NCJ Number
237524
Journal
Forensic Science International: Genetics Volume: 6 Issue: 1 Dated: January 2012 Pages: 97-101
Date Published
January 2012
Length
5 pages
Annotation
This paper presents a method for measuring the degree of degradation of a sample and demonstrates how to incorporate this in estimating the probability of allelic drop-out.
Abstract
DNA samples found at a scene of crime or obtained from the debris of a mass disaster accident are often subject to degradation. When using the STR DNA technology, the DNA profile is observed via a so-called electropherogram (EPG), where the alleles are identified as signal peaks above a certain level or above a signal to noise threshold. Degradation implies that these peak intensities decrease in strength for longer short tandem repeat (STR) sequences. Consequently, long STR loci may fail to produce peak heights above the limit of detection resulting in allelic or locus drop-outs. In this paper, the authors present a method for measuring the degree of degradation of a sample and demonstrate how to incorporate this in estimating the probability of allelic drop-out. This is done by extending an existing method derived for non-degraded samples. The performance of the methodology is evaluated using data from degraded DNA, where cases with varying amounts of DNA and levels of degradation are investigated. (Published Abstract)