Front End Separation of Compromised Blood Mixtures for Single Source DNA Profiling

• NCJ Number: 253064
• Date Published: July 2018
• Author(s): Christopher Ehrhardt; M. Katherine Philpott
• Length: 11 pages
• Grant Number(s): 2015-DN-BX-K024
• Agencies: NIJ-Sponsored
• Publication Type: Research (Applied/Empirical); Report (Summary); Program/Project Description

Annotation

This is the Final Summary Overview of the findings and methodology of a project whose primary objective was to test new methods for increasing the efficiency of antibody tagging and cell sorting on degraded blood samples, with the ultimate goal of developing a robust approach for obtaining single source STR profiles from compromised biological mixtures.

Abstract

Findings are reported for white-blood-cell characterization and an antibody hybridization survey in dried samples. Other findings address the separation of two-person dried blood mixtures, the separation of two-person blood-buccal cell mixtures, and the auto-fluorescence profiling of forensically relevant cell types. A discussion of the implications of the findings for criminal justice policy and practice in the United States notes that they can impact the forensic community by adapting a technique widely used in biomedical research to the demands of forensic casework. Cell mixtures are noted to be a widespread problem in forensic laboratories, which often leads to inconclusive results and loss of evidence. To avoid complicated DNA interpretation methodologies, there is a need for techniques that physically separate cells from different contributors prior to DNA extraction. Since most samples examined in forensic casework are compromised to some extent, the research reported here will be instrumental in bridging the gap between the demonstrated utility of fluorescent activated cell sorter (FACS) and its relevance for forensic casework. Also, in advancing the understanding of the mechanics of degraded cells, this research opens a fertile field for the study of forensic applications of FACS. In addition, it also provides valuable information that can be applied for the improvement of results in other areas of DNA analysis, such as determination of cell type and the age of biological evidence.