Higher demands for genomes are satisfied by the stronger promoter of the anti-genome template relative to that of the genome template. Anti-genome templates are only utilized to amplify genomes, while genome templates are used to amplify both anti-genomes and mRNAs, and they are also incorporated into virion progeny particles. The higher demands for genome by these multiple tasks are satisfied by the stronger promoter of the anti-genome template compared with that of the genome template [30] [31] [32] . More polymerases bind to the stronger promoter of the anti-genome, ultimately enhancing the production of genomes over anti-genomes ( Figure 2 ). In our model the parameter S prom measures the strength of the anti-genomic promoter relative to that of the genomic promoter ( Table 1 ). The production ratio of genomes to anti-genomes was estimated to be dynamically changed [33] , varying from one to 30 (wild-type VSV case (S prom ¼ 5.4), Figure S1 ). Such oscillatory changes in the production ratio shown in Figure S1 follow from the on-off use of the genomes for transcription or replication. They also arise owing to the staggered shifting of dominant templates between genomes and anti-genomes during replication. A large value of S prom favors use of anti-genome templates to replicate genomes. However, as genome templates accumulate in large excess relative to anti-genome templates, they successfully compete for replication resources. Synthesis of anti-genomes then dominates until they accumulate and serve again as the dominant templates.