Focused efforts by several international laboratories have resulted in the sequencing of the genome of the causative agent of severe acute respiratory syndrome (SARS), novel coronavirus SARS-CoV, in record time. Using cumulative skew diagrams, I found tht mutational patterns in the SARS-CoV genome were strikingly different from other coronaviruses in terms of mutation rates, although they were in general agreement with the model of the coronavirus lifecycle. These findings might be relevant for the development of sequence-based diagnostics and the design of agents to treat SARS.