Chapter 5 - DNA barcoding and taxonomic practice

Summary

This chapter investigates how taxonomists have responded to DNA barcoding, a high-throughput, semi-automated method of assigning unique identifiers to taxa. In this chapter it is argued that barcoding is an evolving method, and assessments of barcoding's weaknesses, and improvements upon its strengths, are ongoing. Barcodes are created from a tissue sample of a field or museum specimen, extracting the DNA, amplifying the barcode region, and then sequencing it. Operational taxonomic units (OTUs) arise from applications of the sequence divergence benchmark, a process that creates operational terminal nodes in genetic phylogenies. Automated sequencing of barcodes, particularly with increasing throughput of specimens, presents challenges for creating algorithms to identify OTUs. The strongest criticism about the technology and method itself raises doubts about the use of distances between varying nucleotide sequences to differentiate specimens. Integrative taxonomy aims to combine the frequently separated tasks of delimiting and classifying species.