DNA Stability Studies
Participants: Margaret C. Kline and Janette W. Redman
Project Timeframe: 1994 to 2004
Purpose: Many DNA sample repositories or “DNA banks” exist, primarily for the support of epidemiological and genetic research or to enable identification of forensic evidence or human remains. Whole blood, plasma, and buccal epithelium are convenient and minimally intrusive sources of DNA for current DNA analysis technologies. Given that "banking" tissue below ambient temperature is expensive (equipment, space, and energy) and problematic (assuring continuous operation), banking facilities are evaluating sample types, storage media and temperature to ascertain the optimum conditions to successfully recover DNA information. Artificial aging of samples may not be equivalent to natural aging. Therefore, it is desirable to evaluate proposed sample and storage conditions using naturally aged materials.
Progress: Control samples prepared on untreated Schleicher & Schuell 903 paper in 1994 were stored for over ten years at the following temperatures: ambient, -20°C, -80°C, and -150°C. The "release" of the DNA from all of these samples was followed with yield gels and slot-blots as well as with peak heights and areas of STR multiplex loci for the recovery of typeable DNA. To add to the results of the control samples, over 300 anonymous aged bloodstains, field collected on Schleicher & Schuell 903 paper (903)and stored from 2 - 15 years at ambient temperature and humidity, were made available for study. Fifty similarly collected samples stored ‑20°C for 6 years were available for direct comparison. All of the field collected samples yielded typeable DNA, although some loss of the larger STR loci occurred in the older and more degraded samples stored under ambient conditions. Yield gels show the DNA from these samples to be smears of DNA with sizes ranging from 12 kb down to approximately 100 bp while the DNA extracted from the 6 y old samples stored at -20 °C is greater than 12 kb in size. No consistent differences in typeability as a function of extraction technique were observed. All control samples yielded typeable results, however differences were seen at the various storage temperatures.
Publications or Presentations Resulting From This Project:
Margaret Kline talk at American Academy of Forensic Sciences (Atlanta, GA), February 14, 2002
, "Effects of Storage Temperature and Humidity Control on the Recovery of DNA from Aged-Bloodstains" [.pdf]
Margaret Kline talk at Mini-Symposium: Dry-State Storage of DNA (Frederick, MD), March 29, 2005, "Recovery of DNA from Aged Bloodstains" [.pdf]
Margaret Kline poster at International Environmental Specimen Bank Symposium (Charleston, SC), November 13-17, 2005, "Effects of Storage Temperature on the Recovery of DNA from Aged-Bloodstains" [.pdf]
Jan Redman poster at Twelve International Symposium on Human Identification (Biloxi, MS), October 10-11, 2001, "Recovery of DNA from aged-bloodstains on un-treated paper"
Last updated: 06/25/2007
Disclaimer: This project was supported by National Institute of Justice Grant Number 2003-IJ-R-029, which is an interagency agreement between NIJ and the NIST Office of Law Enforcement Standards, awarded by the National Institute of Justice, Office of Justice Programs, US Department of Justice. Points of view in this document are those of the authors and do not necessarily represent the official position or policies of the US Department of Justice. Certain commercial equipment, instruments and materials are identified in order to specify experimental procedures as completely as possible. In no case does such identification imply a recommendation or endorsement by the National Institute of Standards and Technology nor does it imply that any of the materials, instruments or equipment identified are necessarily the best available for the purpose.