分子序列的突变危险性与遗传密码的编码规则

The Mutational Function of Molecular Sequence and the Coding Rule of Genetic Code

定义了分子序列（碱基序列和对应的氨基酸序列）的突变危险性函数；通过危险性函数的极小化可以导出遗传密码的简并规则，终止密码子在密码表上的位置及亲－疏水畴排布，氨基酸在密码表上的定位接近标准密码表．各个生物类别的突变危险性函数值差别不超过５％ ，可看作守恒量．Ｒａｓ 家族癌基因产物具有较大的突变危险性函数值，这提示分子序列的突变危险性函数可能有重要的应用价值和理论意义．

Assuming the origin and the evolution of the genetic code obeying the rules of the minimization of mutational deterioration,considering the deterioration of amino acid substitution which is derived from the codon mutation,we define the mutation deterioration function of genetic code in a molecular sequence.Taking into account that the natural selection force is applied on the molecular sequences (base sequences and corresponding amino acid sequences) directly,by use of the mutational deterioration function of molecular sequences we deduce the following results:1) The degeneracy rules of genetic code have been re deduced from the random genetic code table by the mutation deterioration function of genetic code.2) The distribution of terminators and hydrophilic and hydrophobic domains are re obtained.The distribution of amino acids in genetic code table is close to the standard code table.3) The values of the mutational deterioration function of various kinds of organisms are nearly same and can be considered as a conservation quantity becuase their difference is lower than 5%.The value of virus and the cancer gene product of RAS family is bigger.This gives an example that the mutational deterioration of molecular sequence may be important in the theory and in application.