1. 8.2 Notes – Hair continued

2. Objectives List hair features that are useful for microscopic comparison of human hairs Explain proper collection of forensic hair evidence

3. Identification & Comparison of Hair Human hair comparison is not reliable without DNA –Hair exhibits variable characteristics not only between individuals but within a single individual Body area from which the hair originated can be determined –Head hair, pubic hair, beard hair

4. Identification & Comparison of Hair Microscopic examination can distinguish dyed or bleached from natural –Natural end portion different from dyed portion –Can determine when bleaching occurred based on distance between the two Hair grows at 1 cm per month

5. Identification cont. Can distinguish between races –Negroid hair is normally kinky with dense unevenly distributed pigments Cross-sections are flat to oval in shape –Caucasian hair is normally straight or wavy with fine or coarse pigmentation that is more evenly distributed Cross-sections are oval to round in shape

6. Identification cont. Cannot be easily determined –Age (with exception of infant hair) –Sex (nuclear DNA from the same can allow for determination) Hair with follicular tissue indicates hair was pulled or brushed out

7. Identification cont. Nuclear DNA from the hair root or follicular tissue can be used to identify a particular person –From the root is easier to obtain DNA in the anagen phase Mitochondrial DNA can be used in the absence of nuclear DNA –Cannot be used to individualize

8. Collection & Preservation of Hair Evidence 1.Must be accompanied by a number of standard/reference samples from the victim, the crime scene, and from suspects 2.Standard hairs must come from the same body area

9. Collection & Preservation of Hair Evidence 3.Standard hairs must be sufficient to represent a sample of hair from one area of the body 4.Generally includes 50 full length hairs from scalp; minimum of 2 dozen full length pubic hairs 5.Hair samples collected from the victim during an autopsy

10. Case Studies Read page 201 and 204 –Central Park Jogger Case –Ennis Cosby Murder Case