1. Hairs & Fibers

2. Purpose of Hair Hair on mammals - Hair on mammals - helps to regulate body temperature helps to regulate body temperature decrease friction decrease friction protect against sunlight protect against sunlight Location of hair on humans: Location of hair on humans: Head Head Eyebrows and eyelashes Eyebrows and eyelashes Mustache and beard Mustache and beard Underarms Underarms Auxillary (overall body) Auxillary (overall body) Pubic Pubic

3. Morphology of Hair An appendage of the skin that grows out of an organ known as the hair follicle. An appendage of the skin that grows out of an organ known as the hair follicle. Hair - extends from root or bulb embedded in the follicle, continues into a shaft, and terminates at a tip end. Hair - extends from root or bulb embedded in the follicle, continues into a shaft, and terminates at a tip end.

4. The Shaft of Hair Composed of three layers: cuticle, cortex, and medulla. Composed of three layers: cuticle, cortex, and medulla.

5. Structure of Hair 1.Cuticle – thin outer layer 2.Cortex – thicker middle layer 3.Medulla – inner layer

6. Morphology: Cuticle Protective coating made of overlapping scales, produce a characteristic pattern Protective coating made of overlapping scales, produce a characteristic pattern Scales always point toward tip of hair Scales always point toward tip of hair Not useful in individualizing human hair Not useful in individualizing human hair Can be used for species identification Can be used for species identification http://www.pg.com/science/haircare/hair_twh_35/hair_twh_35_02.jpg

7. Preserving scale pattern Since examination of internal structure of hair requires loss of scale pattern, a scale case is made. Since examination of internal structure of hair requires loss of scale pattern, a scale case is made. Clear nail polish on microscope slide Clear nail polish on microscope slide Hair embedded and allowed to dry before removed. Hair embedded and allowed to dry before removed.

8. Cuticle - Scales Three basic scale structures that make up the cuticle: Three basic scale structures that make up the cuticle: coronal (crown-like) coronal (crown-like) spinous (petal-like) spinous (petal-like) imbricate (flattened) imbricate (flattened) Combinations and variations of these types are possible. Combinations and variations of these types are possible. http://www.fbi.gov/hq/lab/fsc/backissu/jan2004/research/2004_01_research01b.htm

9. Cuticle - Scales The coronal, or crown-like scale pattern: The coronal, or crown-like scale pattern: found in hairs of very fine diameter and resemble a stack of paper cups. found in hairs of very fine diameter and resemble a stack of paper cups. commonly found in: commonly found in: hairs of small rodents and bats –but- hairs of small rodents and bats –but- rarely in human hairs rarely in human hairs http://www.fbi.gov/hq/lab/fsc/backissu/jan2004/research/2004_01_research01b.htm

10. Cuticle - Scales Spinous or petal-like scales: Spinous or petal-like scales: triangular in shape and protrude from the hair shaft. triangular in shape and protrude from the hair shaft. Found at the proximal region of mink hairs and on the fur hairs of seals, cats, and some other animals. Found at the proximal region of mink hairs and on the fur hairs of seals, cats, and some other animals. Never found in human hairs!! Never found in human hairs!! http://www.fbi.gov/hq/lab/fsc/backissu/jan2004/research/2004_01_research01b.htm

11. Cuticle - Scales  Imbricate or flattened scales:  Consists of overlapping scales with narrow margins  commonly found in human hairs and many animal hairs.

12. Morphology: Cortex Embedded with pigment granules that give hair its color Embedded with pigment granules that give hair its color Three things for forensic comparison: Three things for forensic comparison: color color shape shape distribution of the granules distribution of the granules www.pg.com/science/haircare/hair_twh_59.htm

13. Morphology: Medulla canal like structure of cells that runs through the center of the cortex canal like structure of cells that runs through the center of the cortex

14. Types of Medulla The medulla (the inner section) can be hollow or filled, absent, fragmented, continuous, doubled, pigmented, or un- pigmented.

15. Medullary Index Measure of the diameter of the medulla relative to the diameter of the hair shaft Measure of the diameter of the medulla relative to the diameter of the hair shaft Usually expressed as a fraction Usually expressed as a fraction Humans: medullary index < 1/3 Humans: medullary index < 1/3 Animals: medullary index > 1/2 Animals: medullary index > 1/2

16. Medullae of Different Species

17. Medulla Shape Medulla shape is another characteristic that varies from species to species Medulla shape is another characteristic that varies from species to species UNISERIAL (rabbit) MULTISERIAL (rabbit) VACUOLATED (dog, fox, common) LATTICE (deer) AMORPHOUS (human, common) 17

18. Medulla of Different Species

19. Forensic Analysis of Medulla Presence of medulla varies quite a bit: even hair to hair Presence of medulla varies quite a bit: even hair to hair Human head hairs generally have no medulla or may be fragmented ones Human head hairs generally have no medulla or may be fragmented ones except Mongoloid (Asian) race - medulla is usually continuous except Mongoloid (Asian) race - medulla is usually continuous Most animals - medulla that is continuous or interrupted Most animals - medulla that is continuous or interrupted The shape of the medulla can help identify a species The shape of the medulla can help identify a species Examples: Examples: Most animals and humans: cylindrical Most animals and humans: cylindrical Cats: pearl shape Cats: pearl shape Deer: spherical occupying whole hair shaft Deer: spherical occupying whole hair shaft

