Punctuated evolution of mitochondrial gene content: High and variable rates of mitochondrial gene loss and transfer to the nucleus during angiosperm evolution
Punctuated evolution of mitochondrial gene content: High and variable rates of mitochondrial gene loss and transfer to the nucleus during angiosperm evolution
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DOI：
10.1073/pnas.042694899
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发表时间：
2002-07-23
影响因子：
11.1
通讯作者：
Palmer, JD
中科院分区：
文献类型：
--
作者：
Adams, KL;Qiu, YL;Palmer, JD
为了研究植物中线粒体基因丢失的速度和模式，通过 Southern blot 杂交对 280 个开花植物属的 DNA 进行了调查，以确定是否存在 40 个线粒体蛋白基因。在被子植物进化过程中，所有 14 个核糖体蛋白基因和两个 sdh 基因已多次从线粒体基因组中丢失（6 至 42 次），而在其他 24 个基因中仅检测到两次丢失。基因丢失的系统发育分布非常不均匀，某些谱系会出现一段停滞期，然后突然丢失。大多数最古老的被子植物群体的线粒体基因含量仍处于长期停滞状态，其基因组与其十亿多年前的藻类祖先几乎相同。与此形成鲜明对比的是，其他植物迅速失去了许多或全部 16 个线粒体核糖体蛋白和 sdh 基因，从而趋于减少基因含量，更像动物或真菌而不是典型植物。在这些以及许多丢失数量较少的谱系中，核糖体蛋白和 sdh 基因丢失的速率超过（有时大大超过）线粒体同义替换的速率。大多数线粒体基因丢失可能是基因转移到细胞核的结果。因此，被子植物中功能性基因转移的速率也可能存在显着差异。
To study the tempo and pattern of mitochondrial gene loss in plants, DNAs from 280 genera of flowering plants were surveyed for the presence or absence of 40 mitochondrial protein genes by Southern blot hybridization. All 14 ribosomal protein genes and both sdh genes have been lost from the mitochondrial genome many times (6 to 42) during angiosperm evolution, whereas only two losses were detected among the other 24 genes. The gene losses have a very patchy phylogenetic distribution, with periods of stasis followed by bursts of loss in certain lineages. Most of the oldest groups of angiosperms are still mired in a prolonged stasis in mitochondrial gene content, containing nearly the same set of genes as their algal ancestors more than a billion years ago. In sharp contrast, other plants have rapidly lost many or all of their 16 mitochondrial ribosomal protein and sdh genes, thereby converging on a reduced gene content more like that of an animal or fungus than a typical plant. In these and many lineages with more modest numbers of losses, the rate of ribosomal protein and sdh gene loss exceeds, sometimes greatly, the rate of mitochondrial synonymous substitutions. Most of these mitochondrial gene losses are probably the consequence of gene transfer to the nucleus; thus, rates of functional gene transfer also may vary dramatically in angiosperms.