I'm not sure what all the implications of this find are, but it may
shed some light on the evolution of the earliest life forms. I'll have
to get a copy of the journal article.
http://tinyurl.com/2e4k5
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Yellowstone virus tied to earliest life; Unique organism from geyser
basin enthralls scientists
Associated Press
A virus discovered in Yellowstone National Park may provide a link to
ancient life on Earth before the primordial soup of life began dividing
into more distinct forms over 3 billion years ago, Montana State
University scientists say.
The virus may help scientists understand a common ancestor that
scientists believe was present before life split into forms such as
bacteria, heat-loving organisms and the building blocks that led to
plants and animals.
"It's a clue that helps you say, 'Yeah, there probably was a common
ancestor at some point or sets of ancestors,' " said George Rice, one of
the MSU scientists who participated in the study. "It's food for
thought."
Understanding the origin of life on Earth has been one of the basic
goals of science. For many scientists, that means tracing back the
branches in the "tree of life" to a point where the three "domains" or
categories of life - known as bacteria, archaea and eukarya - come
together in a single trunk.
While still far from painting a picture of that common ancestor,
researchers are now able to ponder the implications for early life on
Earth and may even apply it in looking for life forms on other planets.
"If we're going to go to non-Earth-based bodies to look for life, this
discovery gives NASA an approach for looking for life in hot-temperature
environments, which we know to exist off of Earth," said Mark Young,
another MSU scientist involved in the study.
Many archaea, which are similar to bacteria, thrive in places like
Yellowstone's hot, acidic geothermal basins. Like other living things,
they can't escape viral infections.
Rice began hunting for thermophilic (heat-loving) viruses in Yellowstone
five years ago. In 2001, he and others found several apparently unique
viruses associated with an organism living near Midway Geyser Basin
where temperatures ranged from 158 to 197 degrees Fahrenheit.
"It was basically something living in boiling acid," Rice said.
Although several new viruses were discovered, one in particular caught
their eye.
After characterizing the structure and genome (the set of genetic
information) of the virus, they found that its protein shell, shaped
roughly like a soccer ball, was similar to a bacterial virus and to an
animal virus. The similarity suggests to the scientists that the three
viruses may share a common ancestor that predates the branching off of
life forms more than 3 billion years ago.
"This is something that was predicted but hadn't been shown before,"
Rice said.
The discovery was published in the May 3 issue of the Proceedings of the
National Academy of Sciences.
For a long time, scientists classified all life forms as plant or
animal. That classification system expanded as more life forms were
discovered. Eventually, biologists divided life into five kingdoms -
plants, animals, bacteria, fungi and protists.
A more recent approach divides life into three domains: bacteria,
eukarya (including plants, fungi, animals and others) and archaea (which
means "ancient").
Archaea is likely the least understood of the domains, according to the
paper's authors. Archaea may have been among the first forms of life on
Earth. Able to thrive in the hot, gaseous and volcanic terrain of early
Earth, they could also survive in the very inhospitable geothermal
features of the Yellowstone of today.
Now that scientists know the Yellowstone virus's ancient structure seems
to span all three domains of life, scientists plan additional studies on
its genes to figure out what they tell the virus to do. Viruses can play
a crucial evolutionary role in passing genes from one organism to
another.
"Anywhere there's life, we expect viruses," Young said. "They are the
major source of biological material on this planet."
The virus and others found at Yellowstone will give researchers a hand
in the search for life on other planets, including Mars.
"These bugs are living and doing business in a harsh environment," Rice
said. "This may be clues about what to look for."
http://www.billingsgazette.com/index.php?id=1&display=rednews/2004/05/12/
build/wyoming/30-yellowstone-virus.inc
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--
John Hachmann aa #1782
"Men become civilized not in their willingness to believe, but in
proportion to their readiness to doubt." - H. L. Mencken
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