Huh? I hate to quibble (I think), but aren't you being overly constrictive in your term 'DNA'? By using DNA as meaning nuclear DNA only you are overlooking the 'DNA mechanism' -- meaning RNA, etc.
I am no molecular biologist, but I do know the cellular (proteins?) and gunk are 'built' using the 'DNA mechanism'.
It's a question of the cell's needs, what the cell is able to absorb from its environment, and what it has to manufacture for itself. While blood is an unusually hospitable environment to support something as complicated as a red blood cell, the earliest cells probably didn't have very sophisticated needs.
I see here you are being more specific, and tracing your thread back I see we are talking about minimal DNA requirements for a 'living cell'...
To me, sematic convenience causes us to define a living cell as something that includes cells that are dependent on environment for their functioning ability -- even 100% dependent -- but that definition could apply to something simular to a micro-encapsulated drug...
Lets back up, are you saying there are cells that do not have a 99% faithful reproduction of nuclear DNA of thier host? Are there cells that have no nucleus at all?
Exactly. The definition of life would get awfully fuzzy in the very early going. There's an intellectual gimmick that creationists often use to avoid this: they say 1) evolving things must be alive, 2) there is a simplest possible life form, 3) this life form cannot have evolved, because anything simpler wouldn't be alive by my definition and therefore cannot evolve by my definition, therefore 4) life cannot evolve from nonlife.
Viruses are good examples of things that only behaves like an organism in the right environment. And then there are the prion diseases...
Lets back up, are you saying there are cells that do not have a 99% faithful reproduction of nuclear DNA of thier host?
I don't know about 99%, but yes, not all reproductions are perfectly faithful.
Are there cells that have no nucleus at all?
Eukaryotes (like you and me) have cells with nuclei; prokaryotes (like bacteria) do not. (Bacteria still have DNA, of course.)