Biological material –collection, characterization and storage - An Introduction to Forensic Genetics - page 22

Table 3.1 Types of biological material that can be recovered from a crime scene.
The DNA profiles generated from crime scene material are compared against reference
profiles that are provided by suspects (or to a collection of reference samples held on
a DNA database), and in some cases, the victims
Scenes of crime Reference samples

Blood Blood

Semen Buccal swabs

Hair Pulled hairs (containing roots)

Epithelial cells - shed skin cells:
Saliva -

Dandruff -

Clothing -

Cigarette butts -

Drinking vessels/food -

Urine -

Vomit -

Faeces -

Touch DNA -

(a) (b)
Figure 3.1 Blood is the most common form of biological material that is recovered from crime
scenes. (a) Large volumes of blood can be collected using a swab; if the blood is liquid then a
syringe or pipette can be used. (Picture provided by Allan Scott, University of Central Lancashire.)
(b) Blood on clothing is normally collected by swabbing or cutting out the stain. (Picture provided
by Elizabeth Wilson)

handles are examples were no biological material is visible but is highly likely to be
present. Hairs are naturally shed, and can also be pulled out through physical contact
and can be recovered from crime scenes. Naturally shed hairs tend to have very little
follicle attached and are not a good source of DNA, whereas plucked hairs or hairs
removed because of a physical action often have the root attached, which is a rich
source of cellular material.
The four most common nucleated cell types that are recovered from scenes of crime
are white blood cells, spermatozoa, epithelial cells and hair follicles (Figure 3.2).