A forensic scientist who studied the morphology (shape, form, and structure) of a hair specimen could testify as to the gross physical characteristics of the hair (color, degree of curl, etc.), its internal and external structural characteristics, the likely somatic region from which the hair originated (scalp, beard, …
What can you determine from hair using morphological features?
The body area from which a hair originated can be determined by general morphology. Length, shape, size, color, stiffness, curliness, and microscopic appearance all contribute to the determination of body area. Pigmentation and medullar appearance also influence body area identification.
Why is hair considered good forensic evidence?
Hair samples are one of the most important resources in the forensic analysis of crime scenes, often providing valuable information that can help to lead to the identification of a suspect or victim. … Hair can also be used to extract DNA for analyses that can help to narrow down who may have been involved in a crime.
How do forensic scientists analyze hair?
Nuclear DNA analysis can be done on human hairs. The trace section assists the DNA section by screening hairs and determining their suitability for DNA testing. A microscope is used to examine the root end of the hairs, in order to determine if they are suitable.
What features of hair do forensic scientists examine to make comparisons?
Head hairs must be compared with known head-hair samples, and pubic hairs must be compared to known pubic-hair samples. The comparison process involves the side-by-side analysis of a questioned hair and known hair samples using a comparison microscope.
What are the three major types of hair analysis?
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 is the limitation of hair without the follicle?
What are the limitations of the information that hair can provide? Hair is considered class evidence. Alone (without follicle cells attached), it cannot be used to identify a specific individual.
Is hair biological or physical evidence?
Physical evidence is comprised of those forms of data that can be measured or quantified. Examples include fingerprints, accelerants, hair or fibers, etc. These types of evidence can be measured, weighed, and defined by a number of other physical methods.
What are 5 ways of collecting hair evidence?
The most common methods used to collect hair and fiber evidence include the following:
- 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. …
Can hair be used as DNA evidence?
Hair analysis is used to provide DNA evidence for criminal and paternity cases. For DNA testing, the root of one hair is needed to analyze DNA and to establish a person’s genetic makeup. Hair analysis is less commonly used to test for heavy metals in the body, such as lead, mercury, and arsenic.
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.
Does hair have DNA?
The hair follicle at the base of human hairs contains cellular material rich in DNA. In order to be used for DNA analysis, the hair must have been pulled from the body — hairs that have been broken off do not contain DNA. Any body tissue that has not been degraded is a potential source of DNA.
What techniques are used in forensic fiber analysis?
The most common use of fiber analysis is microscopic examination of both longitudinal and cross sectional samples. While this is the most common method of undertaking fiber analysis, others do exist. These include the burning and solubility methods.
What gives fingerprints their unique characteristic?
The fingerprints are made of unique pattern of ridges, each of which contains pores, that are linked to sweat glands beneath the skin. All these ridges of fingerprints form a pattern called as arches, loops and whorls. The loops start from one side and exit on the other side.
When can hair be used as individual evidence?
Hair is considered class evidence when the follicle is not attached because the follicle is the part that contains DNA. When the follicle is attached, it is considered individual evidence.
How long does hair DNA last?
Researchers have found that the half life of the molecule, the time taken for half the bonds in the molecule to be broken will be 521 years under ideal conditions. The time taken for all the bonds of the DNA molecule to be broken is 6.8 million years.