Effect of reference database on frequency estimates of polymerase chain reaction (PCR)-based DNA profiles

Keith L. Monson, Bruce Budowle

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8 Scopus citations


A variety of general, regional, ancestral and ethnic databases is available for the polymerase chain reaction (PCR)-based loci LDLR, GYPA, HBGG, D7S8, Gc, DQA1, and D1S80. Generally, we observed greater differences in frequency estimations of DNA profiles between racial groups than between ethnic or geographic subgroups. Analysis revealed few forensically significant differences within ethnic subgroups, particularly within general United States groups, and multi-locus frequency estimates typically differ by less than a factor of ten. Using a database different from the one to which a target profile belongs tends to overestimate rarity. Implementation of the general correction of homozygote frequencies for a population substructure, advised by the 1996 National Research Council report, The Evaluation of Forensic DNA Evidence, has a minimal effect on profile frequencies. Even when it is known that both the suspect and all possible perpetrators must belong to the same isolated population, the special correction for inbreeding, which was proposed by the 1996 National Research Council report for this special case, has a relatively modest effect, typically a factor of two or less for 1% inbreeding. The effect becomes more substantial (exceeding a factor of ten) for inbreeding of 3% or more in multi-locus profiles rarer than about one in a million.

Original languageEnglish
Pages (from-to)483-488
Number of pages6
JournalJournal of Forensic Sciences
Issue number3
StatePublished - May 1998


  • D758 EC
  • DQA1
  • Forensic science
  • Frequency estimation
  • GYPA
  • HBGG
  • LDLR
  • Polymerase chain reaction
  • Population databases
  • Population genetics


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