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magazine / ma07
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March/April 2007 issue |
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FEATURE
Barcoding life
Identifying each of the 15 million or so species on the planet may seem an impossible task. Can a genetic shortcut
developed by a Canadian scientist do the job in mere decades?
Excerpt of story by Siobhan Roberts
Life is short in Churchill, Man., where ice
lingers on Hudson Bay until July and by
September, it's snowing again. Even with
these limitations, the tundra teems with
activity and beckons biodiversity hunter Paul
Hebert like a pet store to a wide-eyed child.
Over three weeks last summer, he conducted
a "biodiversity blitz" in Churchill — a census of
all the
organisms he could get his hands on.
top
Hebert, an evolutionary biologist at the University of
Guelph, along with about 30 staff and students grabbed
samples from the flotsam parts they found lying about:
feathers from the ptarmigan and hawk-eyed snowy owl,
tufts of hair from the woodland caribou, skin swabs from the
beluga whale, along with specimens of caplin, fairy shrimp
and tiny jet-black water fleas.
"Our prize catch occurred just two days ago," Hebert
reported in an e-mail from the field. "We found a specimen
of the black witch moth on a rock bluff right beside Hudson
Bay. This is a migratory species that breeds in Mexico. It now
stands as the most northern record ever for this species; it
beats a 1957 record from Juneau, Alaska!"
Back in the lab, the team is reading a snippet of DNA
from the tens of thousands of invertebrate specimens and
the hundred or so vertebrate samples it collected. "We are
not out slaughtering organisms," explains Hebert. The
Churchill expedition deployed what some consider a revolutionary
new taxonomical tool: a standardized method
for identifying species using a short DNA sequence from
a common locality on the genome. Hebert debuted this
technique in a 2003 article in the Proceedings of the Royal
Society of London, where he proclaimed that "these
sequences can be viewed as genetic ‘barcodes' that
are
embedded in every cell."
For the rest of this story, visit your local newsstand or go to our store to buy this issue.
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