The Promise of DNA Barcoding for Taxonomy

8/8/2019 The Promise of DNA Barcoding for Taxonomy

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852 SYSTEMATIC BIOLOGY VOL.54

Syst. Biol.54(5):852859, 2005Copyright c Society of Systematic BiologistsISSN: 1063-5157 print / 1076-836X onlineDOI: 10.1080/10635150500354886

The Promise of DNA Barcoding for Taxonomy

PAUL D. N. HEBERT AND T. RYAN GREGORYDepartment of Integrative Biology, Biodiversity Institute of Ontario, University of Guelph, Guelph, Ontario, N1G 2W1, Canada;

E-mail: [email protected] (P.D.N.H.)

DNA barcoding is a novel system designed to providerapid, accurate, and automatable species identications by using short, standardized gene regions as internalspecies tags. As a consequence, it will make theLinnaeantaxonomic system more accessible, with benets to ecol-ogists, conservationists, and the diversity of agenciescharged with the control of pests, invasive species, andfood safety. More broadly, DNA barcoding allows a dayto be envisioned when every curious mind, from pro-fessional biologists to schoolchildren, will have easy ac-cess to the names and biological attributes of any specieson the planet. In addition to assigning specimens toknown species, DNA barcoding will accelerate the paceof species discovery by allowing taxonomists to rapidlysort specimens and by highlighting divergent taxa thatmay represent new species. By augmenting their capa- bilities in these ways, DNAbarcodingoffers taxonomiststhe opportunity to greatly expand, and eventually com-plete, a global inventory of lifes diversity.

Despite the potential benets of DNA barcoding to both the practitioners and users of taxonomy, it has beencontroversial in some scientic circles (Wheeler, 2004;Will andRubinoff,2004;EbachandHoldredge, 2005;Willet al., 2005).A fewhave even characterizedDNA barcod-ingas beinganti-taxonomy, arguing that its implemen-tation will signal the death of a system 250 years in themaking. We feel that this opposition stems from miscon-ceptions about the DNA barcoding effort. As such, wewelcome this opportunity to clarify both the rationaleand potential impacts of DNA barcoding. In respond-ing to this set of questions, we emphasize the multiplepositive impacts of this approach for taxonomy and bio-diversity science.

QUESTIONS1. Given two billion US dollars (the amount a

comprehensive program of DNA barcoding is estimated tocost [Whiteld, 2003]), how would you spend this money tobenet taxonomic and biodiversity research, and what would

be the legacy of these data?This question ignores an inescapable reality; there is

no prospect of a single $2 billion infusion of support forany biodiversity research program. Such a level of in-vestment may ultimately be achievedbut, if so, it willreect a staged and geographically dispersed process ofpositive funding decisions that will depend heavily on both scientic progress and societal demand for species-level identications. The small amount of funding so far

directed to DNA barcoding has yielded a rich harvestof scientic insights. This fact has led new organizationsto provide the support needed to explore the scalabil-ity of these results across the animal kingdom. The earlyand positive results from this second wave of investi-gations have now motivated larger research groups tocoalesce. In fact, the rst alliances with a global reachhave been assembled to lead the development of bar-

code sequence libraries forall birds andshes. Segmentsof much more species-rich groups, such as plants andlepidopterans, are in the earlier stages of this process(www.barcoding.si.edu). These research groups may, inthe longer term, form the nuclear units needed for the barcode initiative to move into the big science do-main where success depends upon the coupling of aclearly enunciated, socially signicant research agendawith strong international research alliances.

It is also important to note that the quest for large-scale support forDNAbarcoding is notbeing carriedoutat the expense of taxonomic funding. Indeed, it is clearthat any successful campaign to generate this supportwill result in a substantial infusion of funding for insti-tutions and individuals engaged in taxonomic research.Overall, the costs associated with DNA sequencing willrepresent a small component of DNA barcoding efforts;the majority of funding will be employed for global col-lection efforts, for the curation of resultant specimens,and for developing online databases containing detailedinformation about them. Moreover, it bears pointingout that the funding already acquired has come fromlarge foundations and government agencies and pro-grams with no tradition of supporting taxonomic re-search, and that in some cases DNAbarcoding proposalshave competed directly with medical and comparativegenomics projects rather than any related to taxonomicresearch. Viewed from this perspective, any large-scaleDNA barcoding effort will represent a substantial boon, bothnanciallyand scientically, to biodiversityand tax-onomic research. It will certainly leave a lasting legacy inthe form of a comprehensive, widely accessible systemfor the identication of species.

