Molecular Evidence

The deepest evidence is written in DNA. Nearly all life uses the same genetic code — the same three-letter words for the same amino acids — which makes sense if it was inherited once, from a single common ancestor.^[1] More telling still, the amount of DNA difference between any two species sorts them into a branching tree — and that tree, built from molecules alone, matches the one drawn from anatomy and fossils. Humans and chimpanzees share about 98–99% of their DNA; the pattern of shared genes (and shared mistakes in them) lines up precisely with descent.^[2]