article · Zhongguo shengwu huaxue yu fenzi shengwu xuebao · 2002
Degeneracy or Polymorphism? ——An Evolutionary Insight into the Assignment of Genetic Codons
Xiao Jing
Cited by 0Abstract and details only
Abstract
Genetic codons display puzzling polymorphism in their assignment: the number of codons assigned to each amino acid ranges from 1 to 6 but 5. The characteristic reflects tremendous heterogeneity of genetic codons existing in either translation behavior or evolutionary track, and the convergent term “degeneracy fails to define the evolutionary essence of such polymorphism. Two codons, AUG (Met) and UGG (Trp), having no synonymous codon are not degenerative at all. The other codons are classified into two major classes: one class includes codon groups each having 4 synonymous codons with identical first two bases. They might have evolved from a two\|letter primitive codon ( XYN ) encoding specifically for a single amino acid, and following 2 out of 3 reading rule, which are simply the relics from the primitive codons still in use, and in this sense, also are not degenerative. The other class mainly includes groups each including 2 synonymous codons and obeying 3 out of 3 reading rule. They might have come from the ambiguous primitive codons each for two amino acids via the assignment of the unassigned 3 rd bases N to make two specific modern codons. As for the peculiar codon groups each having 6, or actually 4+2, synonymous codons might imply heterologous origins from the above two groups. The origin of polymorphism of the assignment of genetic codons is believed to initiate from the interaction between amino acids and specific terminal doublets of certain nucleotides at the earliest stage, and finalize via the differentiation of the 3 rd bases of ambiguous procodons mediated by cognate aminoacyl tRNA synthetases. These evolutionary traces have been dimmed by the traditional term “degeneracy. As a result, the substantial criterion for the judgment of the plausibility of any hypothesis concerned and the consensus basis for different concepts in this field have been covered. This may explain the long term controversies among various theories in the field of the origin of genetic codons.
Cite this paper
Jing, X. (2002). Degeneracy or Polymorphism? ——An Evolutionary Insight into the Assignment of Genetic Codons. Zhongguo shengwu huaxue yu fenzi shengwu xuebao.
Jing, Xiao. “Degeneracy or Polymorphism? ——An Evolutionary Insight into the Assignment of Genetic Codons.” Zhongguo shengwu huaxue yu fenzi shengwu xuebao, 2002.
Jing, Xiao. 2002. “Degeneracy or Polymorphism? ——An Evolutionary Insight into the Assignment of Genetic Codons.” Zhongguo shengwu huaxue yu fenzi shengwu xuebao.
Jing, X. (2002) ‘Degeneracy or Polymorphism? ——An Evolutionary Insight into the Assignment of Genetic Codons’, Zhongguo shengwu huaxue yu fenzi shengwu xuebao.
@article{jing2002degeneracy,
title = {{Degeneracy or Polymorphism? ——An Evolutionary Insight into the Assignment of Genetic Codons}},
author = {Jing, Xiao},
journal = {Zhongguo shengwu huaxue yu fenzi shengwu xuebao},
year = {2002}
}Made from the index record. Check names, capitalisation and page numbers against the paper. Need another style? AI for Research has over 10,000.