The Carnegie Institution of Washington, Department of Plant Biology, Stanford, California 94305.
Proc Natl Acad Sci U S A. 1981 Sep;78(9):5533-7. doi: 10.1073/pnas.78.9.5533.
We have mapped all the cleavage sites for the restriction endonucleases BstEII, Kpn I, Pst I, Pvu II, Sac I, Sal I, Sma I, and Xho I on the circular chloroplast chromosomes from mung bean and pea. The mung bean chloroplast genome measures 150 kilobase pairs (kb) in length; it includes two identical sequences of 23 kb that contain the ribosomal genes and are arranged as an inverted repeat separated by single-copy regions of 21 and 83 kb. The pea chloroplast genome is only 120 kb in size, has only one set of ribosomal genes, and does not possess any detectable repeated sequences. The mung bean inverted repeat structure is common to all other nonleguminous higher plant chloroplast genomes studied, whereas the pea structure has been found only in the closely related legume Vicia faba. We conclude from these data that loss of one copy of the inverted repeat sequence has occurred only rarely during the evolution of the Angiosperms, and in the case of the legumes after the divergence of the mung bean line from the pea-Vicia line. We present hybridization data indicating that rearrangements that change the linear order of homologous sequences within the chloroplast genome have been quite frequent during the course of legume evolution.
我们已经在绿豆和豌豆的环状叶绿体染色体上定位了所有限制内切酶 BstEII、Kpn I、Pst I、Pvu II、Sac I、Sal I、Sma I 和 Xho I 的切割位点。绿豆叶绿体基因组长度为 150 千碱基对(kb);它包含两个相同的 23 kb 序列,其中包含核糖体基因,并排列为一个倒置重复序列,由 21 和 83 kb 的单拷贝区域隔开。豌豆叶绿体基因组只有 120 kb 大小,只有一套核糖体基因,并且没有任何可检测到的重复序列。绿豆的反向重复结构在所有其他非豆科高等植物叶绿体基因组中都是常见的,而豌豆的结构只在密切相关的豆科植物 Vicia faba 中发现。我们从这些数据中得出结论,在被子植物的进化过程中,反向重复序列的一个拷贝丢失很少发生,而在豆类中,这种情况只发生在绿豆与豌豆-野豌豆分支分化之后。我们提出了杂交数据,表明在豆科植物的进化过程中,改变叶绿体基因组中同源序列线性顺序的重排非常频繁。