DNA Criminalist and Court Appearance

1. Margaret Aceves State of California Dept. Of Justice Jan Bashinski DNA Laboratory DNA Criminalist and Court Appearance

2. If Case goes to Court, • Our role as Criminalists is to present the facts to the jury • Case approach is to leave sufficient evidence for re-analysis.

3. DNA Criminalist in court • Deputy District Attorney qualifies DNA Analyst as an expert through their education, training and experience • What is DNA is explained to the court and jury. • The DNA Analysis is briefly explained • Specific DNA results are presented • Significances of match is explained

4. Qualifying as an Expert • Education of a DNA Analyst • A Bachelors degree in a Natural Science AND • FBI requires specific courses to participate in CODIS • Molecular Biology • Genetics • Biochemistry • Training in statistics

5. Training of a DNA Analyst

6. Experience of a DNA Analyst • How many cases completed • How many times have you testified • Results of Proficiency

7. DNA Basics What is DNA? DNA stands for Deoxyribonucleic Acid • It is the genetic material found in all plants and animals. • “Blueprint of Life” – It contains all of the information for passing genetic traits from one generation to the next generation.

8. Where is DNA found in your body? • Our bodies are made up of cells. • The nucleus of each cell contains DNA.

9. Types of Biological Evidence • Blood • Semen • Saliva • Hair • Sweat • Teeth • Bone • Tissue • Urine Important Point: All cells in your body have the same DNA.

10. How is DNA inherited? DNA is packaged in the form of chromosomes. Humans have 23 pairs of chromosomes. • ½ is inherited from your Mother • ½ is inherited from your Father

11. Human Chromosomes

12. Terms to Understand • Chromosome – Physical structure that DNA is packaged in. Humans have 23 pairs. • Genetic Marker (locus) – specific location on a chromosome. • Allele – Alternative possibility for a genetic marker.

13. Forensic DNA Typing • More than 99% of our DNA is the same (this is why we all have one head, two eyes, two arms, two legs, etc). • Short tandem repeats (STRs) are used in forensic DNA typing. • STRs vary from person to person by the number of the repeating sequences.

14. AATG Short Tandem Repeats (STRs) 7 repeats 8 repeats the repeat region is variable between samples while the flanking regions are constant

15. TPOX D3S1358 TH01 D8S1179 D5S818 VWA FGA D7S820 CSF1PO Sex-typing AMEL D13S317 AMEL D16S539 D18S51 D21S11 Location of 13 CODIS Core STR Loci

16. Process of Forensic DNA Analysis • Document evidence • Sample evidence • Apply chemicals and heat to separate the DNA from the rest of the cellular components • Purify DNA • Determine concentration of DNA

17. Actual Analysis • Hours of on hands sample manipulation

18. How much DNA? • qPCR Instrument to quantitate the DNA extract

19. Amplification of DNA • Polymerase Chain Reaction (PCR) • Areas of DNA are replicated millions of times.

20. Polymerase Chain Reaction (PCR)

21. Applied Biosystems 3130 Genetic Analyzer

22. 3130 is a 4 capillary instrument

23. DNA Analysis-hours at the computer!

24. Identifiler- 15 loci and amelogenin

25. Identifiler- 15 loci and amelogenin

26. Identifiler Tables

27. IDENTIFILER LOCI

28. Analysis continued • A report with a table of results is generated • The laboratory work and report are technically reviewed by a qualified analyst. • The laboratory work and report are administratively reviewed. • Report is released.

29. Comparison of Genetic Profiles • Possible Outcomes of comparison of DNA Results to Known Reference DNA profiles • Inclusion (reference profile matches evidence profile) • Exclusion (reference profile does not match evidence profile) • Inconclusive (not enough information to make comparison)

30. Matching results from comparison • What is the significance of a match between the reference profile and the evidence profile? Another way to think about this question is: How rare is the evidence profile in the population?

31. How rare is the evidence profile? First: Population Study • A study that counts how many times a certain allele is seen for a genetic maker. • The published data from the FBI is used for the 3 major racial/ethnic groups (Caucasian, African American and Hispanic).

32. 45 40 35 30 Caucasians (N=427) 25 Percent Blacks (N=414) 20 Hispanics (N=414) 15 10 5 0 6 7 8 9 9.3 10 Number of repeats STR Allele Frequencies TH01 Marker *Proc. Int. Sym. Hum. ID (Promega) 1997, p. 34

33. Conveying Frequency • A dice is six-sided. Therefore one in six= 1/6=0.1667. • A 20-car parking lot full of cars, how many are blue? 5, 5 in 20= 5/20= 0.25

34. How rare is the evidence profile? Second: Apply Statisti • Multiply the allele frequencies for each genetic marker. D3S1358 Evidence 15 , 16 .24631 or 25% X .23153 or 23% = .11 (in Caucasians)

35. How rare is the evidence profile? Second: Apply Statistics • Multiply the frequencies for each genetic marker together to determine the overall frequency for entire the profile. D3S1358 VWA FGA D8S1179 15, 16 16, 18 22,25 13, 15 .11 X .09 X .03 X .07 1 in # quadrillion, 15 zeros Frequencies of 11 more genetic markers =

36. Discrimination power of Identifiler

37. Population of Calif. and USA

38. World Population ~ 6.79 Billion

39. Conclusion • The evidence is presented and the strength of the match conveyed. • We leave the decision of guilt or innocence for the jury to decide.