• False Exclusions - perpetrator may go free
• False Inclusions - innocent individual may be falsely convicted
• False exclusions are more common than false inclusions
• False inclusions are of greater concern in legal system because the U.S. considers conviction of an innocent party to be a more serious problem than allowing a guilty person to go free

Issues of Concern with STR/Microsatellite Analysis

• Correct ID of known genotype
  • extraneous alleles (mixture/contamination)
  • allele dropout
• No more than 2 alleles (could be only one) for any one individual at any one locus
• No fewer than 1 allele (could be two) for any one individual at any one locus
• Peak heights should be similar for both alleles of heterozygous individual
• No stutter products
• Consistent results when testing same sample (or multiple samples from same individual)
• Each common allele readily separated (distinguished) from the others
• Size standard produces predicted fragment pattern
• Matrix file used prevents dye pull-up
• Peaks sharp
• Peaks within vertical range
• Peals outside of size range for a particular locus are indicative of a problem
• Proper protocol followed - volumes/times/reagents recorded in notebook or on lab sheets
• Deviations from protocol noted for troubleshooting purposes
• Samples logged in and out
• Chain of custody maintained by proper handoffs/signoffs

Certification

• Qualifications of individual criminalist/technician
• Voluntary not Required - encouraged (highly favorable) - helps credibility in court
• Exams administered by American Board of Criminalistics (ABC)
• General Knowledge Exam ==> Diplomate
• Written Specialty Exam plus annual hands-on proficiency testing ==> Fellow
• Technical Specialist - combines specialist exam plus some questions from General Knowledge Exam - not widely accepted yet
• Failure of more than one proficiency test in a 4-year period ==> temporary revocation of Fellow staus
• Reinstated when deficiency is remedied to satisfaction of the ABC review committee and a successful re-test is completed
• Many laboratories employ non-certified technicians
• However, many laboratories will only allow certified technicians to present evidence in court
• Some labs have a certified technician as a supervisor over non-certified technicians and the certified individual must sign off on all procedures and results

Accreditation

• Qualifications of the testing laboratory
• Voluntary & Self-Regulated
• Standards established and accreditation overseen by American Society of Crime Lab Directors/ Laboratory Acreditation Board (ASCLD/LAB)
• Accreditation also offered by the National Forensic Science and Technology Center (NFSTC)
• Laboratory must demonstrate that they meet standards for:
  • management
  • operations
  • personnel
  • procedures
  • equipment
  • physical plant
  • security
  • health & safety
• Laboratory must also participate in a periodic proficiency testing program
• Accreditation is for 5 years providing standards are maintained
• Initial accreditation and reaccreditation require a full review of the laboratory including an on-site inspection

SWGDAM (The Scientific Working Group on DNA Analysis Methods)

• Formerly TWGDAM (The Working Group on DNA Analysis Methods)
• Established at request of FBI
• Forensic scientists and experts from academic communities
• Forum for Forensic Laboratories to:
  • discuss issues
  • conduct studies
  • decide on methods to be used
  • exchange data
  • establish laboratory guidelines
• Established
  • Quality Control/Quality Assurance guidelines
  • Database development guidelines
  • Validation guidelines for new systems
  • Consensus statements regarding:
    • validity and reliability of various DNA techniques and calculations
    • guidelines for statistical treatment of DNA data
    • responses to DNA-testing challenges

NRC I and II (National Research Council Reports)

• The National Research Council is a part of the National Academy of Sciences
• Prestigious body of well-respected sciences
• DNA first used in forensic casework in UK in 1985
• FBI began testing in 1988
• Questions of reliability and validity (and laboratory dependability) began to surface
• NRC was asked, and agreed, to address the genral applicability and appropriateness of DNA technology to forensic science
• Established the Committee on DNA Technology in Forensic Science
• First report issued in 1992 (NRC I)
• Engendered some controversy
• Second report issued in 1996 to clarify (NRC II)
• Specific recommendations from both reports are detailed in Appendix I of your text (pp 253-262)

NRC I (DNA Technology in Forensic Science; 1992)

Recommendations in 6 Areas
• Technical considerations
• Statistical interpretation
• Laboratory standards
• Databanks & privacy
• Legal considerations
• Societal & Ethical issues
• Controversial Areas

  • Statistical interpretation - had no basis in scientific principle
  • "Ceiling principle" for rare alleles was conservative but had no scientific basis
  • "Interim ceiling principle" was even more conservative
  • Laboratory error rates were discussed but an error was never defined
  • Acceptable vs, unacceptable risk for error was not defined
  • Called for QA/QC standardization
  • Argued for case-by-case admissibility
  • Called for national databank with updatable technologies
  • Cautioned against overselling of DNA evidence in court
  • Who should render expert opinion
    • Forensic scientists with knowledge of the field and of application - well-informed but may be biased
    • Molecular biologists/Geneticists - Greater general knowledge and unbiased but no experience with forensic application ==> incomplete knowledge

NRC II (The Evaluation of Forensic DNA Evidence; 1996)

• Refines the statistical interpretation using more meaningful scientific/statistical principles (e.g. the product rule)
• Incorporates new data on population substructure
• Provides additional consideration of lab operations and the risk of lab error
• Withdrew recommendation of "Ceiling Principle" and/or "Interim Ceiling Principle" in favor of methods based on (but appropriately modified from) population genetics
• Discouraged "adjustment of frequencies by combination with an error rate"
• Promoted raising lab standards
• Emphasized current lab practices not past performance
• Recommended saving a portion of any sample for subsequent independent testing
• Stated that "reliability and validity of properly collected and analyzed DNA data should not be in doubt"

Federal DNA Advisory Committee (DNA Advisory Board; DAB)

• Established by the DNA Identification Act of 1994
• Appointed by FBI from nominees submitted by National Academy of Sciences and other organizations
• Provide guidelines on a variety of issues
  • Quality Assurance Standards for Forensic DNA Testing Laboratories - 1998
  • Quality Assurance Standards for Convicted Offender DNA Databsing Laboratories - 1999
  • Quality Assurance Audit for Forensic DNA and Convicted Offender DNA Databasing Laboiratories - 2000
    (to be used by Inspection Teams)
• Substantial power
  • Any agency requesting federal funding for DNA development must comply with standards set by DAB
  • De facto standard for any laboratory providing DNA serevices to courts
• Provided guidelines on "Statistical and Population Genetics Issues Affecting the Evaluation of the Frequency of Occurrence of DNA Profiles Calculated from Pertinent Population Database(s)" - Appendix H (pp. 245-252)
  http://www.fbi.gov/hq/lab/fsc/backissu/july2000/dnastat.htm
• DAB was Phased Out in 2000 and responsibilities assumed by SWGDAM

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