Using terms like "invent" and personifying nature can lead to some pretty serious confusion. Indeed, it is one of the flaws I see in creationist arguments regularly. Anyway, RNA, as well as proteins, etc., through certain chemical processes that would've taken place on early Earth. My understanding is that the information storage was a by-product. RNA would "held the fort down" until more complex DNA and proteins took the stage. Finding a a being with only RNA (such as bacteria) would strongly confirm this.
This is just my idea, and I may be wrong on some of it. Please correct me if so.