Forensics Marking Period 2 Quarterly
Restriction Enzyme
"molecular scissors"; a molecule that cuts a DNA molecule at a specific base sequence
Collection Methods of Entomological Evidence
Aerial- using a net to collect flies; Hand- using a gloved hand or forceps to collect flies; Live- letting the sample live to watch them develop in the lab
Contamination of DNA Evidence
Contamination of DNA evidence can occur when DNA from another source is accidentally mixed with DNA that is relevant to the case.
Livor Mortis
Lividity first becomes noticeable about 2 hour after death. The discoloration becomes permanent after 8 hours.
Rigor Mortis
Rigor Mortis usually becomes apparent within 2 hours after death. The stiffness progresses from smaller muscle groups to larger muscle groups. After 12 hours, the body is at its most rigid state. 2 to 6 hours, rigor begins, body becomes stiff and stiffness moves through body, stiffness begins in small muscles, such as those of the face, and progresses to larger muscle groups. 12 hours, rigor complete, peek rigor is exhibited, entire body is rigid. 15 to 36 hours, slow loss of rigor, rigor is uneven, rigor is slowly lost first in smaller muscles and later in larger muscles. 36 to 48 hours, rigor absent, muscles relaxed, many variables may extend rigor beyond the normal 36 hours.
STR
Short Tandem Repeats. An individual's DNA STR profile is unique. A child inherits one allele from each parent for each STR locus
Factors that Affect the Rate of Decompositon
Temperature (Cold temperature inhibits rigor, slower onset and slower progression of rigor. Warm temperature accelerates rigor, faster onset and faster progression of rigor.) Activity Before Death (Anaerobic exercise, accelerates rigor, lack of oxygen to muscle, buildup of lactic acid, and higher body temperature accelerate rigor. Sleep slows rigor, fully oxygenated muscles exhibit rigor more slowly) Body Mass (Obese, slows rigor, fat stores oxygen. Thin, accelerates rigor, body loses oxygen quickly)
The FBI and the 13 Core STRs
The FBI uses 13 core STRs for identification of Americans
Stomach and Intestinal Contents
Within 2 to 6 hours, the stomach empties its contents into the small intestines. Within 12 more hours, the food leaves the small intestine. Withint about 24 hours, the wastes are released through the rectum
Familial Studies
Y STRs- trace ancestry through the male line mtDNA- only mothers pass on mitochondrial DNA mtDNA and Y STRs- can only yield class evidence Fourth amendment rights may become a concern as DNA technology advances
odontology
a branch of forensic medicine that deals with teeth and marks left by teeth (as in identifying the remains of a dead person)
Crop
a digestive organ used for storage of food
tendons
a flexible but inelastic cord of strong fibrous collagen tissue attaching a muscle to a bone
Angiosperm
a flowering plant that produces seeds within a fruit
how bones connect
a joint is the location where bones meet; they contain 3 kinds of connective tissues: cartilage, ligaments and tendons
Polymerase Chain Reaction (PCR)
a method of amplifying (duplicating) minute amounts of DNA evidence for use in investigations
Electrophoresis
a method of separating molecules, such as DNA, according to size
Pupa
a nonfeeding stage of development between larva and adult
Medical Examiner
a physician who performs autopsies, determines the cause and manner of death, and oversees death investigations
Gymnosperm
a plant with "naked" seeds that are not enclosed in a protective organ (fruit); most are evergreens
Insect Succession
a predictable sequence of changing species that inhabit a decomposing body
Pollen Grain
a reproductive structure that contains the male gametes or seed plants
The Body Farm
a research facility where decomposition can be studied in a variety of settings. The aim is to gain a better understanding of the decomposition process, permitting the development of techniques for extracting information (such as the timing and circumstances of death) from human remains
Suicidal Manner of Death
caused by self-directed injurious behavior with an intent to die as a result of the behavior
aging of bones
children build bones faster than they are broken down; At age 30, the process begins to reverse, making it easier to break bones
Algor Mortis
cooling of the body after death
Fresh (initial) (Stage of Decomposition)
corpse appears normal on the outside, but is starting to decompose from the action of bacteria and autolysis. The body temperature drops. Insects lay eggs.
Advanced Decay (Stage of Decomposition)
corpse is drying out. Most flesh is gone. Adipocere is forming. Fewer insects remain.
