I think most researchers would generally say the opposite: DNA barcodes are bad for phylogeny but good for species identification. However, two interesting papers published recently (both including my MSc supervisor as a co-author) take these alternative positions.
In The Effect of Geographical Scale of Sampling on DNA Barcoding the authors found that "The average genetic distance (to the closest heterospecific) dropped from >7% for samples within 1km, to <3.5% for samples up to >6000 km apart" and also that "The success of identifying queries decreased with increasing spatial scale of sampling; liberal methods declined from 100% to around 90% whereas strict methods dropped to below 50% at continental scales". I predict we will see more studies looking at the effect of geographical scale on DNA barcoding published very soon.
Utility of the DNA barcoding gene fragment for parasitic wasp phylogeny (Hymenoptera: Ichneumonoidea): data release and new measure of taxonomic congruence investigates the phylogenetic signal in DNA barcodes and found "a broad correlation between taxonomic congruence and number of included sequences". So increased taxon sampling does increase the phylogenetic signal after all. Obviously the methods applied, both for phylogenetic reconstruction and measurement of taxonomic congruence, have a big impact on the results. I hope to see more studies continuing along this line of investigation too.
About me
- johnjameswilson
- Liverpool, United Kingdom
- I am interested in how we can use DNA sequences to understand biodiversity – how do we recognise species, and how are species related at taxonomic, ecological and geographic levels? My passion for biodiversity research has led me from the world’s largest natural history collection - Natural History Museum, London, where I completed my MSc, to the Biodiversity Institute of Ontario - global centre for the international Barcode of Life, as a PhD student, and to the hyper-diverse tropics of Southeast Asia. The tropics will be the first regions to experience historically unprecedented climates and this will happen within the next decade. Consequently my recent research has focussed on understanding the effects of urbanisation and climate change on tropical and subtropical biodiversity - encompassing both species richness and ecological integrity across a diversity of taxonomic groups.
