6 - DNA Barcoding of Life: Development of DNA-based Species Identification Technologies
Submitting Institution
Imperial College LondonUnit of Assessment
Biological SciencesSummary Impact Type
EnvironmentalResearch Subject Area(s)
Biological Sciences: Ecology, Evolutionary Biology, Genetics
Summary of the impact
Taxonomy is of key relevance to the environment, agriculture, food
production, and human health. However, describing all living organisms is
such a daunting task that it calls for new approaches. A DNA-based system
for species identification, called 'DNA Barcoding', is one such solution.
Imperial researchers identified DNA barcodes for plants in 2008, which
have since had impacts on the environment, health and welfare and in
commerce. The plant DNA barcodes have been endorsed by the Consortium for
the Barcoding of Life and have led to multiple applications ranging from
facilitating biodiversity inventories, helping authentication of material
(herbal medicine) for trade control in Malaysia, South Africa, India and
Nigeria, and combating invasive species and smuggling in Africa.
Underpinning research
- A DNA-based system for species discovery, identification and
delimitation could complement, or even substitute, the existing
centuries-old taxonomic system. It would 'democratise' species
identification even for non-specialists, while being applicable to all
life stages and partially preserved specimens. This approach — either
called DNA Barcoding or DNA Taxonomy — requires a reference sequence
database at species level to ultimately catalogue and provide
identifications for the estimated 10 million species on Earth. The
implementation of such system requires the discovery of suitable genetic
markers for species identification (i.e. 'DNA Barcodes'), biologically
meaningful methods for defining species entities, and a
proof-of-principle of the methods in complex ecosystems. Researchers in
the Division of Ecology and Evolution at Imperial have been instrumental
in designing and trialling a DNA-based taxonomic approach.
- Research was carried out between 2005 and 2012.
-
Key researchers:
Professor Vincent Savolainen, Professor of Organismic Biology, 01/10/07
- present
Professor Timothy Barraclough, Professor of Evolutionary Biology,
01/11/96 - present
Professor Alfried Vogler, Professor of Molecular Systematics, 01/01/95 -
present
-
Key research insights: Professor Alfried Vogler was
instrumental in developing the basic principle for animals and, together
with Professor Vincent Savolainen (then based at the Royal Botanical
Gardens, Kew), was involved in developing an international consortium of
major natural history museums [3]. Professor Timothy Barraclough's key
contribution was the design of a method for DNA-based species
delimitation [4], which was trialled in insect tropical communities.
Finally, Professor Vincent Savolainen and Professor Barraclough's
research led to development of a universal DNA barcode for plants [1,
2], a particularly challenging problem — e.g., as reported in Science:
`Wanted: a DNA barcode for Plants' (318:190, 2007). Specifically,
Professor Savolainen combined results from research in Costa Rica and
Africa and, together with Professor Barraclough, demonstrated the
feasibility of DNA barcoding plants using the matK locus. They
found that this genetic marker exhibited the necessary 'barcoding gap';
that is, it is well conserved within a plant species but varies
extensively between them. This DNA barcode was trialled in (sub)tropical
plant communities, leading to the discovery of a new species of orchids
and demonstrating its use for identifying taxa covered by the Convention
on International Trade in Endangered Species of Wild Fauna and Flora
(CITES) regulations [1]. The corresponding paper was endorsed by the
International Consortium for the Barcoding of Life (e.g. [2]). The
papers above have been very quickly highly cited and the methodologies
have been applied across most groups of animals and plants. Ongoing
research is validating methods for DNA taxonomy from environmental DNA
samples in animals [5]. We published additional technical protocols to
facilitate the use of matK by the broadest possible stakeholder
audience [6].
References to the research
(* References that best indicate quality of underpinning research)
[1] *Lahaye R., van der Bank M., Bogarin D., Warner J., Pupulin F., Gigot
G., Maurin O., Duthoit S., Barraclough T. G., Savolainen V., `DNA
barcoding the floras of Biodiversity hotspots', PNAS 105: 2923-2928
(2008). DOI, 209
citations (as at 12/11/12)
[2] CBOL Plant Working Group (incl. Savolainen V.)., `A DNA
barcode for land plants', PNAS 106:12794-12797 (2009). DOI,
256 citations (as at 12/11/12)
[3] *Savolainen, V., Cowan, R.S., Vogler, A.P., Roderick,
G., Lane, R., `Towards writing the encyclopaedia of life: an
introduction to DNA barcoding'. Phil. Trans. Roy. Soc. B 360,
1805-1811 (2005). DOI,
182 citations (as at 12/11/12)
[4] *Pons, J., Barraclough, T.G., Gomez-Zurita, J., Cardoso, A.,
Duran, D.P., Hazell, S., Kamoun, S., Sumlin, W.D., Vogler, A.P.,
2006. `Sequence-based species delimitation for the DNA taxonomy of
undescribed insects', Syst. Biol. 55, 595-609 (2006). DOI,
237 citations (as at 12/11/12)
[5] Tang, C.Q., Leasi, F., Obertegger, U., Kieneke, A., Barraclough,
T.G., Fontaneto, D., `The widely used small subunit 18S
rDNA molecule greatly underestimates true diversity in biodiversity
surveys of the meiofauna', PNAS 109: 16208-16212 (2012). DOI,
1 citation (as at 25/4/13)
[6] Dunning, L.T., Savolainen, V., `Broad-scale amplification
of matK for DNA barcoding plants, a technical note', Bot. J. Linn.
