Hiratsuka J, Shimada H, Whittier R, Ishibashi T, Sakamoto M, Mori M, Kondo C, Honji Y, Sun C R, Meng B Y
Center for Gene Research, Nagoya University, Japan.
Mol Gen Genet. 1989 Jun;217(2-3):185-94. doi: 10.1007/BF02464880.
The entire chloroplast genome of the monocot rice (Oryza sativa) has been sequenced and comprises 134525 bp. Predicted genes have been identified along with open reading frames (ORFs) conserved between rice and the previously sequenced chloroplast genomes, a dicot, tobacco (Nicotiana tabacum), and a liverwort (Marchantia polymorpha). The same complement of 30 tRNA and 4 rRNA genes has been conserved between rice and tobacco. Most ORFs extensively conserved between N. tabacum and M. polymorpha are also conserved intact in rice. However, several such ORFs are entirely absent in rice, or present only in severely truncated form. Structural changes are also apparent in the genome relative to tobacco. The inverted repeats, characteristic of chloroplast genome structure, have expanded outward to include several genes present only once per genome in tobacco and liverwort and the large single copy region has undergone a series of inversions which predate the divergence of the cereals. A chimeric tRNA pseudogene overlaps an apparent endpoint of the largest inversion, and a model invoking illegitimate recombination between tRNA genes is proposed which accounts simultaneously for the origin of this pseudogene, the large inversion and the creation of repeated sequences near the inversion endpoints.
单子叶植物水稻（Oryza sativa）的整个叶绿体基因组已被测序，其长度为134525碱基对。已鉴定出预测的基因以及水稻与先前测序的叶绿体基因组（双子叶植物烟草（Nicotiana tabacum）和地钱（Marchantia polymorpha））之间保守的开放阅读框（ORF）。水稻和烟草之间30个tRNA基因和4个rRNA基因的互补情况相同。烟草和地钱之间广泛保守的大多数ORF在水稻中也完整保守。然而，水稻中完全没有几个这样的ORF，或者它们仅以严重截短的形式存在。相对于烟草，基因组的结构变化也很明显。叶绿体基因组结构特征性的反向重复序列向外扩展，包括烟草和地钱中每个基因组仅出现一次的几个基因，并且大单拷贝区域经历了一系列倒位，这些倒位发生在谷物分化之前。一个嵌合的tRNA假基因与最大倒位的一个明显端点重叠，并且提出了一个涉及tRNA基因之间非法重组的模型，该模型同时解释了这个假基因的起源、大倒位以及倒位端点附近重复序列的产生。
