Grantham R, Gautier C, Gouy M, Mercier R, Pavé A
Nucleic Acids Res. 1980 Jan 11;8(1):r49-r62. doi: 10.1093/nar/8.1.197-c.
Frequencies for each of the 61 amino acid codons have been determined in every published mRNA sequence of 50 or more codons. The frequencies are shown for each kind of genome and for each individual gene. A surprising consistency of choices exists among genes of the same or similar genomes. Thus each genome, or kind of genome, appears to possess a "system" for choosing between codons. Frameshift genes, however, have widely different choice strategies from normal genes. Our work indicates that the main factors distinguishing between mRNA sequences relate to choices among degenerate bases. These systematic third base choices can therefore be used to establish a new kind of genetic distance, which reflects differences in coding strategy. The choice patterns we find seem compatible with the idea that the genome and not the individual gene is the unit of selection. Each gene in a genome tends to conform to its species' usage of the codon catalog; this is our genome hypothesis.
已在每个已发表的包含50个或更多密码子的mRNA序列中确定了61种氨基酸密码子各自的频率。这些频率针对每种基因组以及每个单独的基因进行了展示。在相同或相似基因组的基因之间存在令人惊讶的选择一致性。因此，每个基因组或每种基因组似乎都拥有一种在密码子之间进行选择的“系统”。然而，移码基因与正常基因有着广泛不同的选择策略。我们的研究表明，区分mRNA序列的主要因素与简并碱基之间的选择有关。因此，这些系统的第三位碱基选择可用于建立一种新的遗传距离，它反映了编码策略的差异。我们发现的选择模式似乎与基因组而非单个基因是选择单位这一观点相符。基因组中的每个基因都倾向于遵循其物种对密码子目录的使用方式；这就是我们的基因组假说。
