A really cool paper (in Science)!
Scientists have made RNA molecules that, at room temperature, assemble copies of themselves from smaller substrates (actually, given the nature of complementation, they create copies of each other, just like DNA does).
Not only do they make accurate copies but they are truly enzymatic in that, given enough substrate, they run on indefinitely, i.e. until the substrate in the ‘test tube’ is finished.
And to top it off, the scientists even managed to get evolution going – randomly mutated molecules were put in a pool and let to compete against each other. Recombinant forms of the molecules arose spontaneously (i.e. in the pool, not designed by the scientists) and went on to dominate the population.
Of course, this is an excellent proof-of-principle for how an early form of ‘life’ may have functioned on earth – just two strands of complementary RNA, no amino acids or proteins, no cell membrane, no cofactors.
One step closer to elucidating the origin of life!
(A good review of the paper in this post on the Pharingula blog.)