"What is DNA What is a DNA profile"
What is DNA DNA, deoxyribonucleic acid, is found in every cell with a nucleus in all living things. DNA consists of a chain of four different chemical compounds (adenine, guanine, cytosine, and thymine) that appear in pairs known as base pairs. The unique order in which a person’s base pair are arranged determines physical characteristic like sex and hair color, as well as other genetic traits such as predisposition to certain diseases. Some segments of DNA are inactive, contributing nothing to a person’s physical traits. These segments are sometimes referred to as “junk” DNA. What is a DNA profile In the criminal justice context1 , “DNA profile” refers to a numerical representation of 13 specific points (“loci”) on a person’s “junk” (that is, inative) DNA which has been developed by a criminal laboratory for the purpose os solving crimes. Also known as a “DNA identification profile” or “DNA fingerprint,” a profile is a unique identifier that allows law enforcement to compare evidence from a crime scene to other crime scenes or to known individuals, just as a fingerprint does. A profile can be developed from a biological sample provided by a known person, or from biological material left behind at the scene of a crime (such as blood, semen, skin cells, and saliva). 1 Hospital laboratories of other private laboratories may analyze other loci which do code for physical traits, but government-run crime laboratories in New York never perform this type of analysis, and are not equipped or able to do such testing. The 13 loci that are analyzed in order to create a profile were chosen by the FBI and the science community for two reasons: 1) Each one varies a great deal between individuals. By analyzing the same 13 loci of DNA from crime scene evidence and people, government crime laboratories across the United States create standardized profiles which may be compared to one another. A “hit” indicating that two samples match and come from one person occurs when the loci from the 13 regions are the same. 2) They do not reflect personal traits. A single person’s DNA contains approximately three billion base pairs. A DNA profile, which amounts to nothing more than a string of 26 numbers, catalogues less than one-millionth of all the information contained in a person’s DNA. Only this information, which is not useful for indentifying any type of mental or physical trait, tendency or disease, is stored in a state or local data bank. Profiles Can: Profiles Cannot: Be used to compare DNA samples to Reveal a person’s physical traits one another Identify genetic diseases carried by a person What is a local crime laboratory? A local crime laboratory is a government-operated laboratory that performs forensic DNA testing on biological samples in a criminal investigation or proceeding. Local crime labs can develop DNA profiles from samples obtained from known persons involved in an investigation (i.e., suspects, victims, and persons who are not suspects but whose biological material is likely to be found at the scene of the crime, such as a homeowner whose house has been burgled2 ) or from biological evidence left behind at crime scenes. 2 The last category is often referred to as “elimination samples.” As explained above, when a lab creates a “DNA profile” it generates a list of numbers which is only useful for comparing one profile to another; the numbers are not useful for identifying any type of metal or physical trait, tendency or disease. Local crime laboratories are technologically incapable of performing tests which go beyond the analysis of the 13 loci needed to create a DNA profile (for example, they cannot test for genetic disease). There are seven local crime laboratories in New York State: those run by the counties of Nassau, Monroe, Suffolk, Erie, Onondaga, and Westchester, and the lab run by the New York City Office of the Chief Medical Examiner. Local crime laboratories are sometimes referred to as Local DNA Index System (“LDIS”) labs. (Note: State DNA Index System labs are called “SDIS” labs, and the National DNA Index System is called “NDIS.”) The New York State Police lab also has a crime laboratory which functions both as an LDIS site and as the “SDIS site” for New York State. As the SDIS site, in addition to analyzing evidence related to crime scene and suspect investigation, the State Police lab also processes samples from convicted offenders for the statewide data bank. As such, the State Police lab is the only laboratory that will face an increased workload if the convicted offender data bank is expanded to include all misdemeanants and/or some arrestees. Local Crime Labs Can: Local Crime Labs Cannot: Extract DNA profiles from biological Perform any tests on biological material materials left at a crime scene beyond the development of a basic Extract DNA profiles from persons DNA profile whose identity is known to Disclose DNA records or test results to investigators (suspect, victims, people unauthorized parties, under penalty of a giving elimination samples) felony Use DNA records or test results for unauthorized purposes, under penalty of a felony Analyze samples taken from convicted offenders for inclusion in the statewide data bank. The only laboratory authorized to