析遗传密码子多态性之谜

建立了1个由16个“3读2”原始密码子组成的系统。它们分为“语义确切”的,和“双义的”,两大类。后者,通过不同的分化方式,进一步分化为语义确切的“3读3”现代密码子;前者则无需再分化,仍保留着“3读2”原始形态,成为孑遗密码子。首次解释了氨基酸具有不同数目密码子,以及线粒体内存在反常密码子的多态性现象,初步建立了密码子进化树,并提出了原始氨酰基－tRNA合成酶可能在密码子进一步分化中起关键作用的观点。

Analysis of the Mystery of Polymorphism of Genetic Codons

A system of 16"two out of three"primitive codons is organized, which consists of two groups: the "accurate primitive codon", each definitely assigned to one amino acid; and the "ambiguous"one, shared by two amino acids each. The later differentiated further into "three out of three"current codons via various modes; whereas no further differentiation is needed for the former, and their "two out of three" original forms have remained invariant as "relics". Thus the polymorphism phenomenon that different amino acids are encoded by different number of synonymous codons, and exceptional codons appear in mitochondria is plausibly explained for the first time. An evolutionary dendrogram of genetic codons is sketched, and primitive aminoacyl tRNA synthetases are thought to play a crucial role in the further differentiation of procodons.