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Kling D, Phillips C, Kennett D, Tillmar A. Investigative genetic genealogy: Current methods, knowledge and practice. Forensic Sci Int Genet 2021; 52:102474. [PMID: 33592389 DOI: 10.1016/j.fsigen.2021.102474] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 01/12/2021] [Accepted: 01/27/2021] [Indexed: 12/15/2022]
Abstract
Investigative genetic genealogy (IGG) has emerged as a new, rapidly growing field of forensic science. We describe the process whereby dense SNP data, commonly comprising more than half a million markers, are employed to infer distant relationships. By distant we refer to degrees of relatedness exceeding that of first cousins. We review how methods of relationship matching and SNP analysis on an enlarged scale are used in a forensic setting to identify a suspect in a criminal investigation or a missing person. There is currently a strong need in forensic genetics not only to understand the underlying models to infer relatedness but also to fully explore the DNA technologies and data used in IGG. This review brings together many of the topics and examines their effectiveness and operational limits, while suggesting future directions for their forensic validation. We further investigated the methods used by the major direct-to-consumer (DTC) genetic ancestry testing companies as well as submitting a questionnaire where providers of forensic genetic genealogy summarized their operation/services. Although most of the DTC market, and genetic genealogy in general, has undisclosed, proprietary algorithms we review the current knowledge where information has been discussed and published more openly.
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Affiliation(s)
- Daniel Kling
- Department of Forensic Genetics and Forensic Toxicology, National Board of Forensic Medicine, Linköping, Sweden; Department of Forensic Sciences, Oslo University Hospital, Oslo, Norway.
| | - Christopher Phillips
- Forensic Genetics Unit, Institute of Forensic Sciences, University of Santiago de Compostela, Santiago de Compostela, Spain.
| | - Debbie Kennett
- Research Department of Genetics, Evolution and Environment, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Andreas Tillmar
- Department of Forensic Genetics and Forensic Toxicology, National Board of Forensic Medicine, Linköping, Sweden; Department of Biomedical and Clinical Sciences, Faculty of Medicine and Health Sciences, Linköping University, Linköping, Sweden
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Kruijver M. Characterizing the genetic structure of a forensic DNA database using a latent variable approach. Forensic Sci Int Genet 2016; 23:130-149. [DOI: 10.1016/j.fsigen.2016.03.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 02/24/2016] [Accepted: 03/21/2016] [Indexed: 12/11/2022]
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Slooten K. Familial searching on DNA mixtures with dropout. Forensic Sci Int Genet 2016; 22:128-138. [DOI: 10.1016/j.fsigen.2016.02.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Revised: 12/11/2015] [Accepted: 02/01/2016] [Indexed: 11/25/2022]
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Gill P, Haned H, Bleka O, Hansson O, Dørum G, Egeland T. Genotyping and interpretation of STR-DNA: Low-template, mixtures and database matches-Twenty years of research and development. Forensic Sci Int Genet 2015; 18:100-17. [PMID: 25866376 DOI: 10.1016/j.fsigen.2015.03.014] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Revised: 03/19/2015] [Accepted: 03/24/2015] [Indexed: 12/17/2022]
Abstract
The introduction of Short Tandem Repeat (STR) DNA was a revolution within a revolution that transformed forensic DNA profiling into a tool that could be used, for the first time, to create National DNA databases. This transformation would not have been possible without the concurrent development of fluorescent automated sequencers, combined with the ability to multiplex several loci together. Use of the polymerase chain reaction (PCR) increased the sensitivity of the method to enable the analysis of a handful of cells. The first multiplexes were simple: 'the quad', introduced by the defunct UK Forensic Science Service (FSS) in 1994, rapidly followed by a more discriminating 'six-plex' (Second Generation Multiplex) in 1995 that was used to create the world's first national DNA database. The success of the database rapidly outgrew the functionality of the original system - by the year 2000 a new multiplex of ten-loci was introduced to reduce the chance of adventitious matches. The technology was adopted world-wide, albeit with different loci. The political requirement to introduce pan-European databases encouraged standardisation - the development of European Standard Set (ESS) of markers comprising twelve-loci is the latest iteration. Although development has been impressive, the methods used to interpret evidence have lagged behind. For example, the theory to interpret complex DNA profiles (low-level mixtures), had been developed fifteen years ago, but only in the past year or so, are the concepts starting to be widely adopted. A plethora of different models (some commercial and others non-commercial) have appeared. This has led to a confusing 'debate' about the 'best' to use. The different models available are described along with their advantages and disadvantages. A section discusses the development of national DNA databases, along with details of an associated controversy to estimate the strength of evidence of matches. Current methodology is limited to searches of complete profiles - another example where the interpretation of matches has not kept pace with development of theory. STRs have also transformed the area of Disaster Victim Identification (DVI) which frequently requires kinship analysis. However, genotyping efficiency is complicated by complex, degraded DNA profiles. Finally, there is now a detailed understanding of the causes of stochastic effects that cause DNA profiles to exhibit the phenomena of drop-out and drop-in, along with artefacts such as stutters. The phenomena discussed include: heterozygote balance; stutter; degradation; the effect of decreasing quantities of DNA; the dilution effect.
