What are best practices for preserving and collecting DNA evidence?

• A. Touch items with bare hands to gather DNA, mix samples, disregard chain of custody, store in hot sun.
• B. Wear gloves, avoid contamination, package items separately, label properly, maintain chain of custody, and preserve conditions to avoid degradation.
• C. Collect only digital DNA and skip physical samples.
• D. Destroy evidence to avoid contamination.

Answer: (B)

Preserving and collecting DNA evidence hinges on keeping the sample pure, properly documented, and protected from degradation from collection to courtroom presentation. Wearing gloves prevents introducing the collector’s DNA or other contaminants. Packaging each item separately minimizes cross-contamination and preserves the original condition of each piece. Labeling items accurately and thoroughly ensures traceability and linkage to the source, time, and place. Maintaining a clear chain of custody records every transfer and handling step, which is essential for admissibility in court. Keeping the evidence in appropriate environmental conditions slows degradation and preserves DNA integrity for accurate testing. Collecting only digital DNA misses the actual physical material that contains DNA, so it’s not a valid substitute for standard forensic analysis. Destroying evidence or handling items with bare hands would compromise results and violate proper procedure.