President's DNA Initiative
Advancing Justice Through DNA Technology
DNA Analyst Training
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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.

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:

  1. Assess the internal size standards (ISS), allelic ladders, and controls.
  2. Assess each sample for the presence of extraneous peaks and determine if they may interfere with the interpretation process.
  3. Assess the data from each sample.

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© 2007 NFSTC Science Serving Justice®
NOTE TO USERS: The President’s DNA Initiative DNA Analyst Training program and assessment were completed and published in 2005, in cooperation with the National Institute of Justice. The science and techniques in the program are sound and proven, however, program content has not been updated to include tools and technologies developed and in use after 2005, including many kits and robots. Assessment questions address only content delivered in this program and may not contain the full range of tools in use in your laboratory.