it is proposed that the low level of spontaneous mutagenesis observed in the reca , lexa , umuc , and the uvrd recb strains is due to errors made during dna replication , while the enhanced level of spontaneous mutagenesis observed in the wild type , and especially in the uvra and uvrb strains , is due to excisable lesions that are produced in the dna by normal metabolic reactions , and that such unexcised lesions induce mutations via error-prone dna repair .
C0598312
dna replication
C0012854
dna