TY - JOUR
T1 - Patterns of nucleotide substitution in pseudogenes and functional genes
AU - Gojobori, Takashi
AU - Li, Wen Hsiung
AU - Graur, Dan
PY - 1982/9
Y1 - 1982/9
N2 - 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.
AB - 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.
KW - Base content
KW - Functional constraints
KW - Neutral mutation
KW - Substitution mutagenesis
KW - Transitions and transversions
UR - http://www.scopus.com/inward/record.url?scp=0020317308&partnerID=8YFLogxK
U2 - 10.1007/BF01733904
DO - 10.1007/BF01733904
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AN - SCOPUS:0020317308
SN - 0022-2844
VL - 18
SP - 360
EP - 369
JO - Journal of Molecular Evolution
JF - Journal of Molecular Evolution
IS - 5
ER -