Are Synonymous Substitutions in Flowering Plant Mitochondria Neutral?
Are Synonymous Substitutions in Flowering Plant Mitochondria Neutral?
复制标题
开花植物线粒体中的同义取代是中性的吗？
DOI：
10.1007/s00239-015-9704-x
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发表时间：
2015
影响因子：
3.9
通讯作者：
A. Christensen
中科院分区：
文献类型：
--
作者：
Emily L. Wynn;A. Christensen
被子植物线粒体基因似乎具有非常低的突变率，而非基因区域扩张、分化和重排迅速。对这种差异的一种可能的解释是，植物线粒体基因中的同义替换并不是真正的中性的，选择使它们的发生率很低。如果这是真的，对基因和非基因突变率差异的解释需要考虑选择和DNA修复机制。在大多数植物线粒体基因组中，Rps14与cob和rpl5共转录，但在一些基因组中，Rps14已经复制到细胞核中，在线粒体中留下一个假基因。这提供了一个机会来比较中性取代率在假基因与同义取代率在同源物。对rps14的基因和假基因在不同物种间进行了比对，并计算了突变率。假基因的中性取代率和基因的同义取代率存在显著差异，证明植物线粒体基因的同义取代不是完全中性的。这种非中性并不足以完全解释陆地植物线粒体基因组异常低的突变率，但选择性力量似乎起了很小的作用。
Angiosperm mitochondrial genes appear to have very low mutation rates, while non-gene regions expand, diverge, and rearrange quickly. One possible explanation for this disparity is that synonymous substitutions in plant mitochondrial genes are not truly neutral and selection keeps their occurrence low. If this were true, the explanation for the disparity in mutation rates in genes and non-genes needs to consider selection as well as mechanisms of DNA repair. Rps14 is co-transcribed with cob and rpl5 in most plant mitochondrial genomes, but in some genomes, rps14 has been duplicated to the nucleus leaving a pseudogene in the mitochondria. This provides an opportunity to compare neutral substitution rates in pseudogenes with synonymous substitution rates in the orthologs. Genes and pseudogenes of rps14 have been aligned among different species and the mutation rates have been calculated. Neutral substitution rates in pseudogenes and synonymous substitution rates in genes are significantly different, providing evidence that synonymous substitutions in plant mitochondrial genes are not completely neutral. The non-neutrality is not sufficient to completely explain the exceptionally low mutation rates in land plant mitochondrial genomes, but selective forces appear to play a small role.
DOI：
10.1073/pnas.84.24.9054
发表时间：
1987-12-01
影响因子：
11.1
作者：
WOLFE, KH;LI, WH;SHARP, PM
通讯作者：
SHARP, PM