Evolution of the molecules of life

Like anatomical structures, the structures of the molecules of life are evidence for evolution.

Evidence of a common ancestor for all of life is reflected in the universality of DNA as the genetic material, as well as in the near universality of the genetic code and the machinery of DNA replication and expression. The relatedness of groups of organisms is reflected in the similarity of their DNA sequences, exactly the pattern that would be expected from descent and diversification from a common ancestor.

DNA sequences have also shed light on some of the mechanisms of evolution. For example, it is clear that the evolution of new functions for proteins commonly occurs after gene duplication events that allow the free modification of one copy by drift, mutation, or selection, while the second copy continues to produce a functional protein.