- To produce the same sequences at the (sticky/asymmetrical) cut ends of the fragments from the different sources
- That the (sticky) ends from the differently-sourced fragments will join together by complementary base-pairing
- If different restriction enzymes were used, only the cut end from the DNA fragments from the same source would be able to re-join by complementary base-pairing.
Q7. Explain why the same restriction enzyme must be used to cut the fragments in preparing recombinant plasmids