Download Forensic Science Glossary of Words

Forensic Science Glossary
Forensic Science Glossary of Words
a
absorption – passage of alcohol across the wall of the stomach and small
intestine into the blood stream.
accelerant – any material used to start or sustain a fire. The most common
accelerants are combustible liquids.
acid – a compound capable of donating a hydrogen ion to another compound.
acid phosphatase – an enzyme found in high concentration in semen.
agglutination – the clumping together of red blood cells by the action of an antibody.
algor mortis – postmortem changes that cause a body to lose heat.
allele – any of several alternative forms of a gene located at the same point on a
particular pair of chromosomes. For example, the genes determining the blood
types A and B are alleles.
alpha ray – a type of radiation emitted by a radioactive element. The radiation is
composed of helium atoms minus their orbiting electrons.
alveoli – small sacs in the lungs through whose walls air and other vapors are exchanged
between the breath and the blood.
amelogenin gene – a genetic locus found useful for determining gender.
amino acid – the building blocks of proteins. There are 20 common amino acids.
Amino acids are linked together to form a protein. The types of amino acids and
the order in which they’re linked determine the character of each protein.
amorphous solid – a solid in which the constituent atoms or molecules are arranged in
random or disordered positions. There is no regular order in amorphous solids.
anabolic steroid – steroids that promote muscle growth.
anagen phase – the initial growth phase during which the hair follicle is actively
producing hair.
analgesic – a drug or substance that lessens or eliminates pain.
anthropometry – a system of identification of individuals by
measurement of parts of the body, developed by
Alphonse Bertillon.
antibody – a protein that destroys or inactivates a specific
antigen. Antibodies are found in the blood serum.
anticoagulant – a substance that prevents coagulation or
clotting of the blood.
antigen – a substance, usually a protein, that stimulates the
body to produce antibodies against it.
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Forensic Science Glossary
antiserum – blood serum in which there are specific antibodies.
arch – a class of fingerprints characterized by ridge lines that
enter the print from one side and flow out the other side.
artery – a blood vessel that carries blood away from the heart.
aspermia – the absence of sperm; sterility in males.
atom – the smallest unit of an element; not divisible by ordinary
chemical means. Atoms are made up of electrons,
protons and neutrons plus other subatomic particles.
Arch in fingerprint pattern
atomic mass – the sum of the number of protons and neutrons in
the nucleus of an atom.
atomic number – the number of protons in the nucleus of an
atom. Each element has its own unique atomic number.
autopsy – the medical dissection and examination of a body in
order to determine the cause of death.
Image from a Furby
autopsy following the
removal of skin.
b
base – a compound capable of accepting a hydrogen ion.
Becke line – a bright halo that is observed near the border of a particle
immersed in a liquid of a different refractive index.
beta ray – a type of radiation emitted by a radioactive element. The radiation
consists of electrons.
binocular – a microscope with two eyepieces.
birefringence – a difference in the two
indices of refraction exhibited by
most crystalline materials.
black powder – normally, a mixture of
potassium nitrate, carbon and sulfur
in the ratio 75/15/10.
bookmark – a feature that allows the user
to designate favorite sites for fast
and easy access.
bore – the interior of a firearm barrel.
breechblock – the rear part of a firearm barrel.
browser – the program that runs on a computer and allows access to web sites.
buccal cells – cells derived from the inner cheek lining.
buccal swab – swab of inner portion of cheek; cheek cells are usually collected to
determine the DNA profile of an individual.
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Forensic Science Glossary
c
caliber – the diameter of the bore of a rifled firearm. The caliber is usually
expressed in hundredths of an inch or millimeters; i.e., .22 caliber and 9 mm.
capillary – a tiny blood vessel across whose walls exchange of materials
between the blood and the tissues takes place; receives blood from arteries and
carries ti to veins.
catagen phase – a transition stage between the anagen and telogen phases of hair growth.
catalyst – a substance that accelerates the rate of a chemical reaction but is not itself
permanently changed by the reaction.
Celsius scale – the temperature scale using the melting point of ice as 0° and the boiling
point of water as 100°, with 100 equal divisions or degrees between.
chain of custody – a list of all persons who came into possession of an item of evidence.
charred document – any document that has become darkened and brittle through
exposure to fire or excessive heat.
chemical properties – properties that describe the behavior of a substance when it reacts
or combines with another substance.
choke – an interior constriction placed at or near the muzzle end of a shotgun’s barrel for
the purpose of controlling shot dispersion.
chromatography – any of several analytical techniques whereby organic mixtures are
separated into their components by their attraction to a stationary phase while
being propelled by a moving phase.
chromosome – a rodlike structure in the cell nucleus, along which the genes are located.
