hair analysis

Why is hair considered valuable evidence?

Hair easily transfers, sticks to surfaces, and can be left behind without someone knowing.

What kind of evidence does hair usually provide?

Class evidence.

When can hair provide individual evidence?

When the hair has a root or follicle with nuclear DNA.

What DNA is found in hair without a root?

Mitochondrial DNA.

What can mitochondrial DNA show?

Family relationships, not a specific person.

Name one chemical test used on hair.

Gas chromatography or isotope ratio analysis.

What is one limitation of hair evidence?

It cannot show when the hair was left at the scene.

Why is hair considered trace evidence?

It can transfer easily and does not prove guilt by itself.

What was an early advancement in hair analysis?

The comparison microscope.

Why did hair analysis methods change in the 2000s?

Some wrongful convictions were linked to hair analysis.

What is one function of hair?

It helps regulate body temperature.

What are the three stages of hair growth?

Anagen, catagen, and telogen.

What is the follicle of hair?

The root area that contains blood vessels and DNA.

What is the hair shaft?

The part of hair that is not growing and contains mitochondrial DNA.

How can hair differ on the body?

By length, shape, thickness, and texture.

Name two types of hair found on the body.

Head hair and pubic hair.

What does treated hair show?

Dyeing, bleaching, or other chemical changes.

How can hair show ethnic or ancestral traits?

Through differences in shape, texture, and structure.

What is the medullary index?

The ratio of the medulla to the entire hair diameter.

How does human hair differ from animal hair?

Human hair usually has one color and flatter cuticle scales.

How should hair firmly attached to clothing be collected?

Leave it in place and package the clothing.

How should loose hair be collected?

Use clean forceps and place it in a small container.

What is macroscopic hair analysis?

Examining hair with the naked eye.

What is microscopic hair analysis?

Examining hair using microscopes.

What can chemical analysis of hair show?

Drugs, toxins, or substances a person was exposed to.

Why does hair help create a timeline?

Hair grows slowly and traps chemicals over time.

Name one modern advance in hair analysis.

Isotope ratio mass spectroscopy

Why is microscopic hair analysis considered subjective?

Results depend on the examiner’s interpretation.