Standardization of Regulations
Standardization of Regulations
Forensic work is performed in laboratories worldwide for criminal casework and development of DNA databases. Laboratories often have their own particular methods and protocols for performing their analyses, which may present problems when it comes to the final evaluation of the data by a third party, especially when matters of guilt or innocence are at stake. Laboratories must demonstrate that the results they have obtained are reliable and justifiable in court. For this reason, standardized methods and techniques have been generated by governing forensic bodies in order to provide a common means by which forensic laboratories can work. In addition, particular DNA loci (the locations of selected genes on a chromosome ) have been chosen that represent the basis for the creation of standard DNA databases. Standardized methods and DNA profile databases have revolutionized the manner in which crimes are solved.
Standards and guidelines are extremely beneficial to forensic laboratories as demonstration of conformity establishes a high level of quality assurance and competence within the laboratory. This is especially important when forensic evidence is presented in a court of law where it is subjected to the utmost scrutiny and skepticism. Furthermore, because of the nature of the investigations, most forensic DNA work is processed under strict confidentiality. Utilization of a defined standard protocol minimizes both the need to review confidential records and the potential non-inclusion of evidence where methods have been questioned.
Guidelines and standardized methods utilized by forensic labs are created by several different governing bodies in the forensic industry. For example, the Federal Bureau of Investigation (FBI ) in the United States, the European Network of Forensic Science Institutes (ENFSI), and the International Standards Organization (ISO) are a few of the groups that work to ensure validated methods are followed for forensic analyses. The quality assurance guidelines set forth in documentation provided by the aforementioned groups are composed of a variety of specific requirements.
All forensic laboratories must maintain a documented system in which they demonstrate their level of quality of all components of a standard program. These components include much more than guidelines for scientific data evaluation. Specific guidelines are provided on the organization and management of the lab; training level and method of training staff; facilities; control of evidence, including complete documentation of the chain of custody ; the methods, analysis, and validation process; equipment maintenance; review process; proficiency testing; corrective action; and audits.
Standards for DNA testing are constantly being monitored and reviewed. Within each of the organizations and governing bodies, there is a segment of people or expert working group, who meet specifically to ensure that the level of the standards and guidelines are high in all forensic laboratories. These groups include the Scientific Working Group on DNA Analysis Methods (SWGDAM) of the FBI and the DNA Profile Monitoring Expert Group (DNA MEG) of Interpol .
Three major DNA databases exist worldwide, each of which hold and catalogue DNA profiles. Each profile consists of the DNA sequence of a particular set of standard loci. The profiles contained in the databases are based on STRs, or short tandem repeats of DNA sequences that are obtained using PCR (polymerase chain reaction) to amplify the specific regions of DNA. Although these loci exist in the same place on the chromosome of all humans, the DNA sequence of the region is highly variable, such that when several are combined together, there is an extremely high probability that a particular combination can only be associated with a single person. These databases are maintained by Interpol (ISSOL), the FBI (CODIS ), and ENFSI and contain several common loci. The FBI's CODIS database contains the most loci, at 13 per profile.
CODIS, ISSOL, and ENFSI databases have greatly increased the ability to solve violent crime on a worldwide level. Because they share loci, it is possible to link offenders to existing samples not only within a single country, but internationally. Two aspects exist to each database, one contains DNA profiles collected from evidence found at crime scenes and the second contains DNA profiles of convicted offenders. Initially, most countries only collected samples from convicted sex offenders or perpetrators of other violent crimes. However, as even small offenders tend toward a pattern of crime, the value of retaining profiles of all convicted offenders has been recognized. Thus, investigators can now compare DNA samples obtained at crime scenes and potentially obtain a match from the offender database.
see also CODIS: Combined DNA Index System; DNA; DNA profiling; European Network of Forensic Science Institutes; STR (short tandem repeat) analysis.