It is composed of DNA surrounded by other material, mainly proteins.
class characteristics – properties of evidence that can only be associated with a group
and never with a single source.
combustion – the rapid combination of oxygen with another substance accompanied by
the production of noticeable heat and light.
comparison – the process of ascertaining whether two or more objects have a common
origin.
complementary base pairing – the specific pairing of base a with T and base C with G
in double-stranded DNA.
compound – a pure substance composed of two or more elements.
concentric fracture – a crack in a glass that forms a
rough circle around the point of impact.
condenser – lens system located under the
microscope stage that focuses light onto the
specimen.
confirmation – a single test that specifically
identifies a substance.
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Forensic Science Glossary
continuous spectrum – a type of emission spectrum
showing a continuous band of colors all
blending into one another.
control – physical evidence whose origin is known,
such as blood or hair from a suspect, that can
be compared to crime-scene evidence.
cortex – the main body of the hair shaft.
crystalline solid – a solid in which the constituent
atoms have a regular arrangement.
cuticle – the scale structure covering the exterior
of the hair.
d
deflagration – a very rapid oxidation reaction accompanied by the generation of
a low-intensity pressure wave that can have a disruptive effect on the
surroundings.
density – a physical property of matter that is equivalent to the mass-per-unit volume of a
substance.
density-gradient tube – a glass tube filled from bottom to top with liquids of
successively lighter densities; used to determine the density distribution of soil.
depressant – a substance used to depress the functions of the central nervous system.
Depressants calm irritability and anxiety and may induce sleep.
depth of focus – the thickness of a specimen entirely in focus under a microscope.
detonating cord – a cordlike explosive containing a core of high-explosive material,
usually PETN; also called primacord.
detonation – an extremely rapid oxidation reaction accompanied by a violent disruptive
effect and an intense, high-speed shock wave.
digital imaging – a process through which a
picture is converted into a series of
square electronic dots known as pixels.
Manipulation of the picture is
accomplished through computer
software that changes the numerical
value of each pixel.
dispersion – the separation of light into its
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Forensic Science Glossary
component wavelengths.
distance determination – the process of determining the distance between the firearm
and a target, usually based on the distribution of powder patterns or the spread of
a shot pattern.
DNA – abbreviation for deoxyribonucleic acid, the
molecules carrying the body’s genetic information.
DNA is double-stranded in the shape of a double
helix.
domain – a designation that indicates the type of web site.
For example, commercial (.com), nonprofit (.org)
and government (.gov).
download – the transfer of a file over a modem from a
remote computer to a desktop computer.
e
egg – the female reproductive cell.
ejector – the mechanism in a firearm that throws the cartridge or fired case from
the firearm.
electromagnetic spectrum – the entire range of radiation energy from the most
energetic cosmic rays to the least energetic radio waves.
electron – a negatively charged particle that is one of the fundamental structural units of
the atom.
electron orbital – the pathway of electrons as they move around the nuclei of atoms;
each orbital is associated with a particular electronic energy level.
electrophoresis – a technique for the separation of molecules through their migration on
a support medium while under the influence of an electrical potential.
element – a fundamental particle of matter. An element cannot be broken down into
simpler substances by chemical means.
e-mail – electronic mail.
emission spectrum – light emitted from a source and separated into its component colors
or frequencies.
endothermic reaction – a chemical transformation in which heat energy is absorbed
from the surroundings.
energy – the combined ability or potential of a system or material to do work. Some
forms of energy are heat energy, chemical energy and electrical energy.
enzyme – a type of protein that acts as a catalyst for certain specific reactions.
epithelial cells – the outer layer of skin cells. These DNA-bearing cells often fall off or
are rubbed off only objects retrieved from crime scenes.
