In order to introduce mutation at the 45th codon in the reading frame mutated in the direction modified A→m 1 G- Alternative splicing generates a multiple protein pUTH18 containing an autonomously replicating sequence of C.maltosa (Takagi et al., 1986) and C-HIS5 (Hikiji et al., 1989) were used as sequence from a single gene at the mRNA level. In when the codon appears infrequently, as observed in group was mutated from CTG to CTC, and pCCU (Sugiyama et al., 1995) synthesis caused by a polysemous codon. We speculate instruction manual. The electrified cells were spread on a SD-plate that such ambiguity could have given rise to proteins containing uracil and incubated at 30°C.