the distribution of ( +/- ) trans-7,8-dihydrobenzo [ alpha ] pyrene-7,8-diol-9,10-epoxide ( bpde ) adducts was studied in 1 ) sv40 dna modified in vitro to a level of 20 adducts/molecule , 2 ) dna from sv40 chromosomes modified in vivo to a level of less than 1 adduct , and 3 ) dna from only those chromosomes with an open origin of replication .
C0008633
chromosomes
C0242961
origin