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Forensic Science Glossary
erasure – the removal of writings, typewriting or printing from a document. Normally
accomplished by either chemical means or an abrasive instrument.
erythrocyte – a red blood cell.
excited state – that state in which an atom is supplied energy and an electron is moved
from a lower to a higher energy level.
excretion – elimination of alcohol from the body in an unchanged state; alcohol is
normally excreted in breath and urine.
exemplar – an authentic sample used for comparison purposes, such as handwriting.
exothermic reaction – a chemical transformation in which heat energy is liberated.
expert witness – an individual whom the court determines possesses knowledge relevant
to the trial that is not expected of the average layperson.
explosion – a chemical or mechanical action resulting in the rapid expansion of gases.
extractor – the mechanism in a firearm by which a cartridge of a fired case is withdrawn
from the chamber.
eyepiece lens – the lens of a microscope into which the viewer looks; same as the ocular
lens.
f
Fahrenheit scale – the temperature scale using the melting point of ice as 32° and
the boiling point of water as 212°, with 180 equal divisions or degrees between.
field of view – the area of the specimen that can be seen after it is magnified.
finished sketch – a precise rendering of the crime
scene, usually drawn to scale.
firearms identification – a discipline mainly
concerned with determining whether a
bullet or cartridge was fired by a particular
weapon. Not to be confused with ballistics,
which is the study of a projectile in motion.
flammable range – the entire range of possible
gas or vapor fuel concentrations in air that
are capable of burning.
flash point – the minimum temperature at which a liquid fuel will produce enough vapor
to burn.
fluoresce – to emit light when exposed to light of a shorter wavelength.
follicular tag – a translucent piece of tissue surrounding the hair’s shaft near the root. It
contains the richest source of DNA associated with hair.
forensic anthropology – the specialty that is concerned primarily with the identification
and examination of human skeletal remains.
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Forensic Science Glossary
forensic engineering – specialty concerned with failure analysis, accident reconstruction
and causes and origins of fires or explosions.
forensic entomology – the study of insects and their relation to a criminal investigation.
forensic odontology – specialty that is concerned with the identification of victims
through the structure of teeth, their alignment and overall structure of the mouth.
forensic psychiatry – specialized area in which the relationship between human behavior
and legal proceedings is examined.
frequency – the number of waves that pass a given point per second.
fuel cell – a detector in which chemical reactions are used to produce electricity.
g
gamma ray – a high-energy form of electromagnetic radiation emitted by a
radioactive element.
gas (vapor) – a state of matter in which the attractive forces between molecules are
small enough to permit them to move with complete freedom.
gauge – size designation of a shotgun, originally the number of lead balls with the same
diameter as the barrel that would make a pound. For example, a 12-gauge
shotgun would have a bore diameter of a lead ball 1/12 pound in weight. The
only exception is the .410 shotgun, in which the bore size is 0.41 inch.
gene – a unit of inheritance consisting of a DNA segment located on a chromosome.
genotype – the particular combination of
genes present in the cells of an
individual.
glowing combustion – burning at the fuelair interface. Examples are a red-hot
charcoal or a burning cigarette.
greiss test – a chemical test to develop
patterns of gunpowder residues
around bullet holes.
grooves – the cut or low-lying portions
between the lands in a rifled bore.
h
hallucinogen – a substance that induces changes in mood, attitude, thought or
perception.
heat of combustion – the heat evolved when a substance is burned in oxygen.
hemoglobin – a red blood cell protein responsible for transporting oxygen in the
bloodstream and the red coloring of blood.
heterozygous – having two different allelic genes on two corresponding positions of a
pair of chromosomes.
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Forensic Science Glossary
high explosive – explosive with a velocity of detonation greater than 1,000 meters per
second. For example, dynamite and RDX.
homozygous – having two identical allelic genes on two corresponding positions of a
pair of chromosomes.
human genome – the total DNA content found within the nucleus of a cell. In humans,
it is composed of approximately 3 billion base pairs of genetic information.
hybridization – the process of joining two complementary strands of DNA together to
form a double-stranded molecule.
hybridoma cells – fused spleen and tumor cells used to produce identical monoclonal
antimbodies in a limitless supply.
hydrocarbon – any compounds consisting only of carbon and hydrogen.
hypertext – links to other web sites. The linked document is displayed by clicking on a
highlighted word or icon.
i
identification – the process of determining a substance’s physical or chemical
identity.
ignition temperature – the minimum temperature at which a fuel will spontaneously
ignite.
indented writings – impressions left on papers positioned under a piece of paper that has
been written upon.
individual characteristics – properties of evidence that can be attributed to a common
source with an extremely high degree of certainty.
infrared – invisible short frequencies of light before red in the visible spectrum.
infrared luminescence – a property exhibited by some dyes that emit infrared light when
exposed to blue-green light.
inorganic – a chemical compound not based on carbon.
intensive property – a property that is not dependent on the size of an object.
iodine fuming – a technique for visualizing latent fingerprints by exposing them to
iodine vapors.
ion – an atom or molecule bearing a positive or negative charge.
iso-enzymes – multiple molecular forms of an enzyme, each having the same or very
similar enzyme activities.
isotope – an atom differing from another atom of the same element in the number of
neutrons it has in its nucleus.
