Forensic Serology and DNA Mrs. Faulconer and Dr. Walker

1. Forensic Serology and DNAMrs. Faulconer and Dr. Walker

2. Ancient Forensic Serology • In 1235, a Chinese death investigator lined up suspects and watched as flies gathered around one man and his sickle

3. Main Job Functions: • Determine type and characteristics of bodily fluids (including blood, semen, saliva, sweat, fecal matter) • Preparation of Testimony, Presentations at Trial • May or may not be involved with DNA typing

4. Write bold Evidence in the Courts • Class, not Unique • never possible to say "this bloodstain originated from this person“ • Talk about the odds of a sample NOT being that person • FBI estimates odds of unrelated persons sharing 13 typically tested genetic marker – 1 in 113 billion!! • possible to conclude "this bloodstain cannot have originated from this person“

5. Write bold Saliva • Digestive fluid produced by parotid, sublingual, and submandibular glands inside mouth • 99.5% water • Mucus • Enzymes (α-amylase, lingual lipase) • Electrolytes: (Na, K, Ca, Mg, Cl, bicarbonate, PO4-3) • Antibacterial compounds (thiocyanate, H2O2, and secretory immunoglobulin A) “Identification of Saliva”. Nelson, David. Journal of Forensic Medicine, Volume 10, No: 1: January-March (1963). Pages 14-21.

6. Write bold Tests for Saliva • 4 presumptive tests for saliva: • amylase (sensitive) • phosphatase (sensitive, not specific to saliva) • nitrite (sensitive to recent specimens) • thiocyanate (sensitive, absence does not exclude saliva presence)

7. Write all Blood • Slightly alkaline • pH = 7.2 – 7.4 • Components • Red Blood Cells • White Blood Cells • Plasma • Platelets

8. Write all Blood • Purpose: Transportation • Nutrients • Oxygen • Waste

9. Write bold Immune System • Antigens • Any material that can provoke an immune response • Proteins/Carbohydrates/Fats • Material attached to foreign bodies (bacteria, viruses) • Attached to surface of red blood cells

10. Write bold Immune System • Antibodies • Proteins that bind tightly to specific antigens (foreign material) and remove them from the bloodstream • Exist because of allergies or disease (TB, smallpox, hepatitis, HIV, etc.) • Blood may also contain HIV antibodies, syphilis, and cholesterol • Iron Deficiency (Anemia)

11. Write bold Blood Typing • A-B-O system discovered in 1901 • Karl Landsteiner • Antigen/Antibody system started in 1937 • ABH, MN, Rh, and Gm

12. Write bold Blood Typing • Blood types are normally distributed in a population as follows: O A B AB 43-45% 40-42% 10-12% 3-5% O+ 39% A+ 35% B+ 8% AB+ 4% O- 6% A- 5% B- 2% AB- 1% O + is most common AB – is least common

13. Relative Frequency of BloodTypes in Human Populations http://www.bloodbook.com/world-abo.html

16. Write all

17. Compatibility • Type O : Universal Donor • No antigens, A and B antibodies • Type AB: Universal Recipient • A and B antigens, No antibodies • Type A: • B antibodies, A or O compatible • Type B: • A antibodies, B or O compatible

18. Write bold Rh Factor • (Rhesus Disease) • + means blood has protein found in Rhesus monkeys • 85% of people have + Rh • O+ 1 in 3 persons • O- 1 in 15 persons • A+ 1 in 3 persons • A- 1 in 16 persons • B+ 1 in 12 persons • B- 1 in 67 persons • AB+ 1 in 29 persons • AB- 1 in 167 persons • Rh - can donate to Rh +, not the other way around

19. Blood Typing and Parents

20. Blood Typing and Parents

21. Write bold Polymorphisms • Multiple alleles of a gene within a population • Allele – alternate form of a gene • PGM 2-1 phosphoglucomutaseEAP erythrocyte acid phosphatase EsD esterase DAK adenyl kinase ADA adenoisine deaminase GPT glutamic pyruvate transaminase 6-PGD 6-phosphogluconate dehydrogenase G-6-PD glucose-6-phosphate dehydrogenase Tf transferrin • Each has known distributions in populations (just like A-B-O and Rh) • Can calculate probability estimate

22. Let’s Do the Math… • Suppose you had a crime scene sample and a suspect which both were characterized by: • type A blood (42%) • basic subtype A2 (25%) • protein AK (15%) • enzyme PGM 2 (6%) • What would the probability of finding two people in the population with this exact type be?