Soc. Vol 164:1 1-9 (2010). DOI,
16 citations (as at 25/4/13)
Grant Support:
[G1] V. Savolainen (PI), `Regional patterns of biodiversity and
conservation in South Africa: the flora of the Kruger National Park as a
case study', The Royal Society, 1/9/07-31/3/13, £240,735
[G2] A. Vogler (PI), `Large-scale DNA sequencing in taxonomy', BBSRC,
01/07/04-30/09/07, BBS/B/04358,
£329,549
[G3] T. Barraclough (PI), `The evolutionary characterisation of bacterial
diversity from DNA sequence data', BBSRC, BB/G004250/1
, 01/02/09-20/04/12, £316,984
Details of the impact
Nature of the impact: The DNA-based method has truly changed the
approach to taxonomic questions and the use of taxonomy. Until the
publication by Savolainen & Barraclough [1], the botanical community
relied heavily on morphology-based species identification from
well-preserved specimens, struggling to reach a consensus on a suitable
DNA barcode. Paper [1] set "the community standard" [A] for DNA
barcoding. After we showed the appropriateness of the matK locus
as barcodes, DNA-based authentication from any part of a plant, even
reduced to powder, was made possible and led to various applications as
described below. We published additional technical protocols to facilitate
the use of matK by the broadest possible stakeholder audience [6].
The Consortium for the Barcoding of Life (CBOL) endorsed matK as
one of the barcodes for plants in its 2009 PNAS paper [2], and the
technique is now used in "hundreds of laboratories around the world"
[A].
Beneficiaries: the taxonomic community, museum scientists,
botanical gardens, the International Barcode of Life Project, government
bodies and agencies involved in trade control and consumer fraud.
Significance: For centuries, all users of species identification
have relied on time-consuming morphology-based expertise by a few
specialists of each taxonomic group. This expertise has been reduced
severely over the past decades (Systematics
and Taxonomy Report 2008; House of Lords Science and Technology
Committee). With the advances of DNA barcoding, taxonomic identification
has become easier and much more affordable to non-specialist users. As an
example of the widespread utility of DNA barcoding, the International
Barcode of Life Project (iBOL), a 25-nation consortium, aims to create 5
million barcode records from 500,000 species (including plants) that are
endangered, of particular socio-economic importance or used in
environmental assessment by 2015 [B].
Date of Impact: 2008-2013
Impact on environment:
- Biodiversity inventories have been facilitated in numerous public
bodies and charities by using DNA barcoding protocols using the matK
locus method. For example:
o The Botanical Garden of Wales has been barcoding the flora of
Wales, which has about 75% of UK flowering plants [C], intensively.
The Barcode Wales project has created a reference database of DNA
barcodes based on "the 1143 native flowering plants and conifers of
Wales, assembling over 5700 DNA barcodes" [D]. This has made
Wales "the first country in the world to DNA barcode all of its
flowering plants" [D]. The Barcode Wales project has created a
powerful platform for a broad range of research from biodiversity
conservation to human health and "Welsh flora DNA barcodes are
freely available on the Barcode of Life Database (BOLD) for use by
researchers throughout the world" [D, E].
o Following the completion of the Barcode Wales project, the team at
National Botanic Gardens of Wales has joined forces with teams from
the Royal Botanic Garden Edinburgh and the Royal Botanic Gardens Kew
to DNA barcode the rest of the UK flora [E]. As a further example, The
Royal Botanical Gardens at Kew confirms that it has been barcoding
medical plants of Nigeria and Gabon using the matK marker [F].
o In Southern Africa, Kruger National Park (South Africa) has been
barcoding its woody flora (Yessoufou et al., J. Ecol., 2013, DOI).
By mid-2010 "most taxa of trees and shrubs (93 percent) [had been]
completed for the rbcL and matK regions" [G]. The barcodes of
woody vegetation in the Cheringoma District in Mozambique have been
collected since 2010 [G]. The African Centre for DNA Barcoding (ACDB)
lists a total of 9 plant DNA barcoding projects in Southern Africa and
reports that 11,451 specimens and 6,932 species have been barcoded (as
of Jan 2013) [H].
- In South Africa, a DNA barcoding project has started with the aim of
stopping the smuggling of endangered cycad species. The DNA database
will enable customs officials to identify specimens and help prevent the
illegal trade [I]. A database for 50 tree species from the Convention on
International Trade in Endangered Species of Wild Flora and Fauna
(CITES) that are expected to be encountered at South African ports and
borders is also being built [G].
