DNA Unit
The DNA Unit of the Delaware Division of Forensic Science (DFS) conducts forensic DNA testing of biological materials associated with official investigations including sexual assaults, homicides, firearm possession cases, and property crimes. The DNA Unit consists of 2 sections: Casework Section and CODIS Database Section. Both sections of the DNA Unit utilize the latest in Polymerase Chain Reaction (PCR) technology to assist law enforcement in cases involving DNA evidence.
Additional information regarding the DNA Unit may be found in the Division of Forensic Science Annual Report.
Casework Section
The Forensic DNA Analysts in the Casework Unit are responsible for examination of evidence, performing preliminary tests to determine the type of biological fluid on an item of evidence, extracting DNA, analyzing/interpreting data, reporting DNA results, and testifying to those results in court.
All Forensic DNA Analysts in the DNA Unit must have at a minimum a BS/BA degree in a biology, chemistry, or forensic science including coursework in genetics, biochemistry, statistics, and molecular biology.
A new graduate hired as a Forensic DNA Analyst receives training at DFS with qualified Analysts using established protocols. The training lasts at a minimum of six months. The goal of DNA Section is to ensure the quality, integrity, and accuracy of the DNA typing data and its presentation.
Case Submission
DNA evidence is any biological evidence associated with the crime or crime scene. A DNA reference is either a blood or buccal sample from the victim, suspect, relative of the victim or suspect, or some other person of interest related to a case. Before a case is accepted, the submitting law enforcement officer and/or the assigned Attorney (Deputy Attorney General or Assistant Public Defender) must complete the DNA Evidence Submission Form. The form must be downloaded and emailed to the DNA Technical Leader for approval.
Once the submission form is reviewed and the case is accepted, the DNA Technical Leader will notify the Forensic Evidence Specialists. They will schedule an appointment with the officer to transfer the evidence and reference items to the DFS DNA Unit. Evidence and reference items should be submitted at the same time unless otherwise approved by the DNA Technical Leader or designee.
Laboratory staff will not re-analyze evidence that has been previously analyzed by another Laboratory. Exceptions may be granted by the Director and require written correspondence from the respective laboratory or an appropriate representative of the court.
When applicable, elimination reference samples shall be submitted by the law enforcement agency. Elimination reference samples are needed when a person may have handled the item of evidence prior to or after the incident. An example of when an elimination sample is needed would be a case involving a stolen vehicle. An elimination sample would be needed from the owner of the vehicle. If elimination samples are not submitted, the DFS DNA Unit will request such samples. If the elimination sample is received after a DNA profile has been entered into CODIS and it is determined that the DNA profile of the elimination sample matches that of the associated forensic unknown, the forensic unknown DNA profile shall be removed from CODIS. The removal of a DNA profile will be documented. The law enforcement agency and DOJ will be notified.
Presumed reference samples, such as toothbrush, cup, hairbrush, etc., from an individual will need approval from the Technical Leader before they can be used for comparison.
CODIS Section
CODIS stands for Combined DNA Index System. There are two levels of CODIS in Delaware: the National DNA Index System (NDIS) and the State DNA Index System (SDIS). NDIS is managed by the FBI and SDIS is managed by our CODIS Unit. These agencies work in collaboration to track and manage the hits in the database. This database includes DNA profiles of offenders, profiles developed from evidence in solved and unsolved cases, and profiles from missing persons and unidentified human remains. The profiles are kept in the CODIS database indefinitely.
Prior to January 2017, the FBI required DNA profiles submitted for CODIS entry to include the following 13 loci or locations, called Core Loci (shaded area). Amelogenin is used for gender determination.
In January 2017, the FBI expanded the number of required loci from the original 13 core loci to 20 loci.
Forensic DNA Analysts in the CODIS Section at the Delaware Division of Forensic Science (DFS) are responsible for obtaining and analyzing DNA profiles for convicted felons in the state according to Delaware State Statute. The program was initiated in Delaware in 1994 when legislation was passed approving the collection of blood or buccal samples from qualifying individuals.
At the DFS, the CODIS section works closely with the casework section. Evidentiary profiles developed by the DNA casework section may be eligible for CODIS entry and searched at SDIS and/or NDIS against DNA profiles obtained from other cases and offenders.
To be entered at SDIS:
- An evidentiary profile, at a minimum, must have 7 of the original core loci and an MME1 greater than 1 e+03.
- A convicted offender profile, at a minimum, must have 7 of the original core loci.
To be entered at NDIS:
- An evidentiary profile, at a minimum, must have 8 of the original core loci with an MME1 or MRE2 greater than 1 e+07. If all 13 of the original core loci are present in a single source evidentiary profile, then no MME1 or MRE2 is required.
- A convicted offender profile, at a minimum, must have 13 of the original core loci.
- Profiles associated with missing person/unidentified remains are entered at NDIS.
Evidentiary profiles and convicted offender profiles are searched in SDIS twice a week, at a minimum. Evidentiary profiles and offender profiles (13 loci) are searched in NDIS daily. Evidentiary profiles from unsolved homicide, sexual assault, kidnapping, and/or terroristic threat case(s) consisting of 13 of the original core loci may be searched multiple times throughout the day. The DNA Laboratory will contact the police department to obtain the necessary information if an evidentiary profile meets the criteria to be searched multiple times throughout the day. Missing persons or unidentified remains profiles are searched in NDIS monthly, at minimum. Any profile searched at NDIS is also searched at SDIS.
Missing Persons, Unidentified Human Remains Cases, and Family Reference Material
Any missing persons or unidentified human remains case will follow the same process for case acceptance as noted above. DNA reference sample(s) from family members will require a DNA Sample Collection Consent form to be completed prior to uploading that DNA profile into CODIS.
MME1 = Moderate Match Estimation; requirement for CODIS only; the estimation that a moderate stringency match may occur in the CODIS database.
MRE2 = Match Rarity Estimation; requirement for CODIS only; the estimation that a moderate stringency match may occur. Allows analysts to limit match results based on the DNA profile in the CODIS database.
