1. Target 2-2b Tuesday, October 17, 2017
Hair Evidence
Target 2-2b
Tuesday, October 17, 2017

2. Target 2-2b
I can include and exclude suspects by analyzing hair evidence.

3. What is HAIR?? HAIR… Is a protein Grows through the skin of mammals
Helps regulate temperature
Helps with sensing the environment

4. What Makes a Hair?
SHAFT
OIL GLAND
ROOT
FOLLICLE
NERVES

5. Inside a Hair Shaft
CUTICLE: outermost layer of hair shaft; overlapping cells that provide protection
CORTEX: thick main layer of hair shaft; where melanin (color), water, nutrients are
MEDULLA: innermost layer of hair shaft; soft and highly variable

6. Types of Medullas
Medullas are the most unstructured part of the hair and can vary widely, even on the same person:

7. Practice!
Label each medulla as continuous, interrupted, fragmented, or absent.

9. Thickness of medullas
The thickness of the medulla can help identify the origin of the hair:
Humans = medulla is less than 1/3 of the shaft
Other animals = medulla is more than 1/2

10. Practice!
Label each hair as human or animal.

12. How was the Hair Removed?
Naturally shed hairs will have roots intact and clean
Hairs that were pulled out will have stretched roots and/or clumps of tissue attached
Hairs that were cut will have clean edges, no roots
Hairs that were broken will have jagged edges, no roots

13. Practice!
How was each hair removed from the body?

15. Collecting Hair Evidence
You need at least hairs for a comparison analysis
When collecting samples from a suspect/victim, choose a widespread selection of hairs
Hair samples can only be compared to the same body part
Ex) head hair and arm hair will be too different

16. Hair as Evidence We can determine:
Whether the hair is human
How the hair was removed
Which part of the body the hair came from
We can include and exclude based on pigmentation (color), texture, and medullary index

17. We can get DNA from the follicle only
What about DNA??
We can get DNA from the follicle only
Hair must have tissue attached to the root
Hair must be forcibly yanked out

18. Exit Ticket
Draw a hair shaft and label the cuticle, cortex, and medulla.
Sketch a fragmented medulla.
Is this hair human or animal? Why?
How was this hair removed? How do you know?