|Coddington, Jonathan - SMITHSONIAN INSTITUTE|
Submitted to: Molecular Ecology Notes
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 27, 2007
Publication Date: November 12, 2007
Citation: Rowley, D.L., Coddington, J, Norrbom, A., Ochoa, R., Vandenberg, N., Greenstone, M.H. 2007. Vouchering specimens for documenting arthropod barcodes: a non-destructive method for DNA extraction. Molecular Ecology Notes.(7):915-924. Interpretive Summary: All biological research requires accurate identification of species. Most species identification depends on differences in external form, referred to as morphology. However, when species are closely related, not well known, or represented by immature individuals, the morphology may not be distinctive enough to support accurate identification. For such situations, short fragments of DNA, known as DNA barcodes, are replacing morphology as a source of characteristics for identification. In order to be sure that the DNA is properly matched to the organism from which it was taken, the organism itself needs to be deposited in a museum so that it can be reviewed by experts. Unfortunately, DNA barcoding procedures may destroy the specimen. To solve this problem, we developed a method to remove the DNA by simply soaking the organism for a few hours in a chemical solution. We subjected a group of organisms that are very important in most terrestrial habitats to the procedure. We were able to extract useful DNA from each species, and the specimens left after extraction were suitable for morphological identification to species. These results will be especially useful to scientists interested in ecology and systematics, and to policy makers concerned with measuring and preserving biodiversity.
Technical Abstract: The correct identification of species is essential to the performance of ecological research. Morphology-based keys support accurate identification of many taxa. However, for taxa that are not well studied, or for which distinguishing morphological characters have not been discerned, identification can be difficult. Accurate identification is especially problematic for very small organisms, for members of sibling species, for eggs, and for immatures. For such cases, DNA barcodes may provide diagnostic characters. Ecologists deposit museum vouchers to document the species studied in their research. If barcodes are to be used for identification, then both the DNA and the specimen from which it was extracted should be vouchered. We describe a protocol for the non-destructive extraction of DNA from terrestrial arthropods, using as examples members of the orders Acarina, Araneae, Coleoptera, Diptera, and Hymenoptera, which were chosen to represent the ranges in size, overall sclerotization, and delicacy of key morphological characters in terrestrial arthropods. We successfully extract sequenceable DNA from all species after 1 – 4 h of immersion in extraction buffer. The extracted carcasses, processed and imaged using protocols standard for the taxon, were distinguishable from closely related species, and adequate as morphological vouchers.