A microbial geneticist isolates a new mutation in E. coli and wishes to map its chromosomal location. She uses interrupted-mating experiments with Hfr strains and generalized-transduction experiments with phage P1. Explain why each technique, by itself, is insufficient for accurate mapping. Solution Hfr cells undergoing conjugation transfer host genes in a linear fashion. The genes transferred depend on both the Hfr strain and the length of time during which the transfer occurred. F factors arise from improper excision of an Hfr from bacterial chromosome. They can have only specific bacterial genes on them because the integration site is fixed for each strain. P1 does not recognize pseudo-pac sites on the chromosome. P1 seems to begin packaging from random double-stranded breaks on the chromosome that are generated during phage infection. Generalized transduction is the process by which any bacterial gene may be transferred to another bacterium via a bacteriophage, and very rarely a small number of phages carry the donor. A restricted set of genes will not be able to transfer by this method. She wanted to transfer a specific gene to a specific located which is not doen by generalized transduction, so accurate gene mapping will be difficult by these methods..