perform this function in New York is the State Police laboratory. How do local crime laboratories develop a DNA profile from a biological sample? LDIS labs are “accredited” under national and state standards and operate under the same stringent standards as SDIS and NDIS and develop profiles. The local crime labs, like all accredited labs in the U.S., use a method of DNA analysis called Polymerase Chain Reaction – Short Tandem Repeat Testing, or PCR-STR. The test measures the number of times certain chemical combinations are repeated at each of the 13 locations (i.e., loci) that are tested in every DNA sample analyzed. What kinds or regulations do local crime laboratories have to follow? The Forensic Science Commission (“FSC”), established by Article 49-B of the Executive Law, has oversight over all forensic laboratories run by state and local governments in New York State. Accreditation of a forensic DNA laboratory is granted through the DNA Subcommittee of the FSC. The Subcommittee also advises the FSC on any matter related to the implementation of science controls and quality assurance procedures for the performance of forensic DNA analysis. To become accredited, DNA laboratories must demonstrate compliance with standards set by both the American Society of Crime Laboratory Directors/Laboratory Accreditation Board (ASCLD/LAB) and the FBI. The labs must be-accredited by ASCLD/LAB every five years, and undergo a full inspection in the middle of each 5-year cycle. Each of the 8 local crime laboratories has been accredited by the DNA Subcommittee of New York’s Forensic Science Commission. What does the government do with the original biological samples (a.k.a. “cheek swabs”) taken from convicted offenders or personal involved in criminal investigations? Samples are placed in a controlled environment to preserve their integrity should retesting be required for technological, quality control, or prosecutorial/defense purposes. Retained Biological Samples are used Retained Biological Samples Cannot For: be Used For: Ensuring quality control of laboratory Further tests which would provide non- test law enforcement-related information Re-testing if technology changes (as (such as details regarding the health, previously happened in New York in physical traits, ect. of a person) the 1990s) Additional testing by the defense (for example, a suspect sample that excludes the suspect may be needed for trial of a defendant who claims the original suspect is the culprit) How can a person who has been ruled out as the perpetrator in a case get his or her genetic information and biological materials back from the government? If a person who submitted DNA voluntarily or under warrant or court order is subsequently acquitted, not prosecuted, or has his or her conviction overturned, he or she may, per Executive Law §995-c(9)(b), petition the court for expunction of all DNA records, analyses, samples, and related documents. The original sample must be destroyed and the records must be returned to him or her. What kind of databases of DNA information does the government keep? The state places the DNA profiles of persons who have been convicted of certain designated offenses in a searchable database which is linked to the FBI’s national DNA database. Profiles of unidentified perpetrators developed from crime scene evidence are periodically compared to this permanent index of known offenders. The crime scene data banks and convicted offender data banks are collectively known as “CODIS” – the Combined DNA Index System. LDIS, SDIS, and NDIS are components of CODIS. Some local crime laboratories place DNA profiles of persons who have been identified to them as “suspects” by police into searchable databases. (The New York City database is known as “Linkage.”) Local crime laboratories never place “elimination” (like the aforementioned homeowner whose house was burgled or “victim” samples into these or any other databases. →A local database of suspect profiles acts as an “early warning system” for local law enforcement. Investigators with access to a local suspect data bank can gain a two-week investigative advantage, because while profiles can be uploaded to a local database at any time, the state database only accepts new profiles new profiles every other week. Local crime laboratories also maintain other DNA databases containing profiles of known persons which were not taken in connection with any criminal investigation. These non-suspect databases are not part of CODIS and the profiles are never uploaded for inclusion in CODIS database. They are nonetheless essential to the work performed by local crime labs. For example, labs may index the DNA profiles of their own employees to guard against contamination in the lab, or index profiles from mass disaster victims and their family members in order to facilitate the identification of human remains. How is the information in these databases secured? Pursuant to 9 NYCRR 6192.5, the state data bank has a server containing the data bank; software and hardware designed to prevent unauthorized electronic access to DNA records; the creation of an electronic audit trail when records are entered or edited; and annual audits to ensure that no illegal disclosures of DNA records have taken place.