DNA barcoding

DNA barcoding aims to speed up the process of cataloguing life on earth. It is based on the premise of using a standard short region of DNA as a universal tool for identifying organisms. The aim is to establish a large-scale reference sequence database against which unknown samples can be queried for identification. Where sequences are found that are divergent from others in the database, the corresponding specimens are flagged up as potential new species warranting further investigation.

A DNA sequence

Current research effort on DNA barcoding includes:

Chairing the Scientific Steering Committee of the International Barcode of Life Project (iBOL).

IBOL is the largest biodiversity genomics project that has been undertaken. Its aim is to generate DNA barcodes from 5 million specimens representing 500K species by 2015, as a tool for species identification and species discovery.  Pete Hollingsworth chairs the Scientific Steering Committee (SSC) of iBOL – the committee responsible for scientific direction and coordination of international activities to realise this goal.

Selecting an appropriate region of DNA for barcoding land plants

Pete Hollingsworth is chair of the Plant Working Group of the Consortium for the Barcode of Life (CBOL PWG). This group has been comparing the performance of different candidate barcoding loci with the aim of reaching agreement on a standard DNA barcode for land plants. This work was published in August 2009 in PNAS with the recommendation of rbcL+matK as a standard land plant barcode. Further discussion on the process of choosing and using a plant barcode is presented in a 2011 paper in PLOSone

Barcoding the British liverwort flora

Liverwort species can be difficult to identify using morphological characters, cryptic species frequently occur, and there is a shortage of taxonomic experts. DNA barcoding can thus be used as a tool for species identification and taxonomic clarification. In collaboration with RBGE's bryologist David Long, we are using the British liverwort flora (ca 300 species) as a model to evaluate the performance of DNA barcoding in liverworts.

General evaluation of the performance of DNA barcoding techniques

Sequencing a small number of plastid regions will not provide species level resolution in all plant groups. Recent diversification and hybridisation will result in the sharing of haplotypes among species. We are interested in establishing how often plastid barcoding provides species level resolution in different plant groups, and conversely in which groups additional assays are required.

Protocol development for DNA barcoding

We are currently working on protocol development to improve amplification strategies for matK in DNA barcoding studies. This involves design of primers and primer cocktails aiming to improve the amplification efficiency of the proposed barcoding region from angiosperms and other land-plant groups.

For more information on DNA barcoding at the Royal Botanic Garden Edinburgh, contact Pete Hollingsworth

Recent DNA barcoding publications:

RBGE staff involved in DNA barcoding

Pete Hollingsworth
Michelle Hollingsworth
(Science and Technical Services Group)
James Richardson (Tropical Biology Group)
Alan Forrest
Laura Forrest

Rebecca Yahr
David Mann (Cryptogamic group)
David Long (Cryptogamic group)

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