A summary of current DNA methods for herb and SPICE identification

Abstract

Appropriate use of genetic methods for botanical identification is based on the type of sequencing used as well as testing region selection. Although Sanger sequencing is useful for single-target species identification, targeted next generation sequencing is ideal for testing blended products or those that contain unexpected species. Unknown, fresh, or lightly processed materials are best tested through the use of long, universal deoxyribonucleic acid (DNA) regions (e.g., DNA barcodes). For highly processed products, using shorter and more specific regions helps to prevent false negatives and positives. All approaches must use DNA extraction techniques that address the presence of inhibitory compounds, which often occur in abundance within herbs and spices. The accuracy of identifications is improved when comparing genetic data of any type with a reference database that contains expertly determined vouchered materials, a variety of closely related species, and multiple specimens of the same species.