From the Castle

Barcoding 101

Mosquitoes cause half a billion malaria infections that kill a million people annually. The mosquito Anopheles oswaldoi causes malaria only in northern Brazil, even though it is found throughout the country. Why? There are 3,500 mosquito species with many look-alikes; in 2006, a revolutionary new species identification system called DNA barcoding identified A. oswaldoi as four different species. The one that carries malaria lives only in the north. That knowledge enabled public health officials to focus malaria eradication efforts on the one problem species.

DNA barcoding has the potential to become enormously useful in a variety of applications. The U.S. Environmental Protection Agency is testing it for use in monitoring water quality, and the Federal Aviation Administration hopes that the system's more precise species identification will help the agency reduce bird-airplane collisions. Barcoding also shows great promise as an aid in fighting major agricultural pests and in protecting critical natural resources such as fish.

DNA barcoding was invented by Canadian geneticist Paul Hebert. In a supermarket, it occurred to him that the 11-digit UPC barcodes on products are able to distinguish millions of items; he posited that a short stretch of DNA code should likewise be able to distinguish species of flora and fauna. Hebert found a stretch that differentiates animal species: a segment of DNA called COI, which is 650 base pairs long. Smithsonian and other scientists are close to finding a counterpart DNA region that will work for plants. DNA sequencing machines read COI all at once, similar to the way a scanner reads the black-and-white UPC stripes at checkout. Using the Smithsonian's vast collections (30 million insects, 7 million fish, 5 million plants and many other specimens) our scientists were among the first to publish barcode research. In 2004, soon after Hebert's pioneering work, the Alfred P. Sloan Foundation funded the 160-member, 50-country Consortium for the Barcode of Life (CBOL). Headquartered at the Smithsonian's National Museum of Natural History, CBOL is organizing efforts around the world to compile a global reference library of DNA barcodes.

Eventually, your child may carry a portable "barcorder" on field trips, just as ecologists will survey biodiversity with barcorders and GPS devices. Inspectors will use hand-held barcorders to protect us from invasive species and mislabeled imported food and medicinal products. Science and technology working to benefit society. That's an important part of what the Smithsonian is all about.

Cristián Samper is Acting Secretary of the Smithsonian Institution.

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