標題: The evolutionary landscape of the Mycobacterium tuberculosis genome
作者: Wang, Tai-Chun
Chen, Feng-Chi
生物科技學系
Department of Biological Science and Technology
關鍵字: Mycobacterium tuberculosis;Selection pressure;Nonsynonymous substitution;Synonymous substitution;Neutral substitution rate
公開日期: 10-四月-2013
摘要: Mycobacterium tuberculosis is one of the most deadly human pathogens. The major mechanism for the adaptations of M. tuberculosis is nucleotide substitution. Previous studies have relied on the nonsynonymous-to-synonymous substitution rate (d(N)/d(S)) ratio as a measurement of selective constraint based on the assumed selective neutrality of synonymous substitutions. However, this assumption has been shown to be untrue in many cases. In this study, we used the substitution rate in intergenic regions (d(i)) of the M. tuberculosis genome as the neutral reference, and conducted a genome-wide profiling for d(i), d(s), and the rate of insertions/deletions (indel rate) as compared with the genome of M. canettii using a 50 kb sliding window. We demonstrate significant variations in all of the three evolutionary measurements across the M. tuberculosis genome, even for regions in close vicinity. Furthermore, we identified a total of 233 genes with their d(s) deviating significantly from d(i) within the same window. Interestingly, d(s) also varies significantly in some of the windows, indicating drastic changes in mutation rate and/or selection pressure within relatively short distances in the M. tuberculosis genome. Importantly, our results indicate that selection on synonymous substitutions is common in the M. tuberculosis genome. Therefore, the d(N)/d(S) ratio test must be applied carefully for measuring selection pressure on M. tuberculosis genes. (c) 2012 Elsevier B.V. All rights reserved.
URI: http://dx.doi.org/10.1016/j.gene.2012.11.033
http://hdl.handle.net/11536/21326
ISSN: 0378-1119
DOI: 10.1016/j.gene.2012.11.033
期刊: GENE
Volume: 518
Issue: 1
起始頁: 187
結束頁: 193
顯示於類別:會議論文


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