Analysis of DNA Typing Data for Forensic Applications

• NCJ Number: 160143
• Author(s): S P Daiger; E Boerwinkle; R Chakraborty
• Date Published: 1995
• Length: 1000 pages
• Grant Number(s): 90-IJ-CX-0030
• Agencies: NIJ-Sponsored
• Publication Type: Best Practice/State-of-the-Art Review

Annotation

This report presents the findings, bibliography, and background materials for a study that collected and analyzed data sets of DNA typing results to address questions regarding the power and reliability of methods for calculating the probability of DNA matches.

Abstract

Results revealed that different types of DNA markers, such as VNTRs, TRs, and microsatellites showed different modes of evolution, but the differences are too slight to affect forensic calculations. The study developed novel measures of genetic distance to evaluate the differences between populations. These measures demonstrated that any statistical biases in measuring population frequencies are either too slight to affect forensic calculations or are always conservative and benefit a defendant. The study established that a data sample must include at least 100-150 individuals and evaluated the occurrence and consequences of null or overlapping VNTR alleles. Thus, most current data sets used in forensic cases are of adequate size. The study also developed a technically correct method for determining confidence intervals in calculating the probability of DNA matches. The study also demonstrated that the presence of population substructure does not pose any problem in providing conservative forensic calculations. Reprints of journal articles and 871 references