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How do restriction enzymes help scientists create recombinant DNA molecules?

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DNA extraction and recombinant DNA technology — recombinant DNA The process of DNA extraction is necessary to isolate molecules of DNA from cells or tissues. A series of steps, including the use of protease enzymes to strip proteins from the DNA, are required for isolating pure DNA that is suitable for use in later procedures, such as cloning or sequencing.

Restriction enzymes act as "molecular scissors" that are essential for creating recombinant DNA molecules. These enzymes, originally derived from bacteria, recognize and cleave DNA at specific target sequences.12

To create recombinant DNA, scientists use the same restriction enzyme to cut both the donor DNA (containing the gene of interest) and the vector DNA (the carrier molecule). Many of these enzymes make staggered cuts, leaving single-stranded "overhangs" at the cleavage sites. Because these overhangs consist of complementary nucleotide sequences, they naturally pair with one another when the donor and vector fragments are mixed.2

Once the donor fragment is inserted into the vector, the sugar-phosphate backbone of the DNA is sealed by an enzyme called DNA ligase, resulting in a stable, continuous double helix. This process allows researchers to combine DNA from different sources, creating molecules that do not exist in nature.2