2. Globally, alpha taxonomic research (the discovery anddescription of new species) is in crisis. Is DNA barcoding an

expedient solution to this problem or will it expediteits decline?

In our view the decline of alpha taxonomy is not aconsequence of the growing use of molecular methods,


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as hassometimesbeen suggested(Wheeler, 2004).In fact,we expect DNA barcoding to aid the resurgence of tax-onomy. DNA barcoding programs will certainly directnew funding into the collection and cataloguing of spec-imens. They will, as well, aid taxonomic investigations by helping to reveal cryptic species (Hebert et al., 2004a,2004b), by connecting sexes and life stages (Beskanskyet al., 2003),and byclarifying problems ofsynonymy thatnow consume much taxonomic effort (Alroy, 2002). Thenovelty and scientic promise of DNA barcoding willadditionally draw public interest to taxonomic and bio-diversity issues, encouraging young researchers to en-ter the discipline and both academic departments and biomanagement agencies to hire them.

We are condent that DNA barcoding will play an in-creasingly important role as a taxonomic screening tool because of its ability to rapidly reveal the genetic dis-continuities thatordinarilyseparate distinct species (e.g., Janzen et al., 2005; Smith et al., 2005). Its application inthis fashion will allow an inversion of standard taxo-nomic approaches that operate in an a priori fashionseeking the morphological discontinuities that signalreproductive isolation among unsorted assemblages oforganisms. By contrast, DNA barcoding allows a moreefcient a posteriori approach where predened, genet-ically divergent groups are examined for trait variation.In this sense, DNA barcoding will clearly be a powerfulenabler of alpha taxonomy.

3. Overlapping character variation between and withinspecies is well documented for many character systems. Why

is this any more or less of a problem for DNA barcoding?Overlap in the variation of single characters is not

problematic for any taxonomic system, be it morpho-logical or molecular, so long as multiple characters areemployed for taxon diagnosis. One common misunder-standing of DNA barcoding is that it is based on a singlecharacter, namely one DNA sequence. In fact, the 648- bp cytochrome c oxidase subunit I ( cox1 or COI ) generegion used as the DNA barcode standard for membersof the animal kingdom represents a complex compos-ite character involving hundreds of independently vary-ing components. Some of these component charactersare invariant and therefore not all 648 bp are informativewithin a given taxonomicassemblage, but most are vari-able. For example, we have found variation at 512 of the648 sites in a large set of lepidopteran barcodes (9715 se-quences from 2215 species and 1047 genera). This meansthat even within a single insect order, DNA barcodesintegrate the patterning of similarities and differencesamong hundreds of characters. In a certain sense, it islike the patterning generated by the scales on a mothswingeach scale is of almost no signicance, but thecomposite character of wing coloration pattern is highlyinformative.

DNA barcoding using a single gene region doesnot assure complete taxonomic resolution, but it doespromise proximity. Based on past results for varied an-imal groups, DNA barcoding will deliver species-level

resolution in 95% to 97% of cases (Hebert et al., 2004b; Janzen et al., 2005; Ward et al., 2005). When it fails,it will narrow the options to a small number of con-generic taxa (which, in many cases, could be resolvedfully with additional genetic or other data). This impres-sive performance reects two important, and perhapsunexpected, observations: the rarityof mitochondrial se-quence sharing among species and the dearth of deep barcode divergences within species. Constrained in-traspecic variation in diverse animal groups is a keyearly nding of the DNA barcode effort; one that meritsdeeper scientic investigation. Certainly, cox1shows farless variation within species than some early critics hadprojected would be the case (e.g., Mallet and Willmott,2003), and this may reect the impact of selective sweepsrelated to the coevolution of nuclear and mitochondrialgenomes. Importantly, for the use of barcodes as species-level identiers, barcode differences appear to accumu-late quickly, making it possible to distinguish all but theyoungest of sister species.

4. Many taxonomists already practice DNA barcodinginformally when delimiting and discovering species. Is thiswrong, and what data are sufcient to demonstrate that a

series of specimens represents a new species with traditionalor barcoding methods?

We recognize both the general utility of genetic datain taxonomic studies and the strong concordance intaxonomic signals from different genes. However, weemphasize that there is no such thing as informalDNA barcoding. A DNA barcode is not just any DNAsequenceit is a rigorously standardized sequence of aminimum length andqualityfrom an agreed-upon gene,deposited in a major sequence database, and attached toa voucher specimen whose origins andcurrent statusarerecorded. In fact, it hasalready been established that onlythose cox1sequences that meet these strict criteria will bedesignated as DNA barcodes by the National Center forBiotechnology Informations GenBank (NCBI, GenBank;www.ncbi.nlm.nih.gov/Genbank), the EuropeanMolec-ularBiologyLaboratory (EMBL; www.embl.org),and theDNA Data Bank of Japan (DDBJ; www.ddbj.nig.ac.jp).

