How should DNA collection be performed according to the guidelines?

The correct answer is based on the principles of preserving the integrity and quality of the DNA collected. When DNA samples are collected, it is essential to minimize contamination and degradation.

Using the tip of a swab allows for concentrated sampling from a specific area, which can yield a higher quantity and quality of DNA. Allowing the sample to air dry is important because moisture can lead to degradation of the DNA or promote bacterial growth, both of which can compromise the sample. Sealing the dried swab in a coin envelope helps protect the sample from contamination and environmental factors, maintaining its viability for later analysis.

This method aligns with best practices in forensic science, which emphasize the importance of careful handling, proper drying, and secure packaging to ensure that DNA evidence is usable in investigations and legal proceedings.