Just to be clear, I don't believe in a God. But when it comes to the argument that a God must exist because nature is just too fantastically complex to have happened by accident then, so far, the best supporting evidence that I've seen for that is DNA. Every detail of its multi-level structure - the way it's coiled, and the coils are looped, and the loops are folded over one another - matters. The DNA in every single cell is being damaged by background chemistry 10,000 times a day, and there are multiple mechanisms inside the cell which are repairing that damage 10,000 times a day. It is almost literally unbelievable.