- Course Introduction
- 01: Evidence & DNA
- 02: Forensic Biology
- 03: DNA Extraction & Quantitation
- 04: DNA Amplification
- 05: Amplified DNA Product Separation
- 06: STR Data Analysis & Interpretation
- Data Troubleshooting
- Data Interpretation & Allele Calls
President's DNA Initiative
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Advancing Justice Through DNA Technology
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Advancing Justice Through DNA Technology
DNA Analyst Training
Step 2: Extraneous Peaks
Home > STR Data Analysis & Interpretation > Data Interpretation & Allele Calls > Step 2: Extraneous Peaks
The second step is to assess each sample to determine if there are any extraneous peaks, and if they interfere with the interpretation process. Extra peaks within an allele range should be assessed following laboratory procedures.
Click here to read more about Extraneous Peaks in Subject 06, Module 02.
Artifacts
Various artifacts can complicate and/or interfere with the interpretation process. Prior to interpreting allele designations, the analyst should evaluate each sample to determine if artifacts are present. All samples, to include controls and ladders, should be assessed for the following:
- Stutter
- 3′-A nucleotide addition
- Spurious peaks (spikes, blobs, noise)
- Pull-up
If any of these artifacts are present, the analyst should follow the procedures established by the laboratory.
