8.1 Introduction to DNA Fingerprinting and Forensics

1. 8.1 Introduction to DNA Fingerprinting and Forensics • Forensic science – intersection of law and science • Historic examples • 1800s – photography • Early 1900s – fingerprints • DNA Fingerprinting – 1985 • Unique signature found in each person’s genetic makeup

2. Fingerprinting Fingerprints have been used as a means of identification dating back well over two thousand years. Over the past century, the fingerprinting process has become more sophisticated, and it has been put to many more uses. The first documented fingerprints were taken in India in 1858 by Sir William J. Hershel. Soon thereafter advances were made on several fronts, and Sir Edward Henry devised a classification system around the turn of the 20th century that is still in practice today

3. Types of Fingerprints The three distinct types of fingerprints that can be recovered from a crime scene are patent, plastic, and latent prints. The knowledge of the types of fingerprints hastens the investigator's quest to identify the source of the fingerprints

4. PATENT PRINTS - are visible prints that occur when a foreign substance on the skin of a finger comes in contact with the smooth surface of another object. These prints leave a distinct ridge impression that is visible with the naked eye without technological enhancement of any kind. The tried and true "blood on his hands" evidence is an example of patent prints recovered from a crime scene or scene of interest to investigators. These foreign substances contain dust particles which adhere to the ridges of the fingers and are easily identifiable when left on an object.

5. PLASTIC PRINTS - are visible, impressed prints that occur when a finger touches a soft, malleable surface resulting in an indentation. Some surfaces that may contain this type of fingerprint are those that are freshly painted or coated, or those that contain wax, gum, blood or any other substance that will soften when hand held and then retain the finger ridge impressions. These prints require no enhancement in order to be viewed, because they are impressed onto an object and are easily observable.

6. LATENT PRINTS - are fingerprint impressions secreted in a surface or an object and are usually invisible to the naked eye. These prints are the result of perspiration which is derived from sweat pores found in the ridges of fingers. When fingers touch other body parts, moisture, oil and grease adhere to the ridges so that when the fingers touch an object, such as a lamp, a film of these substances may be transferred to that object. The impression left on the object leaves a distinct outline of the ridges of that finger. These fingerprints must be enhanced upon collection and, because they serve as a means of identifying the source of the print, they have proven to be extremely valuable over the years in the identification of its source.

7. Fingerprint Classification Fingerprint classification was developed by Sir Francis Galton in 1888 so that fingerprints could be retrieved in a reasonable amount of time. Sir Edward Henry expanded on Galton's system, and his manual filing system paved the way for the computerized classification systems that exist today.

8. The patterns of the ridges of our fingers are distinct in every individual. The four basic pattern classifications established by Sir Edward Richard Henry in 1896 are the arch, the loop, the whorls, and the composites (loops). Even to this day, Sir Henry's work on fingerprint patterns has held up under critical review.

11. Fingerprint Criticism The human element eliminates the infallibility of the fingerprint methodology as a personal identification mechanism. Mistakes can be made by the administrator in the process of printing, or by the expert who is responsible for making the final determination upon review of the possible matches. There is no data available that could quantify the percentage of errors made in personal identification through the utilization of fingerprints. There are also errors that can occur in the process of taking inked fingerprints. The fingerprints can be rendered illegible in the inking process if: The finger has not been rolled fully from side to side. The entire finger from its joint to its top has not been inked. The finger is not held securely in place. If the technician holds the fingers too loosely (or too securely), there could be a smudging or blurring of the prints, thus rendering a false pattern of prints. The usage of an inappropriate texture of ink can result in running of the ink and pattern distortion. Black printer's ink of a heavy texture is the advisable texture to use. The usage of too much ink can distort the patterns. The usage of too little ink will render the ridge patterns indistinguishable. Temporary disabilities to the fingerprint subject, such as cuts and blisters, can distort the pattern of the ridges. Excessive perspiration on the fingers of the subject may inhibit the ink from adhering to the fingers which would result in a blurred and inaccurate outcome. Errors made on the information card that accompanies the fingerprints, such as name, date of birth, sex and age can lead to complications as to the authenticity of the prints.

12. Defense Fingerprints are the ultimate source in the establishment of both the verification and recognition of a person's identity. This statement is based on three factors: fingerprints are distinct and unique to each individual, and no two people have identical prints; fingerprints are unchangeable over the course of a lifetime of a person; and fingerprints can be extracted from any surface they come into contact with. Inexpensive Reliable Fast Results Multi-faceted usage, including criminal, commercial, financial and civilian identifications Deterrent to crime and fraud Effective in streamlining business processes Preservation of personnel and financial resources in both the private and public sectors. Fingerprinting is the most basic and assured of security mechanisms. World wide computerized system is already in effect and extremely valuable during criminal investigations, since the database has been established. Identifies who a person is, as opposed to what a person has, such as a password, pin # or other identification of that nature. It establishes identification through the identification of unchangeable personal characteristics. A person may change hair color, but cannot alter fingerprints. One cannot guess, fake or forget fingerprints as can occur in non-biometric identification methodologies. The individual who is fingerprinted must be physically present in order to be processed.

