Aldrich J, Cherney B W, Williams C, Merlin E
BP America, Research and Development, Cleveland, OH 44128.
Curr Genet. 1988 Nov;14(5):487-92. doi: 10.1007/BF00521274.
We have determined the nucleotide sequence at the junction of the large single copy (LSC) region and the right and left members of the large inverted repeat, IRA and IRB, respectively, of the petunia chloroplast (cp) genome. As in Nicotiana debneyi and spinach (Zurawski et al. 1984), coding sequences of rps19 of petunia overlap the junction of IRB and LSC. Immediately into the LSC region upstream of IRA in the petunia cp genome are two small insertions relative to N. debneyi that occur at sites just inside IRA of N. debneyi. We discuss how these additions in one copy of the large inverted repeat of an N. debneyi-like ancestor to petunia resulted in shortening of the petunia large inverted repeat by 8 bases and in the resultant slight movement of rps19 farther into LSC. On a larger scale, the large inverted repeat in the tobacco, N. debneyi and petunia lineage relative to a spinach-like ancestor may have sustained several contractions due to deletions between short direct repeats found within IRA and the IRA/LSC junction. We also show how the large inverted repeat of N. debneyi instead may have been expanded relative to a tobacco-like ancestor by insertion into the large inverted repeat of bases between short inverted repeat sequences in LSC and the LSC/IRB junction.
我们已经确定了矮牵牛叶绿体（cp）基因组中大单拷贝（LSC）区域与大反向重复序列IRA和IRB的左右成员连接处的核苷酸序列。与烟草和菠菜一样（Zurawski等人，1984年），矮牵牛rps19的编码序列与IRB和LSC的连接处重叠。相对于烟草，在矮牵牛cp基因组中IRA上游的LSC区域内紧邻有两个小插入，它们出现在烟草IRA内部的位点。我们讨论了矮牵牛一个类似烟草的祖先的大反向重复序列的一个拷贝中的这些添加如何导致矮牵牛大反向重复序列缩短了8个碱基，并导致rps19进一步向LSC方向轻微移动。在更大的尺度上，相对于类似菠菜的祖先，烟草、烟草和矮牵牛谱系中的大反向重复序列可能由于IRA内和IRA/LSC连接处发现的短直接重复序列之间的缺失而经历了几次收缩。我们还展示了相对于类似烟草的祖先，烟草的大反向重复序列如何通过在LSC和LSC/IRB连接处的短反向重复序列之间插入碱基而相对于烟草进行了扩展。
