Neil deGrasse Tyson believes that BIG
question of the 21st century is will we discover life somewhere other
than on Earth? He views it as an “unimpeachable first goal” in our
exploration of the cosmos.
And what most fascinating is the
question of whether that life has DNA. It’s fascinating, Tyson says,
because either DNA is inevitable as the foundation for the coding of
life, or life started with DNA in only one place in the solar system
and then spread among the livable habitats through panspermia.
Microbial life can land on and seed another planet, thereby not
requiring that you have to create life from scratch multiple times and
in multiple places.
Another totally intriguing possibility, one of many that deGrasse
Tyson Director of the Hayden Planetarium at the American Museum of
Natural History and host PBS’s NOVA scienceNOW., describes in Origins: Fourteen Billion Years of Cosmic Evolution, is that there is life that has encoding that has nothing to do with DNA.
It is the relentless shifting and mutating of DNA, says Dennis Overbye in a brilliant essay in The New York Times,
that generates the raw material for evolution to act on and ensures the
success of life on Earth (and perhaps beyond). Dr.Paul Davies
co-director of the Arizona State University Cosmology Initiative said
that he had been encouraged by the discovery a few years ago “that some
sections of junk DNA seem to be markedly resistant to change, and have
remained identical in humans, rats, mice, chickens and dogs for at
least 300 million years.”
But Dr. Gill Bejerano, Assistant Professor of Developmental Biology and of Computer
Science
at Stanford, one of the discoverers of these "ultraconserved" strings
of the genome, said that many of them had turned out to be playing
important command and control functions.
"Why they need to be so
conserved remains a mystery," Berjerano said, noting that even regular
genes with known functions undergo more change over time. Most junk
bits of DNA that neither help nor annoy an organism mutate even more
rapidly, Overbye points out.
What your quess: Is the DNA the
cosmic code for life in the universe, or is it possible that there’s
are alien, unknown foundations? At the Galaxy, we place our chips on
DNA.
Posted by Casey Kazan.
http://www.pbs.org/wgbh/nova/origins/tyson.html
http://www.nytimes.com/2007/06/26/science/26DNA.html?_r=2&oref=login&oref=login
Image Credit: Copyright Jimmy Turrell
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