23. Write all Bloodstain Characterizations 1. Is the sample blood? Tests: Phenolphthalein Kastle-Meyer Test – H2O2 + phenolphthalein – turns sample pink Luminol

24. Write bold Bloodstain Characteristics 2. Is the sample human blood? -Precipitin Test • Anti-human serum placed on bloodstain, clotting means human • Made by injecting rabbit with human blood, develops anti-human antibodies, thus “anti-human serum”

25. Write all Bloodstain Characteristics • 3. If animal blood, from what species? • Can make animal specific “anti-serum”

26. Write all Bloodstain Characteristics • 4. If human blood, what type? Direct A-B-O typing

27. Write all Bloodstain Characteristics • 5. Can age, sex, race be determined? • Age • Hormonal concentrations • Testosterone vs. Estrogen • Lower before puberty (early teens), after menopause (after 45-50) • Clotting/Crystallization • Lower for elderly • Gender • Hormone Levels • Testosterone vs. Estrogen • Ethnic background • Genetic Markers (controversial)

28. Write bold DNA DNA: deoxyribonucleic acid- the molecules carrying the body’s genetic information

29. Write all DNA • Parts of DNA • Ribose sugar • Phosphate • Nucleobase • Purines • Adenine, Guanine – 2 rings • Pyrimidines • Cytosine, Thymine – 1 ring

30. Write all • DNA is Double stranded • Strands connected by hydrogen • bonds between hydrogens on one nucleobase to nitrogen • or oxygen on another

31. Write all Why can we use DNA? • Highly polymorphic • Alleles (alternate forms of a gene) • Mutations (additions, deletions, substitutions) • These can create or remove “recognition sites” for restriction enzymes, probes, and primers

32. Write bold Using DNA • Whole genomes are not scanned!! • 13 DNA regions, or loci, are scanned • This information creates the DNA fingerprint • Chance of someone matching in all 13 regions depends on exact method of analysis • Usually about 1 in 1 billion

33. DNA Technology RFLP PCR

34. Write all RFLP • Restriction Fragment Length Polymorphism • Cuts apart DNA sample into more managable lengths of DNA • Uses “restriction enzymes” that cut DNA at specific sequences

35. Write bold RFLP • After DNA sample is cut, it is separated by electrophoresis • Different lengths of DNA are present • Use DNA probes to bind to “complimentary sequence” • ACGT on one strand would bind to TGCA on another

36. Write all RFLP • Weaknesses • Need a lot of sample • Takes several weeks to perform • Need high quality sample (won’t work with degraded sample) • As a result, this is no longer frequently used

37. Isolate the DNA Use Restriction Enzymes

38. Write all Gel Electrophoresis • Agarose gel • Separates based on size • Migrates because of charge • Visualize results by staining • So many fragments that DNA seen as smear rather than obvious banding

40. Write all PCR • Polymerase Chain Reaction • Developed by Kary Mullis in 1983 • Uses STR (short tandem repeats) to replicate a desire sequence of DNA • Small sample size, degraded or old • quick test • Biological Xerox Machine (copies DNA millions of times)

41. Write all DNA In Criminal Cases • First use • Conviction of Colin Pitchfork in 1987 (UK) • DNA Testing performed by Sir Alec Jeffries (University of Leicester)

42. Write all Southern Blot • Southern Blot • Soak in alkali solution to denature (break hydrogen bonds) DNA • “blotting” – transfer of DNA from the gel to nylon membrane • Gel can dry out, break up, stick to surfaces – can’t be manipulated • DNA permanently absorbed, easier to manipulate

43. Write all Southern Blot • Southern Blot • Radioactive DNA sequence will bind to complimentary sequence • A binds to T, C binds to G on the other strand • Placed on X-ray film • Only DNA fragments with a probe will show up • Local radioactivity from probe causes exposure of film

44. A. Child 1 B. Child 2 C. Child 3 D. Child 4 E. NONE of the children

45. A. Lane 1 B. Lane 2 C. Lane 3 D. Lane 4 E. Lane 5

49. A. B and C B. A and B C. A and C D. B and D E. A and D