Scientists don't "cut out" DNA when copying it. They use a process called polymerase chain reaction (PCR) to amplify (make many copies of) a specific piece of DNA.

Here's how PCR works:

1. Denaturation: The DNA is heated to separate the two strands.

2. Annealing: Short pieces of DNA called primers bind to specific sequences on the template DNA strands.

3. Extension: An enzyme called DNA polymerase uses the primers as starting points to build new DNA strands that are complementary to the template strands.

Key point: PCR doesn't involve cutting out DNA. It uses primers to select specific regions of DNA for copying.

If you're asking about gene editing, where scientists modify DNA sequences, then they might need to cut DNA using restriction enzymes. These enzymes recognize specific DNA sequences and cut the DNA at those sites. But this is different from simply copying DNA.