13. 8.2 What Is a DNA Fingerprint? Every individual carries a unique set of genes Chemical structure of DNA is same, but the order of the base pairs differs Every cell contains a complete set of DNA that identifies the organism as a whole Only one tenth of 1% of DNA differs from person to person

14. 8.2 What Is a DNA Fingerprint? Two Main Types of Forensic DNA Testing RFLP (restriction fragment length polymorphism) Requires larger amounts of DNA DNA cannot be degradedRFLP was one of the first applications of DNA analysis to forensic investigation. With the development of newer, more efficient DNA-analysis techniques, RFLP is not used as much as it once was because it requires relatively large amounts of DNA. In addition, samples degraded by environmental factors, such as dirt or mold, do not work well with RFLP. Log onto: http://www.pbs.org/wgbh/nova/sheppard/analyze.html PCR (polymerase chain reaction) Less DNA and DNA can be partially degraded Extremely sensitive to contaminating DNA

15. Lets try a virtual DNA fingerprint lab! Want to see the evidence from the OJ case? http://www.law.umkc.edu/faculty/projects/ftrials/Simpson/simpson.htm Click on incriminating evidence Then DNA evidence (on the top in the center)

16. 8.2 What Is a DNA Fingerprint? DNA profiling depends on a small portion of the genome Exons code proteins (proteins that are expressed) These are the 99.9% that makes us similar Introns do not code for proteins (these are what make us different) The introns contain repeated sequences of between 1 and 100 base pairs Called variable number tandem repeats (VNTR’s) Some VNTR’s are inherited from mother and some from father

17. 8.2 What Is a DNA Fingerprint? DNA fingerprinting is restricted to the detection of microsatellites 1 to 6 nucleotide repeats dispersed throughout the chromosomes Probes used to identify the microsatellite surround the specific microsatellite being analyzed Also called short tandem repeats (STR) FBI has chosen 13 unique STRs for testing Combined DNA Index System (CODIS)

18. 8.3 Preparing a DNA Fingerprint Specimen Collection Search for sources of DNA Collection requires scrupulous attention to detail Wear disposable gloves; change them frequently Use disposable instruments Avoid talking, sneezing, and coughing Avoid touching any item that might contain DNA (face, nose, or mouth) Air-dry evidence before packaging; mold can contaminate a sample

19. 8.3 Preparing a DNA Fingerprint Enemies of Evidence Sunlight and high temperature Bacteria Moisture DNA fingerprinting is a comparative process Samples from crime scene must be compared to suspect DNA Best sample from suspect DNA is fresh, whole blood Extraction of DNA DNA can be purified Chemically (using detergents) Mechanically (pressure to force DNA out of cell)

20. 8.3 Preparing a DNA Fingerprint RFLP Analysis: Restriction Fragment Length Polymorphism Treat DNA with restriction enzyme Restriction enzyme cuts DNA at restriction sites Use several restriction enzymes in sequence or combined Use agarose gel electrophoresis to separate the pieces Gel is chemically treated or heated to denature the DNA Allows the binding of a single-stranded probe Try a virtual RFLP gel electrophoresis: http://learn.genetics.utah.edu/content/labs/gel/

21. 8.3 Preparing a DNA Fingerprint Southern Blot Technique Transfer DNA fragments from gel to nitrocellulose or nylon membrane Membrane incubated with a probe Short strand of complementary DNA with a radioactive or fluorescent tag Targeted area on the DNA fragment is called a locus Expose X-ray (photo) film to membrane to obtain permanent record of results

23. 8.3 Preparing a DNA Fingerprint PCR – used to amplify DNA found at crime scene into an amount that can be analyzed DNA produced is identical to the original sample Use amplified DNA in a Dot Blot Analysis DNA amplified by PCR is blotted onto specially prepared blot strips Each dot on the strip is a different DNA probe from human DNA Try a virtual one for yourself! http://www.wiley.com/college/boyer/0470003790/animations/animations.htm http://learn.genetics.utah.edu/content/labs/pcr/

24. STR Analysis STR: Small Tandem Repeats Use primers to amplify STR’s in DNA using PCR FBI uses 13 STR regions Odds that two individuals will have the same 13-loci DNA profile are more than one in a billion Check out the 13 loci profiles that get loaded into CODIS (the FBI’s DNA Database!) http://www.cstl.nist.gov/strbase/fbicore.htm

