Over the past twenty years, there’s been a gradual shift in the way forensic scientists approach the evaluation of DNA profiling evidence that is taken to court. Many laboratories are now adopting ‘probabilistic genotyping’ to interpret complex DNA mixtures. However, current practice is very diverse, where a whole range of technologies are used to interpret DNA profiles and the software approaches advocated are commonly used throughout the world.
Forensic Practitioner’s Guide to the Interpretation of Complex DNA Profiles places the main concepts of DNA profiling into context and fills a niche that is unoccupied in current literature. The book begins with an introduction to basic forensic genetics, covering a brief historical description of the development and harmonization of STR markers and national DNA databases. The laws of statistics are described, along with the likelihood ratio based on Hardy-Weinberg equilibrium and alternative models considering sub-structuring and relatedness. The historical development of low template mixture analysis, theory and practice, is also described, so the reader has a full understanding of rationale and progression. Evaluation of evidence and statement writing is described in detail, along with common pitfalls and their avoidance.
The authors have been at the forefront of the revolution, having made substantial contributions to theory and practice over the past two decades. All methods described are open-source and freely available, supported by sets of test-data and links to web-sites with further information. This book is written primarily for the biologist with little or no statistical training. However, sufficient information will also be provided for the experienced statistician. Consequently, the book appeals to a diverse audience
1. Cover image - p. i 2. Title page - p. ii 3. Table of Contents - p. iii 4. Copyright - p. iv 5. About the authors - p. xv 6. Contributors - p. xvii 7. Foreword - p. xix 8. Preface - p. xxi 9. List of websites and resources - p. xxv 10. Chapter 1: Forensic genetics: the basics - p. 1 11. Chapter 2: Empirical characterization of DNA profiles - p. 55 12. Chapter 3: Allele drop-out and the stochastic threshold - p. 89 13. Chapter 4: Low-template DNA - p. 111 14. Chapter 5: LRmix model theory - p. 129 15. Chapter 6: A qualitative (semi-continuous) model: LRmix Studio - p. 153 16. Chapter 7: The quantitative (continuous) model theory - p. 181 17. Chapter 8: EuroForMix - p. 239 18. Chapter 9: Validation - p. 277 19. Chapter 10: Development and implementation of DNAxs - p. 309 20. Chapter 11: Investigative forensic genetics: SmartRank, CaseSolver and DNAmatch2 - p. 339 21. Chapter 12: Interpretation, reporting, and communication - p. 385 22. Chapter 13: Interpretation of complex DNA profiles generated by massively parallel sequencing - p. 419 23. Appendix A: Formal descriptions of the genotype probabilities - p. 453 24. Appendix B: Formal description of the probabilistic models - p. 459 25. Bibliography - p. 477 26. Index - p. 497
Over the past twenty years, there’s been a gradual shift in the way forensic scientists approach the evaluation of DNA profiling evidence that is taken to court. Many laboratories are now adopting ‘probabilistic genotyping’ to interpret complex DNA mixtures. However, current practice is very diverse, where a whole range of technologies are used to interpret DNA profiles and the software approaches advocated are commonly used throughout the world.
Forensic Practitioner’s Guide to the Interpretation of Complex DNA Profiles places the main concepts of DNA profiling into context and fills a niche that is unoccupied in current literature. The book begins with an introduction to basic forensic genetics, covering a brief historical description of the development and harmonization of STR markers and national DNA databases. The laws of statistics are described, along with the likelihood ratio based on Hardy-Weinberg equilibrium and alternative models considering sub-structuring and relatedness. The historical development of low template mixture analysis, theory and practice, is also described, so the reader has a full understanding of rationale and progression. Evaluation of evidence and statement writing is described in detail, along with common pitfalls and their avoidance.
The authors have been at the forefront of the revolution, having made substantial contributions to theory and practice over the past two decades. All methods described are open-source and freely available, supported by sets of test-data and links to web-sites with further information. This book is written primarily for the biologist with little or no statistical training. However, sufficient information will also be provided for the experienced statistician. Consequently, the book appeals to a diverse audience
1. Cover image - p. i 2. Title page - p. ii 3. Table of Contents - p. iii 4. Copyright - p. iv 5. About the authors - p. xv 6. Contributors - p. xvii 7. Foreword - p. xix 8. Preface - p. xxi 9. List of websites and resources - p. xxv 10. Chapter 1: Forensic genetics: the basics - p. 1 11. Chapter 2: Empirical characterization of DNA profiles - p. 55 12. Chapter 3: Allele drop-out and the stochastic threshold - p. 89 13. Chapter 4: Low-template DNA - p. 111 14. Chapter 5: LRmix model theory - p. 129 15. Chapter 6: A qualitative (semi-continuous) model: LRmix Studio - p. 153 16. Chapter 7: The quantitative (continuous) model theory - p. 181 17. Chapter 8: EuroForMix - p. 239 18. Chapter 9: Validation - p. 277 19. Chapter 10: Development and implementation of DNAxs - p. 309 20. Chapter 11: Investigative forensic genetics: SmartRank, CaseSolver and DNAmatch2 - p. 339 21. Chapter 12: Interpretation, reporting, and communication - p. 385 22. Chapter 13: Interpretation of complex DNA profiles generated by massively parallel sequencing - p. 419 23. Appendix A: Formal descriptions of the genotype probabilities - p. 453 24. Appendix B: Formal description of the probabilistic models - p. 459 25. Bibliography - p. 477 26. Index - p. 497
