Dynamic evolution of plant mitochondrial genomes: Mobile genes and introns and highly variable mutation rates
Dynamic evolution of plant mitochondrial genomes: Mobile genes and introns and highly variable mutation rates
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DOI：
10.1073/pnas.97.13.6960
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发表时间：
2000-06-20
影响因子：
11.1
通讯作者：
Song, KM
中科院分区：
文献类型：
--
作者：
Palmer, JD;Adams, KL;Song, KM
我们总结了我们最近的研究表明，被子植物线粒体（mt）基因组经历了非常高的基因丢失率，并伴随着转移到细胞核和水平转移的内含子收购。此外，我们发现这些结构突变和点突变的发生率存在很大的谱系特异性差异。这些发现主要来自281种不同被子植物的基因和内含子分布的Southern印迹调查。这些印迹揭示了大量mt核糖体蛋白基因的丢失，但有一个例外，只有呼吸基因的罕见丢失。被子植物的一些谱系保留了所有的线粒体核糖体蛋白基因，而另一些则丢失了大部分。这些大量的丢失似乎反映了被子植物线粒体核糖体蛋白基因向细胞核的功能转移的高速率。最近在豆科植物中cox 2向细胞核的转移提供了细胞器间基因转移的一个例子，也为讨论机械力和选择力在决定细胞器和核基因组之间遗传劳动分配中的作用提供了一个起点。植物mt基因组也通过水平转移获得序列。一个突出的例子是mt cox 1基因中的归巢组I内含子。在被子植物进化过程中，通过最近的一波跨物种水平转移，这种极具侵入性的移动的元素可能已经被单独获得了1,000多次。最后，而所有以前研究的被子植物mtDNA的同义替换率低，两个远亲的被子植物的mtDNA有高度加速的替换率。
We summarize our recent studies showing that angiosperm mitochondrial (mt) genomes have experienced remarkably high rates of gene loss and concomitant transfer to the nucleus and of intron acquisition by horizontal transfer. Moreover, we find substantial lineage-specific variation in rates of these structural mutations and also point mutations. These findings mostly arise from a Southern blot survey of gene and intron distribution in 281 diverse angiosperms. These blots reveal numerous losses of mt ribosomal protein genes but, with one exception, only rare loss of respiratory genes. Some lineages of angiosperms have kept all of their mt ribosomal protein genes whereas others have lost most of them. These many losses appear to reflect remarkably high land variable) rates of functional transfer of mt ribosomal protein genes to the nucleus in angiosperms. The recent transfer of cox2 to the nucleus in legumes provides both an example of interorganellar gene transfer in action and a starting point for discussion of the roles of mechanistic and selective forces in determining the distribution of genetic labor between organellar and nuclear genomes, Plant mt genomes also acquire sequences by horizontal transfer. A striking example of this is a homing group I intron in the mt cox1 gene. This extraordinarily invasive mobile element has probably been acquired over 1,000 times separately during angiosperm evolution via a recent wave of cross-species horizontal transfers. Finally, whereas all previously examined angiosperm mtDNAs have low rates of synonymous substitutions, mtDNAs of two distantly related angiosperms have highly accelerated substitution rates.