"There’s nothing in biology in this system -- no proteins, no cells, no biological matter," said molecular biologist Professor Gerald Joyce of the Scripps Research Institute in San Diego.

"We just provide them with the building blocks."

Professor Joyce worked with PhD student Tracey Lincoln on taking naturally occuring RNA enzymes known as ribozymes and placing them in a growth medium.

They were heated and allowed to replicate until they had exhausted their fuel -- a random subset was extracted and put them in a new medium.

The ribozymes then competed with each other to consume as much of the medium as possible.

The more successful ribozymes came to dominate the culture and grew in complexity -- blindly finding solutions that made them more successful.

"They’re just molecules, so they do what they do until they run out of substrate," said Joyce.

"And this will go for ever -- it’s an immortal molecule, if you like."

"The key thing is it replicates itself, and passes information from parent to progeny down the line."

"There’s roughly 30 bits of information passed."

"Some functions are more fit than others, and those that are more fit ‘breed’ more, and are perpetuated more efficiently, and so it goes Darwinian."

Although the ribozymes have some characteristics of life, they still do not constitute a truly living system.

The challenge for researchers now is to create genetic systems that have all the qualities of life -- but without use of existing biological components.

"The aim is to create systems that have inventive capabilities, that can develop novel solutions to challenges posed by the environment."

"What we do have is a self-sustained chemical system that undergoes Darwinian evolution."

"They are synthetic genetic systems, and they are evolving."

"But they’re not living because they don’t yet show the capacity to invent a whole cloth of functions."

"The idea is to given them enough information wherewithal so they can start inventing their own solutions rather than just optimising existing solutions."