There is an important distinction between describ-ing and delimiting species, but a conation of thetwo has created uneasiness about the use of DNA bar-codes as the foundation of future taxonomic descrip-tions. We emphasizethatDNAbarcoding seeks merelytoaidin delimiting speciestohighlight geneticallydistinctgroups exhibiting levels of sequence divergence sugges-tive of species status. By contrast, DNA barcodesbythemselvesare never sufcient to describenew species.At some stage, clearly divergent DNA barcodes, in com- binationwith other information,will be used as thebasisfor providing a new Linnaean name (Smith et al., 2005)and, as with any taxonomic hypothesis, this would besubject to ongoing reevaluation. For example, in a re-cent survey of North American birds, the threshold fordelineating probable new species was arbitrarily set at10 the average within-species variation of the entire


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barcode data set. This led to the revelation of four pre-sumptive newspecies (Hebert et al., 2004b), butdecisionsregarding the formal recognition of these taxa are left,appropriately, to the ornithological community (notably,existing morphological and behavioral information sup-ports these newhypotheses). Thesynergy between DNA barcoding and studies of morphological/ecological di-versity is further illustrated by the case of the skipper buttery, Astraptes fulgerator, in which a combined mor-phological, natural history and barcoding approach re-vealed a complex of 10 species in one small area of CostaRica. Importantly, several of these species showed a rel-atively small barcode divergence, but a coupling of thisinformation with records on larval host plants and mor-phology illuminated the full diversity of the complex(Hebert et al., 2004a).

5. The proposed barcoding genes can fail to recover accuratespecies trees. Does this matter for DNA barcoding?

We emphasize that DNA barcodes do not aim to re-cover phylogenetic relationships; they seek instead toidentify known species and to aid the discovery of newones. Despite this fact, some opponents have claimedthat DNA barcoding fails as a taxonomic approach be-cause it does not always recover accurate species trees(e.g., Will and Rubinoff, 2004). It is important in this re-gard to emphasize that current taxonomic placementsneed to be viewed as hypotheses not facts. Consider aprimary example offered by Will and Rubinoff (2004)in their critique of DNA barcoding: namely that DNA barcodes suggest a very close afnity between the mothSimyra henrici and certain species of Acronicta (Hebertet al., 2003). Will and Rubinoff (2004:48) argue thatthis placement makes it impossible [for DNA barcod-ing] to recover any taxonomic information below thesuprageneric level, not even genus membership. How-ever, rather than reecting a failure of DNA barcod-ing, we believe this case illustrates the power of theapproach to illuminate taxonomic assignments in needof scrutiny. The traditional placement of S. henrici to adistinct genus reects the fact that its adults have paleyellow forewings, showing striking divergence from thegrey/black forewings of Acronicta species. Yet larvalmorphology, adult forewing patterns, ecological niche,and genital anatomy all suggest that S. henrici has closeafnities to Acronicta oblinata (D. Wagner, personal com-munication), a conclusion reinforced by DNA barcodes(Fig. 1). Its distinctive forewing coloration likely reectsthe fact that larvae of S. henrici feed on grasses, asopposed to the tree-feeding habits of typical Acronictaspecies. A rapid shift in wing color has presumably beendriven by natural selection to aid substrate matching

FIGURE 1. A taxon identication tree generated through neighbor- joining analysis of K2P distances showing patterns of cox1 sequencedivergence for 31 species of Acronicta and 1 species of Simyra. Speci-mens from different provinces (Canada) or states (USA) are shown indifferent colors.


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hypotheses to be testedusing an independent digital (i.e.,DNAnucleotide-based) data stream. Although there has been good correspondence between species recognizedthrough morphological approaches with designations based on barcodes, there are discordances. These casesshould be welcomed as they will strengthen both taxo-nomic hypotheses and methods for analyzing barcodedifferences, and may lead to new discoveries regardingevolution and ecology. All of these benets have beenevidenced in early barcoding efforts.

