Individual identification method using samples associated with doping tests: A comparison of mitochondrial and...

Area of Science:

• Forensic Science
• Biochemistry
• Genetics

Background:

• Doping control involves detecting prohibited substances or sample manipulation.
• Short tandem repeat (STR) analysis is standard for athlete identification but struggles with limited DNA.
• Mitochondrial DNA (mtDNA) offers stability and high copy numbers, making it suitable for degraded samples.

Purpose of the Study:

• To compare the efficacy of mitochondrial DNA (mtDNA) testing against short tandem repeat (STR) analysis in doping control.
• To evaluate sensitivity, concordance across different sample types (blood, dried blood spot, urine), and performance on case-type samples.

Main Methods:

• Sensitivity studies comparing mtDNA and STR analysis.
• Concordance studies using whole blood, dried blood spots, and urine samples.
• Case-type studies involving various biological samples including urine, blood residues, and stains.

Main Results:

• mtDNA testing demonstrated superior sensitivity compared to STR analysis.
• High concordance was observed between mtDNA sequences and STR profiles across all sample types.
• STR analysis showed allelic dropout in some urine samples, whereas mtDNA testing successfully generated DNA profiles from all tested samples, including degraded ones.

Conclusions:

• mtDNA testing is a valuable tool for analyzing highly degraded DNA samples, particularly urine, in doping control.
• Initial urine testing using mtDNA is recommended due to its effectiveness with challenging samples.
• Confirmatory STR analysis from blood may be necessary in cases where a DNA match has significant implications for the athlete.