Oviposition
depositing, or laying, of eggs
Mechanism
describes the specific change in the body that brought about the cessation of life
Putrefaction
destruction of soft tissues by bacteria that results in the release of waste gases and fluids
Instar
each of the three different larval stages of flies in species that undergo complete metamorphosis
height stature estimation
estimation of height from long bones; the length of a bone can be plugged in an equation that varies for the type of bone and the gender, to find the estimated height of the victim; this can help to narrow down or eliminate possible identities of a victim
Biological Profile
estimation of the deceased's sex, age, stature, and ancestry, along with diseases and injuries, as derived from analysis of skeletal remains
ligament
a short band of tough, flexible, fibrous connective tissue that connects two bones or cartilages or holds together a joint; a membranous fold that supports an organ and keeps it in position
number of bones in the human body
adults-206; babies-450
By studying bones, researchers can tell
age, sex, race, approximate height and health; right or left handed; if sports were played or they had a physically active job
characteristics of bone
alive; carry out respiration; regulated by hormones; grow and repair; inside bone-marrow white blood cells are made
Genome
all the DNA found in human cells
Pollen "fingerprint"
also called a pollen profile, the number and type of pollen grains found in a geographical area at a particular time of year
Allele
an alternative form of a gene
Spore
an asexual reproductive structure that can develop into an adult found in certain protists (algae) and plants and fungi
Coroner
an elected official, either a layman or physician, who certifies deaths and can order additional investigations of suspicious deaths
Accidental Manner of Death
any death strictly due to accident, a death resulting from an unusual even that was unanticipated by everyone involved. It should not be intended, expected or foreseeable
Forensic Entomology
application of entomology to civil and criminal legal cases
Growth Plate (Epiphyseal Plate)
area of cartilage between the shaft and the cap of a immature bone responsible for the lengthening of bone
The Blow Fly
arrives within 10 minutes of death, lays eggs on body in cavities, stages of development can help estimate post mortem interval
Complete Metamorphosis
body development in four stages: egg, larva, pupa and adult
cartilage
firm, whitish, flexible connective tissue found in various forms in the larynx and respiratory tract, in structures such as the external ear, and in the articulating surfaces of joints. It is more widespread in the infant skeleton, being replaced by bone during growth.
Joints
locations where bones meet
Osteoporosis
loss of bone density that can result in an increased risk of fractures
male skull
massive and bumpy; frontal bone low and sloping; eye orbits are more square; lower jaw is square with a 90 degree angle
Autopsy
medical examination to determine the cause of death
Dry or Skeletal (Stage of Decomposition)
mostly bones remain
Chromosome
nuclear cell structure that contains DNA in humans
Gene
segment of DNA that codes for a trait
Primer
sequence of DNA added to trigger replication of a specific section of DNA
Short Tandem Repeats (STR)
sequence of repeating bases in noncoding regions of DNA that are used in DNA profiling
Entomology
study of insects and related arthropods
Combined DNA Index System (CODIS)
the FBI's computerized criminal DNA databases as well as the software used to run these databases; includes the National DNA Index System (NDIS)
Forensic Botany
the application of plant science to crime-scene analysis or the resolution of criminal cases
joint
the area where two bones are attached for the purpose of permitting body parts to move
Autolysis
the breakdown of cells as they self-digest
Decomposition
the breakdown of once-living matter by living organisms
osteoblasts
the cells that bones originate from (they build bones)
anthropology/osteology
the examination of human skeletal remains for law enforcement agencies to determine the identity of unidentified bones/the study of skeletal remains for medico-legal purposes and especially for the identification of unknown individuals
Pistil
the female reproductive part of a flower where eggs are produced
Cause of Death
the injury or condition responsible for a person's death (such as heart attack, kidney failure)
Skeletal Trauma Analysis
the investigation of bone and the marks on them to uncover a potential cause of death
Stamen
the male reproductive part of a flower consisting of the anther and filament where pollen is produced
Accumulated Degree Hours (ADH)
the number of hours at an adjusted average temperature it takes for an insect to develop at a given stage
Livor Mortis
the pooling of the blood in tissues after death that results in a red skin color
Ossificiation
the process that replaces cartilage with bones by the deposition of minerals
Cause of Death
the reason someone dies
botany
the scientific study of plants, or the application of plant sciences to criminal investigations
Diaphysis
the shaft of a bone
Mechanism of Death
the specific physiological, physical, or chemical event that stops life
Rigor Mortis
the stiffening of the skeletal muscles after death
osteobiography
the story of a life told by the bones
Palynology
the study of pollen and spores
PMI
the time that has elapsed since a person has died. (Post Mortem Interval)
Pollination
the transfer of pollen form the male part to the female part of a seed plant
osteoclasts
the type of bone cells that are specialized to dissolve bones
Epiphysis
the unattached end of a bone that eventually becomes fused with the bone shaft
Forensic Palynology
the use of pollen and spore evidence to help solve criminal cases
Forensic Anthropology
the use of skeletal anatomy to identify remains for legal purposes
entomology
the use of the insects, and their arthropod relatives that inhabit decomposing remains to aid legal investigations
osteoporosis
the weakening of the bones, causing them to break easier
Postmortem Interval (PMI)
time elapsed between a person's death and discovery of the body
Active Decay (black putrefaction) (Stage of Decomposition)
very strong odor. Flesh is discolored. Skin is rupturing, allowing gases to escape and body to collapse while seepage of fluid continues. Most body mass is lost to insect activity at this stage.
