TY - JOUR
T1 - Using Bayesian networks to track DNA movement through complex transfer scenarios
AU - Taylor, Duncan
AU - Samie, Lydie
AU - Champod, Christophe
PY - 2019/9
Y1 - 2019/9
N2 - Trace DNA and the manner in which it is transferred from item to item is a common topic arising in forensic science, both in case evaluations, and in Court testimony. In order to assign the probability of obtaining DNA findings, given competing propositions that specify transfer mechanisms, consideration must be given to a number of factors. Previous work by the authors developed a simple Object-Oriented Bayesian Network (OOBN) that pooled numerous published studies in order to attempt evaluation of trace DNA results given such propositions. In this work, we expand on the previously published OOBN and formalise a number of class networks that can be used together in a logical way to consider DNA movement through complex chains of transfer events. Specifically, we develop an OOBN that considers the two-way transfer of DNA that occurs when two items contact, and allows for the sampling of intermediary items involved in the chain of transfers. The aim is to show that adopting an approach involving basic building blocks, we offer the possibility to tackle complex and various cases for which the OOBN will be obtained by combining their elementary blocks. We conclude with a demonstration of applying the OOBN being applied to a chain of transfers in a case scenario.
AB - Trace DNA and the manner in which it is transferred from item to item is a common topic arising in forensic science, both in case evaluations, and in Court testimony. In order to assign the probability of obtaining DNA findings, given competing propositions that specify transfer mechanisms, consideration must be given to a number of factors. Previous work by the authors developed a simple Object-Oriented Bayesian Network (OOBN) that pooled numerous published studies in order to attempt evaluation of trace DNA results given such propositions. In this work, we expand on the previously published OOBN and formalise a number of class networks that can be used together in a logical way to consider DNA movement through complex chains of transfer events. Specifically, we develop an OOBN that considers the two-way transfer of DNA that occurs when two items contact, and allows for the sampling of intermediary items involved in the chain of transfers. The aim is to show that adopting an approach involving basic building blocks, we offer the possibility to tackle complex and various cases for which the OOBN will be obtained by combining their elementary blocks. We conclude with a demonstration of applying the OOBN being applied to a chain of transfers in a case scenario.
KW - Activity level propositions
KW - Background DNA
KW - Contact DNA
KW - DNA persistence
KW - DNA transfer
KW - Object-oriented Bayesian networks
UR - http://www.scopus.com/inward/record.url?scp=85067543002&partnerID=8YFLogxK
U2 - 10.1016/j.fsigen.2019.06.006
DO - 10.1016/j.fsigen.2019.06.006
M3 - Article
C2 - 31234042
AN - SCOPUS:85067543002
VL - 42
SP - 69
EP - 80
JO - Forensic Science International: Genetics
JF - Forensic Science International: Genetics
SN - 1872-4973
ER -