Hair Analysis in Forensic Science

Hair Evidence

Hair can be left at crime scenes.

Physical Characteristics

Hair provides class evidence through its features.

Nuclear DNA

Found in hair with attached follicles or roots.

Mitochondrial DNA

Found in hair without roots; indicates family ties.

Gas Chromatography

Chemical test analyzing substances in hair.

Isotope Ratio Analysis

Determines isotopic composition in hair samples.

Comparison Microscope

Used for detailed hair comparison analysis.

Anagen Stage

Active growth phase of hair development.

Catagen Stage

Transitional phase in hair growth cycle.

Telogen Stage

Resting phase before hair falls out.

Medullary Index

Ratio of medulla diameter to hair diameter.

Cuticle Structure

Human hair cuticles are flattened and narrow.

Trace Evidence

Hair does not prove guilt but can link suspects.

Collection Techniques

Photograph and document hair at crime scenes.

Neutron Activation Analysis

Analyzes hair by creating radioactive decay paths.

Isotope Ratio Mass Spectroscopy

Analyzes isotopes for individual evidence in hair.

Protein Keratin

Main component of hair shaft structure.

Microscopic Analysis

Uses various microscopy techniques for hair examination.

Chemical Analysis

Identifies substances absorbed by hair over time.

Innocence Project

Advocates for accurate hair analysis standards.

OSAC

Organization recommending forensic science standards.

Hair Types

Varies by shape, length, diameter, texture, color.

Treated Hair

Altered by bleaching or dyeing processes.

Ethnic Differences

Physical hair characteristics vary by ancestry.