“…finding any lineage of organisms that does not use DNA or RNA as its hereditary material would falsify common descent. But of course, given that every organism we know of uses DNA, it sounds a bit ridiculous.”Now, my apologies to NP because I didn’t take that as a serious test and I misunderstood NP to be saying in advance that he knew it was a ridiculous test. Afterall, he did say "it sounds a bit ridiculous." But NP left another comment saying the following:
"RK, I already pointed out one. Find any organism that does not use DNA/RNA as it's hereditary material. That would falsify the notion that all life on earth has common ancestry."So it seems NP does mean that as a serious test of evolution. But that can’t be a true test because evolution does not require every creature to have DNA/RNA and I’ll show you why. Evolutionists assume there was a supposed common ancestor of all living things. This creature would have been the first reproducing life form on earth and would have had something like RNA. However, there is nothing about evolution that excludes some other life form arising which does not use RNA/DNA to reproduce. So if we found some life form that did not have DNA, it doesn’t falsify evolution in the slightest. It is only evidence that the new life form is not descended from or related to all previously known life forms.
But I want to talk a little more about DNA. The title of this thread is not aimed at NP in particular. Rather, all evolutionists have co-opted DNA and now use it as evidence for their theory. NP’s comments are not originally his (no offense, NP) but I will take the opportunity of his comments to address the evolutionist spin on DNA.
"compare the genome of a chimpanzee to that of a human and a chicken. If the chimp and chicken have more homologous sequences than the chimp and human, that would falsify common ancestry between humans and chimps."That sounds reasonable, doesn’t it? Here’s why similar DNA doesn’t really validate evolution: DNA is often compared to blueprints that provide instructions for the constructing of cells. If two organisms are similar, then doesn’t it only make sense that the instructions that build the organisms would be similar? A human is most like a chimp, less like a bear, and least like a bird. Therefore, a human’s DNA should be most like a chimp’s, less like a bear’s, and least like a bird’s. Of course, that’s exactly what we see in nature. If similar creatures did not have similar DNA, then I would say we know nothing about DNA.
Now, the other angle evolutionists take is the similarity in non-coding DNA. Some people estimate that only about 8% of the human genome is coding DNA. The rest has been called “junk” DNA. So if the non-coding DNA were similar, they say that is evidence of common ancestry. The problem with this hypothesis is the assumption that non-coding DNA is truly non-coding. For the last several years, we’ve continuously discovered function in the non-coding parts of DNA. So if the non-coding part of DNA is truly coding then I direct you again to my first point – similar creatures should have similar DNA.
Finally, DNA should be the silver bullet that kills evolution. Because of DNA, bears only reproduce bears and birds only reproduce birds. The remarkable ability of DNA to repair itself or to mask mutations from being expressed make creatures resistant to change. Yet it is that tiny mutation expressed for thousands of generations that is the hope of evolution. Time and mutation are the heroes of the story; without them, evolution is a fairy tale about a frog turning into a prince – over a million years.
DNA is a broad subject and a lot more could be said about it. In short though, DNA is not the champion of evolution. It’s not even close.