Distribution of proflavin-induced mutations in the genetic fine structure. Offprint

1958. Brenner, Sydney (1927- ); Benzer, Seymour (1921- ); and Barnett, Lesley. Distribution of proflavin-induced mutations in the genetic fine structure. Offprint from Nature 182 (1958). 6, [1]pp. Text diagrams. 212 x 141 mm. Without wrappers as issued. Fine copy, with the ownership stamp of Maurice S. Fox, professor emeritus of molecular biology at MIT.

First Separate Edition. Watson and Crick, in their second 1953 paper published in Nature, had speculated that genetic mutations-both spontaneous and induced-represented a change in the sequence of bases. Based on this speculation, several researchers, including Brenner and Benzer, began developing an explanation of the mutagenic action of certain chemicals. In 1957 Benzer was investigating the mutagenic action of 5-bromouracil, an analog of the base thymine that caused a high degree of mutation in bacteriophage.

"Meanwhile, however, Brenner had been looking into the effects of another potent mutagen, proflavine-not a base analogue but a dye, bright yellow, one of a family of dyes in the yellows and oranges derived from the colorless coal-tar chemical acridine. So while Benzer was spending his year at the Cavendish in 1957-58, vainly hoping to demonstrate the colinearity of gene and protein, he and Brenner, with the help of Leslie Barnett, mapped the mutations induced by proflavine within the rII region in relation to each other and to those induced by bromouracil. Their most curious observation was that the two mutagens were mutually exclusive: not once did they hit the same site on the map. But how the acridine dyes acted to produce mutations was unknown, except that, unlike the base analogues, they were not built into DNA" (Judson, Eighth Day of Creation, pp. 435-36).

Brenner, My Life, pp. 90-91.