Practice question

Agarose gel analysis of recombinant plasmid digested with enzymes flanking insertion site normally separates vector backbone from insert as two bands. If vector alone is 3 kb and after cloning digestion still shows only a single 3 kb band of double intensity, interpretation requires understanding overlapping migration. Total recombinant is 6 kb; digestion releases 3 kb vector and 3 kb insert of identical size that co-migrate as one intense band. Without additional enzymes or size markers, single band may be misinterpreted, but careful intensity comparison indicates insert size equals vector size, here 3 kb.