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DNA Transfer for Lawyers

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1 DNA Transfer for Lawyers
Continuing Legal Education Office of the Allegheny County District Attorney February, 2019 Pittsburgh, PA Mark W Perlin, PhD, MD, PhD © Justice Through Science® 2019 Cybergenetics ©

2 Unexpected DNA The Cat in the Hat holding an umbrella and speaking to a fish in its bowl from “The Cat in the Hat”. It should not be here It should not be about DNA won’t appear When the suspect is out!

3 Random match probability
Simple match statistic for simple DNA evidence

4 DNA mixture eye of newt toe of frog Double, double toil and trouble

5 Pittsburgh skyline

6 Draw a threshold

7 Same heights & vacant lots

8 Simplify data to interpret mixture
Apply threshold to find “alleles” Add allele frequencies (f1 + f2 + …) Square sum, take reciprocal Locus “probability of inclusion” (PI) Multiply locus PI values Combined (CPI) match statistic

9

10 Accurate, unbiased computing

11

12

13 DNA transfer Don’t fear DNA Laughed the clever defense
The Cat in the Hat holding a pink-stained shirt in a bathtub from “The Cat in the Hat Comes Back”. Don’t fear DNA Laughed the clever defense When it transfers we say That it’s not evidence!

14 DNA transfer Lawyers argue Scientists test

15

16 Wet DNA transfer

17 Dry DNA transfer END

18 Justice Denied: Mr. Hopkins Invisible Semen
18 Justice Denied: Mr. Hopkins Invisible Semen American Investigative Society of Cold Cases AISOCC Annual Conference June, 2016 St. Louis, MO Mark W Perlin, PhD, MD, PhD Cybergenetics, Pittsburgh, PA Cybergenetics © Cybergenetics ©

19 1979 murder of Janet Walsh • 23 year old woman • Monaca, Pennsylvania
• strangled with bandana • face down in her bed • nightshirt top only • bathrobe tie on hands • divorcing husband • multiple partners Janet Walsh

20 The crime scene blue nightshirt bathrobe tie
Viewed as homicide, not sex crime

21 Prosecutor theory • sexual misadventure • man straddling woman
• bandana asphyxiation • ejaculates, and hits nightshirt & robe tie • explains coincidental location on two items Frank Martocci How and when the DNA got there (unusual expert testimony)

22 Defense theory • Hopkins wasn’t there when Walsh died
• old DNA from before • no coincidences • DNA is expected • no semen on hands • with prior sexual relations,     DNA is not probative Hon. James Ross DNA doesn’t say how or when it was left (typical expert testimony)

23 DNA transfer Increases with: • moisture • pressure • friction
• absorbent     cotton material

24 From nightshirt to robe tie
• Walsh struggled, perspired • back moist, shirt wet • old semen stain on shirt • wet shirt moistens robe tie • pressure and friction from     tied hands behind back • sperm moves from shirt     to bathrobe tie • DNA detected years later END

25 Computer Interpretation of Quantitative DNA Evidence
Commonwealth of Pennsylvania v. Carlos Harris August, 2017 Pittsburgh, PA Mark W Perlin, PhD, MD, PhD Cybergenetics, Pittsburgh, PA Cybergenetics © Cybergenetics ©

26 26

27 DNA biology Cell Chromosome Locus Nucleus

28 allele length is 10 repeats
Short tandem repeat DNA locus paragraph Take me out to the ball game take me out with the crowd buy me some peanuts and Cracker Jack I don't care if I never get back let me root root root root root root root root root root for the home team, if they don't win, it's a shame
for it's one, two, three strikes, you're out at the old ball game 23 volumes in cell's DNA encyclopedia "root" repeated 10 times, so allele length is 10 repeats

29 DNA genotype 10, 12 A genetic locus has two DNA sentences,
one from each parent. An allele is the number of repeated words. locus A genotype at a locus is a pair of alleles. mother allele 1 2 3 4 5 6 7 8 9 10 10, 12 ACGT repeated word Many alleles allow for many many allele pairs. A person's genotype is relatively unique. father allele 1 2 3 4 5 6 7 8 9 10 11 12

30 DNA evidence interpretation
Lab Infer Evidence item Evidence data Evidence genotype 10, 12 DNA from one person Compare Known genotype 10, 12

