First Vertebrate Species Description with a DNA Barcode

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In December 1982, Benjamin Victor, founder of the coral reef research initiative Ocean Science Foundation, was diving in a reef just offshore of a Smithsonian Tropical Research Institute field station when he scooped up an adult goby. The fish looked slightly different from its Atlantic goby kin, but its features weren’t unique enough to declare it a new species.

Victor suspected that the differences ran deep in the goby’s genetic makeup, but the species identification system, based purely on physical identifiers such as markings, numbers of fins and shapes of bones, failed him. He would need a second specimen and DNA analysis. So the specimen sat, and sat--on Victor’s desk, actually--for close to 25 years.

In March 2006, Dave Jones of the National Marine Fisheries Service collected a larval specimen reminiscent of Victor’s goby in a trap off of Mexico’s Yucatan. From there, the new taxonomic technique of barcoding allowed Victor to match the DNA of the larva with that of the adult and declare the goby a new species, one that diverges from its Atlantic goby kin by a whopping 25 percent (keep in mind: humans and chimpanzees are only 1-2 percent different).

The fish's claim to fame is that its identity has been nailed down by a DNA barcode. The barcode, taken from an agreed-upon location in the genome, acts like a consumer product’s barcode in that it seals the deal in terms of identification.

Named Coryphopterus kuna, the goby has become the first vertebrate species to have its DNA barcode included in its official species description. About 30,000 known species, from mushrooms to birds, have been barcoded, but in all cases, the species were found and scientifically described before the barcodes were created. The Barcode of Life Initiative, of which the Smithsonian Institution is a partner, is urging that the short DNA strands be collected and put in an open-access database.

"There was no way to make it easy and consistent to identify a fish. You usually had to be an expert and would have to have a good adult specimen to examine and then it was your opinion," says Victor of taxonomy pre-barcoding. "Now anyone with access to barcoding technology can say for sure, the sequence matches species X, even if what you have is an egg, larva, or a scale or piece of skin."

(Courtesy of STRI)

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