A plaque-purified virus was used to infect 216 independent cultures with an average of 231 pfu each (1). The mutation rate was calculated using the null-class method. m = 2.3 ´ 10^-6 s/r and sequencing 47 clones showed that T_s = 7. Hence, m_s/n/r = 3 ´ 2.3 ´ 10^-6 / 7 = 1.0 ´ 10^-6.

1. Cuevas, J. M., S. Duffy, and R. Sanjuán. 2009. Point mutation rate of bacteriophage FX174. Genetics 183:747-749.