Josie Lynn Catindig
International Rice Research Institute, Los Baños, Philippines
Expertise in arthropod taxonomy is now very scarce. There are very few taxonomic experts in the world who can identify specimens to species levels and describe new species discovered in nature. In the national systems, many scientists working on pest management are unable to identify pests and natural enemies to species levels. The shortage of specialists in pest and natural enemy diagnosis is acute and there is a need to find new diagnostic tools. One way to overcome the shortage is through the use of remote microscopy and the internet to link national scientists and taxonomic specialists. Such a system will still require communication between scientists in the field and taxonomic expertise.
The usual way of identifying insects is the use of identification keys based on their morphological features. This is highly dependent of specialized taxonomic expertise and is also time consuming. DNA bar coding can be a useful tool for identification in taxonomy. It is a process where a short but specific gene tags or barcodes are utilized to distinguish one species from another (Hebert & Gregory 2005). The technique was first proposed by Hebert et al in 2003 as a universal species diagnostic in their paper entitled “Biological identification through DNA barcodes”. The mitochondrial gene cytochrome c oxidase I (COI) can serve as the core of a global bioidentification system for animals. Working in collaboration with Dr David Gopurenko, a scientist in molecular systematics in New South Wales, Department of Primary Industries, IRRI is beginning to barcode and establish a barcode reference for identified hymenopteran parasitoids from IRRI’s arthropod collection to be available for use in species matching and identification.
Species identification using DNA barcodes starts with a specimen either fresh or dried. In the laboratory short pieces of DNA that are diagnostic for a species is collected. For example, a tiny piece of the specimen’s tissue such as a leg is used to extract its DNA.
The BOLDSYSTEMS, established in 2005, is like a library with a searchable repository for barcode records. It is an online workbench that aids collection, management, analysis, and use of DNA barcodes. It has three main components: first, it is a repository for the specimen and sequence records that form the basic data unit of all barcode studies; second, it is a workbench that aids the management, quality assurance and analysis of barcode; and third, it provides a vehicle for collaboration across geographically dispersed research communities by coupling flexible security and data entry features with web-based delivery.
To guide the users, the BOLDSYSTEMS has the following menu: Databases link to access resources such as a public data portal, barcode index number, publication and primers used in the generation of barcodes; Taxonomy link provides a page that displays the kingdom of life being bar coded, their images, distribution map and other details for each taxon; Identification link provides access to identification engines of animal, plant and fungi; Workbench link provides access to BOLD data analysis, records of specimen data submitted, and management workbench; and Resources link provide access to site documentation, training materials and workflow documents.
DNA bar coding as a taxonomic tool along with the barcode library such as in the BOLDSYSTEMS will help scientists rapidly sort, compare and identify specimens. It will also emphasize taxa or reveal cryptic species, which may represent new biological species.
BOLDSYSTEMS in http://www.barcodinglife.com
Hebert PDN, Cywinska A, Ball SL, deWaard JR. 2003. Biological identifications through DNA barcodes. Proc. R. Soc. Lond. 270:313-321.
Hebert PDN, Gregory RT. 2005. The promise of DNA barcoding for Taxonomy. Systematic Biology 54(5): 852-859.