We share certain DNA molecules with every other plant and animal on the planet...I don't see how Vit C is somehow more indicative than any others you might name. I cannot argue on this basis- I am a historian, not an expert in DNA science. I have yet to see how the fact that I share DNA with kitties and daisies has offered ANY proof of evolution and far greater experts than any posting here don't see it either.
Like who? The handful of Discovery Institute stars? Behe? Dempski? Johnson? Not. You mean experts in fundamentalist theology who have shielded themselves from any knowledge of modern biological science, I presume? Relative DNA proximity has produced a tree of life that is, with a few micro-quibbles, identical to the tree of life produced by paleontology. This is an astonishing piece of independently derived confirming evidence as has ever been observed in the history of science. Your refusal to look at it does not a refutation make.
OK, once more, slowly this time.
Almost all mammals produce their own ascorbic acid. The exceptions are guinea pigs, some fruit bats, and the great apes, including people.
The really interesting thing is that we share the exact same mutation with the other apes. (Guinea pigs and bats have different mutations).
That is, in our (and chimp and gorilla and...) DNA there there is a stretch that is exactly like the gene for an enzyme called GLO in other mammals, except that there is a single mutation (a frameshift that totally scrambles the protein that corresponds to the gene).
The exact same mutation. One base pair away from not needing vitamin C.
This makes ID quite untenable. If we were designed to need dietary ascorbic acid, why include a defective copy of the gene that synthesizes it in other mammals?
And why should the exact same defect appear only in those species that were already thought to have a common ancestor?
And finally, why is this pattern repeated over and over in the genes of people, chimps, gorillas, et al?
Doesn't standard biology provide the best explanation?