The Combined DNA Index System (CODIS) is the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...

national DNA database A DNA database or DNA databank is a database of DNA profiles which can be used in the analysis of genetic diseases, genetic fingerprinting for criminology, or genetic genealogy. DNA databases may be public or private, the largest ones being nat ...

created and maintained by the

Federal Bureau of Investigation The Federal Bureau of Investigation (FBI) is the domestic intelligence and security service of the United States and its principal federal law enforcement agency. Operating under the jurisdiction of the United States Department of Justice ...

. CODIS consists of three levels of information; Local DNA Index Systems (LDIS) where DNA profiles originate, State DNA Index Systems (SDIS) which allows for laboratories within states to share information, and the National DNA Index System (NDIS) which allows states to compare DNA information with one another. The CODIS software contains multiple different databases depending on the type of information being searched against. Examples of these databases include, missing persons, convicted offenders, and forensic samples collected from crime scenes. Each state, and the federal system, has different laws for collection, upload, and analysis of information contained within their database. However, for privacy reasons, the CODIS database does not contain any personal identifying information, such as the name associated with the DNA profile. The uploading agency is notified of any hits to their samples and are tasked with the dissemination of personal information pursuant to their laws.

Establishment

The creation of a national DNA database within the U.S. was first mentioned by the Technical Working Group on DNA Analysis Methods (TWGDAM) in 1989. In 1990, the FBI began a pilot DNA databasing program with 14 state and local laboratories. In 1994, Congress passed the DNA Identification Act which authorized the FBI to create a national DNA database of convicted offenders as well as separate databases for missing persons and forensic samples collected from crime scenes. The Act also required that laboratories participating in the CODIS program maintain

accreditation Accreditation is the independent, third-party evaluation of a conformity assessment body (such as certification body, inspection body or laboratory) against recognised standards, conveying formal demonstration of its impartiality and competence to ...

from an independent nonprofit organization that is actively involved in the forensic fields and that scientists processing DNA samples for submission into CODIS maintain proficiency and are routinely tested to ensure the quality of the profiles being uploaded into the database. The national level of CODIS (NDIS) was implemented in October 1998. Today, all 50 states, the

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, federal law enforcement, the Army Laboratory, and Puerto Rico participate in the national sharing of DNA profiles.

Database structure

The CODIS database contains several different indexes for the storage of DNA profile information. For assistance in criminal investigations three indexes exist: the offender index, which contains DNA profiles of those convicted of crimes; the arrestee index, which contains profiles of those arrested of crimes pursuant to the laws of the particular state; and the forensic index, which contains profiles collected from a crime scene. Additional indexes, such as the unidentified human remain index, the missing persons index, and the biological relatives of missing persons index, are used to assist in identifying missing persons. Specialty indexes also exist for other specimens that do not fall into the other categories. These indexes include the staff index, for profiles of employees who work with the samples, and the multi-allelic offender index, for single-source samples that have three or more

allele An allele (, ; ; modern formation from Greek ἄλλος ''állos'', "other") is a variation of the same sequence of nucleotides at the same place on a long DNA molecule, as described in leading textbooks on genetics and evolution. ::"The chrom ...

s at two or more loci.

Non-criminal indexes

While CODIS is generally used for linking crimes to other crimes and potentially to suspects there are non-criminal portions of the database such as the missing person indexes. The National Missing Person DNA Database, also known as CODIS(mp), is maintained by the FBI at the NDIS level of CODIS allowing all states to share information with one another. Created in 2000 using the existing CODIS infrastructure, this section of the database is designed to help identify human remains by collecting and storing DNA information on the missing or the relatives of missing individuals. Unidentified remains are processed for DNA by the

University of North Texas Center for Human Identification The University of North Texas Center for Human Identification is a national resource for the identification of missing and unidentified persons at the University of North Texas Health Science Center. UNTCHI combines the services of a forensic DNA l ...

which is funded by the

National Institute of Justice The National Institute of Justice (NIJ) is the research, development and evaluation agency of the United States Department of Justice. NIJ, along with the Bureau of Justice Statistics (BJS), Bureau of Justice Assistance (BJA), Office of Juvenil ...

