What is the responsibility of a Forensic Serologist?
to detect and classify various types of human bodily fluids such as blood, semen/urine, and saliva
How did forensic serology change over time?
it became more relevant and advanced over time
Who is Karl Landsteiner? What were his accomplishments?
- first person to realize that all human blood is not the same
- created blood typing
Who do you get your blood type from?
your parents
Is blood type a class characteristic or individual characteristic?
class
Do identical twins have the same blood type?
they can
Blood Type A
genotype: IAi
antigen: A
antibody: B
receive: A, O
Blood Type B
genotype: IBi
antigen: B
antibody: A
receive: B, O
Blood Type AB
genotype: IAIB
antigen: AB
antibody: none
receive: A, B, AB
Blood Type O
genotype: ii
antigen: none
antibody: A, B
receive: O
What blood type is the universal donor?
O
What blood type is the universal recipient?
AB
What is the ratio of the blood type distribution in the US?
A: 38.8%-40%
B: 11.1%-11%
AB: 3.9%-4%
O: 46.1%-45%
What are the 2 main components of blood?
plasma, solid particles
Erythrocyte
a red blood cell
Leukocyte
a white blood cell
Thrombocyte
(platelets) responsible for blood
What is plasma primarily main of?
water
What is serum?
the liquid that separates from blood when a clot is formed
Antibody
a protein in the blood serum that destroys/inactivated a specific antigen pain of chromosomes
Antigen
proteins that reside on the red blood cell
Rh Factor
blood antigen that may be present on the surface of red blood cells
Locus
the physical location of a gene on a chromosome
Hemoglobin
a red blood cell protein that transports oxygen in the blood stream; it is responsible for the red color of blood
What are the 3 alleles for blood type?
A, B, O
Homozygous
made up of same genes
Heterozygous
made up of different genes
Dominant
characteristic is shown
Recessive
characteristic is hidden
XX
female chromosomes
XY
male chromosomes
How many chromosomes does a human carry?
2
Kastle-Meyer Test
a sample is tested with 1 drop of phenolphthalein and then 1 drop of hydrogen peroxide. turns pink if positive for blood (does not tell species)
Hemastix Test
when moistened w/ distilled water and placed in contact w/ stain; bright green color indicates blood
Luminol Test
capable of detecting diluted bloodstains. it's reaction w/ blood emits light and requires the result to be observed in a dark area
Human Antiserum
human blood - into rabbit - rabbit produces antibodies - blood is drawn from rabbit that contains human antibodies - human antiserum
Precipitate
unknown human blood sample, if human will react w/ human antiserum from the rabbit by forming a precipitate
What are methods of testing for Semen?
acid phosphatase color test - spermatozoa
What items are collected after a Rape or Sexual Assault?
- all outer and under garments
- bedding
- trace evidence
What is the correlation between the height blood is dropped and the width of the blood stain?
the higher the blood is dropped, the wider the width the blood stain will be
What is the Area of Intersection and convergence?
area of origin
Cast-Off
blood pattern created when blood is flung from a blood-bearing object in motion onto a surface
Contact/transfer
blood stain pattern created when a surface that carries wet blood comes in contact w/ a second surface
Arterial Spurt
characteristic blood stain pattern containing spurts that result from blood existing under pressure from an arterial injury
Pool
occurs when blood collects in a level and undisturbed
Who is Paul Kirk?
professor of criminalistics & biochemistry who analyzed the blood stain pattern photos from Shepard's case
What is analyzed during a Scene Pattern Reconstruction?
blood stain pattern photos
What is analyzed during a Lab Results Reconstruction?
- genetic marker typing
- age, source, race, and sex determination
How many liters of blood does the average human have?
5
What is the approximate volume of a blood drop?
0.05 cc
What conditions affect the shape of a blood drop?
- size
- angle of impact
- velocity
- height
- texture of target surface
What questions can be answered by blood spatter interpretation?
- points of origin
- movement/direction of person/object
- # of blows, shots;etc
- distance b/w target & blood
- position of victim
Angle of impact
angle at which blood strikes a target surface
Bloodstain Transfer
when a bloody object comes into contact w/ a surface & leaves a patterned blood image on the surface
Bloodspatter
blood that is directed back toward the surface of energy
Contact Stain
blood stains caused by contact b/w a wet blood-bearing surface & a second surface which may or may not have blood on it
Transfer
an image is recognizable & may be identifiable w/ a particular object
Swipe
wet blood is transferred to a surface which did not have blood on it
Wipe
a non-blood bearing object moves through a wet blood stain
Directionality
relates to the direction of a drop of blood traveled in space from its point of origin
Terminal Velocity
the greatest speed to which a free falling drop of blood can accelerate in the air
High Velocity
greater than 25ft per second (mist)
Medium Velocity
5 to 25ft per second
Low Velocity
5 or less ft per second
Round (blood shape)
if it falls straight down at a 90 degree angle
Elliptical (blood shape)
blood droplets separate as the angle decreases from 90 to 0 degrees
Who is a Secretor?
a person who's blood-type antigens are found in high concentration in their body fluids (saliva, seem, vaginal secretions, gastric juice)