Researchers tracked the mutation rate in SARS-CoV-2 virus’s proteome — the collection of proteins encoded by genetic material — through time, starting with the first SARS-CoV-2 genome published in January and ending more than 15,300 genomes later in May. The team found some regions still actively spinning off new mutations, indicating continuing adaptation to the host environment. But the mutation rate in other regions showed signs of slowing, coalescing around single versions of key proteins.