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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Why we need DNA ID

a) Culex pipiens, b) Culicens incidens, c) C. pipiens larvae, d) C. pipiens eggsBiting insects transmit human and animal diseases, including protozoan (e.g., malaria, leishmania, trypanosoma (sleeping sickness, Chagas disease)), filiarial (e.g., onchocerciasis, Guinea worm), and viral (e.g., yellow fever, West Nile, dengue) diseases. Control measures rely on identifying the insects, which generally requires expert training.

There are 174 mosquito species and subspecies in North America (“Identification and Geographical Distribution of the Mosquitos of North America, North of Mexico,” Richard F. Darsie, Jr. and Ronald A. Ward, University Press of Florida, 2005). Many species bite humans, but only a handful are important disease vectors. It takes an expert to identify Culex pipiens (panel A), which is the major vector for West Nile virus in eastern U.S., and to distinguish this from other species, for example, Culiseta incidens (panel B), which does not transmit human disease. Even experts are challenged by larvae (C), and eggs (D), and the latter are small and easily overlooked (egg raft size shown in inset). Planning and/or applying control measures is best done before adults hatch, but the early stages are what is most difficult.

The reference work cited above includes morphologic keys for identification of adult females and fourth-instar larvae. However, only an expert could make use of these (e.g. “lower mesepimeral setae absent, pale basal band on abdominal tergum II narrowed, or completely interrupted, medially). If mosquito identification is important for society, then reference DNA barcodes are what is needed, as these enable many more persons to name specimens, regardless of life stage. It does not make sense to rely on reference works for the world’s mosquitos that are incomprehensible to anyone who is not already a mosquito specialist.

This entry was posted on Monday, May 10th, 2010 at 3:03 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.

One Response to “Why we need DNA ID”

  1. Haribabu Ejnavarzala Says:

    The information on the number of species of mosquito and the need to distinguish them is very useful, both at cognitive and practical levels. It is one more instance of interface between science and human society in the area of public health.


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.