PATTERNS OF NUCLEOTIDE SUBSTITUTION IN PSEUDOGENES AND FUNCTIONAL GENES
PATTERNS OF NUCLEOTIDE SUBSTITUTION IN PSEUDOGENES AND FUNCTIONAL GENES
复制标题
DOI：
10.1007/bf01733904
复制
发表时间：
1982-01-01
影响因子：
3.9
通讯作者：
GRAUR, D
中科院分区：
文献类型：
--
作者：
GOJOBORI, T;LI, WH;GRAUR, D
点突变的模式是从假基因中的核苷酸替换推断出来的。所获得的模式表明，转换突变比颠换突变发生的频率更高，并且A或T突变比G或C突变更常见。我们的结果进行了讨论，从Topal和Fresco的点（取代）突变的分子基础模型（自然263：285-289，1976）的预测。功能基因密码子第一和第二位的核苷酸替换模式与假基因非常相似，但有义链中C→T转换的相对频率大大降低，而C→G和G→C颠换的相对频率则增加了一倍。两种模式之间的差异可以通过观察到在蛋白质进化中氨基酸取代主要发生在具有相似生物化学性质的氨基酸之间来解释（Grantham，Science 185：862-864，1974）。我们对假基因和功能基因中核苷酸替换模式的研究结果导致了蛋白质编码基因的编码区和非编码区都应该具有高频率的A和T。现有的数据表明，非编码区的A和T确实很高，但编码区的T很低，尽管A很高。
The pattern of point mutations is inferred from nucleotide substitutions in pseudogenes. The pattern obtained suggests that transition mutations occur somewhat more frequently than transversion mutations and that mutations result more often in A or T than in G or C. Our results are discussed with respect to the predictions from Topal and Fresco's model for the molecular basis of point (substitution) mutations (Nature 263:285–289, 1976). The pattern of nucleotide substitution at the first and second positions of codons in functional genes is quite similar to that in pseudogenes, but the relative frequency of the transition C→T in the sense strand is drastically reduced and those of the transversions C→G and G→C are doubled. The differences between the two patterns can be explained by the observation that in the protein evolution amino acid substitutions occur mainly between amino acids with similar biochemical properties (Grantham, Science 185:862–864, 1974). Our results for the patterns of nucleotide substitutions in pseudogenes and in functional genes lead to the prediction that both the coding and non-coding regions of protein coding genes should have high frequencies of A and T. Available data show that the non-coding regions are indeed high in A and T but the coding regions are low in T, though high in A.