The consequences of genetic drift for bacterial genome complexity
The consequences of genetic drift for bacterial genome complexity
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DOI：
10.1101/gr.091785.109
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发表时间：
2009-08-01
期刊：
影响因子：
7
通讯作者：
Ochman, Howard
中科院分区：
文献类型：
--
作者：
Kuo, Chih-Horng;Moran, Nancy A.;Ochman, Howard
遗传漂变在小种群中特别有效，它可以通过影响有害突变的固定来塑造基因组的大小和复杂性。在细菌中，评估遗传漂变对基因组进化的贡献是有问题的，因为基于种内多态性的常规方法可能会因描绘物种边界的困难而受挫。细菌基因组测序的可用性的增加允许应用漂移的替代估计器，蛋白质编码序列的全基因组替代与沉默替代的比率。该比率反映了整个基因组的净化选择作用，与基因组大小呈强烈的反比关系，表明漂变促进了细菌基因组的减少。
Genetic drift, which is particularly effective within small populations, can shape the size and complexity of genomes by affecting the fixation of deleterious mutations. In Bacteria, assessing the contribution of genetic drift to genome evolution is problematic because the usual methods, based on intraspecific polymorphisms, can be thwarted by difficulties in delineating species' boundaries. The increased availability of sequenced bacterial genomes allows application of an alternative estimator of drift, the genome-wide ratio of replacement to silent substitutions in protein-coding sequences. This ratio, which reflects the action of purifying selection across the entire genome, shows a strong inverse relationship with genome size, indicating that drift promotes genome reduction in bacteria.