Purifying and directional selection in overlapping prokaryotic genes
Purifying and directional selection in overlapping prokaryotic genes
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DOI：
10.1016/s0168-9525(02)02649-5
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发表时间：
2002-05-01
影响因子：
11.4
通讯作者：
Koonin, EV
中科院分区：
文献类型：
--
作者：
Rogozin, IB;Spiridonov, AN;Koonin, EV
在重叠基因中，相同的DNA序列使用不同的阅读框架编码两种蛋白质。重叠基因的分析可以帮助理解编码区从非编码DNA进化的模式。我们鉴定了71对3'端重叠超过15个核苷酸的会聚基因，它们在至少两个原核基因组中是保守的。在重叠区域中，我们观察到统计学上显著偏向123：132相位（即一个基因中的第二个密码子碱基面对第二个基因中简并的第三个位置）。这一阶段确保了在两个重叠编码序列中对非保守氨基酸替换的最小相互约束。该相位的过量与作用于重叠编码区域的方向（正）选择兼容。这可能是从非编码序列中出现的基因的一般进化模式，其中蛋白质序列没有受到选择。
In overlapping genes,the same DNA sequence codes for two proteins using different reading frames. Analysis of overlapping genes can help in understanding the mode of evolution of a coding region from noncoding DNA. We identified 71 pairs of convergent genes, with overlapping 3' ends longer than 15 nucleotides, that are conserved in at least two prokaryotic genomes. Among the overlap regions, we observed a statistically significant bias towards the 123:132 phase (i.e. the second codon base in one gene facing the degenerate third position in the second gene). This phase ensures the least mutual constraint on nonconservative amino acid replacements in both overlapping coding sequences. The excess of this phase is compatible with directional (positive) selection acting on the overlapping coding regions. This could be a general evolutionary mode for genes emerging from noncoding sequences, in which the protein sequence has not been subject to selection.