- 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
Overview
Home > STR Data Analysis & Interpretation > Data Interpretation & Allele Calls > Overview
Interpretation of genotypes (allele calls) is based on a pattern of peaks or bands on an electropherogram or gel. A peak or band is a visual representation of a DNA fragment.
- In capillary electrophoresis (CE) a peak on the electropherogram rises sharply from the baseline, has smooth sides, and is symmetrical in shape.
- For gel-based systems, a band on the gel or gel image is distinguishable from the background and defined within a gel lane.
Click here to read more about Capillary Electrophoresis in Subject 05, Module 02.
Gel-based systems, unlike CE, allow analysts to visually compare alleles without a software program. However, most laboratories use software programs for both CE and gel-based sizing.
The steps in data interpretation are:
- Assess the internal size standards (ISS), allelic ladders, and controls.
- Assess each sample for the presence of extraneous peaks and determine if they may interfere with the interpretation process.
- Assess the data from each sample.
