If you have any exposure to the media, you probably already know that the paternity of Anna-Nicole Smith’s child has been determined, thus influencing the fate of the infant and its half-billion inheritance. The identity of the father — not the man Smith was living with — was determined by a DNA test. DNA paternity tests are extremely accurate, as evidenced by the fact that the various claimants to the child immediately agreed with the result (although her grandmother is still fighting for custody).
DNA tests can play an important role in background checks as well. Blood, skin, and various bodily fluids all contain deoxyribonucleic acid (DNA), which uniquely identifies the individual to whom it belongs. If any of these are left behind at a crime scene, they can be used to identify — or clear — a suspect. DNA sequences can be stored in computer-friendly form, making it possible to search milliions of entries. Since many crimes are committed by repeat offenders, it was decided to begin collecting DNA sample from certain convicts. In 1990, the FBI began the Combined DNA Index System (CODIS) with 14 states. The goal was to provide a national DNA index that law enforcement could use. It has since expanded to include all 50 states and the U.S. Army. The index contains over 4 million entries from offenders. Most significantly, it has provided 45,400 matches, which have assisted 46,300 investigations.
As one might expect, the project has inspired some privacy concerns. It is not a full database — personal identifiers such as names are not stored along with the DNA sample. A pointer to the original information is used instead. When a potential match is found, it is considered a “candidate” until a Qualified DNA Analyst confirms the match. Still, the public approval of the DNA index is very strong, and its use has expanded. Originally designed for sex offenders, the index contributions are governed by state law, and typically include a much broader set of convicted criminals. Some states even include individuals who have been arrested, but not necessarily convicted. On the usage side, the index is now also employed for missing or unidentified persons.
Although the index may inspire thoughts of Gattaca, it is very easy to understand its popularity. It can provide the key for many criminal cases that might otherwise go unsolved.