Abstract
Restriction mapping of recombinant plasmids indicated the presence of poison sequence(s) in monkey mtDNA. These plasmids were constructed from a 5.2 K.b. BglII mtDNA fragment and pRSVneo or pdel9 as cloning vectors. The poison sequence(s) caused genetic rearrangement of the vectors' nucleotide sequences. Deletion of the suspected poison sequence(s) from the mtDNA fragment increased the transformation efficiency of the produced recombinant plasmids and conserved the vectors' original nucleotide sequences.