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


Book Description

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




Techniques of Crime Scene Investigation


Book Description

"Techniques of Crime Scene Investigation is a staple for any forensic science library and is routinely referenced by professional organizations as a study guide for certifications. It is professionally written and provides updated theoretical and practical applications using real casework. This text is a must-have for any CSI Unit or course teaching Crime Scene Investigation." – Kevin Parmelee, PhD, Detective (ret.), Somerset County, NJ Prosecutor’s Office Since the first English-language edition of Techniques of Crime Scene Investigation was published in 1964, the book has continued to be a seminal work in the field of forensic science, serving as a foundational textbook and reference title for professionals. This Ninth Edition includes several new chapters and has been fully updated and organized to present the effective use of science and technology in support of justice. New coverage to this edition addresses the debunking of a few forensic science disciplines, long thought to have been based on sound science. The book provides students, crime scene investigators, forensic scientists, and attorneys the proper ways to examine crime scenes and collect a wide variety of physical evidence that may be encountered. While it is not possible to cover every imaginable situation, this book is a comprehensive guide that details and promotes best practices and recommendations. In today’s challenging environment, it is essential that law enforcement personnel thoroughly understand and meticulously comply with the forensic evidence procedures that apply to their function in the investigation process. Criminal investigations remain as complex as ever and require professionals from many disciplines to work cooperatively toward the fair and impartial delivery of justice. Practitioners and students alike need to be aware of the increased scrutiny that they will face in the judicial system. Judges are taking a more involved role than ever before as far as the evidence and testimony that they allow into their courtrooms. No longer will substandard forensic science or crime scene investigation be acceptable. Key features: Newly reorganized contents—including 4 brand new chapters—reflects a more logical flow of crime scene processes and procedures Provides an overview of the crime scene investigation process and procedures, from the first officer on the scene through the adjudication of the case Includes several new cases, photos, and updates in technological advances in both digital evidence and DNA in particular Science and technology applied to CSI solves crimes and saves lives. Investigators, prosecutors, and defense attorneys must be able to use forensic tools and resources to their fullest potential and Techniques of Crime Scene Investigation serves as an invaluable resource to further this cause.




Forensic DNA Profiling


Book Description

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 Science


Book Description

Forensic science is often important in criminal cases, so criminal justice professionals, including lawyers and forensic scene investigators, must have a basic understanding of what is often complex science. This book explains the science underpinning forensic techniques to give those who engage with forensic science professionally, but who are not primarily scientists, a level of understanding that will enable them to use forensic science data effectively. In addition, the book places the use of forensic data in the context of criminal cases to assess the reliability and usefulness of forensic data in court. Succinctly presented, this book covers all the facets of forensic science for students who are hoping to become police officers, lawyers or other members of the criminal justice system. As forensic investigations have advanced, e.g. in DNA profiling, computer modelling and behavioural sciences, so has the need for an increase in the level of scientific knowledge. The author understands the challenges this brings and has written the book to explain complex information in an accessible and undemanding style. Using international case studies, this book will bring forensic science to life and include aspects of the author's personal journey.




Interpreting Complex Forensic DNA Evidence


Book Description

Interpreting Complex Forensic DNA Evidence is a handy guide to recent advances—and emerging issues—in interpreting complex DNA evidence and profiles for use in criminal investigations. In certain cases, DNA cannot be connected to a specific biological material such as blood, semen or saliva. How or when the DNA was deposited may be an issue. The possibility of generating DNA profiles from touched objects, where there may not be a visible deposit, has expanded the scope and number of exhibits submitted for DNA analysis. With such advances, and increasing improvements in technological capabilities in testing samples, this means it is possible to detect ever smaller amounts of DNA. There are also many efforts underway to seek was to interpret DNA profiles that are sub-optimal—either relative to the amount required by the testing kit and, potentially, the quality of the obtained sample. Laboratories often use enhancements in order to obtain a readable DNA profile. The broad-reaching implications of improving DNA sensitivity have led to this next, emerging generation of more complex profiles. Examples partial profiles that do not faithfully reflect the proposed donor, or mixtures of partial DNA from multiple people. A complexity threshold has been proposed to limit interpretation of poor-quality data. Research is now addressing the interpretation of transfer of trace amounts of DNA. Complex issues are arising in trial that need to be reconciled as such complexity has added challenges to the interpretation of evidence and its introduction or dismissal in certain cases in the courts. Key Features: Addresses DNA transfer, from person-to-person as well as to objects Outlines each stage required to produce a DNA profile from an exhibit—including collection, handling, storage, and analysis Discusses ethics, subjectivity, and bias—including cognitive dissonance—as they relate specifically to complex DNA evidence Highlights current techniques and the latest advances in DNA analysis, including advances in familial DNA searches Interpreting Complex Forensic DNA Evidence provides tools to assist the criminal investigator, forensic expert, and legal professional when posed with a DNA result in a forensic report or testimony. The result—and any associated statistic—may not reveal any ambiguity, complexity, or the assumptions involved in deriving it. Questions from resolved criminal cases are posed, and the relevant forensic literature, provided for the reader to assess a DNA result and any associated statistic. Case studies throughout illustrate concepts and emphasize the need for conclusions in the forensic report that are supported by the data.




The Evaluation of Forensic DNA Evidence


Book Description

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.




Misleading DNA Evidence


Book Description

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




A Guide to Forensic DNA Profiling


Book Description

The increasingly arcane world of DNA profiling demands that those needing to understand at least some of it must find a source of reliable and understandable information. Combining material from the successful Wiley Encyclopedia of Forensic Science with newly commissioned and updated material, the Editors have used their own extensive experience in criminal casework across the world to compile an informative guide that will provide knowledge and thought-provoking articles of interest to anyone involved or interested in the use of DNA in the forensic context. Following extensive introductory chapters covering forensic DNA profiling and forensic genetics, this comprehensive volume presents a substantial breadth of material covering: Fundamental material – including sources of DNA, validation, and accreditation Analysis and interpretation – including, extraction, quantification, amplification and interpretation of electropherograms (epgs) Evaluation – including mixtures, low template, and transfer Applications – databases, paternity and kinship, mitochondrial-DNA, wildlife DNA, single-nucleotide polymorphism, phenotyping and familial searching Court - report writing, discovery, cross examination, and current controversies With contributions from leading experts across the whole gamut of forensic science, this volume is intended to be authoritative but not authoritarian, informative but comprehensible, and comprehensive but concise. It will prove to be a valuable addition, and useful resource, for scientists, lawyers, teachers, criminologists, and judges.




Advanced Topics in Forensic DNA Typing: Interpretation


Book Description

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




Forensic Science Evidence and Expert Witness Testimony


Book Description

Forensic science evidence plays a pivotal role in modern criminal proceedings. Yet such evidence poses intense practical and theoretical challenges. It can be unreliable or misleading and has been associated with miscarriages of justice. In this original and insightful book, a global team of prominent scholars and practitioners explore the contemporary challenges of forensic science evidence and expert witness testimony from a variety of theoretical, practical and jurisdictional perspectives. Chapters encompass the institutional organisation of forensic science, its procedural regulation, evaluation and reform, and brim with comparative insight.