Restriction enzymes that are used in the construction of recombinant DNA are endonucleases which cut the DNA at 'specific-recognition sequence'. What would be the disadvantage if they do not cut the DNA at specific-recognition sequence?
Specific-recognition sequence in a DNA provide sticky ends at which recombination of genes takes place. This further leads to the replication of the selected gene. If endonuclease fails to cut DNA at specific-recognition sequence; then recombination or replication will fail to take place.