Here is an interesting news article from Science Daily (June 12, 2009) on how life could have arisen on Earth:
Simple Chemical System Created That Mimics DNA
A team of Scripps Research scientists has created a new analog to DNA that assembles and disassembles itself without the need for enzymes. Because the new system comprises components that might reasonably be expected in a primordial world, the new chemical system could answer questions about how life could emerge.
The work, reported in the journal Science, might also be a starting point on the way to exotic new materials that repair themselves or transform in response to their environment.
Scientists are both bemused and fascinated by the question of how life could have arisen on Earth. One of the most prominent theories is that, before the emergence of DNA, the earliest forms of life used RNA to transmit their genetic codes. The late Leslie Orgel, a co-author of the new paper, first suggested this idea, known as the "RNA World."
One of the theory's challenges is that RNA is still so complex that many researchers [hypothesize] something still simpler must have preceded it. "I have been working for years to learn what replicators and genetic systems might have come before the advent of the RNA World," says team leader of the new research Professor Reza Ghadiri, a Scripps Research chemist.
One key focus for Ghadiri's team has been amino acids' potential primordial role. In 1996, the group showed for the first time that amino acid strands, or peptides, can self-replicate under enzyme-free conditions. In the current work, the Ghadiri lab extends this focus by creating another type of information system that might be capable of something akin to Darwinian evolution. "This work is a beginning step toward that goal," says Ghadiri. [...]
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