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Blood Typing & Spatter Come in and get your notebooks out. We have notes today!

Forensic serology is the detection, classification and study of various bodily fluids such as blood, semen, fecal matter and perspiration, and their relationship to a crime scene. A forensic serologist may also be involved in DNA analysis and bloodstain pattern analysis.

What is Blood? Blood is the bodies main transport system of oxygen and nutrients. Blood carries waste to the lungs, liver, kidney for disposal. Fights against infections and heals wounds. We roughly have 5 liters of blood (7-8% of body weight).

What Makes up our Blood? RED BLOOD CELLS (Erythrocytes) The most abundant cells in our blood; they are produced in the bone marrow and contain a protein called hemoglobin that carries oxygen to our cells. WHITE BLOOD CELLS (Leukocytes) They are part of the immune system and destroy infectious agents called pathogens. PLASMA This is the yellowish liquid portion of blood that contains electrolytes, nutrients and vitamins, hormones, clotting factors, and proteins such as antibodies to fight infection. PLATELETS (Thrombocytes) The clotting factors that are carried in the plasma; they clot together in a process called coagulation to seal a wound and prevent a loss of blood.

History of Blood Serology Early accounts of blood transfusions performed in 1818 1901 Karl Landsteiner Blood Types 1930 Nobel Prize 1937 Rh Factor 1990 Use of blood factors (ABO & MN) linking blood to individual DNA in blood is used to individualize blood evidence

Antigens On the surface of each RBC, chemical structures called antigens, are found The most important antigen systems are the A-B-O and Rh systems If a person has A blood, then they have A antigens B blood has B antigens AB blood has both A and B antigens O has no antigens The presence of A and B antigens determines a person s blood type

D Antigen (Rh factor) While studying Rhesus monkeys, a certain blood protein was discovered. This protein is also present in the blood of some people. Other people, however, do not have the protein. If a person has the D antigen, they are Rh positive If they lack it, then they are Rh negative The presence or absence of three antigens- A, B, and D- must be determined in testing compatibility of the donor and recipient

Antibodies Serum contains proteins called antibodies, which destroy a specific antigen An antibody reacts only with its specific antigen and no other Type A blood has A antigens, anti-b antibodies Type B blood has B antigens, anti-a antibodies Type AB has A and B antigens, no antibodies Type O blood has no antigens, anti-a and anti-b antibodies

What are blood types? There are 3 alleles or genes for blood type: A, B, & O. Since we have 2 genes, there are 6 possible combinations. Blood Types AA or AO = Type A BB or BO = Type B OO = Type O AB = Type AB http://learn.genetics.utah.edu/units/basics/blood/types.cfm

Hey guys, sorry I am not in class today. I am on campus helping out with Bio. Please copy the rest of the notes on this powerpoint (outlined in yellow). There is also a lab simulation that I would like for you guys to do. Tomorrows lab will be almost identical, so you will know how to do it.

Heredity

Heredity All antigens are genetically determined traits Inherited from parents and are part of the biological makeup once that person has been conceived Genetic material is transferred by genes Genes are located on chromosomes that are located inside the nucleus Almost all human cells have 46 chromosomes The only exceptions are the gametes, which are sperm and egg cells, which contain 23 chromosomes

Sex Cells Females carry X chromosomes Males carry X and Y chromosomes When an X sperm fertilizes the female egg, it now contains XX, which is female When a Y sperm fertilizes the female egg, it now contains XY, which is male The sperm cell determines the chromosome pair, so males determine the sex of the child

Genotype and Phenotype A pair of genes makes up the genotype No known lab test can determine an individual s A-B- O genotype A phenotype is a person s outward characteristic, such as having A blood This still does not tell whether the genotype is AA or AO It can only be determined by studying the family history

Paternity testing No blood can appear in a child unless it is present in at least one of the parents Has important implications in disputed paternity cases, which are encountered in civil, not criminal, cases Many cases can be solved by comparing the blood types of mother and suspected father If the father can not be excluded, then all that can be said is that he may be the father because of blood typing, but does not strictly mean he is the father Further testing, such as DNA, will be required

Common Blood Factors

ABO System In the ABO system there are two different blood proteins: A and B The inheritance of these factors is based on codominance of the A and B proteins In codominance, both alleles (different forms of a gene) in the heterozygote express themselves fully There are 3 different blood alleles: The A and B genes are both dominant The o gene is recessive

Abo system (cont.) Based on the 3 genes there are 4 possible phenotypes: Type A blood Type B blood Type AB blood Type O blood There are 6 possible genotypes: AA, Ao, BB, Bo, AB, O Possible Genotypes Blood Types AA Ao BB Bo AB oo Type A Type A Type B Type B Type AB Type O

Abo system (cont.) The inheritance of the ABO system can be predicted using Punnett squares EX: A woman who is heterozygous for Type A blood has a child with a man who is heterozygous for Type B blood. What are the possible genotypes and phenotypes of their child? B A AB o Bo Genotypes: AB, Bo, Ao, oo o Ao oo Phenotypes: Type AB, Type B, Type A, Type O

Abo system (cont.) This system is important not only in forensics but in the medical field It is important for blood transfusions It is essential that the ABO blood types match to prevent the blood from clumping

Mns system Similar to the ABO System A person carries either the M protein, the N protein or the S protein on their blood cells M is found in 30% of the population N is found in 22% of the population S is found in 48% of the population

Rh Factor The Rh protein can be found on the surface of the blood cell Rh+: the person has the Rh antigen; it is found in 84% of the population Rh-: the person does not have the Rh antigen; makes up 16% of the population O+ 38 percent of population O- 7 percent of population A+ 34 percent of population A- 6 percent of population B+ 9 percent of population B- 2 percent of population AB+ 3 percent of population AB- 1 percent of population

Blood Typing

How common is your blood type? 46.1% 38.8% 11.1% 3.9%

Blood Transfusions A blood transfusion is a procedure in which blood is given to a patient through an intravenous (IV) line in one of the blood vessels. Blood transfusions are done to replace blood lost during surgery or a serious injury. A transfusion also may be done if a person s body can't make blood properly because of an illness. Who can give you blood? Universal Donor People with TYPE O blood are called Universal Donors, because they can give blood to any blood type. People with TYPE AB blood are called Universal Recipients, because they can receive any blood type. Rh + Can receive + or - Rh - Can only receive Universal Recipient

Calculating probabilities Knowing the percentages of the population with the different blood factors can be used to determine the likelihood of a certain combination of blood factors By multiplying the ratios of the types, you can determine the probability of having a certain blood type

Calculating probabilities (cont.) EX: What is the probability of a person having blood type A and N and being Rh-? A N Rh- 40% x 22% x 16% =?.40 x.22 x.16 =.01 1 out of every 100 people would have blood type A and N and be Rh-