. Nuclear,

Y-STR A Y-STR is a short tandem repeat (STR) on the Y-chromosome. Y-STRs are often used in forensics, paternity, and genealogical DNA testing. Y-STRs are taken specifically from the male Y chromosome. These Y-STRs provide a weaker analysis than autoso ...

(for males only), and mitochondrial analysis can be performed on both unknown remains and on known relatives in order to maximize the chance of identifying remains.

Statistics

, NDIS contained more than 14 million offender profiles, more than 4 million arrestee profiles and more than one million forensic profiles. The effectiveness of CODIS is measured by the number of investigations aided through database hits. , CODIS had aided in over 520 thousand investigations and produced more than 530 thousand hits. Each state has their own SDIS database and each state can set their own inclusionary standards that can be less strict than the national level. For this reason, a number of profiles that are present in state level databases are not in the national database and are not routinely searched across state lines.

Scientific basis

The bulk of identifications using CODIS rely on short tandem repeats ( STRs) that are scattered throughout the human genome and on statistics that are used to calculate the rarity of that specific profile in the population. STRs are a type of copy-number variation and comprise a sequence of

nucleotide Nucleotides are organic molecules consisting of a nucleoside and a phosphate. They serve as monomeric units of the nucleic acid polymers – deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), both of which are essential biomolecu ...

base pair A base pair (bp) is a fundamental unit of double-stranded nucleic acids consisting of two nucleobases bound to each other by hydrogen bonds. They form the building blocks of the DNA double helix and contribute to the folded structure of both D ...

s that is repeated over and over again. At each location tested during DNA analysis, also known as a locus (plural loci), a person has two sets of repeats, one from the father and one from the mother. Each set is measured and the number of repeat copies is recorded. If both strands, inherited from the parents, contain the same number of repeats at that locus the person is said to be

homozygous Zygosity (the noun, zygote, is from the Greek "yoked," from "yoke") () is the degree to which both copies of a chromosome or gene have the same genetic sequence. In other words, it is the degree of similarity of the alleles in an organism. Mo ...

at that locus. If the repeat numbers differ they are said to be

heterozygous Zygosity (the noun, zygote, is from the Greek "yoked," from "yoke") () is the degree to which both copies of a chromosome or gene have the same genetic sequence. In other words, it is the degree of similarity of the alleles in an organism. ...

. Every possible difference at a locus is an allele. This repeat determination is performed across a number of loci and the repeat values is the DNA profile that is uploaded to CODIS. As of January 1, 2017, requirements for upload to national level for known offender profiles is 20 loci. Alternatively, CODIS allows for the upload of

mitochondrial DNA Mitochondrial DNA (mtDNA or mDNA) is the DNA located in mitochondria, cellular organelles within eukaryotic cells that convert chemical energy from food into a form that cells can use, such as adenosine triphosphate (ATP). Mitochondrial D ...

(mtDNA) information into the missing persons indexes. Since mtDNA is passed down from mother to offspring it can be used to link remains to still living relatives who have the same mtDNA.

Loci

Prior to January 1, 2017, the national level of CODIS required that known offender profiles have a set of 13 loci called the "CODIS core". Since then, the requirement has expanded to include seven additional loci. Partial profiles are also allowed in CODIS in separate indexes and are common in crime scene samples that are degraded or are mixtures of multiple individuals. Upload of these profiles to the national level of CODIS requires at least eight of the core loci to be present as well as a profile rarity of 1 in 10 million (calculated using population statistics). Loci that fall within a

gene In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...

are named after the gene. For example, TPOX, is named after the human thyroid peroxidase gene. Loci that do not fall within genes are given a standard naming scheme for uniformity. These loci are named D + the

chromosome A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins ar ...

