The size of the mating group in bacteriophage T4
In unequal-input, three-factor phage crosses, the kinetics of recombination should depend on the number of vegetative phages participating in each mating. Among a selected class of progeny recombinant for two closely linked markers, a third, freely-segregating marker will achieve genetic equilibrium...
| Summary: | In unequal-input, three-factor phage crosses, the kinetics of recombination should depend on the number of vegetative phages participating in each mating. Among a selected class of progeny recombinant for two closely linked markers, a third, freely-segregating marker will achieve genetic equilibrium immediately if the mating group is very large but will show a drift toward equilibrium if the mating group is small. Data are presented for T4 crosses which are in good agreement with the qualitative predictions for small group (pairwise) mating.
Mating parameters have been measured which permit calculation of the expected kinetics of recombination for various mating group sizes. The predictions are calculated using Steinberg and Stahl's theory of formal phage genetics. The data do not conform precisely to the theory, but it is argued that the disagreement cannot alter the conclusion that the T4 mating group is small.
The significance, or insignificance, of this finding is discussed in the light of recent discoveries concerning the geometry of recombination in T4.
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