Fundamentals of Forensic DNA Typing

1. Chapter 18 Future Trends Fundamentals of Forensic DNA Typing Slides prepared by John M. Butler June 2009

2. Chapter 18 – Future Trends Chapter Summary As the power of forensic DNA typing has been demonstrated over the past two decades, there has been an accelerated growth to the field both in terms of depth and breadth. National DNA databases in the UK and US now number in the millions of samples and are actively used to solve crimes without suspects. While the standard set of STR markers in use will not likely change in the immediate future, techniques and genetic markers capable of extracting more information from a sample will continue to be developed. Trends in human identity testing will likely include the need for more characterized and validated genetic markers to aid application to more complex kinship analysis. Continued growth can be expected for the foreseeable future in this dynamic and important application of modern DNA science.

3. Possible scenarios for extending sets of genetic markers to be used in national DNA databases Core set of markers (e.g., CODIS 13 STRs) (a) Past and Present John M. Butler (2009) Fundamentals of Forensic DNA Typing, Figure 18.1 (b) Future (c) (d)

4. Loci Described Internal Validation Kit Developed Assay Constructed Use in Casework Kit Tested Population Study Court Presentation/ Acceptance Released to Community Information Gathered Research Development Forensic Application Government Funded or Private Typically by Commercial Manufacturer Forensic Labs Primary Steps in Adopting New Genetic Markers John M. Butler (2009) Fundamentals of Forensic DNA Typing, Figure 18.2

5. Challenging kinship search questions Lower amounts of DNA being tested Solution: Additional Markers (Y-chromosome, more STRs) and Multiple Reference Samples Core Competency Standard STR Typing (DNA Profile) Familial Searching Attempts (fishing for brothers or other relatives) Direct Matching (or Parentage) Sufficient DNA quantity (ng) John M. Butler (2009) Fundamentals of Forensic DNA Typing, Figure 18.3 Touch DNA Attempts (poor quality, mixtures, low-level stochastic effects) Solution: Replicate Testing

6. Challenging kinship search questions Lower amounts of DNA being tested Going Beyond the Core Competencies of Forensic DNA Testing Core Competency Standard STR Typing (DNA Profile) Familial Searching Attempts(fishing for brothers or other relatives) Direct Matching (or Parentage) Sufficient DNA quantity (ng) Solution: Additional Markers (Y-chromosome, more STRs) and Multiple Reference Samples John M. Butler (2009) Fundamentals of Forensic DNA Typing, Figure 18.3 Be very cautious when outside the box… Touch DNA Attempts (poor quality, mixtures, low-level stochastic effects) Solution: Replicate Testing

7. Q K (query) (database) Problems of Sibling Searches (a) (b) Mother ’ s alleles 12 13 8,9 12,13 John M. Butler (2009) Fundamentals of Forensic DNA Typing, Figure 18.4 8, 12 8, 13 8 s alleles 8,12 9,12 ’ 9,13 8,13 Father 9 9, 12 9, 13

8. A “Crystal Ball” to the Future? http://medicalcenter.osu.edu/images/healthconnections/winter2003/dnaCrystalBallIllustration.jpg

9. The Present The Future The Past http://www.utexas.edu/its/blackberry/images/blackberry.gif http://perswww.kuleuven.ac.be/~u0013314/computer.gif http://spockswomanjz.20fr.com/images/spock_2.jpg Progress is Being Made…

10. http://www.studyworksonline.com/cda/image/preview/0,1127,937,00.jpghttp://www.studyworksonline.com/cda/image/preview/0,1127,937,00.jpg 100 - 500 bp 50 - 150 bp 500 – 25,000 bp The DNA Field Moves Forward… The Present The Future The Past http://www.bioteach.ubc.ca/MolecularBiology/DNAfingerprint/ STRs SNPs RFLP miniSTRs

11. Lab Automation • Robotics • LIMS • Expert Systems

12. Unique Challenges with Adopting New Technologies by Forensic DNA Laboratories • Validation • Limited funding for capital equipment • Need for court acceptance (Frye and Daubert)

13. Unique Challenges to Forensic DNA Testing • High quality results needed (every time) because of impact on individual’s liberty • Regulated environment • Proficiency testing of analysts • Accreditation of labs • Auditing to National Quality Assurance Standards • Care to prevent contamination • The ever present politics and bureaucracy that exists in many government labs

14. Additional Challenges • Multiplex STR amplification require a fairly narrow amount of input DNA to product high quality results • High-throughput needs for databanking labs • Automated software for data review • An attitude of being (and needing to be) “error-free” • Separating biological fluids – perpetrator’s sperm from victim’s vaginal epithelial cells • Mixture components can be difficult to decipher

