Forensic Practitioner's Guide to the Interpretation of Complex DNA Profiles
Forensic Practitioner's Guide to the Interpretation of Complex DNA Profiles

Author: Peter Gill

Publisher: Academic Press

Published: 2020-06-10

Total Pages: 532

ISBN-13: 0128205687

DOWNLOAD EBOOK

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 - Covers short tandem repeat (STR) analysis, including database searching and massive parallel sequencing (both STRs and SNPs) - Encourages dissemination and understanding of probabilistic genotyping by including practical examples of varying complexity - Written by authors intimately involved with software development, training at international workshops and reporting cases worldwide using the methods described in this book

The Evaluation of Forensic DNA Evidence
The Evaluation of Forensic DNA Evidence

Author: National Research Council

Publisher: National Academies Press

Published: 1996-12-12

Total Pages: 270

ISBN-13: 0309134404

DOWNLOAD EBOOK

In 1992 the National Research Council issued DNA Technology in Forensic Science, a book that documented the state of the art in this emerging field. Recently, this volume was brought to worldwide attention in the murder trial of celebrity O. J. Simpson. The Evaluation of Forensic DNA Evidence reports on developments in population genetics and statistics since the original volume was published. The committee comments on statements in the original book that proved controversial or that have been misapplied in the courts. This volume offers recommendations for handling DNA samples, performing calculations, and other aspects of using DNA as a forensic toolâ€"modifying some recommendations presented in the 1992 volume. The update addresses two major areas: Determination of DNA profiles. The committee considers how laboratory errors (particularly false matches) can arise, how errors might be reduced, and how to take into account the fact that the error rate can never be reduced to zero. Interpretation of a finding that the DNA profile of a suspect or victim matches the evidence DNA. The committee addresses controversies in population genetics, exploring the problems that arise from the mixture of groups and subgroups in the American population and how this substructure can be accounted for in calculating frequencies. This volume examines statistical issues in interpreting frequencies as probabilities, including adjustments when a suspect is found through a database search. The committee includes a detailed discussion of what its recommendations would mean in the courtroom, with numerous case citations. By resolving several remaining issues in the evaluation of this increasingly important area of forensic evidence, this technical update will be important to forensic scientists and population geneticistsâ€"and helpful to attorneys, judges, and others who need to understand DNA and the law. Anyone working in laboratories and in the courts or anyone studying this issue should own this book.

DNA Technology in Forensic Science
DNA Technology in Forensic Science

Author: National Research Council

Publisher: National Academies Press

Published: 1992-02-01

Total Pages: 199

ISBN-13: 0309045878

DOWNLOAD EBOOK

Matching DNA samples from crime scenes and suspects is rapidly becoming a key source of evidence for use in our justice system. DNA Technology in Forensic Science offers recommendations for resolving crucial questions that are emerging as DNA typing becomes more widespread. The volume addresses key issues: Quality and reliability in DNA typing, including the introduction of new technologies, problems of standardization, and approaches to certification. DNA typing in the courtroom, including issues of population genetics, levels of understanding among judges and juries, and admissibility. Societal issues, such as privacy of DNA data, storage of samples and data, and the rights of defendants to quality testing technology. Combining this original volume with the new update-The Evaluation of Forensic DNA Evidence-provides the complete, up-to-date picture of this highly important and visible topic. This volume offers important guidance to anyone working with this emerging law enforcement tool: policymakers, specialists in criminal law, forensic scientists, geneticists, researchers, faculty, and students.

Forensic DNA Trace Evidence Interpretation
Forensic DNA Trace Evidence Interpretation

Author: Duncan Taylor

Publisher: CRC Press

Published: 2023-05-30

Total Pages: 583

ISBN-13: 1000801381

DOWNLOAD EBOOK

Forensic DNA Trace Evidence Interpretation: Activity Level Propositions and Likelihood Ratios provides all foundational information required for a reader to understand the practice of evaluating forensic biology evidence given activity level propositions and to implement the practice into active casework within a forensic institution. The book begins by explaining basic concepts and foundational theory, pulling together research and studies that have accumulated in forensic journal literature over the last 20 years. The book explains the laws of probability - showing how they can be used to derive, from first principles, the likelihood ratio - used throughout the book to express the strength of evidence for any evaluation. Concepts such as the hierarchy of propositions, the difference between experts working in an investigative or evaluative mode and the practice of case assessment and interpretation are explained to provide the reader with a broad grounding in the topics that are important to understanding evaluation of evidence. Activity level evaluations are discussed in relation to biological material transferred from one object to another, the ability for biological material to persist on an item for a period of time or through an event, the ability to recover the biological material from the object when sampled for forensic testing and the expectations of the prevalence of biological material on objects in our environment. These concepts of transfer, persistence, prevalence and recovery are discussed in detail in addition to the factors that affect each of them. The authors go on to explain the evaluation process: how to structure case information and formulate propositions. This includes how a likelihood ratio formula can be derived to evaluate the forensic findings, introducing Bayesian networks and explaining what they represent and how they can be used in evaluations and showing how evaluation can be tested for robustness. Using these tools, the authors also demonstrate the ways that the methods used in activity level evaluations are applied to questions about body fluids. There are also chapters dedicated to reporting of results and implementation of activity level evaluation in a working forensic laboratory. Throughout the book, four cases are used as examples to demonstrate how to relate the theory to practice and detail how laboratories can integrate and implement activity level evaluation into their active casework.

