Transition Metal Catalysts Could Be Key To Origin of Life 145
An anonymous reader writes "One of the big, unsolved problems in explaining how life arose on Earth is a chicken-and-egg paradox: How could the basic biochemicals — such as amino acids and nucleotides — have arisen before the biological catalysts (proteins or ribozymes) existed to carry out their formation? In a paper appearing in the current issue of The Biological Bulletin, scientists propose that a third type of catalyst could have jumpstarted metabolism and life itself, deep in hydrothermal ocean vents."
Fe/Ni-S World Hypothesis? (Score:4, Informative)
Isn't this old news? (pun not entirely intended)... A couple of the more prominent abiogenesis hypotheses have been based on this for most of the decade of not more. Here's a paper from 2003 that, while it has its flaws (some of which have been rectified, some of which have been completely rethought over the last 7 years) offers a fairly complete and very compelling hypothesis for how life may have originated at warm, alkaline thermal vents like those found at the Lost City thermal vent fields:
Martin, W. & Russell, M.J., 2003. On the origins of cells: a hypothesis for the evolutionary transitions from abiotic geochemistry to chemoautotrophic prokaryotes, and from prokaryotes to nucleated cells. Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 358(1429), 59-83; discussion 83-5. Available at: http://rstb.royalsocietypublishing.org/content/358/1429/59.abstract [royalsocie...ishing.org].
And here's a similar but competing hypothesis (still based on Fe/Ni-S, but with a different idea on the origins of membranes and cells):
Wächtershäuser, G., 2006. From volcanic origins of chemoautotrophic life to Bacteria, Archaea and Eukarya. Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 361(1474), 1787-806; discussion 1806-8. Available at: http://rstb.royalsocietypublishing.org/content/361/1474/1787.abstract [royalsocie...ishing.org]
The latter author has been writing papers about this hypothesis since 1992 (though I haven't read his first paper on the subject).
Point being, this doesn't seem to be a new thing, especially as summarized in the summary here and in the linked article. The original paper on which the article is based [biolbull.org] offers a bit more fundamental chemical details regarding the transition metals involved, and suggests good directions for experimental confirmation or refutation, but the overall idea remains pretty much the same, it seems. Still, it will be interesting to see what, if any, research and experiments result from this.
Re:The Missing Ingredients! (Score:5, Informative)
The stuff has been cooking for the last thirty years, and no life has crawled out yet . . .
Hardly a surprise, since the real thing took as much as a billion years in a planet-sized beaker.
FWIW, I'm not sure the U-M experiments properly reflect our current understanding of the chemistry of the early earth, either.
Ribonucleotides & RNA (Score:5, Informative)
Well, I know everybody's just joking around here, but...
One of the more exciting papers I've read in this area appeared in Nature a little while back (14 May 2009). It shows not only that activated ribonucleotides could have been formed directly from simple molecules that were plausibly present on the early earth, but that the necessary reactions are of high yield, are catalyzed by inorganic phosphates, and take place under mild conditions. Because the ribonucleotides are formed as the phosphates ("activated"), they're suitable for polymerization to RNA under similarly mild conditions.
To me, this seals the deal for RNA the same way that Miller-Urey did for amino acids, and maybe even more so (because the reactions take place under ambient conditions, no lightning bolts needed). It's widely thought that early forms of life were based on RNA rather than DNA, so there you go. Now we just need to figure out how to make a ribosome.
See Powner et.al., "Synthesis of activated pyrimidine ribonucleotides in prebiotically plausible conditions," Nature 459, 239-242 (2009).
Sorry for the geekiness here, but of you know a little organic chemistry you'll find this really cool...
Re:The electro-dynamic field came first, of course (Score:4, Informative)
Philosophy of science classes just teach the ideas behind the scientific method, how it came to be, and how the early scientists worked. I don't see what relevance that class has to anything you're talking about, this is not a philosophy that scientists are pushing on people, it is the history of scientific pursuit and tools to be used for future work. There is no agenda, scientists aren't trying to push the ideology on you. The evidence says that is what happened, so they report it. Because you feel persecuted by it because it doesn't jive with your beliefs doesn't make it wrong. It doesn't make it right either, it is simply the best idea we have given the evidence presented thus far. That is all science is.
Your last paragraph is nonsensical. Why do we have to give up quantum mechanics? There is nothing magical about it. It may not even be how things work, it just makes very good predictions. What argument are we following to its logical conclusion? You are simply making statements without fully explaining them. What do atheists have to reject about quantum mechanics?
Re:Ribonucleotides & RNA (Score:5, Informative)
You really shouldn't need to apologize for "geekiness" on Slashdot. If we can't reference and/or link to actual scientific research without apology, then something must be very wrong with this site. ;)
That said, the paper you mentioned looks really interesting. AND, a Google Scholar search [google.com] offers a link to a freely downloadable PDF for those of you, like myself, that don't have access to Nature.
I'm looking forward to reading this. :)
Re:The electro-dynamic field came first, of course (Score:3, Informative)
I can show you that matter causes electric fields. All I need is salt water, copper, and iron. The result is that an electric field will be created from the matter in iron-air battery. The opposite effect would mean that if I produced 0.7 volts, I would have an iron-air battery. Life has an electric field because the material process of evolution choice electric signals as a communication mechanism, because they are fast and readily cause chemical effects. That's also why sapient biological robots (us) used machinery to assemble arrays of semiconductor materials to assemble non-sapient computers. The disproof of this hypothesis will occur when a sapient (or at least self staining) robot is built. If we wanted we could then build a sapient mechanical computer (Babbage style), thus disproving the necessity of electric fields to sapience.
To show that your hypothesis has merit, you must take a set of electric fields, from solar panels or other inorganic sources, and a lot wires, and have organic life pop out. Also, double check to prevent contamination by bacteria. The little critters are everywhere and will clog up the experiment. Now, chemical experiments have not yet have life pop out of them yet. There have been some self-replicating RNA enzymes that came out of nowhere but a pile of individual RNA monomers. Meanwhile, increasing amounts of research (like TFA) is showing where this RNA mixture could have come from. I'm guessing everything, from transition metals, to radio active decay, to rare earth metals and other forms of unobtainium where involved.