the locus is on + S + the order in which the location on that chromosome was described. For example, D3S1358 is on the third chromosome and is the 1358th location described. The CODIS core are listed below; loci with asterisks are the new core and were added to the list in January 2017. The loci used in CODIS were chosen because they are in regions of noncoding DNA, sections that do not code for proteins. These sections should not be able to tell investigators any additional information about the person such as their hair or eye color, or their race. However, new advancements in the understanding of genetic markers and ancestry have indicated that the CODIS loci may contain

phenotypic In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology or physical form and structure, its developmental processes, its biochemical and physiological pr ...

information.

International use

While the U.S. database is not directly connected to any other country, the underlying CODIS software is used by other agencies around the world. , the CODIS software is used by 90 international laboratories in 50 countries. International police agencies that want to search the U.S. database can submit a request to the FBI for review. If the request is reasonable and the profile being searched would meet inclusionary standards for a U.S. profile, such as number of loci, the request can be searched at the national level or forwarded to any states where reasonable suspicion exists that they may be present in that level of the database.

Controversies

Arrestee collection

The original purpose of the CODIS database was to build upon the

sex offender registry A sex offender registry is a system in various countries designed to allow government authorities to keep track of the activities of sex offenders, including those who have completed their criminal sentences. In some jurisdictions, registration ...

through the DNA collection of convicted sex offenders. Over time, that has expanded. Currently, all 50 states collect DNA from those convicted of

felonies A felony is traditionally considered a crime of high seriousness, whereas a misdemeanor is regarded as less serious. The term "felony" originated from English common law (from the French medieval word "félonie") to describe an offense that resu ...

. A number of states also collect samples from juveniles as well as those who are arrested, but not yet convicted, of a crime. Note that even in states which limit collection of DNA retained in the state database only to those convicted of a crime, local databases, such as the forensic laboratory operated by New York City's Office of Chief Medical Examiner, may collect DNA samples of arrestees who have not been convicted. The collection of arrestee samples raised constitutional issues, specifically the Fourth Amendment prohibiting unreasonable

search and seizure Search and seizure is a procedure used in many civil law and common law legal systems by which police or other authorities and their agents, who, suspecting that a crime has been committed, commence a search of a person's property and confisca ...

. It was argued that the collection of DNA from those that were not convicted of a crime, without an explicit order to collect, was considered a warrantless search and therefore unlawful. In 2013, the United States Supreme Court ruled in

Maryland v. King In ''Maryland v. King'', 569 U.S. 435 (2013), the United States Supreme Court decided that a cheek swab of an arrestee's DNA is comparable to fingerprinting and therefore, a legal police booking procedure that is reasonable under the Fourth Ame ...

that the collection of DNA from those arrested for a crime, but not yet convicted, is part of the police booking procedure and is reasonable when that collection is used for identification purposes.

Familial searching

The inheritance pattern of some DNA means that close relatives share a higher percentage of alleles between each other than with other, random, members of society. This allows for the searching of close matches within CODIS when an exact match is not found. By focusing on close matches, investigators can potentially find a close relative whose profile is in CODIS narrowing their search to one specific family. Familial searching has led to several convictions after the exhaustion of all other leads including the Grim Sleeper serial killer. This practice also raised Fourth Amendment challenges as the individual who ends up being charged with a crime was only implicated because someone else's DNA was in the CODIS database. , twelve states have approved the use of familial searching in CODIS.

References

External links

CODIS page on FBI.gov
Accessed May 27, 2015. *

. ACLU. March 1, 1999.
A Not So Perfect Match
CBS, 2007 *
DNA didn't prove anything, as it only had five points out of 13
Juror Explains Verdict In Double Murder". November 13, 2008. {{DEFAULTSORT:Combined Dna Index System Biometrics DNA Federal Bureau of Investigation Law enforcement databases in the United States Identity documents of the United States National DNA databases Sex offender registration Forensic databases Biological databases 1998 introductions