Hill C W, Schiffer D, Berg P
J Bacteriol. 1969 Jul;99(1):274-8. doi: 10.1128/jb.99.1.274-278.1969.
Escherichia coli PB160, which carries a tandem duplication with the gene order metB(+)argH(-)su(159) (+)thi(+): metB(+)argH(+)su(159) (-)thi(+), was used to study the mechanism of P1 transduction of genes in the duplicated region. Transduction of the su(159) (+) allele contained within the duplicated segment yields two kinds of su(159) (+) recombinants: 91% are haploid su(159) (+) and 9% are su(159) (+)/su(159) (-) merodiploids. The duplication in these merodiploid transductants includes the metB locus; however, both copies of the metB locus usually are derived from the recipient. Thus, the requirements for transduction of the "condition of merodiploidy" appear to be the cotransduction of the repeat point (the region where the duplication begins to repeat itself) and, of course, the selected marker (in this case su(159) (+)). A mechanism whereby two recipient chromosomes interact with the transduced "repeat point" region to regenerate the tandem duplication is implicated. It appears that a duplication much larger than the quantity of genetic material carried by a P1 phage can be produced in a transductant.
携带基因顺序为metB(+)argH(-)su(159)(+)thi(+)：metB(+)argH(+)su(159)(-)thi(+)的串联重复序列的大肠杆菌PB160，被用于研究重复区域内基因的P1转导机制。转导重复片段中所含的su(159)(+)等位基因会产生两种su(159)(+)重组体：91%是单倍体su(159)(+)，9%是su(159)(+)/su(159)(-)部分二倍体。这些部分二倍体转导子中的重复序列包括metB位点；然而，metB位点的两个拷贝通常都来自受体。因此，转导“部分二倍体状态”的条件似乎是重复点（重复序列开始自身重复的区域）的共转导，当然还有选择标记（在这种情况下是su(159)(+)）。这暗示了一种机制，即两条受体染色体与转导的“重复点”区域相互作用以再生串联重复序列。似乎在转导子中可以产生比P1噬菌体携带的遗传物质数量大得多的重复序列。
