Combined DNA Index System (CODIS)

The Combined DNA Index System, or CODIS, is a database that stores DNA profiles of individuals who have been arrested or convicted of certain crimes. It was developed in the 1990s as a way to help law enforcement agencies solve crimes using DNA evidence.

Before CODIS, DNA profiling was a relatively new field and there was no standardized system for storing and sharing DNA profiles. This made it difficult for law enforcement agencies to compare DNA evidence from different cases and to identify suspects.

CODIS was designed to address these challenges by creating a centralized database that could store DNA profiles from different law enforcement agencies. It uses a specific set of markers, called STRs (short tandem repeats), to create a unique DNA profile for each individual. These profiles can then be compared to DNA evidence from crime scenes to identify suspects or to link cases that may have been committed by the same person.

Since its inception, CODIS has become an important tool for law enforcement agencies around the world. It has helped to solve countless crimes and has led to the conviction of many dangerous criminals. Today, CODIS is used by law enforcement agencies in over 50 countries and is considered to be one of the most powerful tools in the fight against crime.

CODIS 13

CODIS uses 13 specific STR markers, known as the “CODIS core loci,” to create DNA profiles. These markers are located in non-coding regions of the DNA and do not have any known biological function. They are chosen because they are highly variable and can be easily identified using laboratory techniques.

The 13 short tandem repeat (STR) markers used by the Combined DNA Index System (CODIS) are known as the “CODIS core loci.” They are:

  1. D3S1358
  2. TH01
  3. D21S11
  4. D18S51
  5. D5S818
  6. D13S317
  7. D7S820
  8. CSF1PO
  9. D16S539
  10. Penta E
  11. Penta D
  12. vWA
  13. TPOX

In addition to the 13 CODIS core loci, some CODIS laboratories may use an additional 4 STR markers, known as the “CODIS expansion loci.” These markers are also located in non-coding regions of the DNA and are highly variable, but they are not used by all CODIS laboratories.

The CODIS expansion loci are:

  1. D2S1338
  2. D19S433
  3. D1S1656
  4. D2S441

Using the CODIS expansion loci in addition to the CODIS core loci can increase the discriminatory power of CODIS and may be helpful in certain cases where the 13 CODIS core loci are not sufficient to create a unique DNA profile. However, the use of the CODIS expansion loci is not universal, and their use may vary from one CODIS laboratory to another.

Ethical Concerns

There are a number of ethical concerns surrounding the Combined DNA Index System (CODIS), including:

  1. Privacy: CODIS stores DNA profiles of individuals who have been arrested or convicted of certain crimes, and there are concerns about the potential for this information to be accessed or misused. There is also a risk that innocent individuals could be wrongly implicated by a DNA match in CODIS.
  2. Discrimination: CODIS stores DNA profiles from certain groups, including individuals who have been arrested or convicted of crimes, and there are concerns that this could lead to discrimination against these groups.
  3. Informed consent: Some individuals may not fully understand the implications of providing a DNA sample or the potential uses of their DNA profile in CODIS. There may also be concerns about whether individuals have given fully informed consent to have their DNA stored in the database.
  4. Misuse of DNA evidence: There is a risk that DNA evidence could be mishandled or misused, which could lead to false convictions or wrongful arrests.

Sources & Resources

  1. “Combined DNA Index System (CODIS)” – https://www.fbi.gov/services/laboratory/biometric-analysis/codis This page, from the Federal Bureau of Investigation (FBI), provides an overview of CODIS and its role in helping law enforcement agencies solve crimes using DNA evidence.
  2. “CODIS and NDIS Fact Sheet” – https://www.nij.gov/topics/law-enforcement/forensics/dna/pages/codis-ndis-fact-sheet.aspx This page, from the National Institute of Justice (NIJ), provides a fact sheet about CODIS and the National DNA Index System (NDIS), including information about how CODIS is used and the types of DNA profiles that are stored in the database.
  3. “CODIS Core Loci” – https://www.fbi.gov/services/laboratory/biometric-analysis/codis/codis-and-ndis-fact-sheet#codis This page, from the FBI, provides a list of the 13 CODIS core loci, which are used to create DNA profiles for individuals in the CODIS database.
  4. “CODIS Expansion Loci” – https://www.fbi.gov/services/laboratory/biometric-analysis/codis/codis-and-ndis-fact-sheet#codis This page, from the FBI, provides a list of the 4 CODIS expansion loci, which are used by some CODIS laboratories in addition to the 13 CODIS core loci.
  5. “Direct-to-Consumer Genetic Testing: Ethical, Legal, and Social Implications” – https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3077437/ This page, from the National Center for Biotechnology Information (NCBI), discusses the ethical, legal, and social implications of direct-to-consumer (DTC) genetic testing, including the potential impact on CODIS.
  6. “Direct-to-Consumer Genetic Testing: A Review” – https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2796875/ This page, from the Journal of the American Medical Association (JAMA), provides a review of the ethical, legal, and social implications of DTC genetic testing, including the potential impact on CODIS.
  7. “Ethical Issues in Direct-to-Consumer Genetic Testing” – https://www.genome.gov/27564643/ethicalirect-to-consumer-genetic-testing/ This page, from the National Human Genome Research Institute (NHGRI), discusses the ethical issues surrounding DTC genetic testing, including informed consent, privacy, and discrimination, and the potential impact on CODIS.

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