Actually the information needed for replicating brain is not just limited to the information encoded in DNA. Physics plays a great deal of role in all molecular

Actually the information needed for replicating brain is not just limited to the information encoded in DNA. Physics plays a great deal of role in all molecular biology and from physical interactions arise cell-cell interactions which then give rise to complicated organs that you have in the body. (And, of course, all these arose during billions of years of evolution which is encoded not only in DNA but environment also.) So if you were to simulate the brain, modeling DNA will be A tiny part of it. Encoding the deepest of physics world (yes, quantum effects play many roles in DNA) AND then having enough computational power to model interactions of those particles in real time IS A REALLY BIG DEAL.