Posted by:
The Invisible Green Potato
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Date: May 16, 2016 02:36AM
There are RNA molecules that can self replicate, eg
http://www.ncbi.nlm.nih.gov/pubmed/24388759 Self replicating RNA is likely to have been the first form of self replicating molecule.
RNA is basically an old "technology" so far as evolution is concerned. DNA took over as a better form of data storage, and proteins took over as a better material to function as enzymes. Like radio in the era of television and Blue Rays, the old technology is still around, albeit in a reduced role.
I recommend reading up on "RNA world" eg:
https://en.wikipedia.org/wiki/RNA_worldAll of this is theoretical of course, since direct observation is practically impossible. Maybe life on earth started from bacteria aboard an alien spaceship that landed on earth? It is difficult to prove otherwise. We can rule out "directed evolution" because of the amount of time it took for us to evolve from bacteria. Whether the first self replicating molecule randomly came together, or whether it came here on an asteroid or an alien space ship is a matter of speculation.