Deletional bias across the three domains of life.
Deletional bias across the three domains of life.
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DOI：
10.1093/gbe/evp016
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发表时间：
2009-06-27
影响因子：
3.3
通讯作者：
Ochman H
中科院分区：
文献类型：
--
作者：
Kuo CH;Ochman H
高水平的遗传漂变被假设为影响所有生命形式的基因组大小进化的主导因素。然而，漂移水平的增加似乎与真核生物中的基因组扩增相关，但与细菌中的基因组收缩相关，这表明这两组生物体经历了截然不同的突变输入和选择性约束。为了确定小插入和缺失事件对真核生物和原核生物之间基因组组织差异的贡献，我们系统地调查了生命三个领域的17个分类组。基于非编码区的5,000多个indel事件，我们发现在所有检查的组中，缺失事件的数量超过插入事件。缺失偏倚的程度，当测量插入到缺失的总长度时，揭示了真核生物和原核生物之间的显着差异，而该比率接近于三个真核生物组中的一个，在大多数原核生物中，缺失超过插入至少10倍。此外，缺失偏倚的强度与原核基因组中编码区的比例有关。考虑到遗传漂变是一个随机过程，不能区分突变的确切性质，对缺失的偏倚程度为真核生物和原核生物对漂变水平升高的差异反应提供了解释。此外，缺失偏好，而不是自然选择，是大多数原核生物基因组中保持紧凑基因包装的主要机制。
Elevated levels of genetic drift are hypothesized to be a dominant factor that influences genome size evolution across all life-forms. However, increased levels of drift appear to be correlated with genome expansion in eukaryotes but with genome contraction in bacteria, suggesting that these two groups of organisms experience vastly different mutational inputs and selective constraints. To determine the contribution of small insertion and deletion events to the differences in genome organization between eukaryotes and prokaryotes, we systematically surveyed 17 taxonomic groups across the three domains of life. Based on over 5,000 indel events in noncoding regions, we found that deletional events outnumbered insertions in all groups examined. The extent of deletional bias, when measured by the total length of insertions to deletions, revealed a marked disparity between eukaryotes and prokaryotes, whereas the ratio was close to one in the three eukaryotic groups examined, deletions outweighed insertions by at least a factor of 10 in most prokaryotes. Moreover, the strength of deletional bias is associated with the proportion of coding regions in prokaryotic genomes. Considering that genetic drift is a stochastic process and does not discriminate the exact nature of mutations, the degree of bias toward deletions provides an explanation to the differential responses of eukaryotes and prokaryotes to elevated levels of drift. Furthermore, deletional bias, rather than natural selection, is the primary mechanism by which the compact gene packing within most prokaryotic genomes is maintained.
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影响因子：
14.9
作者：
Benson DA;Cavanaugh M;Clark K;Karsch-Mizrachi I;Lipman DJ;Ostell J;Sayers EW
通讯作者：
Sayers EW
影响因子：
64.8
作者：
Denver, DR;Morris, K;Thomas, WK
通讯作者：
Thomas, WK
影响因子：
14.9
作者：
Christie, KR;Weng, S;Cherry, JM
通讯作者：
Cherry, JM
影响因子：
64.8
作者：
Aury, Jean-Marc;Jaillon, Olivier;Wincker, Patrick
通讯作者：
Wincker, Patrick
影响因子：
12.3
作者：
Dufresne A;Garczarek L;Partensky F
通讯作者：
Partensky F