15. General Predictions for the Future • Refer to The Future of Forensic DNA (NIJ 2000) • STRs will play a major role for the foreseeable future due to large sizes of existing and rapidly growing DNA databases

16. Report published in Nov 2000 • Asked to estimate where DNA testing would be 2, 5, and 10 years into the future • Conclusions • STR typing is here to stay for a few years because of DNA databases that have grown to contain millions of profiles http://www.ojp.usdoj.gov/nij/pubs-sum/183697.htm

17. Introduction Biology of DNA Practical Issues Specific to DNA Evidence Forensic DNA Laboratory Assuring Quality in DNA Testing Understanding a Forensic DNA Lab Report Statistics and Population Genetics Mitochondrial DNA & Y-STR Analysis Forensic DNA Databases Collection of DNA Evidence Pretrial DNA Evidence Issues Victim Issues Trial Presentation Postconviction DNA Cases Emerging Trends Principles of Forensic DNA for Officers of the Court http://www.dna.gov/training/otc/

18. Content of Section 15 “Emerging Trends” from Officers of the Court • Topic 1 :: Single Nucleotide Polymorphisms (SNPs) • Topic 2 :: Automation • Microarrays (Chip Technology) • Portable DNA Typing Laboratory • Low Copy Number DNA Analysis • Topic 3 :: Microbial Forensics and DNA Testing • Topic 4 :: Other Non-human Forensic DNA Analysis • Topic 5 :: DNA Typing and Physical Appearance • Biogeographical Ancestry • Approximate Age Determination http://www.dna.gov/training/otc/

19. More Robotics Expert Systems Animal & Plant DNA Physical Characteristics Ethnicity Estimation http://www.manastungare.com/publications/genetic/dna.gif The Future

20. Crime Event Potential to “Contaminate” Analysis completed Laboratory analysis Opportunity for Adventitious Transfer Investigators arrive, detect, and recover evidentiary material Discovery Opportunity for DNA Transfer from Perpetrator Time Line Showing the Potential for DNA Deposition/Transfer Higher sensitivity techniques are most likely to pick up previously deposited (background) DNA Time Adapted from Gill, P. (2002) BioTechniques 32(2): 366-385, Figure 5

21. Conclusions • This is an exciting time to be involved in forensic DNA testing • However, it is a little scary because technology is advancing so rapidly on some fronts • Thus, training for both the scientific and legal communities is vital to make the most effective use of the wonderful power of DNA technology

22. Improvements in Forensic DNA Analysis • Biology • Improved DNA extraction with automation • New capabilities for recovery of information from degraded DNA samples (e.g., miniSTRs) • Technology • Parallel processing of DNA with capillary arrays • Expert systems for automated data interpretation • Genetics • Ethnicity estimations (with STRs and/or SNPs) • Larger Y-STR and mtDNA population databases Effective Training is Needed in All Areas

23. Training Materials Available or Planned • DNA Basics • Validation • STR Analysis and Capillary Electrophoresis • Y-Chromosome Analysis • Mitochondrial DNA Analysis • Expert Systems • Low-Copy Number (LCN) DNA Testing • Statistics • Mixture Interpretation http://www.cstl.nist.gov/biotech/strbase/training.htm

24. Training Materials and Review Articles • Workshops on STRs and CE (ABI 310/3100) • Taught with Bruce McCord (Florida Int. Univ.) • NEAFS (Sept 29-30, 2004) • U. Albany DNA Academy (June 13-14, 2005) • AAFS Feb 2006 Workshop #6 (February 20, 2006) • Other Workshops • Validation (August 24-26, 2005) • mtDNA Analysis (March 13-15, 2006) • Expert Systems (March 27, 2006) • PowerPoint Slides from Forensic DNA Typing, 2nd Edition • >150 slides available now (~1,000 planned) for download • http://www.cstl.nist.gov/biotech/strbase/FDT2e.htm • Review Articles • ABI 310 and 3100 chemistry – Electrophoresis 2004, 25, 1397-1412 • Core STR Loci – J. Forensic Sci. 2006, 51(2): 253-265 http://www.cstl.nist.gov/biotech/strbase/training.htm

25. Chapter 18 – Points for Discussion • What are some potential advantages to microchip CE devices? • Why are allelic ladders unnecessary with mass spectrometry techniques for STR analysis? • Why are forensic laboratories typically slow to adopt new technologies?