Mitochondrial substitution rates are extraordinarily elevated and variable in a genus of flowering plants
Mitochondrial substitution rates are extraordinarily elevated and variable in a genus of flowering plants
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DOI：
10.1073/pnas.0408302101
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发表时间：
2004-12-21
影响因子：
11.1
通讯作者：
Palmer, JD
中科院分区：
文献类型：
--
作者：
Cho, Y;Mower, JP;Palmer, JD
植物线粒体（mt）基因组在序列上进化缓慢，这是众所周知的。在这里，我们显示显着偏离这种模式的保守进化的属开花植物。在车前属内的谱系之间，同义位点的置换率差异很大。在极端情况下，车前草的比率超过那些特别缓慢的植物谱系大约4,000倍。最快的车前谱系为DNA基因组的快速进化设定了新的基准，甚至超过了最快的动物mt基因组一个数量级。所有六个mt基因的研究显示类似的车前升高的分歧，这意味着整个基因组的替代率是高度加速。相反，在车前属中，所检测四个叶绿体基因和三个核基因中的每一个的置换率显示很少或没有升高。这些结果，结合相对温和的海拔在车前MT基因的非同义置换率，表明MT突变率的主要，可逆的变化可能是同义置换率的广泛变化的基础。这些速率变化可能是由控制线粒体突变率的许多因素的重大变化引起的，从线粒体中氧自由基的产生和解毒到线粒体DNA复制和/或修复的功效。
Plant mitochondrial (mt) genomes have long been known to evolve slowly in sequence. Here we show remarkable departure from this pattern of conservative evolution in a genus of flowering plants. Substitution rates at synonymous sites vary substantially among lineages within Plantago. At the extreme, rates in Plantago exceed those in exceptionally slow plant lineages by approximate to4,000-fold. The fastest Plantago lineages set a new benchmark for rapid evolution in a DNA genome, exceeding even the fastest animal mt genome by an order of magnitude. All six mt genes examined show similarly elevated divergence in Plantago, implying that substitution rates are highly accelerated throughout the genome. in contrast, substitution rates show little or no elevation in Plantago for each of four chloroplast and three nuclear genes examined. These results, combined with relatively modest elevations in rates of nonsynonymous substitutions in Plantago mt genes, indicate that major, reversible changes in the mt mutation rate probably underlie the extensive variation in synonymous substitution rates. These rate changes could be caused by major changes in any number of factors that control the mt mutation rate, from the production and detoxification of oxygen free radicals in the mitochondrion to the efficacy of mt DNA replication and/or repair.