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科学
420 words
Chapter 1
The recipe for making any creature is written in its DNA. So last year, when 1-1
geneticists* published the near-complete DNA sequence of the long-extinct woolly
mammoth, there was much speculation about whether we could bring this giant creature
back to life.
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東京理科大学
Creating a living, breathing creature from a genome* sequence that exists only in a
computer's memory is not possible right now. But someone someday is sure to try it,
predicts Stephan Schuster, a molecular biologist at Pennsylvania State University and a
driving force behind the mammoth genome project.
So besides the mammoth, what other extinct beasts might we bring back to life? Well, 12
10 it is only going to be possible with creatures for which we can recover a complete genome
Without one, there is no chance. And usually when a creature dies, the
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DNA in any flesh left untouched is soon destroyed as it is attacked by sunshine and
bacteria.
sequence.
There are, however, some circumstances in which DNA can be preserved. If your
15 specimen froze to death in an icy wasteland such as Siberia, or died in a dark cave or a
really dry region, for instance, then the probability of finding some intact stretches of
DNA is much higher.
Even in ideal conditions, though, no genetic information is likely to survive more
than a million years. - so dinosaurs are out and only much younger remains are likely
to yield good-quality DNA. "It's really only worth studying specimens that are less than
100,000 years old," says Schuster.
The genomes of several extinct species besides the mammoth are already being
sequenced, but turning these into living creatures will not be easy. "It's hard to say that
something will never ever be possible," says Svante Pääbo of the Max Planck Institute
25 for Evolutionary Anthropology in Germany, "but it would require technologies so far
removed from what we currently have that I cannot imagine how it would be done."
But then
(3) 50 years ago, who would have believed we would now be able to read the
instructions for making humans, fix inherited diseases, clone mammals and be close to
creating artificial life? Assuming that we will develop the necessary technology, we have
30 selected ten extinct creatures that might one day be resurrected. Our choice is based not
just on practicality, but also on each animal's "charisma" - just how exciting the
prospect of resurrecting these animals is.
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