The History of DNA Forensics

1. The History of DNA Forensics

2. What is DNA? • DNA is the chemical substance which makes up our chromosomes and controls all inheritable traits (eye, hair and skin color) • DNA is different for every individual except identical twins • DNA is found in all cells with a nucleus (white blood cells, soft tissue cells, bone cells, hair root cells and spermatozoa) • Half of a individual’s DNA/chromosomes come from the father & the other half from the mother.

3. DNA Review: • DNA is a double-stranded molecule. • The DNA strands are made of four different building blocks. • An individual’s DNA remains the same throughout life. • In specific regions on a DNA strand each person has a unique sequence of DNA or genetic code.

4. Repeated DNA Sequences • VNTR’s--Tandemly repeated DNA sequences. • Interspersed Transposable Elements • SINES • LINES

5. Cutting Variable DNA Sections Father: DNA is a long,long,long long molecule that is tightly wound. Mother: DNA is a long,long molecule that is tightly wound. Restriction Enzymes are proteins that cut DNA molecules at specific cut sites.

6. The History of Forensic DNA Analysis Resembles a War. • Laboratories • Legal System (Prosecutors / Defense Attorneys) • Media Coverage

7. Conventional Blood Typing • Used for more than 50 years • Utilized ABO blood typing groups • Identified genetic variations in blood proteins, tissue specific proteins and serum protein types • Major problem is that the conventional blood protein markers are not found in semen.

8. Development of DNA Analysis Techniques (1970’s) • RFLP (Restriction Fragment Length Polymorphism) • Southern Blot

9. Restriction Fragment Length Polymorphism • Restriction Enzymes (biological catalysts) cut DNA whenever they encounter a specific DNA sequence. • Gel electrophoresis separates the fragments of DNA according to their length.

10. Size Separation of DNA by Gel Electrophoresis Total DNA Gel Electrophoresis Restriction Enzymes

11. Southern Blot • A short segment of DNA that is complementary to a portion of the desired DNA fragments is labeled with a radioactive atom. • This probe binds to the fragment of interest on the gel electrophoresis. • Visualized using X-ray film.

12. A Schematic Representation of RFLP and Southern Blot of a Single-locus VNTR

13. History of DNA Analysis (1980’s) • In 1980 David Botstein and others used RFLP to construct a human gene map. • Used genetic variations as markers

14. Kary Mullis Invented PCR Methods (1984) • Polymerase Chain Reaction amplifies short specific regions of DNA • PCR is an in vitro technique that can yield millions of copies of desired DNA • Does not use radioactivity

16. PCR Amplifies DNA Exponentially

17. In 1984, Alec Jeffreys developed “DNA Fingerprinting.” • Was searching for disease markers • Applied the technique to personal identification • Demonstrated that the DNA could be retrieved from old dried blood stains • Applied the technique to high-profile forensic tests

18. A Typical DNA Profile

19. The Pitchfork Case (1986 & 1987) • Jeffreys was consulted in the case of the murder and rape of two British schoolgirls. • Suspect cleared from analysis of semen samples at the scene and blood samples from the suspect. • “Blooded” 4583 men • Analysis of blood sample from Colin Pitchfork provided a match.

20. Pennsylvania v Pestinikas (1986) • First PCR case done in the United States • Involved allegations of switching body parts at a funeral home

21. Commercial Development of Forensic DNA Testing in the United States: • Lifecodes Corporation—Founded in 1982 in Valhalla, NY as diagnostic company. Began performing forensic DNA testing in 1987 • Cellmark—The US branch of Britain’s Imperial Chemical Industries opened in Germantown, MD in 1987. Performed the testing for the prosecutor in the Simpson case.

22. Trial of Accused Rapist Tommy Lee AndrewsNovember 3, 1987 • First case in the U.S. to identify a criminal by DNA • Trial held in Orlando, Florida • A scientist from Lifecodes and a biologist from M.I.T. testified that semen left on the victim matched Andrew’s DNA (1 in 10 billion) • November 6, 1987 jury returned a guilty verdict.

23. The two major private companies raced each other to the courtroom. • In a shroud of secrecy and an environment of expediency they disregarded the usual methods of testing new scientific methods • Publication and Peer Review • Standardization • Replication • Evaluation of Performance

24. DNA analysis was considered an “infallible” prosecution tool. • “You can’t argue with science.” a juror in Queens • “[DNA evidence] is the single greatest advance in the search for truth since the advent of cross-examination.” Judge Joseph Harris of Albany, NY

25. DNA analysis was considered an “infallible” prosecution tool. • “In rape cases, when the semen has been matched with the defendant’s and the chance that it came from another person is 33 billion to 1, you don’t need a jury.” Robert Brower, defense attorney.

