Phylogenetic trees are graphs representing evolutionary histories and ancestry, and are typically inferred from the genomic data. In genomic epidemiology, for example, DNA sequences of the same pathogen are collected from different hosts (for example, SARS-CoV-2 genomes collected from different patients) and compared with one another. Phylogenetic trees inferred from these genomes can reveal the emergence of drug resistance and new variants of concern, transmission between individuals and countries, and many other details of the evolution and spread of the pathogen4.