Questions: UNIT 3 - MILESTONE 3 Identify the step associated with nucleic acid probing. Tracking dye is added to DNA samples, which are then pippetted into wells. Single-stranded DNA is produced by denaturing DNA samples. DNA samples are cut with restriction enzymes. DNA moves toward a positive electrode.

The step associated with nucleic acid probing is the production of single-stranded DNA by denaturing DNA samples.

Explanation for each option:

1. Tracking dye is added to DNA samples, which are then pipetted into wells.

   • This step is part of the gel electrophoresis process, where DNA samples are prepared for separation based on size. It is not directly related to nucleic acid probing.

2. Single-stranded DNA is produced by denaturing DNA samples.

   • The answer is this one: Single-stranded DNA is produced by denaturing DNA samples. This step is crucial for nucleic acid probing because probes are typically single-stranded and need to hybridize with complementary single-stranded DNA.

3. DNA samples are cut with restriction enzymes.

   • This step involves preparing DNA for analysis by cutting it into smaller fragments. It is not specific to nucleic acid probing.

4. DNA moves toward a positive electrode.

   • This describes the process of electrophoresis, where DNA fragments are separated by size. It is not directly related to nucleic acid probing.

In summary, the step associated with nucleic acid probing is the production of single-stranded DNA by denaturing DNA samples, as this allows the probe to hybridize with its complementary sequence.