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Saturday, July 18, 2009

DNA? Or Maybe Yahtzee? What Governs the Forms of Alien Life, If There Is Any?

Casey Kazan writes:

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's your guess: 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.

link: Neil deGrasse Tyson: "Will DNA Prove to be the Life Code Throughout the Universe?"


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