Contrasting modes and tempos of genome evolution in land plant organelles.
Contrasting modes and tempos of genome evolution in land plant organelles.
复制标题
陆地植物细胞器基因组进化的对比模式和节奏。
DOI：
10.1016/0168-9525(90)90125-p
复制
发表时间：
1990
期刊：
影响因子：
--
通讯作者：
Palmer,JD
中科院分区：
文献类型：
--
作者：
Palmer,JD
在陆地植物中，线粒体DNA编码的蛋白质比叶绿体DNA（cpDNA）少几倍，但平均要大几倍。线粒体DNA的基因组大小也比叶绿体DNA的变异大得多：在迄今为止研究的数千种光合植物中，叶绿体DNA的大小变化不到两倍（120- 217 kb）（参考文献8和几个实验室未发表的数据）。此外，绝大多数cpDNA的大小在140和160 kb之间。虽然只在几十种被子植物中检测到mtDNA，但已知其大小变化超过一个数量级，从200到2500 kb 4，9- 11。基因组大小的变化来自两个过程：重复DNA数量的变化和序列复杂性的变化。这两个过程在cpDNA进化中都很重要，而mtDNA的进化则由后者主导。近三分之二的cpDNA大小变异可以通过单个大反向重复的扩增或收缩来解释，典型大小为20-30 kb，但总体上从0到76 kb不等。因此，光合植物中序列复杂性的总范围仅为110-150 kb 6，8。植物mtDNA通常含有一组或多组相对较大的（1-15 kb）重复序列，有时是三重序列9.1。这些重复往往是相当短暂的，并不构成基因组的大部分，因此，
In land plants, mtDNA encodes several times fewer proteins than does chloroplast DNA (cpDNA), yet is on average several times larger. Genome size is also much more variable in mtDNA than in cpDNA: cpDNA varies less than twofold in size (120--217 kb) among the thousands of species of photosynthetic plants examined thus far (Ref. 8 and unpublished data of several laboratories). Further, the great majority of cpDNAs are between 140 and 160 kb in size. Although mtDNA has been examined in only a few dozen angiosperm species, it is known to vary in size by more than an order of magnitude, from 200 to 2500 kb 4, 9-11.Changes in genome size accrue from two processes: changes in the amount of repeated DNA and changes in sequence complexity. Both processes are important in cpDNA evolution, whereas mtDNA evolution is dominated by the latter. Nearly two-thirds of cpDNA size variation can be accounted for by expansion or contraction of a single large inverted duplication, of typical size 20-30 kb, but which varies overall from zero to 76 kb. Thus, the total range of sequence complexity among photosynthetic plants is only 110-150 kb 6, 8. Plant mtDNAs generally contain one or more sets of relatively large (1-15 kb) duplicated and sometimes triplicated sequences 9.1. These repeats tend to be rather short-lived and do not constitute a large portion of the genome; hence they