26. New York v Castro • First successful defense against DNA analysis • Jose Castro, janitor in a nearby building, was accused of the stabbing deaths of Vilma Ponce and her two-year old daughter, Natasha.

27. New York v Castro • Lifecodes Corporation reported that the blood found on Castro’s watch matched that of Vilma Ponce with a frequency of 1:189,200,000 in the Hispanic population. • Defense mounted the first successful attempt to have DNA evidence excluded.

28. New York v Castro • Two defense and two prosecution witnesses agreed that Lifecodes had failed to use generally accepted scientific techniques. Their data was poor and they did not follow procedures for interpreting the data • Castro later confessed and pled guilty to the murders.

29. The FBI and The Royal Canadian Mounted Police Set Up DNA Laboratories • 1987 FBI with NIH began collaborative research to establish DNA identification techniques • In late 1988 FBI set up their own laboratory at their Pennsylvania Avenue headquarters • RCMP also set up their own DNA laboratory.

30. FBI Worked With Pioneers in the Field • They used four different DNA probes • GeneLex • Dr. Raymond White of Howard Hughes Medical Center • Lifecodes • Cellmark

31. DNA probes and primers are the key patented biomolecules used to identify the individual genetic variability.

32. The FBI and RCMP brought standardization to the indusdry. • Established detailed laboratory protocols • Performed validation studies • Cut through the competitive nature that clouded the environment of the testing methods and tools

33. Defense Strategy • In 1989, National Association of Criminal Defense Lawyers (NACDL) set up a DNA Task Force. • Headed by Barry Scheck, a professor at Benjamin N. Cardozo Law School and Peter Neufeld, a private attorney in Manhattan

34. Defense Strategy • Tried to reopen all the convictions involving evidence processed by Lifecodes • Escalated the conflict surrounding DNA testing • Launched a public relations campaign critical of DNA typing

35. In 1990 Scheck and Neufeld Prepare for United States vs Yee. • Three members of Hell’s Angels motorcycle gang of Cleveland Ohio were accused of killing David Hartlaub thinking he was a member of a rival gang • The victim was shot 14 times with a MAC 10 machine gun.

36. Blood Evidence on the Scene • Most was determined to be that of the victim • Some belonged to one of the defendants • Theory—a ricocheting bullet had hit one of the suspects.

37. Prosecution Expert Witnesses • Thomas Caskey, Baylor College of Medicine • Kenneth Kidd, Yale geneticist • Bruce Budowle, FBI DNA scientist

38. Defense Expert Witnesses • Richard Lewontin, geneticist from Harvard • Daniel Hartl, geneticist at Washington University • Eric Lander, mathematician and geneticist at M.I.T.

39. Defense Argued: • FBI’s published articles on matching criteria were “ambiguous” and “inconsistent.”

40. Prosecution Countered: • In spite of disputes over match criteria, the multi-probe match produced a highly likelihood that the specimens came from two different people.

41. United States vs Yee • DNA matches were admitted as evidence at the trial and at the appeal. • The documents from the FBI would later find their way into the courtroom.

42. The National Academy of Science’s National Research Council (NCR) Report • A federal study intended to be the definitive study on the problems of forensic DNA • The most contended issue--How to calculate statistical probability • The frequencies of sub-groups could differ widely from that in the larger population

43. NCR Report—DNA Technology in Forensic Science (1992) Criticized: • Ceiling principle • No population geneticists or staticians on the panel • Inconsistencies • Did not address paternity cases or PCR

44. NCR Report—DNA Technology in Forensic Science • The report was to be the final word in clarifying the role of DNA forensics. • This document is often cited by defense lawyers in arguing of the exclusion of DNA evidence.

45. The Media and DNA Forensics • First the Media proclaimed that the “new technology was a miracle.” • It recorded it’s “glowing victories.” • Followed by giving opponents to DNA analysis a venue for airing objections and charges (many of which were unfounded and unchallenged)

46. The Media and DNA Forensics • The Washington Post headline read, “Panel Backs DNA Tests as Crime Evidence.”

47. Nature Published Articles Exploring Forensic DNA • Alec Jeffreys announced his methods in Nature. • “DNA fingerprinting dispute laid to rest” Budowle and Lander Oct. 27, 1994

48. “Lander and Budowle declare that after 400 technical papers, 100 scientific conferences, three sets of DNA analysis guidelines, 150 court cases, and an exhaustive three-year study by the National Research Council—’The DNA fingerprinting wars are over.’”

49. 1994 • National Research Council reconvened to try to rectify the deficiencies of their first report. • The trial of the century convened: “Dollars v DNA” or California v OJ Simpson.

50. Summary • Forensic DNA testing was developed rapidly by short-sighted commercial interests • Standards were not developed as quickly as necessary • Prosecution oversold DNA evidence • Expert witnesses had a vested interest in fueling the controversy.