Aim: How is hair analyzed in forensics?

Do Now: Explain the possible drawbacks of analysis of hair for drug metabolites.

Homework:Pg. 230 #’s q 1-10

Substance Urine Hair Blood/SalivaAlcohol 6–24 hours up to 2 days 12–24 hours Methamphetamine 3 to 5 days up to 90 days 1–3 days MDMA (Ecstasy 24 hours up to 90 days 25 hours Cannabis 3 to 7 days, up

to >30 days after heavy use and/or in users with high body fat

up to 90 days 2–3 days in blood, up to 2 weeks in blood of heavy users. Saliva for 2–6 hours

Cocaine 2 to 5 days up to 90 days 2 to 5 days

Cotinine (a break-down product of nicotine)

2 to 4 days up to 90 days 2 to 4 days

Heroin 3 to 4 days up to 90 days 1– 2 days

LSD 24 to 72 hours up to 90 days 0 to 3 hours

What other materials can be traced in hair?• Poisoning by heavy metals (Arsenic, Mercury,

lead)• Dietary deficiencies (low vitamin and mineral

levels)

What is a drawback to hair testing?• Scalp oils coat the cuticle of the hair and sometimes

capture materials from environment Ex: crack smoke in car

• Can cause “false positives”• Scientists must be careful to examine only the cortex

of the hair

Types of Animal Hairs - Key

A B C

D E

Cat

HumanDog

RatRabbit

Parts of a hair strand

• 3. Tip/ End of Hair– Often seen burned cut, razored, or with split ends

How do we get different hair colors?1. The type of natural color pigment melanin present in your

hair's cortex. – Eumelanin (black pigment) – Phenomelanin (red/yellow pigment)

2. How many melanin granules exist

3. Whether those granules are close together or far apart

How do we get straight, wavy, curly, and kinky scalp hair?-It is due to differences in the cross section of the hair

Typically found in people of Native American and Asian descent

Typically found in people of European descent

Typically found in people of African American descent

Wednesday 4/18/12

• AIM: how can we determine the ethnicity of a hair sample?

• DO NOW: Explain how you would determine the species of a hair sample?

• HOMEWORK: textbook page 230-231. questions 11-15.

• I AM COLLECTING MONDAY TUESDAY AND WEDNESDAY’s Homework TOMORROW

How does scalp hair vary by race?• Asian/Native American

– Round hair shaft - straight– Large pigment granules– Patchy distribution of

pigment– Usually continuous medulla

• European/Caucasian– Slightly round to oval hair

shaft(straight to curly)– Finer pigment granules– More even distribution of

pigment– Usually absent or

fragmented medulla

How does scalp hair vary by race?

• African American– Flat to oval hair shaft(curly to kinky)- Largest and most dense pigment granules that are unevenly distributed-Absent or fragmented medulla

HEAD HAIR: Caucasian (left)

Asian/Native American

( bottom left)

African American (bottom right)

Thursday 4/19/12

• AIM: How can we determine the origin of a hair sample?

• DO NOW: 1- Take out the homework from Monday, Tuesday and Wednesday

• 2- 2 minute mystery: speeding train• Homework: THERE IS NONE!

• How can you determine the part of the body a hair comes from?

Can The Body Area From Which A Hair Originated Be Determined?

SCALP HAIR: small variation in diameter uniform distribution of pigment color

BEARD HAIR coarse, triangular in cross section blunt tips from cutting or shaving.

PUBIC HAIR short and curly wide variation in diameter.

SEX - can be determined if DNA is found on the hair.

AGE - cannot be determined from a hair examination with certainty. (except an infant)

Can the Age & Sex of an Individual Be Determined from a Hair Sample?

Hair naturally falling off the body will show a root without any follicular tissue.

A hair root with follicular tissue means that the hair had been pulled out either by another person or by brushing.

Is It Possible to Determine If Hair Was Forcibly Removed from the Body?

This is the best source of DNA in hair.

How Can We Individualize Human Hair?

FOLLICULAR TAG – a translucent piece of tissue surrounding the hair’s shaft near the root.

DNA from the follicular tag can be matched to one individual

50 full-length hairs from all areas of the scalp may be collected as samples

Use a piece of tape to collect and package hair samples from a crime scene

Hairs found at the crime scene are compared to samples from the victim and from the suspects

Collection & Preservation of Hair Evidence

What causes gray hair?• As you age, the natural production of pigment slows

down and your natural color loses its color strength.

• Doesn't happen to every hair at the same time, so the contrast between the hair with no color and the hair that still has some color causes it to look gray.

• So how gray your hair actually looks is determined by the percentage of strands with no color vs. the pigmented strands.

Root of Hair• Provide the tools to produce hair and continue its

growth• 3 Stages of Growth (different looking roots)

– Anagen -initial phase may last up to 6 years, root is flame shaped

– Catagen –transition phase (2-3 weeks), root is elongated

– Telogen –phase where hair naturally falls out of the skin, root is club-shaped

• Hair analysis video