Anderson P, Roth J
Proc Natl Acad Sci U S A. 1981 May;78(5):3113-7. doi: 10.1073/pnas.78.5.3113.
A method is described to detect and measure the frequency of spontaneous tandem genetic duplications located throughout the Salmonella genome. The method is based on the ability of duplication-containing strains to inherit two selectable alleles of a single gene during generalized transductional crosses. One allele of the gene carries an insertion of the translocatable tetracycline-resistance element Tn10; the other allele is a wild-type copy of that gene. Using this technique, we have measured the frequency of tandem duplications at 38 chromosomal sites and the amount of material included in 199 independent duplications. These results suggest that, in one region of the chromosome, tandem duplications are particularly frequent events. Such duplications have end points within rRNA (rrn) cistrons and probably arise by unequal cross-over between these dispersed repeated sequences. Spontaneously duplications of this type are harbored by as much as 3% of the bacterial population. Preliminary evidence suggests that such duplications may play a significant regulatory role under conditions of rapid growth. Our analysis has suggested the position on the genome of an additional rRNA cistron.
本文描述了一种检测和测量沙门氏菌基因组中自发串联基因重复频率的方法。该方法基于含重复序列的菌株在广义转导杂交过程中继承单个基因的两个可选择等位基因的能力。该基因的一个等位基因携带可转移的四环素抗性元件Tn10的插入；另一个等位基因是该基因的野生型拷贝。利用这项技术，我们测量了38个染色体位点的串联重复频率以及199个独立重复中所含物质的量。这些结果表明，在染色体的一个区域，串联重复是特别频繁的事件。此类重复在rRNA（rrn）顺反子内有端点，可能是由这些分散的重复序列之间的不等交换产生的。高达3%的细菌群体携带这种类型的自发重复。初步证据表明，此类重复在快速生长条件下可能发挥重要的调节作用。我们的分析确定了另一个rRNA顺反子在基因组上的位置。
