Validation of the AMPFlSTR SGM plus system for use in forensic casework

Area of Science:

• Forensic Science
• Genetics
• Molecular Biology

Background:

• The AMPFlSTR((R)) SGM Plus system is an advancement over the previous SGM system.
• It incorporates six SGM loci, amelogenin, and four new loci: D3S1358, D19S433, D16S539, and D2S1338.

Purpose of the Study:

• To validate the performance and reliability of the AMPFlSTR((R)) SGM Plus system for DNA profiling.
• To assess its effectiveness in improving match probability and handling challenging forensic samples.

Main Methods:

• Validation studies including ageing and degradation analyses.
• Testing on various biological samples (semen, buccal scrapes) and non-human DNA sources.
• Casework and simulated casework studies comparing SGM and SGM Plus.
• Concordance study of 1000 samples.

Main Results:

• Significantly improved match probability (1 in 10(9)).
• Semen stains were the most stable evidence type; buccal scrapes were least stable.
• Increased sensitivity and success rates with degraded samples due to low molecular weight loci (D3S1358, D19S433).
• Minimal interpretation issues with non-primate DNA; no discernible results from microorganisms.
• Comparable results between SGM and SGM Plus systems, with one null allele instance.

Conclusions:

• The AMPFlSTR((R)) SGM Plus system offers enhanced DNA profiling capabilities with improved discriminatory power.
• The system demonstrates robustness and reliability in forensic applications, including challenging degraded samples.
• Validation studies confirm its suitability for casework, providing comparable and reliable results to the previous system.