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Posted September 9, 2008
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Biotech

DNA Barcoding Uncovers Wasp Diversity

Guelph - DNA barcoding analysis conducted at the University of Guelph has revealed a tiny wasp that is among the most diverse groups of insects on Earth is actually even more varied than previously thought.

The findings appear in this month's Proceedings of the National Academy of Sciences. Using a tiny snippet of DNA from more than 5,000 specimens, researchers found 313 provisional species of wasps in the subfamily Microgastrinae — nearly double the number of species previously identified.

Barcoding revealed that some wasps that looked alike and were once thought to belong to a single species were actually several different species, and that these were incredibly specialized on specific caterpillar hosts. In one extreme case, one species became 36 following barcoding.

The barcoding analysis was led by Alex Smith at the Biodiversity Institute of Ontario (BIO). The research team included Paul Hebert, BIO director and a U of G integrative biology professor; Daniel Janzen and Winnie Hallwachs, ecologists from the University of Pennsylvania; Josephine Rodriguez and James Whitfield, taxonomists from the University Illinois Champaign-Urbana; and Andrew Deans, a taxonomist at North Carolina State University.

"Combining morphological analysis, ecology, and DNA barcoding allowed us to make much more fine-scaled hypotheses of parasitoid diversity and host-specificity than any one of these elements could have produced on its own," Smith said.

"This is important because we demonstrated that barcoding can accelerate not just species identification but also species discovery.”

One advantage of barcoding is the capacity to identify specimens from bits and pieces of tissue. The wasps, known for laying eggs under the skin of caterpillars, are often used as biological control agents, and all of the wasps in the study were reared from caterpillars collected in Area de Conservación Guanacaste (ACG), a biological reserve in northwestern Costa Rica.

Hebert was the first scientist to propose that a short DNA sequence from a standard gene region shared by all multicellular life could be used to identify species. He called the system DNA barcoding, analogous to how retail products are tagged in supermarkets to allow their quick identification. DNA barcoding technology has the capacity to reduce species identification time to hours and, eventually, to minutes.

To date, DNA barcoding has led to the discovery of overlooked species of ants, birds, bats, butterflies, fishes and marine algae. It has also been used to show that seafood sold in restaurants and markets is often mislabelled.

Hebert and the other scientists have established the International Barcode of Life Project, which will involve more than 100 researchers from 25 countries once fully activated. The consortium will create the world’s first reference library of DNA barcodes for use in species identification around the globe. It will also develop new informatics tools and technologies.


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