Information becomes encoded onto these new
molecules -- what will become
DNA -- and RNA starts to lose its primacy.
This replication system starts to resemble what we have now, with DNA storing information and RNA continuing as the service molecule -- doing the work of copying, transcribing, transmitting genetic information.
DNA becomes the storage unit -- redundancy! Security of genetic information! RNA is the messenger.
Eventually, proteins, catalysts, and enzymes get caught up in the mix too, and a complicated system has begun.