Selection intensity against deleterious mutations in RNA secondary structures and rate of compensatory nucleotide substitutions.
Selection intensity against deleterious mutations in RNA secondary structures and rate of compensatory nucleotide substitutions.
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DOI：
10.1093/genetics/159.1.389
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发表时间：
2001-09
期刊：
影响因子：
3.3
通讯作者：
H. Innan;W. Stephan
中科院分区：
文献类型：
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作者：
H. Innan;W. Stephan
提出了一种具有补偿适应度相互作用的可逆突变双位点模型；单突变被认为是有害的，但在适当的组合中是中性的。代偿性核苷酸取代的预期时间是对位点之间紧密连接的情况进行分析计算的。结果表明，当选择强度为n>.1 （N为二倍体群体大小，s为选择系数）时，选择显著增加了替代时间。计算机模拟结果表明，重组增加了替代时间，但在选择较弱的情况下，重组的影响较小。研究了代偿替代过程中产生的连锁不平衡量。结果表明，明显的连锁不平衡在自然种群中是罕见的。该模型应用于果蝇双体3'非翻译区mRNA二级结构。结果表明，对单个有害突变的平均选择强度n不可能大于1。
A two-locus model of reversible mutations with compensatory fitness interactions is presented; single mutations are assumed to be deleterious but neutral in appropriate combinations. The expectation of the time of compensatory nucleotide substitutions is calculated analytically for the case of tight linkage between sites. It is shown that selection increases the substitution time dramatically when selection intensity Ns > 1, where N is the diploid population size and s the selection coefficient. Computer simulations demonstrate that recombination increases the substitution time, but the effect of recombination is small when selection is weak. The amount of linkage disequilibrium generated in the process of compensatory substitution is also investigated. It is shown that significant linkage disequilibrium is expected to be rare in natural populations. The model is applied to the mRNA secondary structure of the bicoid 3' untranslated region of Drosophila. It is concluded that average selection intensity Ns against single deleterious mutations is not likely to be much larger than 1.