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Affiliation(s)
- Peter Gill
- Norwegian Institute of Public Health, Department of Forensic Biology, PO Box 4404 Nydalen, 0403 Oslo, Norway; Department of Forensic Medicine, Sognsvannsveien 20, Rikshospitalet, 0372 Oslo, Norway.
| | - Hinda Haned
- Netherlands Forensic Institute, Department of Human Biological Traces, The Hague, The Netherlands
| | - Oyvind Bleka
- Norwegian Institute of Public Health, Department of Forensic Biology, PO Box 4404 Nydalen, 0403 Oslo, Norway
| | - Oskar Hansson
- Norwegian Institute of Public Health, Department of Forensic Biology, PO Box 4404 Nydalen, 0403 Oslo, Norway
| | - Guro Dørum
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, P.O. Box 5003, NO-1432 Aas, Norway
| | - Thore Egeland
- Norwegian Institute of Public Health, Department of Forensic Biology, PO Box 4404 Nydalen, 0403 Oslo, Norway; Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, P.O. Box 5003, NO-1432 Aas, Norway
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Bleka Ø, Dørum G, Haned H, Gill P. Database extraction strategies for low-template evidence. Forensic Sci Int Genet 2014; 9:134-41. [DOI: 10.1016/j.fsigen.2013.11.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Revised: 11/14/2013] [Accepted: 11/28/2013] [Indexed: 10/25/2022]
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Slooten K, Meester R. Probabilistic strategies for familial DNA searching. J R Stat Soc Ser C Appl Stat 2013. [DOI: 10.1111/rssc.12035] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Klaas Slooten
- Netherlands Forensic Institute; The Hague The Netherlands
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Chung YK, Fung WK. Identifying contributors of two-person DNA mixtures by familial database search. Int J Legal Med 2013; 127:25-33. [PMID: 22270047 PMCID: PMC3538014 DOI: 10.1007/s00414-012-0666-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Accepted: 01/02/2012] [Indexed: 11/28/2022]
Abstract
The role of familial database search as a crime-solving tool has been increasingly recognized by forensic scientists. As an enhancement to the existing familial search approach on single source cases, this article presents our current progress in exploring the potential use of familial search to mixture cases. A novel method was established to predict the outcome of the search, from which a simple strategy for determining an appropriate scale of investigation by the police force is developed. Illustrated by an example using Swedish data, our approach is shown to have the potential for assisting the police force to decide on the scale of investigation, thereby achieving desirable crime-solving rate with reasonable cost.
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Affiliation(s)
- Yuk-Ka Chung
- Department of Statistics and Actuarial Science, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Wing K. Fung
- Department of Statistics and Actuarial Science, The University of Hong Kong, Pokfulam Road, Hong Kong, China
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The evidentiary values of "cold hits" in a DNA database search on two-person mixture. Sci Justice 2011; 51:10-5. [PMID: 21334575 DOI: 10.1016/j.scijus.2010.07.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2010] [Revised: 07/14/2010] [Accepted: 07/18/2010] [Indexed: 11/23/2022]
Abstract
We provide a unified overview on the evaluation of the evidentiary values of cold-hit DNA matches between profiles in a DNA database and a mixed crime sample. Also discussed are methods of handling missing data in evaluating the DNA evidence. Through the analysis of a constructed murder case using Swedish data, we illustrate the applicability of the methods on various situations including the presence of multiple matches and consideration of allele drop-out. We also demonstrate the calculation of the probability of erroneous attribution as a measure of the effectiveness of the database search on DNA mixtures.
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