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A Comparison of the Effects of PCR Inhibition in Quantitative PCR and Forensic STR Analysis

NCJ Number
255289
Date Published
2011
Length
6 pages
Author(s)
Maribel E. Funes-Huacca; Kerry Opel; Bruce McCord; Robyn Thompson
Agencies
NIJ-Sponsored
Publication Type
Research (Applied/Empirical), Report (Study/Research), Report (Grant Sponsored), Program/Project Description
Grant Number(s)
2006-DN-BX-K006
Annotation
This article reports on a project that compared the effects of three representative PCR inhibitors, using quantitative PCR (qPCR) and multiplex STR amplification in order to determine the effect of inhibitor concentration on allele dropout and to develop better ways to interpret forensic DNA data.
Abstract
Researchers used humic acid, collagen, and calcium phosphate at different concentrations to evaluate the profiles of alleles inhibited in these amplifications. These data were correlated with previously obtained results from quantitative PCR, including melt curve effects, efficiency changes, and cycle threshold (Ct) values. Overall, the data show that there are two competing processes that result from PCR inhibition. The first process is a general loss of larger alleles. This appears to occur with all inhibitors. The second process is more sequence specific and occurs when the inhibitor binds DNA, altering the cycle threshold and the melt curve. This sequence-specific inhibition results in patterns of allele loss that occur in addition to the overall loss of larger alleles. The data demonstrate the applicability of using real-time PCR results to predict the presence of certain types of PCR inhibition in STR analysis. (publisher abstract modified)
Date Created: July 20, 2021