遗传密码子进化的阶段性.PDF

6 3 生命科学研究 Vol. 6 No. 3 2002 9 Life Science Research Sep. 2002 X 肖敬平 ( , 510642) :密码子的起源与进化可划分为4 个阶段, 即: 前密码子期, tRN 形成期, 原密码子与 序肽同步起源 期,以及密码子进化期. 不同的观点,大都能在不同时期找到自己的位置,从而是互补的. 在此基础上, 首次将主 要理论的主旨整合为一个进化过程的理论框架, 基本上协调了持续了近半 个世纪的确定论和偶然论之争,并且 解释了密码子设定的多态性的由来. :遗传密码子起源;tRN ; 氨酰-tRN 合成酶; 分子进化;生命起源 :Q493;Q755 : : 1007-7847(2002) 03-0198-06 On the Evolution Stages of the Genetic Codon XI O Jing-ping ( Colleg e of Lfi e Science ,South China Agricultural University , Guangzhou 510642,Guangdong , China) Abstract:The course of origin and evolution of genetic codons has been classified into four stages, i.e, pre-codon phase,tRN emergence phase, phase of synchronous origination of procodon strands and seqenced peptides, and codon evolution phase.Most of different concepts may find their own right at different phases,and thus become com- plementary one another. Based on this dogma,an orchestration of themotifs of major theories to formulate atheoreti- cal framework of evolution course is attempted for the first time.The contradictions of the concepts of determinism school and contingency school,of which the controversial has continued for half a century, have thus been basically solved,and the source of polymorphism of genetic codon assignment,also,been plausibly explained. Key words:origin of genetic codon;tRN ;aminoacy-l tRN synthetase;molecular evolution;origin of life ( Lfi e Science Resea