Lehner A F, Hill C W
J Bacteriol. 1980 Jul;143(1):492-8. doi: 10.1128/jb.143.1.492-498.1980.
As part of our efforts to understand factors influencing chromosomal organization and rearrangements, we studied a family of Salmonella typhimurium tandum duplication mutants. We found that the duplications were originally generated by unequal recombination between pairs of similarly oriented ribosomal ribonucleic acid operons (rrn). This demonstration involved the physical isolation of the duplicated material as circular deoxyribonucleic acid excised from the duplication. The four rrn operons involved embraced the ilv pur D segment of the chromosome and occurred at positions closely analogous to those previously observed for Escherichia coli. The interval between rrnC and rrnA of S. typhimurium was similar in size to that of E. coli (43 versus 39 kilobases), as was the interval between rrnB and rrnE (94 versus 91 kilobases). The rrnA-to-rrnB interval of S. typhimurium, however, was 155 kilobases, substantially greater than the 126 kilobases observed for E. coli.
作为我们了解影响染色体组织和重排因素的努力的一部分，我们研究了鼠伤寒沙门氏菌串联重复突变体系。我们发现这些重复最初是由同向排列的核糖体核糖核酸操纵子（rrn）对之间的不等位重组产生的。这一证明涉及从重复序列中切除的环状脱氧核糖核酸形式的重复物质的物理分离。所涉及的四个rrn操纵子包含染色体的ilv pur D区段，并且出现在与先前在大肠杆菌中观察到的位置非常相似的位置。鼠伤寒沙门氏菌的rrnC和rrnA之间的间隔大小与大肠杆菌的相似（分别为43和39千碱基），rrnB和rrnE之间的间隔也是如此（分别为94和91千碱基）。然而，鼠伤寒沙门氏菌的rrnA到rrnB的间隔为155千碱基，大大大于在大肠杆菌中观察到的126千碱基。