9. Assuming the technical problems of DNA barcodingcan be overcome, is it now, or will it ever be cost-effectiverelative to traditional methods to use DNA barcodes for

bioinventory purposes?A major benet of, and rationale for, DNA bar-

coding lies in its cost-effectiveness for species iden-tication, especially in ambitious bioinventory and biomonitoring programs (Smithet al., 2005).As it stands,

production-line systems for identifying even a smallgroup of thoroughly known species through morpho-logical approaches cost about $2 per specimen (e.g.,mosquitomonitoringprogramsthatdealwithfewerthan60 species; F. C. Hunter, personal communication).Whena team of taxonomic specialists targets a larger assem- blage of species in a specic geographic area, costs risesubstantially and the identication of single specimenscan cost $50 to $100 if all costs are internalized. Today,a DNA barcode can be generated for about $5 per spec-imen including labor and sequencingand this cost isexpected to plummet. In time, DNAbarcodingprogramshave the potential to become self-sufcient by charging asmall fee for identications while still maintaining open

access for academic researchers.Cost is only one criterion in evaluating the utility ofa taxonomic support system for biodiversity research.Speed, reliability, and accessibility are just as important,andwe believe that DNAbarcodingexcels in these areas.By contrast, even smaller-scale biomonitoring programs based on morphology currently face a major challenge indelivering results in a rapid, cost-effective fashion. Thiscan have dramatic economic consequences, as with thecurrent difculty in identifying invasive species earlyenough to suppress an outbreak. Yet, the economic ben-ets of excluding even a single noxious invader, such asthe zebra mussel from North America, would have beensufcient after a decade to barcode most of the animal

species on Earth.

10. Hypothesis-driven research is the foundation upon whichmost research agencies assign funding priorities,

yet taxonomy is discovery driven. How would yourapproach to taxonomy convince these agencies of the

merits of taxonomic studies?We agree that hypothesis-driven science dominates

small-scale funding competitions and that taxonomyfares poorly because of its discovery-driven nature.On the other hand, every big science initiativefrom subatomic physics to the human genome to space

explorationhas been discovery-driven, andthis will bethe funding arena in which the global DNA barcodingprogram will operate if it rises to the challenge. As withmost otherbigscienceprojects,DNA barcodinghas expe-riencedclaimsthatitisnotscience,andthatitthreatenstheability of smallerlaboratoriesto carryouthypothesis-driven research. In past cases, such claims have alwaysproved shortsighted. The repeated observation is thatlarge-scale discovery science spins off hypotheses at afrenetic pace and reveals avenues of investigation thatcould never have been anticipated. In this sense, manyof the criticisms levied at DNA barcoding are remark-ably similar to those given a decade ago regarding thehuman genome project.

DNA barcoding has already been successful in at-tracting substantial funding from varied agencies andorganizations that have not been traditional funders oftaxonomy, but this has not been accomplished by sellingtaxonomy per se. Instead, the DNA barcoding initia-tive promotes thevisionof a broadlyaccessibleinventoryof lifes diversity. It is only by emphasizing the benetsto society and by sparking interest among the taxpay-ingpublic that support fora global biodiversity initiativewill be generated. Ofcourse,thatdoes not mean that tax-onomy is set to become a hightechservice industry forother biologists, as some have suggested (e.g., Lipscombet al., 2003; Wheeler, 2004; Will and Rubinoff, 2004).A major goal of DNA barcoding is to enable the non-taxonomist majority of biologistsand indeed, anyoneto access taxonomic information directly while allowingprofessional taxonomists to focus on generating moresuch knowledge.

POSITION STATEMENTEfforts to inventoryeukaryotic diversity through mor-

phological analyses have enjoyed much success. Thegeneration of nearly two million taxonomic hypothe-ses over the past 250 years is an impressive feat thathas provided a foundational understanding of biolog-ical diversity, but many details await clarication. DNA barcoding is positioned to aid the inventory of life byaccelerating species discovery, by testing current taxo-nomic hypotheses, andbymakingspecies identicationsmore easily available. These contributions will not bemade at the expense of core taxonomic values or fund-ing. DNA barcoding does not seek to abandon mor-phological studies in favor of a narrow and whollymolecular identication system (Will and Rubinoff,2004: 47). Rather, it strives to build alliances betweenmolecular and morphological taxonomists (Hebert andBarrett, 2005). It seeks, as well, to preserve the Linnaeanprinciples by which species are named and classied.DNA barcoding requires existing, morphologically de-rived species names for calibration, and it is thesenames that are recovered when barcoding is used foridentication.

