Published online by Cambridge University Press: 14 April 2009
1. Data from transduction experiments with Salmonella typhimurium can be interpreted in terms of frequencies of recombination by accepting the arguments of Ozeki that all transduced fragments that include a particular locus are equal in length.
2. From a two-point transduction the ratio of the two classes of transductants is not a measure of the ratio of the frequencies of recombination in the two relevant regions but only provides maximum and minimum values for this ratio.
3. From three-point transductions the frequencies of recombination in the regions between the markers, and between the terminal markers and the ends of the fragment, can be estimated.
4. The difficulties of interpreting data from experiments in which a single factor is transduced are briefly discussed.