Rhode Island State Health Laboratories

Forensics

DNA ANALYSIS PROTOCOL

Currently Forensic Biology Laboratory is performing nuclear DNA analysis in cases where sources of DNA have been identified and further characterization is necessary. Priority is given to:

• cases where there is a known suspect
• sexual assaults involving minors
• violent assaults

The lab is currently testing using the method of Short Tandem Repeats (STRs). This is a Polymerase Chain Reaction (PCR) technique that targets specific sequences at thirteen (13) locations on the DNA molecule. Because DNA is the same in every cell throughout the body,  buccal swabs may be used for the collection of known samples.

The following criteria have been established to facilitate processing and to expedite testing:

• Evidence must be packaged and preserved properly when submitted. Chain-of-custody documentation must be filled out completely. Refer to Evidence Collection in Forensic Biology for complete guidelines.
• Known standards from both the victim and suspect are required before testing can begin, with certain exceptions.. Buccal swabs are the sample of choice.  Please contact the laboratory for instructions.. Hair samples (head and pubic) may be collected at the same time for possible trace comparative analysis.
• A letter requesting DNA testing should be submitted to the forensic biology laboratory. This will help us in conjunction with the office of the attorney general, to evaluate, track and prioritize cases. Trial dates are helpful, if known, and updates on court/legal proceedings are encouraged.
• Each case is assigned to an analyst who processes
  the evidence and follows the case through to DNA testing. Communication between the prosecutor,
  investigator, and analyst is important so that the most probative items are tested. Consultation with the analyst and laboratory supervisor (Robin Smith) may be arranged.

March 2007