Forensic scientists perform 3 major types of hair analysis: (1) testing the hair shaft for drugs or nutritional deficiencies in a person’s system, (2) analyzing DNA collected from the root of the hair, and
(3) viewing hair under a microscope to determine if it’s from a particular person or animal
.
What are three uses for hair analysis?
Forensic scientists perform three major types of hair analysis.
Chemical assays are used to assess the use of illegal drugs
, to screen for the presence of heavy metals in the body, and to test for nutritional deficiencies. The root of the hair has cells that contain DNA , which can be used for DNA analyses.
What are the 3 scale patterns for hair?
There are three basic scale structures that make up the cuticle—
coronal (crown-like), spinous (petal-like), and imbricate (flattened)
. Combinations and variations of these types are possible. Figures 85-90 illustrate scale structures.
How do forensic scientists analyze hair?
The hair can be analyzed by
determining the chemical makeup of the hair or extracting DNA from the hair follicle
. Hair can also be analyzed through the use of a microscope or by simply comparing two or more hairs against one another.
How do you analyze hair from a crime scene?
Forensic analysts use
an instrument called a comparison microscope
to view a known hair sample and an unknown sample alongside one another to see if they share similar characteristics and could have come from the same source.
What is the most important part of the hair?
The follicle
is the essential unit for the generation of hair. The hair shaft consists of a cortex and cuticle cells, and a medulla for some types of hairs. Hair follicle has a continuous growth and rest sequence named hair cycle.
What can hair analysis reveal?
Hair analysis can be used to check
if people are blood relatives
. Forensic hair analysis can be done to help identify a criminal by evaluating hair structure and DNA from cells attached to the root of the hair. Hair samples are tested with specific chemicals and looked at under a microscope.
What is the deepest layer of hair?
The medulla
– the deepest layer of the hair shaft, only seen in large and thick hairs. The cortex – the middle layer of the hair shaft which provides the strength, colour and texture of a hair fibre. The cuticle – the outer layer of the hair shaft is thin and colourless.
What is the scale pattern of human hair called?
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.
What is a scale pattern in hair?
The imbricate scale pattern is
a flattened wavy pattern
that is commonly found on human hair and many types of animal hair. The coronal scale pattern is a crown-like pattern that resembles a stack of paper cups, and is normally found only on very fine hair.
Which part of the hair is most rich in DNA?
The hair follicle at the base of human hairs
contains cellular material rich in DNA.
What part of a hair is the most useful for DNA analysis?
What part of the hair is most likely to yield useful DNA evidence?
The follicular tissue adhering to the root, the root itself
, or the follicular tag. The follicular tag is the best source.
How do I test my hair?
- Shampoo and rinse your hair to remove any product buildup.
- Fill a glass with water.
- Once your hair is clean and dry, drop a single strand of your hair into the glass of water.
- Watch the strand to see if it sinks to the bottom of the glass or floats at the top.
What are 5 ways of collecting hair evidence?
- Visual collection. On some surfaces, hairs and fibers can be seen with the naked eye.
- Tape lifting. Trace tapes are available for the collection of trace hair and fiber evidence.
- Vacuuming.
Is hair biological or physical evidence?
Biological evidence
, on the other hand, includes organic things like blood, saliva, urine, semen, hair, and botanical materials, such as wood, plants, pollens and yes, Clarice, moth cocoons.
