Nichols B P, Yanofsky C
Proc Natl Acad Sci U S A. 1979 Oct;76(10):5244-8. doi: 10.1073/pnas.76.10.5244.
The complete nucleotide sequences of trpA of Salmonella typhimurium and Escherichia coli were determined. The nucleotide sequences are 24.8% divergent, compared with amino acid sequence divergence of 14.9%. Over half of the codons of each gene contain synonymous nucleotide changes. The pattern of synonymous nucleotide changes is consistent with the interpretation that such changes result from random mutational events. We do not find any evidence indicating that codon selection or RNA structure is of major selective value. We conclude that polypeptide function is the primary basis of selection in trpA and that most synonymous codon changes are selectively neutral.
测定了鼠伤寒沙门氏菌和大肠杆菌trpA的完整核苷酸序列。核苷酸序列的差异为24.8%,而氨基酸序列的差异为14.9%。每个基因超过一半的密码子含有同义核苷酸变化。同义核苷酸变化的模式与这种变化是由随机突变事件导致的解释一致。我们没有发现任何证据表明密码子选择或RNA结构具有主要的选择价值。我们得出结论,多肽功能是trpA选择的主要基础,并且大多数同义密码子变化是选择性中性的。