Identification and long term stability of DNA captured on a dental impression wafer.

Purpose: The purpose of this study was to determine the quantity and quality of DNA extracted from a dental bite impression wafer immediately after impression and after 12 months of home storage. The authors' hypothesis was that the wafer would retain sufficient DNA with appropriate genetic markers to make an identification match.

Methods: Two impression wafers (Toothprints(®) brand) were administered to 100 3- to 26-year-olds.

Validation of a DNA mixture statistics tool incorporating allelic drop-out and drop-in.

DNA mixture analysis is a current topic of discussion in the forensics literature. Of particular interest is how to approach mixtures where allelic drop-out and/or drop-in may have occurred. The Office of Chief Medical Examiner (OCME) of The City of New York has developed and validated the Forensic Statistical Tool (FST), a software tool for likelihood ratio analysis of forensic DNA samples, allowing for allelic drop-out and drop-in.

Estimating the number of contributors to two-, three-, and four-person mixtures containing DNA in high template and low template amounts.

Aim: To develop guidelines to estimate the number of contributors to two-, three-, and four-person mixtures containing either high template DNA (HT-DNA) or low template DNA (LT-DNA) amounts.

Methods: Seven hundred and twenty-eight purposeful two-, three-, and four-person mixtures composed of 85 individuals of various ethnicities with template amounts ranging from 10 to 500 pg were examined. The number of alleles labeled at each locus and the number of labeled different and repeating alleles at each locus as well over all loci for 2 HT-DNA or 3 LT-DNA replicates were determined.

Validation of testing and interpretation protocols for low template DNA samples using AmpFlSTR Identifiler.

Aim: To test the reliability, robustness, and reproducibility of short tandem repeat (STR) profiling of low template DNA (LT-DNA) when employing a defined set of testing and interpretation parameters.

Methods: DNA from known donors was measured with a quantitative real time polymerase chain reaction (PCR) assay that consistently detects less than 1 pg/microL of DNA within a factor of 0.3.

The application of ultraviolet irradiation to exogenous sources of DNA in plasticware and water for the amplification of low copy number DNA.

Using high sensitivity forensic STR polymerase chain reaction (PCR) typing procedures, we have found low concentrations of DNA contamination in plasticware and water assumed to be sterile, which is not detected by standard DNA procedures. One technique commonly used to eliminate the presence of DNA is ultraviolet (UV) irradiation; we optimized such a protocol used in the treatment of water, tubes, plates, and tips for low copy number DNA (LCN) amplification. UV light from a Stratalinker((R)) 2400 was administered to 0.