Forensic genetics problems and solutions

CODIS was an outgrowth of the Technical Working Group on DNA Analysis Methods (TWGDAM, now SWGDAM) which developed guidelines for standards of practice in the United States and Canadian crime laboratories as they began DNA testing in the late 1980s. TWGDAM was sponsored by the FBI Laboratory which hosted several scientific meetings a year at Quantico, Virginia, to accelerate development of laboratory guidelines and peer-reviewed papers to support forensic DNA testing which was, to some, an unproven forensic tool. TWGDAM completed a white paper in October 1989 which provided conceptual and operational concepts for a Combined DNA Index System to share DNA profiles among crime laboratories similarly to automated fingerprint identification which had become commonplace in law enforcement during the 1980s. The FBI Laboratory began a pilot project with six state and local crime laboratories to develop software to support each laboratory’s DNA testing and allow sharing of DNA profiles with other crime laboratories. The DNA Identification Act of 1994 (42 . §14132) authorized the establishment of this National DNA Index. The DNA Act specifies the categories of data that may be maintained in NDIS (convicted offenders, arrestees, legal, detainees, forensic (casework), unidentified human remains, missing persons and relatives of missing persons) as well as requirements for participating laboratories relating to quality assurance, privacy and expungement. The DNA Identification Act, §14132(b)(3), specifies the access requirements for the DNA samples and records “maintained by federal, state, and local criminal justice agencies (or the Secretary of Defense in accordance with section 1565 of title 10, United States Code)” …and “allows disclosure of stored DNA samples and DNA analyses only— (A) to criminal justice agencies for law enforcement identification purposes; (B) in judicial proceedings, if otherwise admissible pursuant to applicable statutes or rules; (C) for criminal defense purposes, to a defendant, who shall have access to samples and analyses performed in connection with the case in which such defendant is charged; or (D) if personally identifiable information is removed, for a population statistics database, for identification research and protocol development purposes, or for quality control purposes.” Federal law requires that laboratories submitting DNA data to NDIS are accredited by a nonprofit professional association of persons actively engaged in forensic science that is nationally recognized within the forensic science community. The following entities have been determined to satisfy this definition: the American Society of Crime Laboratory Directors/Laboratory Accreditation Board (ASCLD/LAB) and Forensic Quality Services (ANSI-ASQ National Accreditation Board FQS). Scientific basis Identification using CODIS relies on short tandem repeats (STR) that are present in the human genome. These two to six nucleotides are highly susceptible to copy-number variation loci can be amplified using PCR, and analyzed by gel electrophoresis. The size of the DNA fragment is proportional to the number of repeats. Therefore, the number of repeats can be quantified, and the combination of repeats at each locus provides a distinctive genetic fingerprint for each individual. #DNATesting #CODIS #FBI #DNA #forensic #ShortTandemRepeats #pcr #GelElectrophoresis