Second position U C A G JCU UAU JGU Phe JUC ucc Tyr UAC UGC Cys Ser UAA Stop UGA Stop A Leu uUG ucG UAG Stop UGG Trp CUU CCU CAU CGU 〉His cuc ccc CGC Leu CCA Pro CUA CGA Arg CUG cca ccG AUU ACU AGU Asr Ser AUC >lle A Th AGA A ACG AAG >Lys Arg AUG Met ./ G GUU GCU GGU U Asp GUC Val GUA C C Ala a8 Gly A GAG Glu GUG GCC CCG G 减少了变异对生物的影响 减少了变异对生物的影响