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Random Samples
Howdy all.
>From a weekly Science emailing two interesting notes this morning:
-mpc
Michael Patrick Corriss
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Random Samples
Volume 315, Number 5815, Issue of 23 February 2007
Â2007 by The American Association for the Advancement of Science.
NETWATCH: On The Hoof
BIRDS, BATS, AND BAR CODES
NETWATCH: On The Hoof
What does a dromedary camel loping across a sand dune have in common with a
Lippizaner stallion high-stepping around a ring and a rhinoceros luxuriating in
a mud puddle? They are all ungulates, mammals that typically sport the
overgrown toenails known as hooves. To learn more about the group or individual
species, drop by the Ultimate Ungulate page from Brent Huffman, a keeper at the
Toronto Zoo in Canada.
Introductory pages summarize some of the surprises from recent molecular
studies on mammalian evolution, which distanced the ungulates from elephants
and aardvarks, long thought to be their next of kin. Hoofed animals are
actually more closely related to bats. Species accounts cover most of the more
than 250 ungulates, offering details on the animals' diet, habitat, behavior,
and range.
http://www.ultimateungulate.com
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BIRDS, BATS, AND BAR CODES
Fifteen bird species have been newly discovered by a DNA identification
technique called bar coding, researchers reported online 19 February in
Molecular Ecology Notes. They've also uncovered six new bat species in bat-rich
Guyana.
A different bat.
CREDIT: ALEX BORISENKO 2006, ROYAL ONTARIO MUSEUM
The Barcode of Life project seeks to determine the DNA sequence of the same
mitochondrial gene in millions of Earth's fauna. The variations in the sequence
provide a unique, easy-to-read species identifier, scientists say.
Until now, bar coding hadn't been tested in either mammals or widespread bird
populations. For the bird probe, evolutionary biologist Paul Hebert of the
University of Guelph in Canada and colleagues cataloged DNA from 2500 specimens
supplied by museums and bird banders in the United States and Canada. The
samples represent 643 of the 690 known North America-based species. Bar codes
supplied some surprises, revealing 15 "cryptic" species: birds so similar to
other birds that they had not been seen as distinct. What's more, eight
supposed gull species turned out to be just one, and birds from 14 other
supposed species were virtually identical to at least one other species.
In the mammalian end of the project, Hebert's team turned to Guyana, taking
tissue samples from 840 bat specimens in the Royal Ontario Museum. There was
concern that the species would be too closely related to reveal genetic
differences. Yet the researchers easily distinguished the 80 or so species in
the collection and discerned several new ones, Hebert says. Such studies have
the potential to "break bar coding" by proving to skeptics that species can't
always be distinguished on the basis of just one gene, says project member Mark
Stoeckle of Rockefeller University in New York City. "But it's worked
everywhere it's been applied."
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