25. 8.4 Putting DNA to Use DNA fingerprinting is a comparative process Looking for alignment of bands or dots in the fingerprint All tests are based on exclusion Testing continues only until a difference is found If no difference is found after a statistically acceptable amount of testing, the probability of a match is high

26. Narborough Village Murders 1983 first reported use of genetic fingerprinting in a criminal case Sexual assault and murder of girl in United Kingdom The prime suspect’s DNA did not match that found at crime scene Police collected 5500 samples from the area’s population of likely suspects None of the DNA profiles matched the crime scene Friend of suspect had given a sample in the name of the suspect

27. Forest Hills Rapist DNA first used in United States – 1987 Victor Lopez tried for the sexual assault of three women Reported assailant was a black man; Lopez was not a black man DNA was a match to crime scene

28. Terrorism and Natural Disasters They have forced development of new technologies World Trade Center September 11, 2001 Used DNA techniques to identify the remains of victims Tremendous amount of debris, heat, and microbial decomposition of remains Hundreds of thousands of tissue samples from nearly 3,000 individuals

29. World Trade Center Evident that new strategies would be necessary to quickly prepare and organize DNA profiles and compare them with DNA profiles from relatives Within 24 hours, collection points had been established around the city Family filed missing person reports and provided cheek cell swabs for DNA isolation; personal items from the missing were also collected

30. World Trade Center Several companies were involved in developing new software programs to help match DNA samples from family members to DNA profiles of victims Used primarily STR, mtDNA, and SNP analysis

31. South Asian Tsunami December 2004 Lost over 225,000 lives mtDNA (mitochondrial), Y-STR’s (Y-DNA) Within 3 months, 800 victims had been identified

32. 8.5 DNA and the Rules of Evidence DNA fingerprinting had to meet legal standards regarding the admissibility of evidence 5 different standards used Relevancy test The Frye standard The Coppolino standard The Marx standard The Daubert standard

33. Simpson/Goldman Murders Collected 45 samples for DNA analysis, including known blood samples from the two victims and the suspect; blood drops found at the crime scene, in the suspect’s home, and in his car Pre-trial hearings announced that the DNA collected at the crime scene matched that of O.J. Simpson Defense lawyers attacked the procedures used in collecting, labeling, and testing the evidence Possibility that evidence was tainted became obvious DNA evidence not effective Want to see more about the case? http://investigation.discovery.com/videos/crimes-of-the-century-oj-simpson-videos/

34. DNA in the News • Tsunami in Japan • Tornados in Alabama and across the Midwest • Osama Bin Ladden Identification

35. Human Error and Sources of Contamination Chain of custody of samples is compromised Collection of evidence must be systematically recorded and access to evidence must be controlled Follow defined standards of laboratory practice and procedures to prevent DNA damage during the analysis DNA and Juries Must make sense to the jury Statistics can be confusing

36. 8.6 Familial Relationships and DNA Profiles Paternity Testing Analyze samples from child and adults involved Mitochondrial DNA Used to examine samples that cannot be analyzed by PCR or RFLP Older samples that lack nucleated cellular material (hair, bones, and teeth) Inherited from the mother only Changes only about 1% every million years due to random mutation Check out some crimes that have been solved using mtDNA! http://findarticles.com/p/articles/mi_m2194/is_8_71/ai_90819640/pg_5/

38. Y-Chromosome Analysis Passed directly from father to son Useful for tracing relationships among males or analyzing biological evidence involving multiple male contributors • Wanna try some DNA Heritage investigating? • (it will only $159 ) • http://www.dnaheritage.com/mtdna.asp

39. 8.7 Nonhuman DNA Analysis Ginseng $3 million market in U.S. alone Two major herbal products are referred to as ginseng One native to North America, the other native to Asia Asian ginseng boosts energy; American ginseng calms nerves American variety is rarer and more valuable

40. Prove a hunter killed a bear illegally in PA A law makes it illegal to kill a bear in a den Witness reported seeing a hunter discharge gun into den Bear’s premolars were removed at registration station to confirm sex and age of bear Collected blood samples from the den and compared with DNA from bear; were a match DNA Tagging to Fight Fraud Use DNA as an authentication label hidden in a wide variety of products Footballs in 2003 Super Bowl 2000 Sydney Summer Olympics

41. Ancestry of Cabernet Sauvignon Grapes • Hybrid grapes are considered inferior and are legally excluded from bearing the prestigious dinstinction appellation d’origine contrôlée in France • DNA evidence determined that the ancestors of cabernet sauvignon grapes are cabernet franc and sauvignon blanc