20. Root of Hair Provide the tools to produce hair and continue its growth Provide the tools to produce hair and continue its growth 3 Stages of Growth (different looking roots) 3 Stages of Growth (different looking roots) 1. Anagen -initial phase may last up to 6 years, root is flame shaped The cells around the follicle rapidly divide and deposit materials in the hair. The cells around the follicle rapidly divide and deposit materials in the hair. 2. Catagen –transition phase (2-3 weeks), root is elongated 3. Telogen –phase where hair naturally falls out of the skin, root is club-shaped During this stage, hairs easily can be lost. During this stage, hairs easily can be lost.

21. Hair Growth Cycle

22. Root: Anagen Phase When pulled this root may contain a follicular tag (rich source of DNA) When pulled this root may contain a follicular tag (rich source of DNA) Root is flame shaped Root is flame shaped Anagen hair root Root w/ follicular tag

23. Human Hairs Racial Determination Racial Determination Age and Sex? Age and Sex? Forcibly Removed? Forcibly Removed? Can Hairs be Individualized? Can Hairs be Individualized?

24. Can the racial origin of hair be determined? Forensic terms: Caucasoid, Negroid, Mongoloid Forensic terms: Caucasoid, Negroid, Mongoloid Mongoloid Mongoloid continuous medullae continuous medullae Caucasian Caucasian even distribution of pigment in cortex even distribution of pigment in cortex Negroid Negroid unevenly distributed pigment. unevenly distributed pigment. http://www.fbi.gov/hq/lab/fsc/backissu/july2000/deedric1.htm

25. Tip of the Shaft Burned Cut Razored Split

26. Forcibly Removed? Pulled Forcibly Removed Shed

27. A normal telogen hair with a hard 'club' end, seen under (left) a light microscope and (right) an electron microscope An anagen hair that has been plucked out: notice the soft, sticky tail Brushed-out hairs all have this kind of root. This is an anagen hair, one which was pulled out and not ready to be shed.

28. Hair Individualization Nuclear DNA – found in nucleus of each cell Nuclear DNA – found in nucleus of each cell Follicular tag – tissue adhering to root or follicle Follicular tag – tissue adhering to root or follicle Will produce odds as one in billions or one in trillions Will produce odds as one in billions or one in trillions Mitochondrial DNA – found outside nucleus, passed from only mother to child Mitochondrial DNA – found outside nucleus, passed from only mother to child Many more copies compared to nuclear DNA Many more copies compared to nuclear DNA Will not individualize, but will exclude a significant portion of population Will not individualize, but will exclude a significant portion of population Cannot microscopically distinguish similar hairs from people maternally related Cannot microscopically distinguish similar hairs from people maternally related

29. Can DNA individualize hair? Yes! In some cases Yes! In some cases Best evidence to have is matching morphology AND DNA Best evidence to have is matching morphology AND DNA We will talk much more in Chapter 13 about this! We will talk much more in Chapter 13 about this!

30. Collection of Hair Evidence

31. Questioned and Reference hair must come from same area of the body Questioned and Reference hair must come from same area of the body Cannot compare head hair to pubic hair. Cannot compare head hair to pubic hair. Head hairs - 50 full length hairs from all areas of the scalp Head hairs - 50 full length hairs from all areas of the scalp Other body parts – 25 full length hairs Other body parts – 25 full length hairs All collected reference hairs must be full- length All collected reference hairs must be full- length

32. Identification and Comparison of Hair Morphological Characteristics - do not individualize human hair to any single head or body Morphological Characteristics - do not individualize human hair to any single head or body Hair when collected properly - provides strong circumstantial evidence Hair when collected properly - provides strong circumstantial evidence Most often used for comparison Most often used for comparison Scale structure Scale structure Medullary index Medullary index Medullary shape Medullary shape 11 percent of all morphological hair matches are generally found to be non-matches 11 percent of all morphological hair matches are generally found to be non-matches meaning microscopic hair comparisons are presumptive in nature—must be confirmed by DNA comparisons meaning microscopic hair comparisons are presumptive in nature—must be confirmed by DNA comparisons

33. Using Hair in an Investigation Macroscopic investigation can indicate length, color, and curliness. Macroscopic investigation can indicate length, color, and curliness. Microscopic investigation can indicate fine detail in hair structure. Microscopic investigation can indicate fine detail in hair structure. 1. Phase contrast microscopy – focuses light that passes through objects of different refractive indexes shows the presence of dye or other treatments. shows the presence of dye or other treatments. 2. Fluorescence microscope – beam of light of a certain color is used to show particular chemicals Shows fine detail in hair structure Shows fine detail in hair structure 3. Electron microscopes – directs beams of electrons at sample provides more detail of the surface or interior of the sample. provides more detail of the surface or interior of the sample.

