TY - JOUR
T1 - Helping to distinguish primary from secondary transfer events for trace DNA
AU - Taylor, Duncan
AU - Biedermann, Alex
AU - Samie, Lydie
AU - Pun, Ka Man
AU - Hicks, Tacha
AU - Champod, Christophe
PY - 2017/5/1
Y1 - 2017/5/1
N2 - DNA is routinely recovered in criminal investigations. The sensitivity of laboratory equipment and DNA profiling kits means that it is possible to generate DNA profiles from very small amounts of cellular material. As a consequence, it has been shown that DNA we detect may not have arisen from a direct contact with an item, but rather through one or more intermediaries. Naturally the questions arising in court, particularly when considering trace DNA, are of how DNA may have come to be on an item. While scientists cannot directly answer this question, forensic biological results can help in discriminating between alleged activities. Much experimental research has been published showing the transfer and persistence of DNA under varying conditions, but as of yet the results of these studies have not been combined to deal with broad questions about transfer mechanisms. In this work we use published data and Bayesian networks to develop a statistical logical framework by which questions of transfer mechanism can be approached probabilistically. We also identify a number of areas where further work could be carried out in order to improve our knowledge base when helping to address questions about transfer mechanisms. Finally, we apply the constructed Bayesian network to ground truth known data to determine if, with current knowledge, there is any power in DNA quantities to distinguish primary and secondary transfer events.
AB - DNA is routinely recovered in criminal investigations. The sensitivity of laboratory equipment and DNA profiling kits means that it is possible to generate DNA profiles from very small amounts of cellular material. As a consequence, it has been shown that DNA we detect may not have arisen from a direct contact with an item, but rather through one or more intermediaries. Naturally the questions arising in court, particularly when considering trace DNA, are of how DNA may have come to be on an item. While scientists cannot directly answer this question, forensic biological results can help in discriminating between alleged activities. Much experimental research has been published showing the transfer and persistence of DNA under varying conditions, but as of yet the results of these studies have not been combined to deal with broad questions about transfer mechanisms. In this work we use published data and Bayesian networks to develop a statistical logical framework by which questions of transfer mechanism can be approached probabilistically. We also identify a number of areas where further work could be carried out in order to improve our knowledge base when helping to address questions about transfer mechanisms. Finally, we apply the constructed Bayesian network to ground truth known data to determine if, with current knowledge, there is any power in DNA quantities to distinguish primary and secondary transfer events.
KW - Activity level propositions
KW - Bayesian networks
KW - Data
KW - Likelihood ratio
KW - Primary transfer
KW - Secondary transfer
UR - http://www.scopus.com/inward/record.url?scp=85014239488&partnerID=8YFLogxK
U2 - 10.1016/j.fsigen.2017.02.008
DO - 10.1016/j.fsigen.2017.02.008
M3 - Article
C2 - 28273508
AN - SCOPUS:85014239488
VL - 28
SP - 155
EP - 177
JO - Forensic Science International: Genetics
JF - Forensic Science International: Genetics
SN - 1872-4973
ER -