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Hair Analysis Forensic Science Chapter 8. What do you know? Can the body area from which hair...
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Transcript of Hair Analysis Forensic Science Chapter 8. What do you know? Can the body area from which hair...
![Page 1: Hair Analysis Forensic Science Chapter 8. What do you know? Can the body area from which hair originated by determined? o Yes – with little difficulty.](https://reader035.fdocuments.us/reader035/viewer/2022081519/56649e9f5503460f94ba1f7a/html5/thumbnails/1.jpg)
Hair AnalysisHair Analysis
Forensic ScienceChapter 8
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What do you know?What do you know?• Can the body area from which hair originated by
determined?o Yes – with little difficultyo Pigment distribution, cross-section shape, diameter
• Can the racial origin of hair be determined?o Rule of thumb:
• Caucasiano Straight, wavy; even-pigment; oval-round cross section
• African-Americano Kinky; dense; uneven pigment
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What do you know?What do you know?• Can the age and sex of an individual be
determined from a hair sample?o Age – NO (except infant hair – fine, short)o Sex – NO (can get ideas – bleached hair)
• Is it possible to determine if hair was forcibly removed from the body?o Yes – follicular tag will remain if forcibly removed
![Page 4: Hair Analysis Forensic Science Chapter 8. What do you know? Can the body area from which hair originated by determined? o Yes – with little difficulty.](https://reader035.fdocuments.us/reader035/viewer/2022081519/56649e9f5503460f94ba1f7a/html5/thumbnails/4.jpg)
What do you know?What do you know?• Are efforts being made to individualize human
hair?o Nuclear DNA – both parentso Mitochondrial DNA – from mother child
• Can DNA individualize human hair?o Nuclear DNA – 1 in billionso mDNA – can exclude but not individualize!
![Page 5: Hair Analysis Forensic Science Chapter 8. What do you know? Can the body area from which hair originated by determined? o Yes – with little difficulty.](https://reader035.fdocuments.us/reader035/viewer/2022081519/56649e9f5503460f94ba1f7a/html5/thumbnails/5.jpg)
FYIFYI• Hair is class evidence• Avg human body has 5 million hairs• Head hairs:
o Blondes have most – 120,000o Redheads – 80,000o Black/brown – 100,000
• Constantly shedding and replacing hairs – 100 per 24 hour period (scalp)
![Page 6: Hair Analysis Forensic Science Chapter 8. What do you know? Can the body area from which hair originated by determined? o Yes – with little difficulty.](https://reader035.fdocuments.us/reader035/viewer/2022081519/56649e9f5503460f94ba1f7a/html5/thumbnails/6.jpg)
Morphology of HairMorphology of Hair• Morphology – form and structure of hair
o Clues in Crime CD – 5.2
• Made up of polymers – complex long-chained moleculeso Very resistant to breaking downo Grows from hair follicle – a tubelike organ in the dermis
• Hair root embedded in follicle• Follicle is linked to body’s blood supply – everything is distributed
into hair
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Morphology of HairMorphology of Hair• Hair shaft – extends out through epidermis
o Three parts• Cuticle• Cortex• Medulla
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Morphology of HairMorphology of Hair• Cuticle
o Function• Helps resist chem decomposition• Helps retain structure
o Clear outside covering of shafto Made up of tough, overlapping scales (points
towards tip of hair)• Formed by cells that have hardened (keratinized)
then flattenedo Help in species ID
• Humans – much finer pattern; not much variation• Animals – vary from species to species
o See scales?• SEM• Cast
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Morphology of HairMorphology of Hair• Cuticle cont
o Three basic patterns:• Coronal• Spinous• Imbricate
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Morphology of HairMorphology of Hair• Coronal
o Crown-likeo Found in hairs of very fine diameter and resembles a stack of paper
cups o Small rodents and bats but not in human hairs
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Morphology of HairMorphology of Hair• Spinous
o Petal-like scales are triangular in shape and protrude from the hair shaft
o Fur hairs of seals, cats, and some other animals. They are never found in human hairs
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Morphology of HairMorphology of Hair• Imbricate
o Flattened-scale type of overlapping scales with narrow marginso They are commonly found in human hairs and many animal hairs
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Morphology of HairMorphology of Hair• Coronal, Spinous, or Imbricate??
