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发帖数: 29846 | 1 MOSCOW – It was an Ice Age squirrel's treasure chamber, a burrow
containing fruit and seeds that had been stuck in the Siberian permafrost
for over 30,000 years. From the fruit tissues, a team of Russian scientists
managed to resurrect an entire plant in a pioneering experiment that paves
the way for the revival of other species.
The Silene stenophylla is the oldest plant ever to be regenerated, the
researchers said, and it is fertile, producing white flowers and viable
seeds.
The experiment proves that permafrost serves as a natural depository for
ancient life forms, said the Russian researchers, who published their
findings in Tuesday's issue of "Proceedings of the National Academy of
Sciences" of the United States.
"We consider it essential to continue permafrost studies in search of an
ancient genetic pool, that of pre-existing life, which hypothetically has
long since vanished from the earth's surface," the scientists said in the
article.
Canadian researchers had earlier regenerated some significantly younger
plants from seeds found in burrows.
Svetlana Yashina of the Institute of Cell Biophysics of the Russian Academy
Of Sciences, who led the regeneration effort, said the revived plant looked
very similar to its modern version, which still grows in the same area in
northeastern Siberia.
"It's a very viable plant, and it adapts really well," she told The
Associated Press in a telephone interview from the Russian town of Pushchino
where her lab is located.
She voiced hope the team could continue its work and regenerate more plant
species.
The Russian research team recovered the fruit after investigating dozens of
fossil burrows hidden in ice deposits on the right bank of the lower Kolyma
River in northeastern Siberia, the sediments dating back 30,000-32,000 years.
The sediments were firmly cemented together and often totally filled with
ice, making any water infiltration impossible -- creating a natural freezing
chamber fully isolated from the surface.
"The squirrels dug the frozen ground to build their burrows, which are about
the size of a soccer ball, putting in hay first and then animal fur for a
perfect storage chamber," said Stanislav Gubin, one of the authors of the
study, who spent years rummaging through the area for squirrel burrows. "It'
s a natural cryobank."
The burrows were located 125 feet below the present surface in layers
containing bones of large mammals, such as mammoth, wooly rhinoceros, bison,
horse and deer.
Gubin said the study has demonstrated that tissue can survive ice
conservation for tens of thousands of years, opening the way to the possible
resurrection of Ice Age mammals.
"If we are lucky, we can find some frozen squirrel tissue," Gubin told the
AP. "And this path could lead us all the way to mammoth."
Japanese scientists are already searching in the same area for mammoth
remains, but Gubin voiced hope that the Russians will be the first to find
some frozen animal tissue that could be used for regeneration.
"It's our land, we will try to get them first," he said. |
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