Distribution and Frequency of Tandem Duplications of the rII Region of Bacteriophage T4d.

Genetic analyses of 49 duplications of the rII region of bacteriophage T4D suggests that there is a non-random relationship between the end points of duplicated segments, that relaxed packaging restrictions have little if any effect on the distribution of duplications, that segregation is 3-4 times more frequent than normal recombination for the same interval, and that non-tandem duplications are rare. Extrapolation of the r1231 xrJ101 cross data suggests that the minimum frequency of duplications/genome is 1.7 x 10(-6), but possibly 3.4 x 10(-4).