DNA Analysis and CODIS Searching

Family members of missing persons are asked to provide DNA samples that are profiled and uploaded to the National DNA Index System, in an effort to locate missing persons through DNA database searches. These samples, known as Family Reference Samples, are voluntary DNA submissions that are used only in the search for a missing loved one.

The National DNA Index System, or NDIS, is part of the Combined DNA Index System (CODIS). NDIS contains profiles contributed from federal, state, and local participating DNA laboratories across the country. The DNA profiles uploaded to NDIS are organized into indices, such as the Convicted Offender index. Direct profiles from a missing person, which are derived from items such as toothbrushes or tissue samples, are uploaded to the Missing Person index of CODIS. Profiles for unidentified decedents are uploaded to the Unidentified Human index of CODIS. Profiles from family members are uploaded to the Relatives of Missing Persons Index.

Individuals who provide Family Reference Samples in an effort to locate a missing loved one will have their DNA profiles uploaded to the Relatives of Missing Persons index of CODIS, which is searched only against the Unidentified Human index of CODIS. Family reference profiles are notsearched against any of the criminal indices, such as those containing profiles of convicted offenders or unknown suspects.

A family member cannot collect or submit personal DNA samples for profiling and upload to CODIS. All samples must be collected by criminal justice personnel who verify the DNA donors' identity, collect the samples, and contact their assigned NamUs Regional Program Specialist to request testing. See Contact for Regional Program Specialists.

A family reference sample must be collected by a law enforcement officer, medical examiner, coroner, or other medicolegal investigator. All family reference sample requests must be submitted with a completed DNA Sample Collection Form.

First-degree relatives (parent, full sibling, or child) are most beneficial for Short Tandem Repeat (STR) DNA comparisons. Second-degree relatives (half-sibling, aunt, uncle, grandparent, etc.) may be useful for limited STR comparisons, as well as for Y-STR or mitochondrial DNA comparisons; however, first-order relatives are always preferred when available.

In order for proper searching to take place in CODIS, and for potential associations to be identified, DNA profiles from at least two family members should be collected for every missing person case. If no first-degree relatives are available, additional family reference collections may be required. If you have questions regarding DNA collections in a particular case, contact your NamUs Regional Program Specialist.

It is important to note on the DNA submission paperwork if siblings share only one parent, and if they are half-siblings, it is important to note if they are paternally or maternally related, as this information will allow the laboratory to ensure that proper searching takes place within CODIS. For instance, half-siblings who share the same mother will be utilized as both a nuclear and mitochondrial DNA reference.

Once your assigned Regional Program Specialist (RPS) has approved your case for DNA analysis, and you have submitted your samples to the assigned laboratory, the expected turn-around-time is 120 calendar days.  However, factors may impact this timeline, including additional testing required due to sample type and quality. 

Yes, we are still able to process a sample from a deceased individual as long as the obtaining officer completes and signs the Affidavit of Voluntary Collection. This form can be obtained by contacting the Regional Program Specialist assigned to the case.