It is generally accepted that the study of biodiver-sity is seriously underfunded (Godfray, 2002). It is noteasy to attribute this to the theme of investigation, as


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biodiversity science is important and attracts much pub-lic interest. However, this area of research does sufferfrom a culture of conict. Rather than mounting grandcollaborations, the biodiversity community has a tradi-tion of polarization and inghting. DNA barcoding isno stranger to invectivesit has been tagged as theo-retically vacuous technology and as a parlour trick(Wheler, 2004; Will et al., 2005). The coupling of suchcomments with ad hominem attacks on DNA barcodingproponents brings little credit to the discipline.

Some critics charge that the DNA barcoding approachis fundamentally awed,butthe available data tella verydifferent story: the success of DNA barcoding has sofar been startlingly impressive. As Smith (2005) notes, barcoding fared well in a test executed at the PEETconference. More importantly, a series of studies havenow investigated the effectiveness of DNA barcodingin species assemblages from varied geographic settings,and from numerous taxonomic groups with divergentlife history and evolutionary attributes. As a conse-quenceof these sensitivity tests, barcode records arenowavailable for more than 13,000 animal species (and accu-mulating rapidly) and they reveal resolution that is noillusion (www.barcodinglife.org). In group after group,success in species identication exceeds 95% and thefew cases of compromised resolution involve the in-ability to discriminate a small group of closely alliedspecies (Hebert et al., 2004a, 2004b; Hebert et al., un-published). Typical results resemble those in Figure 1,whichshowsthepatterningofDNAbarcodedivergencesfor 31 species of Acronicta, one of the most diverse lepi-dopteran genera in North America. In this case, there isno evidence of the sequence sharing between taxa thatwould be expected if hybridization were occurring orif species were too young to be discriminated. Instead,there is cleanseparation of specieswith barcode cohesionfor conspecics even when they derive from disparatesites in eastern North America.

There is nothing exceptional about the barcode re-sults for Acronictastudies on soil invertebrates fromthe arctic and on lepidopterans from the tropics showsimilar success in species resolution (Hogg and Hebert,2004; Janzen et al., 2005). This performance extendsinto marine settings: a barcode study which exam-ined more than 200 morphologically dened species ofAustralian shes generated 100% success in their dis-crimination (Ward et al., 2005). Sensitivity tests across10-fold gradients in rates of mitochondrial evolution re-vealed high success in species identication from in-sect groups with both the lowest and highest rates ofevolution (Ball et al., 2005; Smith et al., 2005). Shifts innucleotide composition of the mitochondrial genomesimilarly fail to impact the resolution of DNA barcod-ing, as evidenced by success in groups, such as birds,with high G + C composition and others, such as spiders,with extreme A + T bias (Hebert et al., 2004b; Barrett andHebert, 2005).

If these past studies are reective of the general per-formance of barcodes across the animal kingdom, a com-prehensive cox1-based system will deliver taxonomic

resolution in excess of 99.99% when viewed from akingdom-level perspective. To grasp this, one need onlyimagine each of the 10,000 pits in Figure 2 as a reposi-tory for barcode data from a single species. Presumingthat there are 10 million animal species, the barcode library for this kingdom could be represented by just 1000of these pages. The global avifauna, which consists ofabout 10,000 bird species, will occupy only one of thesepages. Barcode records for the shes of the world willoccupy three pages, while beetles will ll several hun-dred pages. Once all 10 million pits have been lled with barcode data, the analysis of any new barcode sequencewill provide immediate transport to the correct page outof 1000, delivering 99.9% resolution. In fact, based ondata for North American birds, the barcode sequencewill provide perfect resolution by leading to an individ-ual species pit on the single bird page in 96% of cases.In the remaining cases, the newly gathered barcode willmatch sequences in two or three adjacent pits. In sum-mary, a short barcode will collapse the uncertainty inspecies identity from any one of 10 million species downto a single species in most cases, and to a small subset ofclosely allied species in other instances.

Funding is now in place to ensure that that the DNA barcode library for animals will grow by at least 500,000records over the next 5 years, providing coverage forsome 50,000 species. Although this will be far from acomplete registry of species, it will allow DNA barcodesto function as an effective identication tool for thosetaxonomic groups with comprehensive barcode records.For example, as barcode coverage for shes, birds, andpest insects approaches completion, this will provideopen access to the identication of these species regard-less of life stage or condition. As this core of speciesrecords is joined by barcodes from other animals, aglobal identication system for this kingdom of life willrise.

