As I said, this seems pretty well understood (with a few gaps) in terms of chemistry and biology.
Not in a chronological sense. "We" are nothing if not biological.
Physics doesn't attempt to explain things that are better understood in other ways. At some point a very detailed analysis becomes too complicated to be meaningful. Much of chemistry can be understood in terms of physical processes and principles (quantum mechanics), and much of biology can be understood in terms of chemical processes. But to try to explain everything in terms of the basic physics would be pointless. It would be like trying to forecast the weather using the quantum theory of nitrogen, oxygen, carbon dioxide and water--even if it could be done, the results would be so complex they would be incomprehensible.
As pointed out above, we know very well what DNA is.
Actually that's not inconceivable. DNA can be synthesised to order; so can many (or most?) of the chemicals that make up an organism. If you mean how would one do it without a chemical laboratory--if I had a few hundred million years to spare, I'd just put everything together and wait.