34. Testing for Substances in the Hair Shaft Neutron Activation Analysis (NAA) : can determine concentrations of substances in the sample. 1. Identifies up to 14 elements in a 2 cm strand of human hair Hair placed in nuclear reactor and bombarded with high energy neutrons Hair placed in nuclear reactor and bombarded with high energy neutrons 2. Probability of two individuals having same concentration of 9 different elements: 1 in a million Some elements: Antimony, argon, bromine, copper, gold, manganese, silver, sodium, zinc Some elements: Antimony, argon, bromine, copper, gold, manganese, silver, sodium, zinc

35. Each element gives off its own gamma radiation with different signals Each element gives off its own gamma radiation with different signals

36. Testing for Substances in the Hair Shaft Chemical Analysis - Chemical Analysis - 1. Chemicals that the skin absorbs often can be detected by analysis of the hair shaft. Arsenic, lead, drugs Arsenic, lead, drugs Can be used to determine poisoning or drug exposure Can be used to determine poisoning or drug exposure 2. Hair shaft can establish a timeline for exposure to toxins. Human hair grows ~1.3 cm per month Human hair grows ~1.3 cm per month If root is present, sections can be dated based on distance from root If root is present, sections can be dated based on distance from root

37. Testing the Hair Follicle Microscopic assessment of the follicle is performed first because it is cost effective and quick. If a microscopic match is found, the follicle can be: If a microscopic match is found, the follicle can be: 1. blood tested and perhaps show the blood type. 2. DNA analyzed to provide identification with a high degree of confidence.

39. Fibers: Natural Derived entirely from animal or plant sources Derived entirely from animal or plant sources Most prevalent plant fiber: Most prevalent plant fiber: cotton. cotton. widespread use has made its evidential value almost meaningless widespread use has made its evidential value almost meaningless Cotton has a ribbon-like shape with twists at regular intervals Cotton has a ribbon-like shape with twists at regular intervals Animal sources: Animal sources: sheep (wool), goats (mohair, cashmere) and many other sources sheep (wool), goats (mohair, cashmere) and many other sources http://www.swicofil.com/images/cotton_microscopic.jpghttp://www.e4s.org.uk/textilesonline/content/6library/report1/images/microscope_2.gif Wool Cotton

40. Man-Made Fibers Fibers derived from either natural or synthetic polymers Fibers derived from either natural or synthetic polymers The fibers are made by forcing polymeric material through the holes of a spinneret The fibers are made by forcing polymeric material through the holes of a spinneret Rayon and then nylon were the first two man-made fibers (year 1911) Rayon and then nylon were the first two man-made fibers (year 1911) http://www.naturalvisions.co.uk/pictures/thumbnail/XMIC_0021_0001XX.jpg

41. Man-Made Fibers Con’t Regenerated Fibers Regenerated Fibers Made from regenerated cellulose (wood or cotton pulp) Made from regenerated cellulose (wood or cotton pulp) Include such fibers as rayon, acetate, and triacetate Include such fibers as rayon, acetate, and triacetate Synthetic Fibers Synthetic Fibers Currently manufactured Currently manufactured Made from synthetic chemicals called polymers Made from synthetic chemicals called polymers Include such fibers as nylons, polyesters, and acrylics Include such fibers as nylons, polyesters, and acrylics

42. Polymers Basic chemical substance of all synthetic fibers Basic chemical substance of all synthetic fibers Consist of long chains of repeating molecules. The repeating molecular units in the polymer are called monomers. (see pic p210) Consist of long chains of repeating molecules. The repeating molecular units in the polymer are called monomers. (see pic p210) Often referred as macromolecules or “big” molecules Often referred as macromolecules or “big” molecules Countless varieties exist Countless varieties exist

43. ID and Comparison of Man- Made Fibers Fabrics that can be fitted together at their torn edge are easy to match Fabrics that can be fitted together at their torn edge are easy to match Microscopic comparison of color and diameter Microscopic comparison of color and diameter Comparison of lengthwise striations and pitting on the surface of a fiber Comparison of lengthwise striations and pitting on the surface of a fiber The shape of the fiber—ex. Wayne Williams case The shape of the fiber—ex. Wayne Williams case Cross sections are generally helpful Cross sections are generally helpful Note: Combined factors of color, size, shape, microscopic appearance, chemical composition, and dye content make it very unlikely to find two different people wearing identical fabrics Note: Combined factors of color, size, shape, microscopic appearance, chemical composition, and dye content make it very unlikely to find two different people wearing identical fabrics

44. Tools and Techniques to Aid in Comparing Fibers Light infrared spectrophotometer—compares colors and chemical composition through spectral patterns Light infrared spectrophotometer—compares colors and chemical composition through spectral patterns Chromatography—compares dye composition Chromatography—compares dye composition Refraction—ID’s fiber by refractive index Refraction—ID’s fiber by refractive index Comparison microscope—reveals shape, coloring, pitting and striations Comparison microscope—reveals shape, coloring, pitting and striations