[The effect on DNA quantification and STR typing from cigarette butts collected at various time points]

Area of Science:

• Forensic Science
• Molecular Biology
• Genetics

Context:

• Cigarette butts are common sources of trace DNA in forensic investigations.
• The stability of DNA on cigarette butts over time is crucial for successful identification.

Purpose:

• To investigate the impact of time on DNA quantification and Short Tandem Repeat (STR) typing from cigarette butts.
• To compare DNA degradation rates between the outer layer and sponge of collected cigarette butts.

Summary:

• DNA was extracted from cigarette butts at 1, 4, 7, and 10 weeks post-collection.
• DNA quantity showed minimal changes, but STR typing detection rates for 16 loci decreased significantly over time.
• The sponge yielded lower STR detection rates compared to the outer layer, with a more pronounced decline.

Impact:

• Findings highlight the time-sensitive nature of DNA evidence on cigarette butts.
• Suggests that prompt analysis of cigarette butt DNA is essential for maximizing forensic success.
• Informs forensic protocols regarding evidence collection and storage timelines.