If you look at the basis of life right back to the first stromatolites – it’s DNA all the way back. I have no problem with that. What I do have a problem with is that it’s continued to be DNA, and only DNA, for the last FOUR BILLION YEARS, and nothing else has come along in all that time.
This strongly suggests to me that DNA did not develop over that first half billion years (in fact it will be considerably less than half a billion years as Earth will have been totally unsuitable for any form of life for a good proportion of that half a billion years), but that it came intact, and from off planet.
