Physics Department, Sapienza University of Rome, Rome, Italy.
Izmir International Biomedicine and Genome Institute (iBG-Izmir), Dokuz Eyll University, 35340, Turkey.
Gene. 2020 Jun 5;742:144554. doi: 10.1016/j.gene.2020.144554. Epub 2020 Mar 13.
The relationship between patterns of codon usage bias (CUB), the preferential usage of synonimous nucleotide triplets encoding the same amino acid, and radioresistance was investigated int he genomes of 16 taxonomically distinct radioresistant prokaryotic organisms and in a control set of 11 non-radioresistant bacteria. The radioresistant species were found to be strongly biased towards G and C in the third synonimous codon position. ENC and neutrality plots also sugest that CUB in radioresistant bacteria is mainly affected by mutational bias. Furthermore, the availability of tRNA gene copy number was analyzed and it was found that nine radioresistant species have the sam number of tRNA gene copies for each codon. This suggests that tRNA gene copies and codon bias co-evolved in a specific way in radioresistant species.
研究人员调查了 16 种具有不同分类的抗辐射原核生物基因组和 11 种非抗辐射细菌的基因组中密码子使用偏性（CUB）模式、偏爱使用编码相同氨基酸的同义核苷酸三联体与抗辐射性之间的关系。研究发现，抗辐射物种在第三个同义密码子位置上强烈偏向于 G 和 C。ENC 和中性分析图也表明，抗辐射细菌中的 CUB 主要受突变偏向的影响。此外，还分析了 tRNA 基因拷贝数的可用性，发现 9 种抗辐射物种的每个密码子的 tRNA 基因拷贝数相同。这表明在抗辐射物种中，tRNA 基因拷贝数和密码子偏性以特定的方式共同进化。
