FINAL by: OSAC Program Office; Version 2, January 13, 2020 1 

OSAC RESEARCH NEEDS ASSESSMENT FORM 

Title of research need: Assessing DNA background and transfer scenarios in forensic casework

Describe

the need:

Trace DNA is characterized by low amounts of DNA and the absence of body fluid 

information. In most cases forensic scientists cannot determine how or when this DNA 

was deposited on an item of evidence, and several plausible activity scenarios may 

explain the findings. This interferes with a straightforward evaluation of the probative 

value of a trace DNA result. In order to appropriately inform investigators and other 

criminal justice stakeholders, scientists need to know more about the movement of 

DNA in the environment. Questions are: how much pre-existing DNA can be commonly 

found on objects, how long would DNA survive on hands or other items serving as a 

transfer vector, how often detectable DNA transfer can occur, and how are the odds of 

detecting trace DNA affected by collection and processing techniques. This 

combination of factors has also been described as DNA transfer, persistence, 

prevalence and recovery (DNA-TPPR). 

While some authors have attempted to assess activity scenarios through simulated 

case studies, practitioners will encounter many different combinations of scenarios 

and variables, and a more general approach is needed. Research should address how 

data on DNA-TPPR should be collected to be applicable across different laboratories, 

and how data points can be combined to provide useful information in specific cases. 

Keyword(s): DNA direct and indirect transfer, background, persistence, probative value

Submitting subcommittee(s): Human Biology Date Approved: 05/04/2021

(If SAC review identifies additional subcommittees, add them to the box above.)

Background Information:

1. Does this research need address a gap(s) in a current or planned standard? (ex.: Field identification system 

for on scene opioid detection and confirmation)

Yes 

2. Are you aware of any ongoing research that may address this research need that has not yet been published 

(e.g., research presented in conference proceedings, studies that you or a colleague have participated in but 

have yet to be published)?

Yes 

3. Key bibliographic references relating to this research need: 

1) Fonnelop, A. E., Ramse, M., Egeland, T., & Gill, P. (2017). The implications of shedder status and 

background DNA on direct and secondary transfer in an attack scenario. Forensic Sci Int: Genet, 29, 

48–60. 
FINAL by: OSAC Program Office; Version 2, January 13, 2020 2 

2) Goray, M., Mitchell, J. R., & van Oorschot, R. A. H. (2012). Evaluation of multiple transfer of DNA 

using mock case scenarios. Legal Medicine, 14(1), 40–46. 

3) Goray, M., Mitchell, R. J., & Van Oorschot, R. A. H. (2010). Investigation of secondary DNA transfer of 

skin cells under controlled test conditions. Legal Medicine, 12, 117–120. 

4) Lehmann, V. J., Mitchell, R. J., Ballantyne, K. N., & Oorschot, R. A. H. Van. (2015). Following the 

transfer of DNA : How does the presence of background DNA affect the transfer and detection of a 

target source of DNA ? Forensic Sci Int: Genet,, 19, 68–75. 

5) Taylor, D., Abarno, D., Rowe, E., & Rask-Nielsen, L. (2016). Observations of DNA transfer within an 

operational Forensic Biology Laboratory. Forensic Sci Int: Genet, 23, 33–49. 

6) Taylor, D., Biedermann, A., Samie, L., Pun, K.-M., Hicks, T., & Champod, C. (2017). Helping to 

distinguish primary from secondary transfer events for trace DNA. Forensic Sci Int Genet, 28, 155–

177. 

7) Van Oorschot, R.A.H., Szkuta, B., Ballnatyne, K.N., Goray, M. (2017) Need for dedicated training, 

competency assessment, authorizations and ongoing proficiency testing for those addressing DNA 

transfer issues. Forensic Sci Int: Genet, Supplement Series 6, e32-e34. 

https://doi.org/10.1016/j.fsigss.2017.09.013 

4. Review the annual operational/research needs published by the National Institute of Justice (NIJ) at 

https://nij.ojp.gov/topics/articles/forensic-science-research-and-development-technology-working-groupoperational#latest? Is your research need identified by NIJ?

Somewhat - Comprehensive, systematic, well‐controlled studies that provide both foundational knowledge

and practical data about "touch evidence" DNA transfer (e.g., primary, secondary) and persistence in the

real world, as well as best practices for interpretation

5. In what ways would the research results improve current laboratory capabilities? 

DNA laboratories have well established procedures to process and report biological fluids like blood, 

semen and saliva. But the majority of casework submissions, in violent cases as well as non-violent 

volume crimes like burglaries, now consist of touched objects, also referred to as contact traces. Any 

DNA results associated with DNA from these items (trace DNA) are routinely challenged in court since 

it often cannot be determined, if the DNA was pre-existing, or if deposited during the commission of the 

crime from direct or indirect contact. Any method helping to distinguish between deposit scenarios 

would benefit laboratories during reporting and testimony and maximize the use of trace DNA results. 

6. In what ways would the research results improve understanding of the scientific basis for the 

subcommittee(s)? 

The evaluation of alternative casework scenarios like direct or indirect transfer in forensic DNA cases 

is currently based on subjective criteria such as the forensic scientist’s casework experience. Data 

based on casework experience were generated on “unknown” samples, and as such are lacking in 

“ground truth”. A more systematic, scientific approach for evaluating trace DNA results beyond the 

random match probability is needed. 

7. In what ways would the research results improve services to the criminal justice system? 

DNA results associated with DNA from touched objects (trace DNA) are routinely challenged in court 

either because the DNA may have been pre-existing, or if it can be established that DNA was deposited 

during the commission of the crime, if that occurred through direct or indirect contact. Any method 
FINAL by: OSAC Program Office; Version 2, January 13, 2020 3 

helping to distinguish between deposit scenarios would ensure that probative results are properly 

recognized, and that non-probative DNA is not used to wrongfully convict an individual. 

8. Status assessment (I, II, III, or IV): II

Major gap in 

current 

knowledge 

Minor gap in 

current 

knowledge 

 

 No or limited

current research is 

being conducted I III 

 Existing current 

research is being 

conducted II IV 

This research need has been identified by one or more subcommittees of OSAC and is being provided as an

informational resource to the community.