Experiments create "RNA World" capable replicating molecules

[Pazuzu]

Interesting! I didn't know that the RNA World hypothesis had gone so far in it's support, but this is GOOD stuff!


http://www.rsc.org/chemistryworld/News/2009/January/09010901.asp

Chemists edge closer to recreating early life

09 January 2009

A test tube based system of chemicals that exhibit life-like qualities such as indefinite self-replication, mutation, and survival of the fittest, has been created by US scientists. The researchers say their perpetually replicating RNA enzymes take us a step closer to understanding the origins of life on Earth, as well as to how life may one day be synthesised in the lab.

The system, created by Gerald Joyce and Tracey Lincoln at the Scripps research institute in La Jolla, California, involves a cross-replicating pair of ribozymes (RNA enzymes), each about 70 nucleotides long, which catalyse each other's synthesis. So the 'left' ribozyme templates the synthesis of the 'right', which in turn templates the 'left' and so on, building each other via Watson-Crick base pairing.

'This is the very end of the line, where chemistry starts turning into biology,' says Joyce. 'It's the first case, other than in biology, of molecular information having been immortalised.'

Joyce's experiment was designed to test the 'RNA World' theory, which proposes that DNA-based life evolved from a stage whereby RNA acted as both an information-storage molecule, like DNA, and as a catalyst, like enzymes, and was also capable of self-replication.

...

Only the strongest will survive

The system also demonstrates natural selection. The team created twelve sets of cross-replicating enzymes ('left' and 'right' 1 to 12) and allowed them to compete for a common pool of oligonucleotide building blocks. Occasionally, a mutation would arise, so instead of making 'right 7', 'left 7' would instead combine oligonucleotides in a new way to make, for example, a 'right 7-left 12' hybrid. Such recombinants arose and then grew over many, many rounds of replication to dominate the population.

'This parallels what happens in biological systems, like natural selection or survival of the fittest,' says Joyce. 'It isn't alive, however, because what it doesn't have is the ability to invent novel functions out of whole cloth. If it could do that then most scientists would say that it crossed the line into life.'

James Urquhart

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http://www.sciencemag.org/cgi/content/abstract/1167856
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Published Online January 8, 2009
Science DOI: 10.1126/science.1167856

Self-Sustained Replication of an RNA Enzyme
Tracey A. Lincoln 1 and Gerald F. Joyce 1*

1 Departments of Chemistry and Molecular Biology and the Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.

An RNA enzyme that catalyzes the RNA-templated joining of RNA was converted to a format whereby two enzymes catalyze each other’s synthesis from a total of four oligonucleotide substrates. These cross-replicating RNA enzymes undergo self-sustained exponential amplification in the absence of proteins or other biological materials. Amplification occurs with a doubling time of about one hour, and can be continued indefinitely. Populations of various cross-replicating enzymes were constructed and allowed to compete for a common pool of substrates, during which recombinant replicators arose and grew to dominate the population. These replicating RNA enzymes can serve as an experimental model of a genetic system. Many such model systems could be constructed, allowing different selective outcomes to be related to the underlying properties of the genetic system.

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[legion]

This is how Cylons reproduce.

[Pazuzu]

Originally Posted by legion

This is how Cylons reproduce.

I'm gonna have to trust you on that one...

[sjf911]

It is truly amazing how rapidly the abiogenisis work is progressing. The RNA world hypothesis has gotten two big advancements between this study and Jack Szostak's recent demonstration of spontaneous RNA polymerization driven micelle "budding"/replication. No magic required.