A retroviral vector containing a neo gene with an amber codon (neutral mutational target) and the hygro gene and was used to s

A retroviral vector containing a neo gene with an amber codon (neutral mutational target) and the hygro gene and was used to score mutations appearing during a single cell infection cycle by selecting clones for resistance to G418 (cells containing proviruses revertant to the functional neo gene) and hygromycin (all provirus-containing cells) (1). The amber reversion frequency was f / c = 4.0 ´ 10^-⁶. It was shown that 7 / 14 revertants were to the wild-type, whereas the other seven were of unidentified nature. Using reversions to the wild-type only, m_s/n/c = 3 ´ 4.0 ´ 10^-⁶ ´ 7 / 14 = 6.0 ´ 10^-⁶.

1. Varela-Echavarria, A., N. Garvey, B. D. Preston, and J. P. Dougherty. 1992. Comparison of Moloney murine leukemia virus mutation rate with the fidelity of its reverse transcriptase in vitro. J. Biol. Chem. 267:24681-24688.