Advanced Topics in Forensic DNA Typing: Interpretation
Advanced Topics in Forensic DNA Typing: Interpretation

Author: John M. Butler

Publisher: Academic Press

Published: 2014-07-28

Total Pages: 609

ISBN-13: 012405854X

DOWNLOAD EBOOK

Advanced Topics in Forensic DNA Typing: Interpretation builds upon the previous two editions of John Butler's internationally acclaimed Forensic DNA Typing textbook with forensic DNA analysts as its primary audience. Intended as a third-edition companion to the Fundamentals of Forensic DNA Typing volume published in 2010 and Advanced Topics in Forensic DNA Typing: Methodology published in 2012, this book contains 16 chapters with 4 appendices providing up-to-date coverage of essential topics in this important field. Over 80 % of the content of this book is new compared to previous editions. - Provides forensic DNA analysts coverage of the crucial topic of DNA mixture interpretation and statistical analysis of DNA evidence - Worked mixture examples illustrate the impact of different statistical approaches for reporting results - Includes allele frequencies for 24 commonly used autosomal STR loci, the revised Quality Assurance Standards which went into effect September 2011

Misleading DNA Evidence
Misleading DNA Evidence

Author: Peter Gill

Publisher: Elsevier

Published: 2014-06-18

Total Pages: 195

ISBN-13: 0124172202

DOWNLOAD EBOOK

Misleading DNA Evidence: A Guide for Scientists, Judges, and Lawyers presents the reasons miscarriages of justice can occur when dealing with DNA, what the role of the forensic scientist is throughout the process, and how judges and lawyers can educate themselves about all of the possibilities to consider when dealing with cases that involve DNA evidence. DNA has become the gold standard by which a person can be placed at the scene of a crime, and the past decade has seen great advances in this powerful crime solving tool. But the statistics that analysts can attach to DNA evidence often vary, and in some cases the statistical weight assigned to that match, can vary enormously. The numbers provided to juries often overstate the evidence, and can result in a wrongful conviction. In addition to statistics, the way the evidence is collected, stored and analyzed can also result in a wrongful conviction due to contamination. This book reviews high-profile and somewhat contentious cases to illustrate these points, including the death of Meredith Kercher. It examines crucial topics such as characterization of errors and determination of error rates, reporting DNA profiles and the source and sub-source levels, and the essentials of statement writing. It is a concise, readable resource that will help not only scientists, but legal professionals with limited scientific backgrounds, to understand the intricacies of DNA use in the justice system. - Ideal reference for scientists and for those without extensive scientific backgrounds - Written by one of the pioneers in forensic DNA typing and interpretation of DNA profiling results - Ideal format for travel, court environments, or wherever easy access to reference material is vital

Inside the Cell
Inside the Cell

Author: Erin E Murphy

Publisher: Bold Type Books

Published: 2015-10-06

Total Pages: 399

ISBN-13: 1568584709

DOWNLOAD EBOOK

Josiah Sutton was convicted of rape. He was five inches shorter and 65 pounds lighter than the suspect described by the victim, but at trial a lab analyst testified that his DNA was found at the crime scene. His case looked like many others -- arrest, swab, match, conviction. But there was just one problem -- Sutton was innocent. We think of DNA forensics as an infallible science that catches the bad guys and exonerates the innocent. But when the science goes rogue, it can lead to a gross miscarriage of justice. Erin Murphy exposes the dark side of forensic DNA testing: crime labs that receive little oversight and produce inconsistent results; prosecutors who push to test smaller and poorer-quality samples, inviting error and bias; law-enforcement officers who compile massive, unregulated, and racially skewed DNA databases; and industry lobbyists who push policies of "stop and spit." DNA testing is rightly seen as a transformative technological breakthrough, but we should be wary of placing such a powerful weapon in the hands of the same broken criminal justice system that has produced mass incarceration, privileged government interests over personal privacy, and all too often enforced the law in a biased or unjust manner. Inside the Cell exposes the truth about forensic DNA, and shows us what it will take to harness the power of genetic identification in service of accuracy and fairness.

