The evaluation of forensic DNA evidence / Committee on DNA Forensic Science: an Update, Commission on DNA Forensic Science: an Update, National Research Council.

Format:

Book

Contributor:

National Research Council (U.S.). Committee on DNA Forensic Science: an Update.

National Research Council (U.S.). Commission on DNA Forensic Science: an Update.

Language:

English

Subjects (All):

Forensic genetics.

Physical Description:

1 online resource (270 p.)

Edition:

1st ed.

Place of Publication:

Washington, D.C. : National Academy Press, 1996.

Language Note:

English

Summary:

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 tool-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 geneticists-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.

Contents:

The Evaluation of Forensic DNA Evidence

Copyright

Preface

Contents

Executive Summary1

INTRODUCTION

CONTENTS OF THE REPORT

RECOMMENDATIONS

Recommendations to Improve Laboratory Performance

Recommendations for Estimating Random-Match Probabilities

Recommendations on Interpreting the Results of Database Searches, on Binning, and on Establishing th ...

Recommendation for Research on Juror Comprehension

Overview

OUR ASSIGNMENT

DNA TYPING

BASIC GENETIC PRINCIPLES

FORENSIC DNA IDENTIFICATION

VNTRs

DNA Profiling

Matching and Binning of VNTRs

Allele (Bin) Frequencies

PCR-Based Systems

ASSURING LABORATORY ACCURACY

POPULATION GENETICS

Randomly Mating Populations

Population Structure

Dealing with Subpopulations

Persons from the Same Subpopulation

SOME STATISTICAL CONSIDERATIONS

The Reference Database

Match Probability, Likelihood Ratio, and Two Fallacies

Bayes's Theorem

Suspect Identified by Database Search

Uniqueness

Uncertainty About Estimated Frequencies

PCR-Based Tests

THE CEILING PRINCIPLES

DNA IN THE COURTS

CONCLUSIONS AND RECOMMENDATIONS

Admissibility of DNA Evidence (Chapter 2)

Laboratory Errors (Chapter 3)

Proficiency Tests

Duplicate Tests

Population Genetics (Chapter 4)

Evidence DNA and Suspect from the Same Subgroup

Insufficient Data

Dealing with Relatives

Statistical Issues (Chapter 5)

Database Searches

Matching and Binning

Ceiling Principles

Further Research

Legal Issues (Chapter 6)

ILLUSTRATIVE EXAMPLE

A Typical Case

Suspect Found by Searching a Database

Suspect and Evidence from the Same Subpopulation

A PCR-Based System

1 Introduction

THE 1992 NATIONAL RESEARCH COUNCIL REPORT

THE COMMITTEE'S TASK

THE VALIDITY OF DNA TYPING.

THE USE OF DNA FOR EXCLUSION

CHANGES SINCE THE 1992 NRC REPORT

Population Data

Technical Improvements

PATERNITY TESTING

REGULATORY OVERSIGHT

SEEMINGLY CONTRADICTORY NUMBERS

VERY SMALL PROBABILITIES

FINGERPRINTS AND UNIQUENESS

DESIGNATING POPULATION GROUPS AND SUBGROUPS

THE NATURE OF OUR RECOMMENDATIONS

2 Genetic and Molecular Basis of DNA Typing

FUNDAMENTALS OF GENETICS1

VNTR TYPING

PCR-BASED METHODS

CONCLUSIONS

3 Ensuring High Standards of Laboratory Performance

QUALITY CONTROL AND QUALITY ASSURANCE IN THE LABORATORY

Current QC and QA Guidelines

The Role of Proficiency-Testing and Audits

SAFEGUARDING AGAINST ERROR

Sample Mishandling and Data-Recording Errors

Faulty Reagents, Equipment, Controls, or Technique

Evidence Contamination

Analyst Bias

SHOULD AN ERROR RATE BE INCLUDED IN CALCULATIONS?

RETESTING

Laboratory Errors

4 Population Genetics

ALLELE AND GENOTYPE PROPORTIONS

RANDOM MATING AND HARDY-WEINBERG PROPORTIONS

HW Proportions in a Large Sample

Exclusion Power of a Locus

DEPARTURES FROM HW PROPORTIONS

Inbreeding and Kinship

Population Subgroups

SUBPOPULATION THEORY

TAKING POPULATION STRUCTURE INTO ACCOUNT

MULTIPLE LOCI AND LINKAGE EQUILIBRIUM

How Much Departure from LE is Expected?

What Do the VNTR Data Show?

RELATIVES

PERSONS FROM THE SAME SUBPOPULATION

PCR-BASED SYSTEMS

A Conservative Rule for PCR Loci

DEVELOPMENT OF NEW SYSTEMS

INADEQUATE DATABASES

APPENDIX 4A

5 Statistical Issues

DATA SOURCES

MATCH PROBABILITY AND LIKELIHOOD RATIO

Mixed Samples

Bayes's Theorem.

Bayes's Theorem in Criminal Cases

TWO FALLACIES

SUSPECT IDENTIFIED BY A DNA DATABASE SEARCH

UNIQUENESS

STATISTICAL ASPECTS OF VNTR ANALYSIS

Determining a Match

Binning

Floating bins

Fixed bins

CONFIDENCE INTERVALS FOR MATCH PROBABILITIES

ALLELES WITH LOW FREQUENCY

INDIVIDUAL VARIABILITY AND EMPIRICAL COMPARISONS

Geographical Subdivision

Differences Among Subgroups

Different Races

MORE CONSERVATIVE FORMULAE

DIRECT COUNT FROM A DATABASE

Statistical Issues

APPENDIX 5A

APPENDIX 5B

APPENDIX 5C

6 DNA Evidence in the Legal System

LEGAL STANDARDS AND PROCEDURES

The Defendant's Right to Discovery

Expertise

General Acceptance and Sound Methodology

Balancing and Weight

Trends in the Admissibility of DNA Evidence

TYPING METHODS

VNTR Profiling

PCR-Based Testing

LABORATORY ERROR

Population and Subpopulation Frequencies

Convenience Samples

The Disagreement About Substructure

Ceiling Frequencies in Court

EXPLAINING THE MEANING OF A MATCH

The Necessity for Quantitative Estimates

Qualitative Testimony on Uniqueness or Infrequency

Quantitative Assessments: Frequencies and Match Probabilities

Quantitative Assessments: Likelihood Ratios and Posterior Odds

Importance of Behavioral Research

APPENDIX 6A

Abbreviations

Glossary1 A

Biographical Information

COMMITTEE CHAIR

COMMITTEE MEMBERS

COMMITTEE ADVISOR

STAFF

Acknowledgments

References2

Index.

Notes:

Bibliographic Level Mode of Issuance: Monograph

Includes bibliographical references (p. 226-0239) and index.

ISBN:

0-309-13440-4

1-280-19283-6

9786610192830

0-309-55662-7

0-585-03781-7

OCLC:

726823023