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Forensic Science Glossary
l
laminated glass – two sheets of ordinary glass bonded together with a plastic sheet.
lands – the raised portion between the grooves in a rifled bore.
laser – light amplification by the simulated emission of radiation. Light that has all
its waves pulsating in unison.
latent fingerprint – a fingerprint made by the deposit of oils and/or perspiration. It is
invisible to the naked eye.
line spectrum – a type of emission spectrum showing a series of lines separated by black
areas. Each line represents a definite wavelength or frequency.
liquid – a state of matter in which molecules are in contact with one another but are not
rigidly held in place.
livescan – an inkless device that captures the digital images of fingerprints and palm
prints and electronically transmits the images to an AFIS.
livor mortis – the medical condition that occurs after death and results in the settling of
blood in areas of the body closest to the ground.
Locard’s exchange principle – whenever two objects come into contact with one
another, there is exchange of materials between them.
locus – the physical location of a gene on a chromosome.
loop – a class of fingerprints characterized by ridge lines that
enter from one side of the pattern and curve around to exit
from the same side of the pattern.
low copy number – fewer than eighteen DNA-bearing cells.
low explosive – explosive with a velocity of detonation less than
1,000 meters per second. For example, black powder and
smokeless powder.
Loop in fingerprint
luminol – the most sensitive chemical test that is capable of
presumptively detecting bloodstains diluted up to 300,000
times. Its reaction with blood emits light and thus
requires the result to be observed in a darkened area.
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Forensic Science Glossary
m
macromolecule – a molecule with a high molecular mass.
mailing list – a list of people with a common interest who receive all the emails sent to the list.
manufactured fibers – fibers derived from either natural or synthetic
polymers; the fibers are typically made by forcing the polymeric material through
the holes of a spinneret.
mass – a constant property of matter that reflects the amount of material present.
matter – all things of substance. Matter is composed of atoms or molecules.
medulla – a cellular column running through the
center of the hair.
metabolize – transforming a chemical in the body to
another chemical for the purpose of facilitating
its elimination from the body.
microcrystalline tests – tests to identify specific
substances by the color and morphology of the
crystals formed when the substance is mixed
with specific reagents.
microspectrophotometer – an instrument that links a microscope to a
spectrophotometer.
mineral – a naturally occurring crystalline solid.
mitochondria – small structures that supply energy to a cell.
mitochondrial DNA – maternally inherited DNA present in small structures located
outside the nucleus of a cell.
modem – a device that connects your computer to another computer through a phone
line.
modus operandi – an offender’s pattern of operation.
molecule – two or more atoms held together by chemical bonds.
monochromatic light – light having a single wavelength or frequency.
monochromator – a device for isolating individual wavelengths or frequencies of light.
monoclonal antibodies – a collection of identical antibodies that interact with a single
antigen site.
monocular – a microscope with one eyepiece.
monomer – the basic unit of structure from which a polymer is constructed.
multiplexing – a technique that simultaneously detects more than one DNA marker in a
single analysis.
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Forensic Science Glossary
n
narcotic – analgesic or pain-killing substance that depresses vital body functions
such as blood pressure, pulse rate, and breathing rate. The regular administration
of narcotics will produce physical dependence.
natural fibers – fibers derived entirely from animal or plant sources.
natural variations – normal deviations found between repeated specimens of an
individual’s handwriting or any printing device.
neutron – a particle having no electrical charge, which along with the proton is a basic
unit in the structure of the nucleus of an atom.
newsgroups – large bulletin board systems that consist of several thousand specialized
discussion groups. Messages are posted to a bulletin board by e-mail for others to
read.
ninhydrin – a chemical reagent used to develop latent fingerprints on porous materials
by reacting with amino acids in perspiration.
nuclear DNA – DNA present within the nucleus of a cell. This form of DNA is inherited
from both parents.
