Maximum-parsimony tree of the salient-lineage pango founder spikes, rooted on A. Named lineages are tips; internal nodes are reconstructed ancestors. Branch lengths are the number of spike amino-acid substitutions, each labelled along its branch. The same tree is shown three times, coloured by region, antigenic region and ACE2 proximity (each legend). Because the tree is built from spike alone, recurrent (homoplastic) substitutions appear on every branch where they arise, and deep splits can differ from the curated lineage backbone. Deletions and insertions are not shown.