimens in the museum collection. However, Phillips and Simon made multiple punctures to the exoskeletons prior to the extraction and did not describe the detailed morphological disruptions after the extraction [10]. The idea to brew whole unimpaired samples in a lysis buffer and to extract DNA from the “soup” has emerged in the field of zoology. Rohland et al. extracted DNA from mammalian teeth without any destruction of the specimen by incubating the whole specimen in a digestion buffer [11]. Gilbert et al. and Rowley et al. applied Rohland’s method to beetles and various insect specimens and tested not only the DNA yields and qualities but also degrees of damages to the exoskeletons [12,