Ch 12 Web Serology

7/30/2019 Ch 12 Web Serology

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Ch 12- Forensic Serology

Blood types and their antigens and antibodies. Agglutination. Whole blood typing. Characterizing a stain as blood. Significance of the precipitin test in serology. Absorption-elution techniques. Contribution of polymorphic enzymes and

proteins to bloods individualization.


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Chromosomes and genes.

Significance of Punnet square.

Lab tests for seminal stauns .

Preservation of stains for lab examination . Collection of physical evidence in rape

investigation .

http://faculty.ncwc.edu/toconnor/425/425lect13.htm http://www.bxscience.edu/publications/forensicbio/articles/serologytoxicology/intro.htm

http://www.rockylab.com/SEROLOGY.html
http://faculty.ncwc.edu/toconnor/425/425lect13.htmhttp://www.bxscience.edu/publications/forensicbio/articles/serologytoxicology/intro.htmhttp://www.bxscience.edu/publications/forensicbio/articles/serologytoxicology/intro.htmhttp://www.rockylab.com/SEROLOGY.htmlhttp://www.rockylab.com/SEROLOGY.htmlhttp://www.bxscience.edu/publications/forensicbio/articles/serologytoxicology/intro.htmhttp://www.bxscience.edu/publications/forensicbio/articles/serologytoxicology/intro.htmhttp://faculty.ncwc.edu/toconnor/425/425lect13.htm


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DNA: abbreviation for deoxyribonucleicacid- the molecules carrying the bodysgenetic information. DNA is double-strandedin the shape of a double helix

Plasma: the fluid portion of unclotted blood

Serum: the liquid that separates from theblood when a clot is formed

Antigen: a substance, usually a protein thatstimulates the body to produce antibodiesagainst it


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Antibody: a protein that destroys or inactivates aspecific antigen. Antibodies are found in the blood

serum

Antiserum: blood serum in which there are specificantibodies

Agglutination: the clumping together of red bloodcells by the action of an antibody

Serology: the study of antigen-antibody reactions

Hemoglobin: a red blood cell protein responsible fortransporting oxygen in the bloodstream and the redcoloring of blood


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Precipitin: an antibody that reacts with itscorresponding antigen to form a precipitate

Secretor: an individual who secretes his orher blood-type antigen(s) in body fluids.Approximately 80 percent of the populationare secretors

Enzyme: a type of protein that acts as acatalyst for certain specific reactions

Polymorphism: the existence of more thanone form of genetic trait


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Iso-enzymes: multiple molecular forms of anenzyme, each having the same or very similarenzyme activities

Gene: a unit of inheritance consisting of aDNA segment located on a chromosome

Chromosome: a rodlike structure in the cellnucleus, along witch the genes are located. Itis composed of DNA surrounded by other

material, mainly proteins Egg: the female reproductive cell Sperm: the male reproductive cell


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Zygote: the cell arising from the union of anegg and a sperm cell

X-chromosome: the female sex chromosome Y-chromosome: the male sex chromosome Locus: the physical location of a gene on a

chromosome Allele: any of several alternative forms of a

gene located at the same point on a particularpair of chromosomes. For example, the genesdetermining the blood types A and B arealleles


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Homozygous: having two identical allelicgenes on two corresponding positions of a pairof chromosomes

Heterozygous: having two different allelicgenes on two corresponding positions of a pairof chromosomes

Genotype: the particular combination of genes present in the cells of an individual

Phenotype: the physical manifestation of agenetic trait such as shape, color, and bloodtype


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Acid phosphatase: an enzyme found in highconcentration in semen

Oligospermia: a condition describing anabnormally low sperm count

Aspermia: the absence of sperm; sterility inmales


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Ch 12 - Body Fluids

Forensic Serology


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Blood

A complex mixture of cells, enzymes,proteins & inorganic substances

Fluid portion of blood is called the plasma(55% of blood content) primarily water red cells (erythrocytes) white cells (leukocytes) platelets


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What is Serology?

A term which describes laboratory testswhich employ a specific antigen and serum

antibody reactions


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Erythrocytes

Transport oxygen from the lungs to thebody tissues

Transport carbon dioxide from the tissues tothe lungs

Red cells possess chemical structures on

their surfaces called antigens oragglutinogens impart blood type characteristics


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Blood Type

Three types (alleles) of blood type gene A, B, O

Each individual inherits one blood typegene from their mother & one from theirfather 6 possible combinations (genotypes)

AA, BB, OO, AB, AO, and BO

Genotype determines blood type


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Antibodies or Agglutinins

Proteins that are present in the serum responsible for ensuring that the only blood

cells that can survive in a person are cells of the correct blood type


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Antibodies produced by the A allelesremove any red blood cells containingB

antigens by clumping them together Antibodies produced by the B alleles

remove any red blood cells possessing A

antigens


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Type O Blood

Possessed by people whose genotype is OO both parents passed on the O gene

have no antigens these cells can be introduced into a person with

Type A or Type B because these cells are notattacked by the antibodies these people possess

have both a & b antibodies can only have other O type cells mixed with this

blood


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Type A

Possessed by people with genotype AA

AO A is dominant to O

Possesses antibody b

will destroy any Type B red cells compatible with A or O red cells


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Type B

Possessed by people with genotype BB

BO B is dominant to O

Possesses antibody a

will destroy any Type A red cells compatible with B or O red cells


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Type AB

Possessed by people with genotype AB

A & B are co-dominant

Possesses no antibody can have A, B, AB, or O cells added

Cant be added to any other blood type withoutbeing destroyed by an antibody


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Blood Typing

Blood typing is done by reacting wholeblood with antibody A and antibody B


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Blood Typing

Anti-A

+ Blood

Anti-B

+ Blood

Antigen

Present

Blood

Type+ - A A

- + B B

+ + A and B AB

- - NeitherA or B

O


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Relative Frequency of Blood

Types in Human PopulationsPo ulation O A B AB

US whites .453 .413 .099 .035US blacks .491 .265 .201 .043Chinese .439 .270 .233 .058Eskimos .472 .452 .059 .017Armenians .298 .499 .132 .080BolivianIndians

.931 .053 .016 .001

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