nucleotide – the unit of DNA consisting of one of four bases – adenine, guanine,
cytosine or thymine – attached to a phosphate-sugar group.
nucleus – the core of an atom containing the protons and neutrons.
o
objective lens – the lower lens of a microscope that is positioned directly over the
specimen.
obliteration – the blotting out or smearing over of writing or printing to make the
original unreadable.
oligospermia – a condition describing an abnormally low sperm count.
organic – a substance composed of carbon and hydrogen, and, often, smaller amounts of
oxygen, nitrogen, chlorine, phosphorus, or other elements.
oxidation – the combination of oxygen with other substances to produce new products.
oxidizing agent – a substance that supplies oxygen to a chemical reaction.
p
parfocal – construction of a microscope such that when an image is focused with
one objective in position, the other objective can be rotated into place and the
field will remain in focus.
periodic table – chart of elements arranged by increasing atomic number. Vertical rows
are called groups or families; horizontal rows are called periods or series.
pH – a symbol used to express the basicity or acidity of a substance. A pH of 7 is
neutral; lower values are acidic, higher values basic.
phase – a uniform piece of matter; different phases are separated by definite visible
boundaries.
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Forensic Science Glossary
phenotype – the physical manifestation of a genetic trait such as shape, color and blood
type.
photon – a small packet of electromagnetic radiation energy. Each photon contains a
unit of energy equal to the product of Planck’s constant and the frequency of
radiation: E = hf.
physical dependence – physiological need for a drug that has been brought about by its
regular use. Dependence is characterized by withdrawal sickness when
administration of the drub is abruptly stopped.
physical developer – a silver nitrate-based reagent formatted to develop latent
fingerprints on porous surfaces.
physical evidence – any and all objects that can establish that a crime has been
committed or can provide a link between a crime and its victim or a crime and its
perpetrator.
physical properties – properties that describe a substance without reference to any other
substances.
physical state – a condition or stage in the physical being of matter; a solid, liquid or gas.
picogram – one-trillionth of a gram, or 0.000000000001 gram.
pixel – an electronic square dot that is used to compose a digital image.
plane-polarized light – light confined to a single plane of vibration.
plasma – the fluid portion of unclotted blood.
plastic print – a fingerprint impressed in a soft surface.
polarizer – a device that permits the passage of light waves vibrating in only one plane.
polyclonal antibodies – antibodies produced by injecting animals with a specific antigen.
A series of antibodies are produced responding to a variety of different sites on
the antigen.
polymer – a substance composed of a large number of atoms. These atoms are usually
arranged in repeating units or monomers.
polymerase chain reaction (PCR) – a technique for replicating or copying a portion of a
DNA strand outside a living cell. This technique leads to millions of copies of the
DNA strand.
polymorphism – the existence of more than one form of a genetic trait.
portal – a web site offering a variety of features, such as news, stock quotes, search
capabilities , e-mail and message boards.
portrait parlé – a verbal description of a perpetrator’s physical characteristics and dress
provided by an eyewitness.
precipitin – an antibody that reacts with its corresponding antigen to form a precipitate.
preservative – a substance that stops the growth of microorganisms in blood.
primary explosion – a high explosive that is easily detonated by heat or shock.
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Forensic Science Glossary
primer – a short strand of DNA used to target a region of DNA for replication by PCR.
product rule – multiplying together the frequencies of independently occurring genetic
markers to obtain an overall frequency of occurrence for a genetic profile.
proteins – polymers of amino acids that play basic roles in the structure and functions of
living things.
proton – a positively charged particle that is one of the basic structures in the nucleus of
an atom.
psychological dependence – the conditioned use of a drug caused by underlying
emotional needs.
pyrolysis – the decomposition of organic matter by heat.
q
r
questioned documents – any document about which some issue has been raised
or that is a subject for investigation.
radial fracture – a crack in a glass that extends outward like the spoke of a wheel
from the point at which the glass was struck.
radioactivity – the particle and/or gamma ray radiation emitted by the unstable
nucleus of some isotopes.
real image – an image formed by the actual convergence of light rays upon a screen.
reconstruction – the method used to support a likely sequence of events by the
observation and evaluation of physical evidence, as well as statements made by
those involved with the incident.
refraction – the bending of a light wave as it passes from one medium to another.
refractive index – the ratio of the speed of light in a vacuum to its speed in a given
substance.
replication – the synthesis of new DNA from existing DNA.
restriction enzymes – chemicals that act as scissors to cut DNA molecules at specific
locations.
restriction fragment length polymorphisms (RFLP) – different fragment lengths of
base pairs that result from cutting a DNA molecule with restriction enzymes.
