Myth of the molecule: DNA barcodes for species cannot replace morphology for identification and classification

Abstract

So-called DNA barcodes have recently been proposed to answer the problem of specimen identification and to quantify global biodiversity. We show that this proposition is wanting in terms of rationale, methodology and interpretation of results. In addition to falling short of all its stated goals, the method abandons the benefits of morphological studies in favor of a limited molecular identification system that would ultimately impede our understanding of biodiversity. Ó The Willi Hennig Society 2004.''If the only tool you have is a hammer, you tend to see every problem as a nail.' Abraham Maslow DNA barcodes for species-level identification may, at first glance, seem to represent an appropriate use of new technology to solve an old problem-identifying and classifying the world's biodiversity. Working toward this goal of understanding biodiversity is commendable, but we see serious flaws in the rationale, methodology, and interpretation of results involved in abandoning morphological studies in favor of a narrow and wholly molecular identification system, as suggested by Hebert et al. (2003a). Recently the concept of DNA taxonomy, of which the DNA barcode is one instance, has been hotly debated (Tautz et al.

Ten species in one: DNA barcoding reveals cryptic species in the neotropical skipper butterflyAstraptes fulgerator

“…Some studies, including extensive analyses of GenBank data, have indicated that even closely related species ordinarily show marked mitochondrial divergence (10,12). However, others suggest that mtDNA markers will often encounter problems in species resolution (28)(29)(30). For example, a review of case studies (31) concluded that nearly one-fourth of all animal species fail the test of mitochondrial monophyly.…”

The taxonomic feedback loop: symbiosis of morphology and molecules

“…Nilsson et al (2004) show that phylogenetic analyses will outperform phenetic analyses in correctly identifying sequences. Will & Rubinoff (2004) also highlight the phenetic analyses of Hebert et al (2003a) as a weakness, and thus we incorporated both cladistic/phylogenetic analyses (maximum parsimony, MP) and phenetic/distance analyses (minimum evolution, ME; multi-dimensional scaling, MDS).…”

“…They argue that 'molecular taxonomy' can use 'DNA barcodes' to identify and classify nearly all animal life. Others have countered that this is a 'caricature of real taxonomy' (Lipscomb et al 2003), arguing that morphology must continue to play the central role (Dunn 2003;Will & Rubinoff 2004). They point out that assigning species boundaries with molecular data is no easier than with morphology (Will & Rubinoff 2004).…”

“…Others have countered that this is a 'caricature of real taxonomy' (Lipscomb et al 2003), arguing that morphology must continue to play the central role (Dunn 2003;Will & Rubinoff 2004). They point out that assigning species boundaries with molecular data is no easier than with morphology (Will & Rubinoff 2004). Molecules have been effective in discovering cryptic taxa (Proudlove & Wood 2003), but this has not always proved useful for field biologists unable to use this information without a DNA laboratory.…”

Application of rps16 Intron and trnL-trnF Intergenic Spacer Sequences to Identify Rengas clone Riau

“…The identification using DNA barcoding does not work if the DNA barcode sequences for the organism of interest do not exist in a public database like GenBank (Will & Rubinoff, 2004). Moreover, if the DNA barcode sequences of the organism of interest do not match the sequences existed in the public database, there will be 2 possibilities.…”