Many origin-of-life researchers say that RNA chains are too specialised to have been created as a product of random chemical reactions.
The new study, however, claims to provide an alternative theory by arguing primordial DNA-like fragments evolved in this way instead.
The researchers found the self-assembly of DNA fragments just a few nanometres in length have the ability to drive the formation of chemical bonds.
These connect together short DNA chains to form long ones, without the need for a separate biological process.
'Our observations are suggestive of what may have happened on the early Earth when the first DNA-like molecular fragments appeared,' said CU-Boulder physics Professor Noel Clark, a study co-author.
The study suggests that the way in which DNA emerged in the early Earth lies in its structural properties and its ability to self-organise.
In the pre-RNA world, the spontaneous self-assembly of fragments of nucleic acids – the building block of life - may have acted as a template for their chemical self-assembly.
'The new findings show that in the presence of appropriate chemical conditions, the spontaneous self-assembly of small DNA fragments into stacks of short duplexes greatly favours their binding into longer polymers, thereby providing a pre-RNA route to the RNA world,' added Professor Clark.If true, this would mean that life should be common throughout the universe.
Update (4/9/2015): Space.com reports:
For the first time, astronomers have discovered complex organic molecules, the basic building blocks for life, in a disk of gas and dust surrounding an alien star.
To the researchers' surprise, the organics found around a young star called MWC 480 are not only surviving but thriving in quantities slightly higher than those thought to have existed in the early solar system. The prolific amount of material reveals that Earth's solar system is not the only one to contain these complex molecules, suggesting that the ingredients required for life to evolve may exist throughout the universe.