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HalfMooner
Dingaling
Philippines
15831 Posts |
 Posted - 02/07/2008 : 00:01:39
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This article at Discover Magazine throws new light on the infant subject of abiogenesis.| As Miller and his former student Jeffrey Bada brushed the frost from the vial that morning, they could see that something had happened. The mixture of ammonia and cyanide, normally colorless, had deepened to amber, highlighting a web of cracks in the ice. Miller nodded calmly, but Bada exclaimed in shock. It was a color that both men knew well—the color of complex polymers made up of organic molecules. Tests later confirmed Miller's and Bada's hunch. Over a quarter-century, the frozen ammonia-cyanide blend had coalesced into the molecules of life: nucleobases, the building blocks of RNA and DNA, and amino acids, the building blocks of proteins. The vial's contents would support a new account of how life began on Earth and would arouse both surprise and skepticism around the world. |
Okay, the direct precursor components of RNA and DNA, spontaneously assembled in a cryogenic mixture of ammonia and cyanide. Amazing.
But there's more -- the next step: Biebricher sealed small amounts of RNA nucleobases—adenine, cytosine, guanine—with artificial seawater into thumb-size plastic tubes and froze them. After a year, he thawed the tubes and analyzed them for chains of RNA.
For decades researchers had tried to coax RNA chains to form under all sorts of conditions without using enzymes; the longest chain formed, which Orgel accomplished in 1982, consisted of about 40 nucleobases. So when Biebricher analyzed his own samples, he was amazed to see RNA molecules up to 400 bases long. In newer, unpublished experiments he says he has observed RNA molecules 700 bases long. Biebricher's results are so fantastic that some colleagues have wondered whether accidental contamination played a role. Orgel defended the work. “It's a remarkable result,” he said. “It's so remarkable that everyone wants better evidence than they would for an unremarkable result. But I think it's right.”
Biebricher had loaded the deck somewhat, because he wasn't growing RNA chains from nothing. Before he froze his samples, he added an RNA template—a single-strand chain of RNA that guides the formation of a new strand of RNA. As that new RNA strand grows, it adheres to the template like one half of a zipper to the other. This must be how the first genes, made of RNA, would have copied themselves. But the first step was the formation of the original RNA molecule that served as a template, and how that step happened remains a mystery. |
This is not quite a laboratory demonstration of abiogenesis, especially because of the added "starter" RNA. The results need replication by others, as well. But it's very, very interesting.
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“Biology is just physics that has begun to smell bad.” —HalfMooner
Here's a link to Moonscape News, and one to its Archive. |
Edited by - HalfMooner on 02/07/2008 00:05:51
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Dude
SFN Die Hard
USA
6891 Posts |
Posted - 02/07/2008 : 01:07:41 [Permalink]
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Yeah, I read those papers. Very interesting is an understatement.
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Ignorance is preferable to error; and he is less remote from the truth who believes nothing, than he who believes what is wrong.
-- Thomas Jefferson
"god :: the last refuge of a man with no answers and no argument." - G. Carlin
Hope, n.
The handmaiden of desperation; the opiate of despair; the illegible signpost on the road to perdition. ~~ da filth |
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Did ice produce the first RNA?