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Morphology of HairMorphology of Hair Cortex
Made up of keratin (tough protein polymer made up of about 20 different amino acids)
Contains color pigment – Melanin Eumelanin - responsible for black and brown color Phaeomelanin - responsible for red shades Blondes – low amounts of melanin – shade of blonde depends on
what type of melanin you have Absence of pigment = gray or white hair
Cortical fusi – little sacs of air Come in different size and shapes Can see under a magnification of 100x
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Morphology of HairMorphology of Hair Medulla
Cellular column through center of hair – like a canal or spinal cord; no known function
Predominant feature of hair More than ½ of diameter of hair Medullary index – calculated to help ID species
Medullary index = diameter of medulla diameter of hair shaft
Expressed as a fraction Humans < 1 3 Others > 1
2
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Morphology of HairMorphology of Hair• Medulla – cont
o Varies extensively• NOT all hairs have one• Types:
o Continuouso Interrupted/Intermittent – even breakso Fragmented (segmented) – uneven breakso Absent
Humans normally – absent or fragmented
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Morphology of HairMorphology of Hair• Medulla Conto Patterns
• Uniserial - Cat• Multiserial - Rabbit• Lattice - Deer• Vacuolated - Dog• Amorphous - Human
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Morphology of HairMorphology of Hair• Shape of hair
o Straight, curly, kinkyo Depends on cross-section of the hair shaft
• Round – straight hair• Less Round– curly hair• Oval/Elliptical– kinky hair
o Generalizations:• Asians/Native Americans – round, no twisting• American/European whites, Mexicans, Middle East – less round,
rare twist (undulation), evenly distributed pigment• African – oval or elliptiacl, twist, clumped pigmentation
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Morphology of HairMorphology of Hair• Hair Root
o Grows at about 1cm/montho Three stages of growth
• Anagen Phase• Catagen Phase• Telogen Phase
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Anagen PhaseAnagen Phase• Lasts up to five years• Includes 80-90% of hair follicles at any one time• Initial growth• Hair bulb attached to blood supply• http://www.hairlosshelp.com/hair_loss_research/
hair.cfm
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Catagen PhaseCatagen Phase• Intermediate Phase• Lasts 2-3 weeks• Hair bulb Detached from blood supply• http://www.hairlosshelp.com/hair_loss_research/
hair.cfm
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Telogen PhaseTelogen Phase• Lasts 2-6 months• 8-10% of all hair follicles• Sheds hair naturally• Follicular Tag – tissue pulled with hair; contains
DNA• http://www.hairlosshelp.com/hair_loss_research/
hair.cfm
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Summary of Hair Summary of Hair GrowthGrowth
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Morphology of HairMorphology of Hair• Hair Tip
o External Endo Mature Hair
• Will taper to a pointo Cut Hair
• Will be squared off (but within 2-3 weeks will become rounded)o Frayed or split ends
• Dryness or lack of care
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Identification and Identification and Comparison of HairComparison of Hair
• Identifyo Race
• Generally – yes, by cross-sectional shapeo Age
• No – except infantso Sex
• No – can generalizeo Forcibly Removed?
• Yes – more tissue = more force
![Page 27: Hair Analysis Forensic Science Chapter 8. What do you know? Can the body area from which hair originated by determined? o Yes – with little difficulty.](https://reader035.fdocuments.us/reader035/viewer/2022081519/56649e9f5503460f94ba1f7a/html5/thumbnails/27.jpg)
Identification and Identification and Comparison of HairComparison of Hair
• Compareo Scale structureo Medullary indexo Medullary shapeo Coloro Lengtho Diametero Pigment intensityo Infections/abnormalities
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Hair as a Chemical Hair as a Chemical IndicatorIndicator
• Many drugs and their metabolites (specific product of drug interaction with body) can be detected in just a few mm of hair
• Because of hair slow growth – longer periods of drug use can be detected
• Metal contento Diagnose dietary deficiencies and diseaseo Poisoning
• Hg, Pb, As
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Hair as a Chemical Hair as a Chemical IndicatorIndicator
• Person’s environmento Scalp oils can find traces of environmento Detect smoke from crack cocaine, industrial pollution
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Collection and Collection and Preservation of HairPreservation of Hair
• Always accompanied by reference samples• Normally need
o 50 scalp hairs• Full length• Pull out or clip at skin line
o 24 pubic hairs
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Case StudyCase Study• Ennis Cosby – 1997
o 27 years oldo Got a flat tire – pulled off the road to put spare – Bel-Airo Shortly after – an assailant demanded money and when Ennis didn’t
respond quickly enough, was shot in the templeo A .38 revolver was later found miles from the scene
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Case StudyCase Study• Mikail Markhasev (Ukranian immigrant –
age 19) was arrested and charged with murder
• Hair was recovered from Ennis’s hato Identified 6 DNA markers from tissue that
matched Markhasev’s DNA
• Markhasev was convicted of murdero serving life sentence without
possibility of parole
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Case StudyCase Study• Napoleon
o Died in exile in 1821o By analyzing his hair, some believe he was poisoned by the deliberate
administration of arsenic; others suggest it was vapors from the dyes in the wallpaper that did him in.
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Case StudyCase Study• John Vollman
o Clues in Crime CD
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Wrongful AccusationWrongful Accusation