Improved Analysis of DNA Short Tandem Repeats With Time-of-Flight Mass Spectrometry

• NCJ Number: 188292
• Author(s): John M. Butler; Christopher H. Becker
• Date Published: October 2001
• Length: 84 pages
• Grant Number(s): 97-LB-VX-0003
• Agencies: NIJ
• Publication Type: Research (Applied/Empirical)

Annotation

This report focused on a National Institute of Justice project on the development of a new technology for rapid and accurate analysis of DNA STR markers using time-of-flight mass spectrometry.

Abstract

With law enforcement communities gathering millions of DNA samples from convicted felons, the DNA typing technology was seen as needing improvement. GeneTrace Systems, Inc. based in California developed an integrated high-throughput DNA analysis system involving the use of proprietary chemistry, robotic sample manipulation, and time-of-flight mass spectrometry. The GeneTrace technology allowed several thousand samples to be processed daily. DNA samples can be analyzed in seconds, rather than minutes or hours, and with improved accuracy compared with conventional electrophoresis methods. This technology showed promise in being cost effective in the long run. The National Institute of Justice (NIJ) initiated a project to adapt the GeneTrace technology to human identity DNA short tandem repeat (STR) markers commonly used by forensic laboratories. Time-of-flight mass spectrometry offered a rapid, cost-effective alternative for genotyping large numbers of samples. Due to the increased accuracy, STR alleles can be reliably typed without comparison with allelic ladders. Mass spectrometry would be valuable for large-scale DNA database work. In summary, the positive features of mass spectrometry for STR analysis include: (1) rapid results; (2) accuracy; (3) direct DNA measurement; (4) automated sample preparation and data collection; (5) high-throughput capabilities; and (5) flexibility in that single nucleotide polymorphism (SNP) assays can be run on the same instrument platform. This project demonstrated that both STR and SNP analysis were reliably performed with GeneTrace's mass spectrometry technology. References and appendices