Drake (2) reported a mutation rate to loss of function of gene cI of 2.0 ´ 10-5 per strand copying, based on previous work (1).  Screening of over 300 cI null mutants showed that ca. 5% were to amber codons (2).  The number of possible substitutions leading to amber codons in the cI gene is Ts = 38.  Therefore, ms/n/r =3 ´ 2 ´ 10-5 ´ 0.05 / 38 = 7.9 ´ 10-8.

 

    1.    Dove, W. F. 1968. The genetic of the lambdoid phages. Annu. Rev. Genet. 2:305-340.

    2.    Drake, J. W. 1991. A constant rate of spontaneous mutation in DNA-based microbes. Proc. Natl. Acad. Sci. USA 88:7160-7164.