The Barcode Blog

A mostly scientific blog about short DNA sequences for species identification and discovery. I encourage your commentary. -- Mark Stoeckle

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Seeing in color

A raft of recent articles show the strength and versatility of a standardized genetic approach to identifying species, ie DNA barcoding. Just as color vision helps us rapidly sort objects into unambiguous categories, DNA analysis usually reveals distinct differences among species, including those whose biological differences lie outside the range of our perception, ie cryptic species. I highlight two of the recent articles below.


In March 20, 2007 Proc Natl Acad Sci USA, researchers at University of Guelph, Canadian Agricultural Department, and University of Pennsylvania apply DNA barcoding to 16 species of apparently generalist parasitoid tachnid flies. Smith et al found 73 distinct mitochondrial DNA lineages among 2,134 flies from the 16 morphospecies. The mitochondrial lineages were supported by collateral ecological differences and, where tested, by independent nuclear gene markers. In an accompanying commentary, Scott Miller, Smithsonian Institution, looks at how DNA barcoding is contributing to the “renaissance of taxonomy” and is “emerging as a cost-effective standard for rapid species identification”.

In 26 March 2007 Mol Ecol Notes, scientists from the University of Auckland apply DNA to identifying rat species in Southeast Asia. Geographic variation in mitochondrial DNA of commensal rats provides a window into patterns of human dispersal and migration, but studies are complicated by the presence of multiple rat species in Southeast Asia, and the difficulty of distinguishing among species in subfossil remains at archeological sites.  Robins et al found DNA barcoding with COI mtDNA barcodes distinguished most species, even when short DNA fragments of COI were used (such as might be recoverable from sub-fossil material), and was similarly effective as tree-based methods using COI, cytochrome b, and D-loop sequences.  The genetic methods revealed some polytypic and paraphyletic species, suggesting a need for taxonomic revisions in this group.

This entry was posted on Tuesday, April 10th, 2007 at 9:34 pm and is filed under General. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.

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About this site

This web site is an outgrowth of the Taxonomy, DNA, and Barcode of Life meeting held at Banbury Center, Cold Spring Harbor Laboratory, September 9-12, 2003. It is designed and managed by Mark Stoeckle, Perrin Meyer, and Jason Yung at the Program for the Human Environment (PHE) at The Rockefeller University.

About the Program for the Human Environment

The involvement of the Program for the Human Environment in DNA barcoding dates to Jesse Ausubel's attendance in February 2002 at a conference in Nova Scotia organized by the Canadian Center for Marine Biodiversity. At the conference, Paul Hebert presented for the first time his concept of large-scale DNA barcoding for species identification. Impressed by the potential for this technology to address difficult challenges in the Census of Marine Life, Jesse agreed with Paul on encouraging a conference to explore the contribution taxonomy and DNA could make to the Census as well as other large-scale terrestrial efforts. In his capacity as a Program Director of the Sloan Foundation, Jesse turned to the Banbury Conference Center of Cold Spring Harbor Laboratory, whose leader Jan Witkowski prepared a strong proposal to explore both the scientific reliability of barcoding and the processes that might bring it to broad application. Concurrently, PHE researcher Mark Stoeckle began to work with the Hebert lab on analytic studies of barcoding in birds. Our involvement in barcoding now takes 3 forms: assisting the organizational development of the Consortium for the Barcode of Life and the Barcode of Life Initiative; contributing to the scientific development of the field, especially by studies in birds, and contributing to public understanding of the science and technology of barcoding and its applications through improved visualization techniques and preparation of brochures and other broadly accessible means, including this website. While the Sloan Foundation continues to support CBOL through a grant to the Smithsonian Institution, it does not provide financial support for barcoding research itself or support to the PHE for its research in this field.