Rockefeller University

Program for the Human Environment

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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COI solves leech mix-ups

Relying on morphologic species descriptions lacking DNA sequences is like diagnosing patients without laboratory tests. An experienced clinician can often make the correct diagnosis from examination alone, but laboratory tests are frequently needed to confirm or point to other causes. Many advances in medicine reflect incorporating laboratory testing into routine evaluation. Two papers on leeches suggest similar benefits to taxonomy from incorporating mtDNA analysis into routine practice.

In May 2005 Conservation Genetics 6:467 researchers at the American Museum of Natural History analyze morphology, mitochondrial COI, and nuclear ND-I sequences of genus Helobdella leeches from Austrialia, New Zealand, South Africa, Hawaii, and South America. The tale starts with a leech discovered in Germany in 1985, H. striata, re-named H. europaea in 1987. 

Authors Siddall and Budinoff found that H. europaea is morphologically and genetically indistinguishable from a leech “discovered” in Australia in 1998, H. papillornata. Including COI sequences in initial species descriptions would have prevented wasted taxonomic effort, and a species native to South America would probably not be given the unfortunate name europaea.

In December 2006 Evol Devel 8:491, scientists from University of Maryland and University of California, Berkeley, apply COI barcoding to another Helobdella leech, H. robusta, a model organism in developmental biology and one of the lucky species selected for genome sequencing. Researchers Bely and Weisblat obtained leech specimens from laboratory cultures and field sites. They found that isolates thought to be H. robusta actually represent four species, 2 of which co-exist at the same locality. The authors observe “the perils of misidentification and taxonomic confusion in the lab are numerous and costly” and conclude with a call for routine application of DNA barcoding and collection of voucher specimens to confirm identity of laboratory organisms. 

This entry was posted on Saturday, January 13th, 2007 at 1:03 am 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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Contact: mark.stoeckle@rockefeller.edu

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.