Transcript Forensic Palynology_edited

FORENSIC PALYNOLOGY
Jaclyn Seelagy
Department of Forensic Science at
George Washington University
WHAT IS FORENSIC PALYNOLOGY?
Use
of pollen and
spores in criminal
investigation.
Used often in New
Zealand,
Australia, UK.
WHAT IS FORENSIC
PALYNOLOGY?
A
type of associative evidence.
Used to make associations between
people, between a suspect and a crime
scene, any type of evidence and a
particular location
 Ex: The transportation history of
drugs.

 Can
also help determine
when/where a body was dumped.
A FEW DEFINITIONS
 Pollen:
grains produced by flowering or conebearing plants to carry male sex cells to other
plants.
 Spores: small reproductive bodies of plants
and other organisms that don’t produce pollen:
ferns, mosses, algae, fungi, etc.
 Locard’s Exchange Principle: Whenever
two objects come together, there is an
exchange of material (the principle behind
trace/associative evidence).
WHAT MAKES POLLEN SO USEFUL?
 Size
Microscopic.
 Generally goes unnoticed.
 Suspect picks up evidence of his/her
presence at a crime scene without
realizing it, therefore without taking
precautions.
 Variable morphology
 Durability
 Limited dispersal.

VARIATIONS IN MORPHOLOGY
 Different
types of
pollen look different
under a microscope.
 Shape (sphere, oval,
triangle, etc).
 Sculpture patterns
on surface (spines,
granules, pores).
 Wall
structure/thickness.
Bruce and Dettmann, p. 91
DURABILITY
 Wall
of a pollen grain contains
sporopollenin.

Survives almost anything including bleach.
 Can
recognize a pollen grain’s distinctive
shape even after it has been on a body or
a suspect’s clothes for a long time.
 Traces of pollen can remain on clothing
for days if the clothing isn’t washed.
DISPERSAL
 Wind-dispersed
pollen
 Plant produces a lot of it.
 Pollen can go fairly far from the plant.
 Only gives a general idea of location.
 Animal-dispersed pollen
 Includes insects, bats, birds, etc.
 Tends not to go far from the plant.
 Can associate a suspect or object with a
narrow scene.
 Direct contact (brushing against a plant).
 leaves larger amounts of pollen.
 pinpoints a subject’s proximity even more
exactly.
METHODS
METHODS
 Samples

analyzed microscopically.
Samples taken from an item (suspect’s clothing,
corpse, wheel wells of a car, etc.)
 Individual
grains compared to reference
samples for identification.
 Examiner counts each type of pollen, calculates
percentages.
 Compares these percentages to the pollen
content of regional control samples to see if
they resemble the pollen of a scene.
METHODS (CONT’D)
Can also use DNA to determine plant species from
pollen (more time consuming, expensive)
 Certain seasonal pollen grains can help
determine season of death:
 While pollen on the ground or clothing
accumulates over time, pollen only remains in the
air temporarily.
 A person inhales pollen, trapping it in his/her
nose, or traps it in hair or eyebrows.
 Pollen found in hair or nose samples from a body
was likely trapped there in the few days before
death.

QUESTIONS?
REFERENCES

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Horrocks M, Walsh KAJ. Fine resolution of pollen
patterns in limited space: differentiating a crime scene
and alibi scene seven meters apart. J Forensic Sci
1999;44(2):417-420.
Mildenhall DC. Hypericum pollen determines the
presence of burglars at the scene of a crime: an example of
forensic palynology. Forensic Sci Int’l 2006;163:231-235.
Horrocks M, Walsh KAJ. Pollen on grass clippings:
putting the suspect at the scene of the crime. J Forensic
Sci 2001;46(4):947-949.
Brown AG, Smith A, Elmhurst O. The combined use of
pollen and soil analyses in a search and subsequent
murder investigation. J Forensic Sci 2002;47(3):614-618.
Bruce RG, Dettmann ME. Palynological analyses of
Australian surface soils and their potential in forensic
science. Forensic Sci Int’l 1996;81:77-94.
REFERENCES (CONT’D)
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Editorial: Mildenhall DC, Wiltshire PEJ, Bryant VM.
Forensic palynology: why do it and how it works. Forensic
Sci Int’l 2006;163:163-172.
Mildenhall DC. An unusual appearance of a common
pollen type indicates the scene of the crime. Forensic Sci
Int’l 2006;163:236-240.
Bull PA, Morgan RM, Segovsky A, Hughes GJA. The
transfer and persistence of trace particulates:
experimental studies using clothing fabrics. Sciene&
Justice 2006;46(3):185-195.
Montali E, Mercuri AM, Grandi GT, Accorsi CA. Towards
a “crime pollen calendar”—pollen analysis on corpses
throughout one year. Forensic Sci Int’l 2006;163:211-223.
Eliet JR, Harbison SA. The development of a DNA
analysis system for pollen. Int’l Congress Series
2006;1288:825-827.