Lloyd A T, Sharp P M
Department of Genetics, Trinity College, Dublin, Ireland.
Mol Gen Genet. 1991 Nov;230(1-2):288-94. doi: 10.1007/BF00290679.
Synonymous codon usage in genes from the ascomycete (filamentous) fungus Aspergillus nidulans has been investigated. A total of 45 gene sequences has been analysed. Multivariate statistical analysis has been used to identify a single major trend among genes. At one end of this trend are lowly expressed genes, whereas at the other extreme lie genes known or expected to be highly expressed. The major trend is from nearly random codon usage (in the lowly expressed genes) to codon usage that is highly biased towards a set of 19-20 "optimal" codons. The G + C content of the A. nidulans genome is close to 50%, indicating little overall mutational bias, and so the codon usage of lowly expressed genes is as expected in the absence of selection pressure at silent sites. Most of the optimal codons are C- or G- ending, making highly expressed genes more G + C-rich at silent sites.
对丝状子囊菌构巢曲霉基因中的同义密码子使用情况进行了研究。共分析了45个基因序列。采用多变量统计分析来确定基因间的单一主要趋势。在这一趋势的一端是低表达基因，而在另一端则是已知或预期高表达的基因。主要趋势是从几乎随机的密码子使用（在低表达基因中）到高度偏向于一组19 - 20个“最优”密码子的密码子使用。构巢曲霉基因组的G + C含量接近50%，表明总体上几乎没有突变偏向，因此在沉默位点没有选择压力的情况下，低表达基因的密码子使用情况符合预期。大多数最优密码子以C或G结尾，使得高表达基因在沉默位点的G + C含量更高。
