We retrieved somatic cytochrome c protein sequences for 16 diverse eukaryotes from UniProt/NCBI.

Cytochrome c is a small electron-carrier protein (~104-112 amino acids) essential in mitochondrial 
respiration. Because it evolves slowly under strong functional constraint, it obeys a molecular clock 
reasonably well — making it a classic target for UPGMA. The resulting tree broadly recapitulates the 
accepted phylogeny of eukaryotes, with plants and fungi as outgroups to animals, and mammals 
clustering together with primates most closely related.

Pairwise distances are Levenshtein (edit) distances between protein sequences.