Grub
worm like beetle larva
Maggot
worm like fly larva
Larva
worm like stage of insect development after egg
Algor Mortis
Algor Mortis PMI estimates can be accurate for death that occurred within the past 24 hours if the corpse has not been subject to unusual heat-loss conditions. For the first 12 hours after death, the body cools at a rate of .78 degrees Celsius (1.4 degrees Fahrenheit) per hour. After the first 12 hours, the body cools about .39 degrees Celsius (.7 degrees Fahrenheit) per hour until the body reaches the same temperature as the surroundings. Theses rates are an estimate and may vary.
STR Allele Frequencies
An allele frequency is a calculation of how often a particular allele appears within a given population. The number of times an allele is observed in a given population / the total alleles observed in the population
"Rule of Thumb" PMI Estimate
Body feels warm and is flaccid (dead less than 3 hours) Body feels warm and is stiff (dead 3 to 8 hours) Body feels cold and is stiff (dead 8 to 36 hours) Body feels cold and is flaccid (dead more than 36 hours)
Restriction Fragment
DNA fragment that restriction enzymes create, as in preparation for gel electrophoresis
Body Changes After Death
Death is a sequence of events that affect some cells sooner than others Stage 1: Stoppage Stage 2: Autolysis, or cell-destruction
Dr. Alec Jeffreys
Developed techniques for DNA fingerprinting and DNA profiling which are now used worldwide in forensic science to assist police detective work and to resolve paternity and immigration disputes. Uses variations in the genetic code to identify individuals.
PCR
Polymerase chain reaction. Used to make trace samples of DNA evidence amplified so that adequate amounts of DNA evidence are available for testing
gender differences in bones
The pelvis of the female is wider. Makes have a narrow subpubic bone. The rib cage and shoulders of males are generally wider and larger than that of females. They are also more likely to have an extra rib.
Collection of DNA Evidence
To avoid contamination of DNA evidence, the following precautions must be taken: Wear disposable gloves and change them often Use disposable instruments for handling each sample Avoid touching the area where DNA may exist Avoid talking, sneezing, and coughing on evidence Avoid touching your face when collecting and packaging evidence Air-dry evidence thoroughly before packaging If wet evidence cannot be dried, it may be frozen, refrigerated, or placed in a paper bag Put evidence into new paper bags or envelopes Moisture may compromise DNA evidence because humidity encourages mold growth, which may damage DNA Prolonged direct sunlight and warm conditions are also harmful to DNA
female skull
frontal bone is higher and more rounded; eye orbits are more rounded; lower jaw is sloped with an angle of more than a 90 degree angle
Assemblage
group of plant species in an area dominated by one species that share the same habitat requirements
Bloating (putrefaction) (Stage of Decomposition)
odor of decaying flesh is present, and the corpse appears swollen. The skin becomes marbled in coloration and may split open from collected gases, resulting in fluid seepage. Insect activity increases.
Manner of Death
one of five ways in which a person's death is classified (i.e., natural, accidental, suicidal, homicidal, or undetermined)
Homicidal Manner of Death
one person killing one or more people
DNA Fingerprint (profile)
pattern of DNA fragments obtained by analyzing a person's unique sequences of noncoding DNA
Parts of a nucleotide
phosphate - sugar - nitrogenous base
Karyotype
picture of the paired homologous chromosomes and sex chromosomes in a cell
Intron
portion of a gene that is not expressed
Exon
portion of gene that is expressed
Natural Manner of Death
primarily attributed to an illness or an internal malfunction of the body not directly influenced by external forces
Polymorphism
region of repeating DNA within an intron that is highly variable from person to person
Spiracles
respiratory organs of insects that are used by researchers to identify a larval stage as first, second, or third instar