Interpreting DNA Evidence
Interpreting DNA Evidence

Author: Ian Evett

Publisher: Sinauer Associates Incorporated

Published: 1998-01-01

Total Pages: 278

ISBN-13: 9780878931552

DOWNLOAD EBOOK

Interpretation of DNA profile matches depends on the use of statistical weights. This text provides the background information in statistics and genetics for the reader to arrive at these weights.

Forensic DNA Profiling
Forensic DNA Profiling

Author: Jo-Anne Bright

Publisher: CRC Press

Published: 2019-12-09

Total Pages: 192

ISBN-13: 0429671423

DOWNLOAD EBOOK

DNA testing and its forensic analysis are recognized as the “gold standard” in forensic identification science methods. However, there is a great need for a hands-on step-by-step guide to teach the forensic DNA community how to interpret DNA mixtures, how to assign a likelihood ratio, and how to use the subsequent likelihood ratio when reporting interpretation conclusions. Forensic DNA Profiling: A Practical Guide to Assigning Likelihood Ratios will provide a roadmap for labs all over the world and the next generation of analysts who need this foundational understanding. The techniques used in forensic DNA analysis are based upon the accepted principles of molecular biology. The interpretation of a good-quality DNA profile generated from a crime scene stain from a single-source donor provides an unambiguous result when using the most modern forensic DNA methods. Unfortunately, many crime scene profiles are not single source. They are described as mixed since they contain DNA from two or more individuals. Interpretation of DNA mixtures represents one of the greatest challenges to the forensic DNA analyst. As such, the book introduces terms used to describe DNA profiles and profile interpretation. Chapters explain DNA extraction methods, the polymerase chain reaction (PCR), capillary electrophoresis (CE), likelihood ratios (LRs) and their interpretation, and population genetic models—including Mendelian inheritance and Hardy-Weinberg equilibrium. It is important that analysts understand how LRs are generated in a probabilistic framework, ideally with an appreciation of both semicontinuous and fully continuous probabilistic approaches. KEY FEATURES: • The first book to focus entirely on DNA mixtures and the complexities involved with interpreting the results • Takes a hands-on approach offering theory with worked examples and exercises to be easily understood and implementable by laboratory personnel • New methods, heretofore unpublished previously, provide a means to innovate deconvoluting a mixed DNA profile, assign an LR, and appropriately report the weight of evidence • Includes a chapter on assigning LRs for close relatives (i.e., “It’s not me, it was my brother”), and discusses strategies for the validation of probabilistic genotyping software Forensic DNA Profiling fills the void for labs unfamiliar with LRs, and moving to probabilistic solutions, and for labs already familiar with LRs, but wishing to understand how they are calculated in more detail. The book will be a welcome read for lab professionals and technicians, students, and legal professionals seeking to understand and apply the techniques covered.

Forensic DNA Evidence Interpretation
Forensic DNA Evidence Interpretation

Author: John S. Buckleton

Publisher: CRC Press

Published: 2016-04-21

Total Pages: 500

ISBN-13: 1482258927

DOWNLOAD EBOOK

Now in its second edition, Forensic DNA Evidence Interpretation is the most comprehensive resource for DNA casework available today. Written by leaders in the fields of biology and statistics, including a contribution from Peter Gill, the father of DNA analysis, the book emphasizes the interpretation of test results and provides the necessary formulae in an easily accessible manner. This latest edition is fully updated and includes current and emerging techniques in this fast-moving field. The book begins by reviewing all pertinent biology, and then provides information on every aspect of DNA analysis. This includes modern interpretation methods and contemporary population genetic models available for estimating DNA frequencies or likelihood ratios. Following a chapter on procedures for validating databases, the text presents overviews and performance assessments of both modern sampling uncertainty methods and current paternity testing techniques, including new guidelines on paternity testing in alignment with the International Society for Forensic Genetics. Later chapters discuss the latest methods for mixture analysis, LCN (ultra trace) analysis and non-autosomal (mito, X, and Y) DNA analysis. The text concludes with an overview of procedures for disaster victim identification and information on DNA intelligence databases. Highlights of the second edition include: New information about PCR processes, heterozygote balance and back and forward stuttering New information on the interpretation of low template DNA, drop models and continuous models Additional coverage of lineage marker subpopulation effects, mixtures and combinations with autosomal markers This authoritative book provides a link among the biological, forensic, and interpretative domains of the DNA profiling field. It continues to serve as an invaluable resource that allows forensic scientists, technicians, molecular biologists and attorneys to use forensic DNA evidence to its greatest potential.