Essential genes are more evolutionarily conserved than are nonessential genes in bacteria
Essential genes are more evolutionarily conserved than are nonessential genes in bacteria
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DOI：
10.1101/gr.87702
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发表时间：
2002-06-01
期刊：
影响因子：
7
通讯作者：
Koonin, EV
中科院分区：
文献类型：
--
作者：
Jordan, IK;Rogozin, IB;Koonin, EV
“基因敲除率”预测认为，基本基因应该比非基本基因在进化上更为保守。这是因为作用于必需基因的负选择（纯化）预期比作用于非必需基因的负选择更为严格，非必需基因在功能上更可有可无和/或冗余。然而，最近的一项关于酿酒酵母和秀丽隐杆线虫蛋白质进化距离的调查并没有发现必要基因和非必要基因的进化速度有任何差异。一项对小鼠和大鼠同源基因的分析还发现，当被认为在定向选择下进化的基因被排除在分析之外时，必要基因和非必要基因的进化速度相似。在本研究中，我们将基因组序列数据与实验敲除数据相结合，以比较进化速率和必要与非必要细菌基因的选择水平。与真核生物基因的结果相反，在相对较短（微观进化）和较长（宏观进化）的时间尺度上，细菌必需基因似乎比非必需基因更保守。
The "knockout-rate" prediction holds that essential genes should be more evolutionarily conserved than are nonessential genes. This is because negative (purifying) selection acting on essential genes is expected to be more stringent than that for nonessential genes, which are more functionally dispensable and/or redundant. However, a recent survey of evolutionary distances between Saccharomyces cerevisiae and Caenorhabditis elegans proteins did not reveal any difference between the rates of evolution for essential and nonessential genes. An analysis of mouse and rat orthologous genes also found that essential and nonessential genes evolved at similar rates when genes thought to evolve under directional selection were excluded from the analysis. In the present study, we combine genomic Sequence data with experimental knockout data to compare the rates of evolution and the levels of selection for essential versus nonessential bacterial genes. In contrast to the results obtained for eukaryotic genes, essential bacterial genes appear to be more conserved than are nonessential genes over both relatively short (microevolutionary) and longer (macroevolutionary) time scales.