Recovery of DNA From Aged Bloodstains on Untreated Paper
Participants: Margaret C. Kline, Janette W. Redman, David L. Duewer, and John M. Butler
Project Timeframe: Summer 2001
Purpose: To assess the stability of “field” collected and ambient stored aged bloodstains for STR typeability. Laboratories have DNA banks of reference samples, mostly stored at -20° C – requiring equipment, energy, and storage space resources. The question “Can I store my samples at ambient temperature?” has been asked on numerous occasions.
Progress: Many reference DNA sample repositories or “DNA banks” are now in existence, primarily for 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. The nature of the sample, how it is collected, and how it is stored are critical issues for the ultimate utility of any DNA banking effort. Successful DNA typing requires that samples contain an adequate quantity of DNA and that this DNA can be isolated from polymerase chain reaction (PCR) inhibitors (heme, proteins, and many other whole-blood components). Current methods of DNA typing use multiplexes of short tandem repeat (STR) loci detected as PCR amplified products, ranging in size from 100 through 450 nucleotide basepairs (bp).
More than 300 anonymous bloodstains that have been stored on untreated Schleicher & Schuell 903 paper (S&S 903) from 2 to 15 years at ambient temperatures with no humidity control were examined as well as samples that were stored at -20° C for 6 years. The examinations included different methods of extraction (Chelex®, and salting-out) and also evaluated the quality of the recovered DNA (yield gel) and typeability of the DNA obtained.
All samples yielded typeable DNA. A loss of some of the larger STR loci was noted in some of the older and more degraded samples. Images of yield gels indicate that the DNA extracted from the 6-yr old samples stored at -20° C had intact DNA greater than 12 kb in size whereas the ambient samples appeared as smears of DNA with sizes ranging from 12 kb down to approximately 100 bp.
These quantitative results enable DNA banks to make a more informed decision on whether they should continue to store samples at -20° C. NIST intends to continue longitudinal studies on aged samples stored on several media and under a variety of conditions.
Presentations and Publications Resulting From This Project:
Redman presented a poster at the Twelfth International Symposium on Human
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]
Last updated: 06/20/2007
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.