A plaque-purified virus was used to infect 216 independent cultures with an average of 231 pfu each (1). Cultures were incubated until an average of 3.3 ´ 10⁵ pfu per culture were produced and then plated onto E. coli gro89, a mutant of the rep gene similar to the one used in the phage FX174 estimate (i). A total of 239 mutants were scored, thus f = 239 / 3.3 ´ 10^-5 / 216 = 3.4 ´ 10^-6. Sequencing of 47 clones showed that T = T_s = 7. Taking B = 180 (2), c = log (3.3 ´ 10⁵ / 231) / log 180 = 1.4. The fact that T_s was determined implies that there was no selection bias due to lethals. Also the bias due to non-lethal effects should be small because c was close to 1.0. Thus, m_s/n/c = 3 ´ 3.4 ´ 10^-6 / 7 / 1.4 = 1.0 ´ 10^-6. Data from this experiment can also be used obtain an estimate of the mutation rate per strand copying.

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

2. De Paepe, M. and F. Taddei. 2006. Viruses' life history: towards a mechanistic basis of a trade-off between survival and reproduction among phages. PLoS Biol. 4:e193.