There is no 'who' necessary, both DNA and RNA by their nature replicate as a simple function of their chemical composition. Whether the DNA 'code' is more or less complex than computer code is irrelevant, computer code is not, by its very nature, capable of replication. It does not take intelligence for a group of chemicals to combine, all it takes is an influx of energy.
It's only logical that some intelligence has to be the maker of the original dna code. We always know there is a maker to say, an automobile. It just couldn't gather itself together and yet our bodies are alot more complex.