DNA barcodes: Genes, genomics, and bioinformatics
- Department of Botany, MRC-166, National Museum of Natural History, Smithsonian Institution, P.O. Box 37012, Washington, DC 20013-7012
It is not a coincidence that DNA barcoding has developed in concert with genomics-based investigations. DNA barcoding (a tool for rapid species identification based on DNA sequences) and genomics (which compares entire genome structure and expression) share an emphasis on large-scale genetic data acquisition that offers new answers to questions previously beyond the reach of traditional disciplines. DNA barcodes consist of a standardized short sequence of DNA (400–800 bp) that in principle should be easily generated and characterized for all species on the planet (1). A massive on-line digital library of barcodes will serve as a standard to which the DNA barcode sequence of an unidentified sample from the forest, garden, or market can be matched. Similar to genomics, which has accelerated the process of recognizing novel genes and comparing gene function, DNA barcoding will allow users to efficiently recognize known species and speed the discovery of species yet to be found in nature. DNA barcoding aims to use the information of one or a few gene regions to identify all species of life, whereas genomics, the inverse of barcoding, describes in one (e.g., humans) or a few selected species the function and interactions across all genes (Fig. 1). The work of Lahaye et al. (2) reported in a recent issue of PNAS brings the application of DNA barcoding one step closer to implementation in plants.
The matrix of genetic information and taxonomic diversity, with DNA barcoding at one extreme (with high species diversity and limited genetic coverage) and genomics (with limited species diversity but complete gene description) at the other extreme.
The deceptively simple task of selecting an appropriate locus to serve as a plant barcode has been much more complex than expected and has engendered considerable debate. Despite the current lack of consensus on a universal plant barcode, …
*To whom correspondence should be addressed. E-mail: kressj{at}si.edu
