Structure & Parts
Name the outermost layer of a hair strand made of overlapping scales.
Cortex or Cuticle.
Cuticle
What do we call hair collected from a crime scene with unknown origin?
Questioned hair
Should hair samples be packaged in plastic or paper containers?
Paper containers
What tool allows side-by-side comparison of two hair samples?
Microscope
Which DNA source provides the highest potential for unique individual identification when present?
Nuclear DNA
Name the middle layer of a hair strand.
Medulla, Cuticle, or Cortex.
Cortex
What is hair collected from a suspect or victim for comparison called?
Known hair (control sample)
Name one critical practice to avoid contamination when collecting hair samples.
Use clean/sterilized tools for each sample (or wear gloves and change tools as needed).
Name one microscopic feature analysts examine on hair.
Cuticle scale patterns, pigmentation distribution, or cross-sectional shape
Which type of DNA is found in the hair shaft and is maternally inherited?
Mitochondrial DNA
What is the central core of hair that may be continuous, fragmented, or absent?
Medulla
What type of hair evidence indicates physical contact between people or between a person and an object?
Transfer hair
Why is documenting the exact location of each hair sample important?
It preserves context and supports interpretation of how and where evidence was deposited.
What does cross-sectional shape help distinguish?
Differences between hair types (e.g., human vs. animal), possbly a person's race.
What laboratory method is used to amplify small amounts of DNA for analysis?
Polymerase Chain Reaction (PCR)
Which part of the hair can contain nuclear DNA useful for individual identification?
Root (hair follicle/root sheath)
Why might treated hair (dye, perm) be important to note during analysis?
Treatments can alter chemical and microscopic features and affect DNA recovery and interpretation.
What is the purpose of maintaining a chain of custody?
To document every transfer/handling of evidence and help ensure integrity and admissibility in court.
Name two limitations that can reduce success rates of DNA retrieval from hair.
Age of the sample, environmental degradation, chemical treatments, and absence of root material can affect DNA recovery.
Describe one reason why cuticle scale pattern is useful in forensic hair analysis.
Scale patterns help determine species and can provide comparison features between samples.
Give two ways animal hair evidence can be useful in an investigation.
Linking a suspect to a scene via pet hair; distinguishing human from animal origin; or matching species or breed characteristics.
Explain why collecting control samples from multiple body areas is recommended.
It provides a variation baseline for comparison and helps account for differences in hair type by body region.
List three kinds of chemical analyses performed on hair.
Toxicology screening (including drugs), analysis of certain metals, and environmental exposure indicators.