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Forensic Science Glossary
ridge characteristics (minutiae) – ridge
endings, bifurcations, enclosures
and other ridge details, which must
match in two fingerprints in order
for their common origin to be
established.
rifling – the spiral grooves that are formed
in the bore of a firearm barrel to
impact a spin to the projectile when
it is fired.
rigor mortis – the medical condition that occurs after death and results in the shortening
of muscle tissue and the stiffening of body parts in the position they are in when
death occurs.
rough sketch – a draft representation of all essential information and measurements at a
crime scene. This sketch is drawn at the crime scene.
s
safety fuse – a cord containing a core of black powder. It is used to carry a flame at
a uniform rate to an explosive charge.
screening test – a test that is nonspecific and preliminary in nature.
search engine – a web site devoted to searching information on the internet by key
words.
secondary explosion – a high explosive that has to be detonated by a primary explosive.
secretor – an individual who secretes his or her blood-type antigen(s) in body fluids.
Approximately 80% of the populations are secretors.
sequencing – a procedure used to determine the order of the base pairs that comprise
DNA.
serology – the study of antigen-antibody reactions.
serum – the liquid that separates from the blood when a clot is formed.
short tandem repeats (STRs) – regions of a DNA molecule that contain short segments
consisting of three to seven repeating base pairs.
smokeless powder (double-base) – an explosive consisting of a mixture of nitrocellulose
and nitroglycerin.
smokeless powder (single base) – an explosive consisting of nitrocellulose.
solid – a state of matter in which the molecules are held closely together in a rigid state.
spectrophotometry – an analytical method for identifying a substance by its selective
absorption of different wavelengths of light.
sperm – the male reproductive cell.
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Forensic Science Glossary
spontaneous combustion – a fire caused by a natural heat-producing process in the
presence of sufficient air and fuel.
standard/reference sample – physical evidence whose origin is known, such as blood or
hair from a suspect, that can be compared to crime-scene evidence.
stimulant – a substance taken to increase alertness or activity.
sublimation – a physical change from the solid directly into the gaseous state.
substrate control – uncontaminated surface material close to an area where physical
evidence has been deposited. This sample is to be used to ensure that the surface
on which a sample has been deposited does not interfere with laboratory tests.
super glue fuming – a technique for visualizing latent fingerprints on nonporous surfaces
by exposing them to cyanoacrylate vapors; named for the commercial product,
Super Glue.
t
tandem repeats – a region of a chromosome that contains multiple copies of a core
DNA sequence that are arranged in a repeating fashion.
telogen phase – the final growth phase in which hair naturally falls out of the skin.
tempered glass – glass to which strength is added by introducing stress through the rapid
heating and cooling of the glass surfaces.
transmitted illumination – light that passes up from the condenser and through the
specimen.
u
v
ultraviolet – invisible long frequencies of light beyond violet in the visible
spectrum.
uniform resource locator (URL) – a standard method by which internet sites are
addressed.
vein – a blood vessel that transports blood toward the heart.
vertical or reflected illumination – illumination of a spectrum from above; in
microscopy it is used to examine opaque specimens.
virtual image – an image that cannot be seen directly. It can only be seen by a
viewer looking through a lens.
visible light – colored light ranging from red to violet in the electromagnetic spectrum.
visible print – a fingerprint made when the finger deposits a visible material such as ink,
dirt or blood onto a surface.
voiceprint – a pictorial representation of the frequency, duration and amplitude of human
voice sounds.
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Forensic Science Glossary
w
wavelength – the distance between crests of adjacent waves.
weight – a property of matter that depends both on the mass of a substance
and the effects of gravity on that mass.
whorl – a class of fingerprints that includes ridge patterns that
are generally rounded or circular in shape and have two
deltas.
Whorl in fingerprint
x
y
z
x chromosome – the female sex chromosome.
x-ray – a high-energy, short-wavelength form of electromagnetic radiation.
x-ray diffraction – an analytical technique for identifying crystalline materials.
y chromosome – the male sex chromosome.
Y-STRs – short tandem repeats located on the human Y chromosome. The
utility in forensic science is that they originate only from a male donor of DNA.
zygote – the cell arising from the union of an egg and a sperm cell.
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