a heteroduplex dna molecule , constructed from the dna of simian virus 40 ( sv40 ) mutant with a deletion of the map region 0.54-0.55 and the dna of a second sv40 mutant having a deletion of the map segment 0.70-0.73 , is cleaved twice with s1 endonuclease .
C0012931
constructed
C0012854
dna