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STR Data Analysis and Interpretation for Forensic Analysts

Allele Dropout

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Allele dropout occurs when a sample is typed and one or more alleles are not present.

This can be due to a variety of factors:  

  • The initial input quantity of DNA is too low, resulting in the failure to amplify one or more alleles in the sample.
  • A mutation in the primer binding site is present, which causes a failure in the amplification of the allele.
  • An allele sizes outside of the normal calling range for a particular locus and goes undetected.
Allele dropout
National Institute of Justice (NIJ) (see reuse policy).

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