azichettello"The researchers, at the Scripps Research Institute, created molecules that self-replicate and even evolve and compete to win or lose. If that sounds exactly like life, read on to learn the controversial and thin distinction."
"Specifically, the researchers synthesized RNA enzymes thatcan replicate themselves without the help of any proteins or other cellular components, and the process proceeds indefinitely. "Immortalized" RNA, they call it, at least within the limited conditions of a laboratory.
"RNA is the close cousin to DNA. More accurately, RNA is thought to be a primitive ancestor of DNA. RNA can't run a life form on its own, but 4 billion years ago it might have been on the verge of creating life, just needing some chemical fix to make the leap. In today's world, RNA is dependent on DNA for performing its roles, which include coding for proteins." (2009)
Here's a link to the paper:
Self-sustained Replication of an RNA Enzyme
And from a more recent paper by that group: Evolution in an RNA World (2009)
Is it Alive?
No. The artificial genetic system based on RNA enzymes that catalyze their own replication has many of the properties of a living system, but lacks the ability to bring about inventive Darwinian evolution. The molecules can undergo self-sustained replication with exponential growth. “Self-sustained” in this context refers to their ability to operate without the aid of an external catalyst. All of the genetic information that is necessary for the system to replicate and evolve is part of the system that is undergoing replication and evolution [....]
And an excerpt from "The Emergence Of Life On Earth" (found reposted on a forum here. Originally a summary of the state of art research in Abiogenesis)
Having established that RNA was synthesisable under prebiotic conditions, researchers then turned to the matter of establishing the existence of self-replicating species of RNA molecules. This was duly successful[30, 43, 45 - 47], establishing that such species could have arisen among the extant RNA molecules being synthesised on a prebiotic Earth, and of course, once one self-replicating species exists, the process of evolution can begin, which has also since been demonstrated to apply to replicating RNAs in appropriate laboratory experiments[48].
Once a self-replicating molecule that can form the basis of an inheritance mechanism exists, the next stage scientists postulate to be required is encapsulation within some sort of selectively permeable membrane. The molecules of choice for these membrane are lipids, which have been demonstrated repeatedly in the laboratory to undergo spontaneous self-organisation into various structures, such as bilayer sheets, micelles and liposomes. Indeed, in the case of phospholipids, they can be stimulated to self-organise by the simple process of agitating the solution within which they are suspended - literally, shake the bottle[49 - 53]. Moreover, research has established that these lipids can encapsulate RNA molecules, and selectively admit the passage of base and sugar molecules to facilitate RNA replication[54, 55]. With the advent of this discovery in appropriate laboratory research, protocell formation is but a short step away, and indeed, the latest research is now actively concentrating upon the minimum components required in order for a viable, self-replicating protocell to exist. Prebiotic lipid formation is also a part of the repertoire of the literature in the field, and some papers now extant document the first experiments aimed at producing viable self-replicating protocells[55 - 70].
[30] Nucelotide Synthetase Ribozymes May Have Emerged First In The RNA World by Wentao Ma, Chunwu Yu, Wentao Zhang and Jiming Hu, The RNA Journal, 13: 2012-2019, 18th September 2007
[43] A Self-Replicating Ligase Ribozyme by Natasha Paul & Gerald F. Joyce, Proc. Natl. Acad. Sci. USA., 99(20): 12733-12740 (1st October 2002)
[45] Ribozymes: Building The RNA World by Gerald F. Joyce, Current Biology, 6(8): 965-967, 1996
[46] Self-Sustained Replication Of An RNA Enzyme by Tracey A. Lincoln and Gerald F. Joyce, ScienceExpress, DOI: 10.1126/science.1167856 (8th January 2009)
[47] The Origin Of Replicators And Reproducers by Eörs Szathmáry, Philosophical Transactions of the Royal Society Part B, 361: 1689-1702 (11th September 2006)
[48] Darwinian Evolution On A Chip by Brian M. Paegel and Gerald F. Joyce, Public Library of Science Biology, 6(4): e85 (April 2008)
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Came up in a discussion today. This is the closest that humanity has gotten towards creating life by my research. Figured you'd be interested in this.
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