A single viral plaque was isolated and re-plated to isolate new plaques (2). The consensus sequence of gene NS (L = 849, T_s = 849 ´ 3 = 2547) was obtained for the parental and derived plaques after two amplification passages by direct sequencing of the purified RNA: 3f_s / T_s = 7.6 ´ 10^-5 and c = 5. Hence, from Equation 5, min[m_s/n/c] = 7.6 ´ 10^-5 / 5 = 1.5 ´ 10^-5 whereas no max[m_s/n/c] can be obtained because mutation sampling was selective. The estimated selection correction factor using the exponential plus lethal class model with E(s_v) = 0.12, p_L = 0.3, c = 5, selective sampling, and B » 50 as estimated in another work (1) is a = 0.33 (Figure 1) Thus, m_s/n/c = 1.5 ´ 10^-5 / 0.33 = 4.5 ´ 10^-5.

1. Nobusawa, E. and K. Sato. 2006. Comparison of the mutation rates of human influenza A and B viruses. J Virol. 80:3675-3678.

2. Parvin, J. D., A. Moscona, W. T. Pan, J. M. Leider, and P. Palese. 1986. Measurement of the mutation rates of animal viruses: influenza A virus and poliovirus type 1. J Virol. 59:377-383.