Highlights
- •Extensions of previous work on DNA database matching probabilities.
- •Relaxation of exact matching to include wild cards.
- •Incorporates the concepts of rare alleles in DNA database matching.
- •All methods are implemented in open source software.
- •Numerical examples demonstrate the effect of wild cards and rare alleles.
Abstract
Forensic DNA databases are powerful tools used for the identification of persons of
interest in criminal investigations. Typically, they consist of two parts: (1) a database
containing DNA profiles of known individuals and (2) a database of DNA profiles associated
with crime scenes. The risk of adventitious or chance matches between crimes and innocent
people increases as the number of profiles within a database grows and more data is
shared between various forensic DNA databases, e.g. from different jurisdictions.
The DNA profiles obtained from crime scenes are often partial because crime samples
may be compromised in quantity or quality. When an individual's profile cannot be
resolved from a DNA mixture, ambiguity is introduced. A wild card, F, may be used in place of an allele that has dropped out or when an ambiguous profile
is resolved from a DNA mixture.
Variant alleles that do not correspond to any marker in the allelic ladder or appear
above or below the extent of the allelic ladder range are assigned the allele designation
R for rare allele. R alleles are position specific with respect to the observed/unambiguous allele. The
F and R designations are made when the exact genotype has not been determined. The F and R designation are treated as wild cards for searching, which results in increased chance
of adventitious matches. We investigated the probability of adventitious matches given
these two types of wild cards.
Keywords
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Article info
Publication history
Published online: December 15, 2014
Accepted:
December 9,
2014
Received in revised form:
December 5,
2014
Received:
September 29,
2014
Identification
Copyright
© 2014 Elsevier Ireland Ltd. Published by Elsevier Inc. All rights reserved.