Although we believe that the generality of barcodinghas now been demonstrated for the animal kingdom,there remains a need to both establish and evaluate bar-code protocols for the other kingdoms of life. The coreprinciples of barcode analysis (minimalization and stan-dardization of sequence targets) are surely applicable tothese organisms, but the selection of gene regions andtests of their effectiveness remain in progress althoughearly results on plants (Kress et al., 2005) and protists(G.W. Saunders,personal communication)providecauseforoptimism.Aside fromitssuccess inseparating knownspecies, DNA barcoding will be a powerful aid in re-solving other taxonomic issues. Overlookedspecies have been regularly revealed, even in well-studied groupssuch as North American birds (Hebert et al., 2004b), but-teries (Hebert et al.,2004a), andsilk moths (Janzen etal.,2005). Its role in associating life stages (Beskansky et al.,2003) and genders (Janzen et al., 2005), and in clarify-ing synonymies, will also be of assistance in many othertaxonomic investigations.

The activation of anymajor science program demandsnot just a strong scientic rationale, but a demonstra-tion of societal relevance. DNA barcoding exhibits such


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FIGURE 2. A graphic representation of a matrix that would store barcode data on 10,000 species (e.g., nearly all known bird species). Onethousand such pages would house barcode records for 10 million species. In addition to providing a species epithet, such a system would act asa portal to all other collected information on a given species by linking into other comprehensive biological databases.

relevance by providing new access to identications invaried contexts.Efforts to conserve lifeare currentlycon-strained by the need for an identication system, and we believe that this need can only be met by DNA barcod-ing (see also Smithet al., 2005). The ability of barcodes toidentify fragments of life has applications ranging fromthe resolution of cases of species substitution in the mar-ketplace (Marko et al., 2004) to the protection of food se-curity through, for example, screening animal feedstuffsfor ruminant waste. More generally, the ability of DNA barcoding to deliver identications quickly and cheaplyhas the potential to revolutionize humanitys relation-ship with biological diversity (Janzen, 2004).

If DNA barcoding proceeds on a large scale, it willgenerate important by-products for the scientic com-munity. All DNA extracts produced during the barcode

analysis of voucheredspecimenswill be stored, allowingfuture efforts to examine patterns of sequence diversityin other gene regions, and the collection programs in-stigated by DNA barcoding will expand the specimensavailable for morphological analysis. The barcode initia-tive will also create a Web-based system delivering not just automated identications, but also providing a por-tal to biological information for all species included inthe registry. Although DNAbarcodingwill notcreate theencyclopediaof life, it will generate its index and tableof contents.

Because of both positive scientic results and its rec-ognized societal benets, there is growing enthusiasmfor a large-scale DNA barcoding initiative. Two meet-ings at Cold Spring Harbor during 2003 claried plansfor action (Stoeckle, 2003), and more meetings have


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followed. The most recent, which was hosted by theNatural History Museum in London, attracted morethan230researchers (Marshall,2005). Thebarcodemove-ment also has a central organizing force: the Consortiumfor the Barcode of Life (CBOL), hosted by the Smith-sonian Institution in Washington, which was launchedin mid-2004. More than 80 organizations from 25 na-tions, including many prominent museums, have al-ready joined CBOL(www.barcoding.si.edu). The rstglobal barcode campaigns have been activated under itsauspices; they include plans to barcode all 10,000speciesof birds and all 15,000 marine shes by 2010. Clearly,work needs to expand beyond individual laboratoriesto tackle major projects such as these, and national bar-code networks are forming to establish specimen supplychains and to oversee core analytical facilities. The rstof these, the Canadian Barcode of Life Network, whichsaw activation in May 2005 (www.bolnet.ca), intends to barcode at least 10,000 Canadian animal species over thenext 5 years.

We view these signs of growing synergy among thevarious sectors of the biodiversity community as ex-tremely hopeful. If developed to their full potential, his-tory may view the DNA barcoding enterprise as one thatnot only enhanced access to taxonomic information, butalsostrengthenedalliancesamongallthosewithinterestsin the documentation, understanding, and preservationof biodiversityan exciting prospect indeed.

ACKNOWLEDGEMENTS

We thank Mark Stoeckle and Dan Janzen for valuable revisionarysuggestions to earlier drafts of this article. We are also very grate-ful to the Gordon and Betty Moore Foundation, NSERC, CFI, andOIT for their support of DNA barcoding research at the University ofGuelph.

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First submitted 25 April 2005; reviews returned 9 June 2005; nal acceptance 12 July 2005

Associate Editor: Vincent Savolainen

The Promise of DNA Barcoding for Taxonomy

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