Warm-Up Something extraordinary happened on May 6th 1978 at 12:34am, what was it that happened?

Hair Evidence

SKIN The skin has two layers: Epidermis- this is the outer layer which is dead skin cells Dermis- this is the living portion where hair is produced Hair is composed of keratin, a type of protein

Function of Hair Regulate body temperature (insulation) Decrease friction Protect against sunlight Sense organ

Hair Shaft Three layers: Cuticle: surface of hair Cortex: main body, contains pigment Medulla: hollow core

Hair Diagram

The Hair Growth Cycle Hair follicles grow in repeated cycles. Anagen - Growth Phase Approximately 85% of all hairs Vary from two to six years. Hair grows approximately 10cm per year. Catagen - Transitional phase Lasts about one or two weeks. Hair follicle shrinks to about 1/6 of the normal length. The lower part is destroyed and the hair may fall out. Telogen - Resting Phase Lasts about 5-6 weeks. Approximately 10-15% of all hairs are in this phase at an one time. At the end of the Telogen the hair follicle re-enters the Anagen phase. Lower part reforms and a new hair begins.

Cuticle : Outer Layer Transparent, outer layer Scales point down from younger end towards older ends of hair Has three patterns Coronal (crown-like) Spinous (petal-like) Imbricate (flattened) Can have combinations

The coronal, or crown-like scale pattern is found in hairs of very fine diameter and resemble a stack of paper cups. Coronal scales are commonly found in the hairs of small rodents and bats but rarely in human hairs.

Spinous or petal-like scales are triangular in shape and protrude from the hair shaft. They are found at the proximal region of mink hairs and on the fur hairs of seals, cats, and some other animals. They are never found in human hairs.

The imbricate or flattened scales type consists of overlapping scales with narrow margins. They are commonly found in human hairs and many animal hairs. Photomicrograph of Human Hair Scale Pattern

Cortex: Color Layer Largest part of hair shaft Melanin = pigment granules

Pigment granules are absent in grey hairs

Properties of the Medulla Medullary index (ratio of medulla:shaft) Pattern (continuous, interrupted, fragmented, or absent) Shape (human vs. animal)

Human Medulla Patterns

Medulla Shape In human hairs, the medulla is generally amorphous (without shape) in appearance. In animal hairs, its structure is frequently very regular and well defined.

Animal

Human

Body Area Head (scalp) Eyebrows and eyelashes Beard and mustache Underarm Axillary (underarm) or body hair Pubic hair Pubic Hair Beard Hair Limb Hair

Mongoloid (Asian) Hair Racial Origin Negroid (African) Mongoloid (Asian) Hair Caucasiod (European)

Scissor-cut Broken Burned Razor-cut

Dyed Hair Lice Egg Case

DNA Evidence Shaft: mitochondrial DNA (mtDNA) Root: nuclear DNA

Collecting Hair Evidence Methods used to collect hairs from clothing and bedding items are: Scraping Shaking Taping Picking Debris from large carpeted surfaces might be vacuumed into a filtered canister. If the specific location of a hair on a clothing item is important, it might be necessary to pick off the hair or tape the item and record where the hair was removed

Testing For Chemicals Neutron activation analysis (NAA) – identify 14 different elements in hair Antimony, argon, bromine, copper, gold, manganese, silver, sodium, zinc Hair grows about 1.3 cm per month – calculate timeline for exposure to toxins or poison

Testing the Hair Follicle Macroscopic views indicate length, color, and curliness. Microscopic views indicate fine detail in hair structure. The follicle can be blood tested or DNA analyzed.