31 DNA mixture interpretation
Lab Infer Evidence item Evidence data Evidence genotype 10, 20% 11, 30% 11, 50% DNA from two people Compare Known genotype 11, 12

32 Computers can use all the data
Quantitative peak heights at locus D7S820 peak size peak height

33 How the computer thinks
Consider every possible genotype solution Better explanation has a higher likelihood Explain the peak pattern

34 How the computer thinks
Consider every possible genotype solution Better explanation has a higher likelihood Explain the peak pattern

35 How the computer thinks
Consider every possible genotype solution Better explanation has a higher likelihood Explain the peak pattern

36 How the computer thinks
Consider every possible genotype solution Better explanation has a higher likelihood Explain the peak pattern

37 How the computer thinks
Consider every possible genotype solution Worse explanation has a lower likelihood

38 Evidence genotype Objective genotype determined solely from the DNA data. Never sees a comparison reference. 45% 37% 10% 8%

39 How much more does the suspect match the evidence
DNA match information How much more does the suspect match the evidence than a random person? Prob(evidence match) Prob(coincidental match) 9x 45% 5%

40 Match information at 15 loci

41 Is the suspect in the evidence?
A match between the Glock pistol slide serrations and Carlos Harris is: 221 billion times more probable than a coincidental match to an unrelated African-American person 62.9 billion times more probable than a coincidental match to an unrelated Caucasian person 133 billion times more probable than a coincidental match to an unrelated Hispanic person

42 Match statistics 6.51 million 62.9 billion Item Description 28 Daren
Scott 35 Carlos Harris 36 Michael Shipps-Smith 37 Jaron Satterwhite 18A1 Glock pistol frame 6.51 million 18B1 Opening and follower of the magazine 20A Glock pistol slide serrations 62.9 billion

43 Match statistics END 6.81 10.80 Item Description 28 Daren Scott 35
Carlos Harris 36 Michael Shipps-Smith 37 Jaron Satterwhite 18A1 Glock pistol frame 6.81 18B1 Opening and follower of the magazine 20A Glock pistol slide serrations 10.80 END

44 44

45 45 Wet DNA transfer END

46 Computer Interpretation of Quantitative DNA Evidence
Commonwealth of Pennsylvania v. Defendant April, 2018 Pittsburgh, PA Mark W. Perlin, PhD, MD, PhD Cybergenetics, Pittsburgh, PA Cybergenetics © Cybergenetics ©

47 Match statistics 2.21 quadrillion 9.29 thousand Item Description K1
Victim K2 Defendant K3 Elimination Q3M Underwear, sperm fraction 2.21 quadrillion 9.29 thousand

48 END

49 Computer Interpretation of Quantitative DNA Evidence
State of Georgia v. Johnny Lee Gates May, 2018 Columbus, GA Mark W. Perlin, PhD, MD, PhD Cybergenetics, Pittsburgh, PA Cybergenetics © Cybergenetics ©

50 Match statistics one in 1.5 million one in 134 thousand
Item Description 76C Johnny Lee Gates 76C robe belt side 1 swab one in 1.5 million 76C robe belt side 2 swab one in 134 thousand 76C front of black tie swab one in 4.33 million 76C back of black tie swab one in 963 million 76C robe belt M-vac filter one in 902 trillion 76C black tie M-vac filter one in 825 billion

51 51 END

52 Computer Interpretation of Quantitative DNA Evidence
Commonwealth of Virginia v. Bernard Duse, Jr. August, 2018 Warrenton, VA Mark W Perlin, PhD, MD, PhD Cybergenetics, Pittsburgh, PA Cybergenetics © Cybergenetics ©

53 Match statistics 227 octillion 40.6 quintillion Item Description 19
Rex Olsen 65 Bernard Duse, Jr. 13 Pants pocket octillion 40.6 quintillion

54 54 END

55 Computer Interpretation of Quantitative DNA Evidence
People of California v. John Doe March, 2019 Mark W Perlin, PhD, MD, PhD Cybergenetics, Pittsburgh, PA Cybergenetics © Cybergenetics ©

56 Are the references in the evidence?
Based on the TrueAllele results, comparing all evidence with all references produced exclusionary match statistics.

57 57 END

58 TrueAllele® interpretation
58 TrueAllele® interpretation • Courses • Newsletters • Newsroom • Presentations • Publications • Webinars TrueAllele YouTube channel

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