How did DNA evolve?

[lightburst]

Evolution as it works on already fairly complex creatures is what I like to think I understand. Using Natural Selection, however, to arrive at these fairly complex creatures from simple ones such as from the very beginning when life was just spawning confused me on the validity of Evolution as a means to describe the origin of life.

 

I tried Googling it but seems to only spawn creationist pages, from what I can tell.

 

Although I don't mind a detailed explanation, something fit for a layperson in terms of biology is preferred.

[granpa]

http://en.wikipedia.org/wiki/PAH_world_hypothesis