Evolutionary pattern assessed using DNA

Beyond identifying an individual species, DNA can also be used to work out how different species relate to one another evolutionarily - a question that morphology (physical appearance) alone often cannot answer reliably, since unrelated species can look superficially similar (convergent evolution) while closely related species can look quite different. The approach compares DNA content and, more precisely, DNA sequence similarities and differences (sequence homology) across a set of plant taxa, on the reasonable assumption that species which diverged from a common ancestor more recently will still share more of their DNA sequence in common than species that diverged much longer ago. The result of this kind of comparison is typically displayed visually as a cladogram - a branching, tree-like diagram in which the pattern of branch points reflects genetic distance between the taxa being compared, and which, …