- DNA barcoding is being used to combat alien invasive species in South
Africa, where over 500 naturalized plant species listed are known to
have entered once pristine habitats. Alien plant species are of growing
concern in South Africa due to their negative impacts on biodiversity.
In 2011, a government-funded collaborative project between the ACDB, the
South African National Biodiversity Institute and the Early Detection
and Rapid Response Programme of the Working for Water Programme was
formed as part of the iBOL project. The project collected invasive plant
and animal samples in South Africa, as well as South African species
known to be invasive elsewhere in the world, over an eight-month period
for DNA barcoding and provided access to the barcode data through the
BOLD system (see below) [J].
Impact on economy/commerce:
- The matK barcode and protocols to use it have been implemented
in the BOLD systems in Canada, which provides species identification
commercially. In April 2013, BOLD listed 176,905 species formally DNA
barcoded (plants and animals) [K]. BOLD came into existence at the
beginning of the DNA barcoding movement, funded by the Canadian
government. Until the research reported here, it was only archiving DNA
barcodes of animals. After references [1] and [2], it has been archiving
and making available plant DNA barcodes to a large range of users.
Impact on health/welfare:
- Consumer fraud prevention in teas and herbal medicines now uses
protocols based on DNA barcoding protocols (as reported at the
International Meeting of DNA Barcoding of Life, Adelaide, Australia,
2011). Demonstrating the importance of accessible plant barcoding,
Stoeckle et al. findings indicate unlisted ingredients are common in
herbal teas (Scientific Reports, 1, 42, 2001, DOI).
Government bodies, museums and botanical gardens are using these
techniques, although they might ask university laboratories to carry out
the work. By 2011, a library with DNA barcodes for "Malaysia's 1,200
plant species with potential medicinal value" was in development to
offer "`a quick one step detection kit' to reduce fraud in the lucrative
herbal medicine industry" [L]. At that time, DNA barcode libraries were
also under construction for the medicinal plants of several other
nations, including South Africa, India and Nigeria [L].
- An integrated web medicinal materials DNA database, MMDBD (Medicinal
Materials DNA Barcode Database, [M]) was also created to archive plant
DNA barcodes for use in authentication of herbal medicines, particularly
Chinese medicines (published in BMC Genomics 11:402, 2010, DOI).
The database can be accessed by anybody needing to identify medicinal
plants with DNA barcoding and had archived 1,658 species and 31,468
sequences by May 2012 [M].
Sources to corroborate the impact
[A] Letter from Chair of the Plant Working Group of the Consortium for
the Barcoding of Life, Botanical Garden Edinburgh, 26/11/12 (available
from Imperial on request)
[B] The International Barcode of Life project, `What Is iBOL?',
http://www.barcodeoflife.org/content/about/what-ibol
(archived at
https://www.imperial.ac.uk/ref/webarchive/sjf
on 26/4/13)
[C] BBC News, `National Botanic Garden of Wales logs plant DNA barcode',
26/6/12,
http://www.bbc.co.uk/news/uk-wales-18590298
(archived at
https://www.imperial.ac.uk/ref/webarchive/vjf
on 26/4/13)
[D] Letter from Head of Conservation and Research, National Botanic
Garden of Wales, 13/11/12 (available from Imperial on request)
[E] Barcode Wales, http://www.gardenofwales.org.uk/science/barcode-wales/
(archived at https://www.imperial.ac.uk/ref/webarchive/wjf
on 26/4/13)
[F] Letter from Director of the Jodrell Laboratory, Royal Botanic
Gardens, Kew, 28/11/12 (available from Imperial on request)
[G] Barcode Bulletin, Vol.1, No.2, June 2010, pages 16 & 14, `Q&A
with Michelle van der Bank', (archived here)
[H] African Centre for DNA Barcoding, http://acdb.co.za
(archived at
https://www.imperial.ac.uk/ref/webarchive/yjf
on 26/4/13)
[I] Cape Times, `Scientists use DNA barcodes to fight cycad smuggling'
12/1/10,
http://acdb.co.za/uploads/File/Press/47.Cape%20Times%2012.01.2010.pdf
(archived here)
[J] DNA barcoding of terrestrial and fresh water invasive species in
South Africa, ACDB,
http://acdb.co.za/index.php/sa-invasive-project-new/project-presentation-2.html
(archived at
https://www.imperial.ac.uk/ref/webarchive/1jf
on 26/4/13)
[K] BOLD Systems, http://www.boldsystems.org/index.php/TaxBrowser_Home?target=Plant
(archived at https://www.imperial.ac.uk/ref/webarchive/dkf
on 29/4/13)
[L] News-Medical.net article, "New creative uses of DNA 'barcoding'",
28/11/11, http://www.news-medical.net/news/20111128/New-creative-uses-of-DNA-barcoding.aspx
(archived at
https://www.imperial.ac.uk/ref/webarchive/5jf
on 26/4/13)
[M] Medical Materials DNA Barcode Database, http://137.189.42.34/mherbsdb/
(archived at
https://www.imperial.ac.uk/ref/webarchive/6jf
on 26/4/13)