lpetrich

Here is a <a href="http://www.chemistry.ucsc.edu/~issol/newsF02.html" target="_blank">report on ISSOL's 2002 Oaxaca Conference</a>; held by the International Society for the Study of the Origin of Life. Its homepage is normally <a href="http://www.issol.org" target="_blank">http://www.issol.org</a> but it has been having server troubles recently. Now to some of the work reported on in that conference:

Meierhenreich did a rebiotic-synthesis experiment that imitated the environment of a Giant Molecular Cloud -- among the organic molecules formed were 16 amino acids. Kobayashi did a similar experiment involving irradiation of impure ice also yielded some amino acids. Which is more evidence that prebiotic organic synthesis is rather "easy" in suitable environments.

Mark van Zuilen reported on work on the 3.8-billion-year-old Isua graphites; it is most likely produced by metamorphism of carbonates like siderite (FeCO3), and that its C13 abundance was the result of fractionation at temperatures of 500-600K. Which means that these graphites are most likely not the remains of microorganisms, as was suggested from their isotope signatures.

Jim Kasting pointed out that the rise of atmospheric O2 happened at about 2.3 billion years ago; before then, there could have been a methane greenhouse that had warmed the Earth -- and even a Titan-like organic haze.

James Cleaves reported on some work on how montmorillite clay can catalyze the polymerization of a modified form of RNA.

Jeffrey Bada reported on how meteorites could have been a big source of prebiotic molecules for the early Earth.

Nils Holm described how ocean-floor peridotite can do a Fischer-Tropsch reaction on CO2 and CO and H2, forming hydrocarbons; he described actual evidence of 16-to-29-carbon hydrocarbons being formed in the Mid-Atlantic Ridge.

Turning to the question of the RNA world, Harry Noller described how the ribosome's active area is exclusively RNA and not protein -- which further supports the RNA-world hypothesis.

Mario Sobreron reported that there is an interesting sort of gene regulation involved in the synthesis of B vitamin and coenzyme thiamine pyrophosphate. Although gene regulation usually requires a sensor protein, in this case, the thiamine binds directly to the DNA strand's "thi box" sequence.

Janet Siefert reported the widespread presence of an operon (set of genes regulated as a group) for iron-sulfur-cluster enzymes, with one version following the ribosomal-RNA tree, making it ancestral.

Frances Westall described finding evidence of microbial mats and filamentous bacteria in the greenstone-belt sediments of Barbenton, South Africa and Pilbara, Australia, from over 3.4 billion years ago. The bacteria looked very similar, though they did not have cyanobacterium-like morphology.

There was some other stuff reported on, but I've decided to stop here.

Doubting Didymus

Ooo!
I love it! We are getting closer to the answer every year.

Thank you very much for that.

Neruda

no kidding. IMO, this is the most fascinating area of evolutionary science: molecular evolution. Just gives you the tinglies, doesn't it?

Duvenoy

The shape I'm in, if I tingle a lot, something might fall off.

But yes! Very exciting! I think the door will open before too much longer.

Then, I'll take a chance on tingling.

Edited to add: Might not life in the Universe be the rule rather than the exception? Given reasonable conditions, of course.

doov

[ December 04, 2002: Message edited by: Duvenoy ]</p>

Doubting Didymus

'life' the rule rather than the exception? Depending on what we find the abiogenesis thing to be, I would say: no doubt. Intelligent life is another matter, however.