12 January 2015 Blood Types

Do Now What do you know about blood types? What causes differences in blood types? What use do you think they might have for forensics? What questions do you have?

Blood Factors Blood factors are proteins found in blood that differ between individuals More than 250 different blood factors! Some blood factors are also antigens – substances that are capable of causing an immune response in people who don’t have them The blood factors that cause the greatest immune response belong to the ABO and Rh groups.

Antigen – Antibody Reactions Antigens are foreign substances that provoke an immune response – usually the release of antibodies that bind to and attack them Where are they found? Surface of pathogens (e.g. viruses, bacteria, etc.) Vaccines (that’s why they work!) Allergens (e.g. pollen, dust, etc.) Cancer cells (foreign b/c cell has mutated) Transplanted tissue / organs Antibodies are proteins produced by white blood cells that bind to and destroy antigens. Antibodies are specific to certain antigens

Agglutination When antibodies bind to RBCs, they cause agglutination, or clumping Why is this bad? Initially, clumps clog small capillaries, causing pain and reduced blood flow Later, RBCs that are bound to the antibodies lyse or break open, releasing hemoglobin into the blood – which can cause kidney failure

ABO blood group In the ABO blood group, there are two antigens, “A” and “B”, found on the surface of RBCs You can have one type of antigen, both types, or neither You develop antibodies to the type of antigens you don’t have during infancy

Turn & Talk Determine whether each statement is correct as written. If it is not correct, re-write it. The “A” and “B” antigens are examples of blood factors. If you have type “B” blood then you have “B” antigens. If you have type “AB” blood then you have “O” antibodies. For people who have allergies, pollen is an antibody. Agglutination occurs when antibodies bind to the antigens in blood. Antibodies are found on the surface of red blood cells. Correct! “A” antigens Do not have “A” or “B” antibodies antigen Correct! In the blood plasma

ABO blood group & transfusions The key to transfusions: You cannot give a person blood that has antigens for which they have antibodies, otherwise, their immune system will attack that blood. Fill out the chart … Blood Type Can donate to Can receive from A   B AB O Which type is the universal donor? Which type is the universal recipient?

ABO blood group & transfusions The key to transfusions: You cannot give a person blood that has antigens for which they have antibodies, otherwise, their immune system will attack that blood. Fill out the chart … Blood Type Can donate to Can receive from A  A, AB  A, O B  B, AB  B, O AB  AB  A, B, AB, O O  O Which type is the universal donor? O Which type is the universal recipient? AB

Rh Blood Group The Rh blood group describes ~45 different (but similar) antigens on RBCs. These antigens are called antigen “D” People are Rh + if they have any of the various D antigens. They are Rh – if the do not have any D antigens. Unlike the ABO system, Rh- people must be sensitized to the D antigen before developing antibodies. That means Rh- people will NOT have an agglutination reaction the first time they encounter Rh+ blood … but they will if they have it a second time. Blood Type Can donate to Can receive from Rh+ Rh-

Rh Blood Group The Rh blood group describes ~45 different (but similar) antigens on RBCs. These antigens are called antigen “D” People are Rh + if they have any of the various D antigens. They are Rh – if the do not have any D antigens. Unlike the ABO system, Rh- people must be sensitized to the D antigen before developing antibodies. That means Rh- people will NOT have an agglutination reaction the first time they encounter Rh+ blood … but they will if they have it a second time. Blood Type Can donate to Can receive from Rh+ Rh-, Rh+ Rh-

Rh Blood Group & Pregnancy Rh- moms can carry a Rh+ baby if the dad is Rh+ The first baby is usually born without any problems, but during delivery, some of the baby’s D antigens will contact the mom’s blood, causing her to be sensitized to D antigens. If the mom becomes pregnant with a second Rh+ baby, her immune system will attack the baby’s blood, causing brain damage or death to the fetus. This can be prevented by giving the mother medicine that prevents her from developing antibodies against D antigens. No problems occur if the baby is Rh- and the mom is Rh+

Blood Typing Antiserum is a solution that contains antibodies against a specific antigen (i.e. antiserum A contains type A antibodies). Blood type is determined by adding antiserum A, B, and D to blood and observing whether or not agglutination occurs.

Blood Typing Antiserum is a solution that contains antibodies against a specific antigen (i.e. antiserum A contains type A antibodies). Blood type is determined by adding antiserum A, B, and D to blood and observing whether or not agglutination occurs.

Congo-line review Front two rows… Back rows … On the front of a notecard / scrap paper, draw a possible result for a blood typing test. On the back, write the correct blood type. Back rows … On the front of a notecard / scrap paper , write a question about blood transfusions. On the back, write the answer.

How is blood type used in forensics? To identify people or link suspects to crime scenes To identify paternity

Genetics Refresher We have two versions – or alleles – of every gene. One inherited from our mom, one from our dad. The two alleles (genotype) interact to determine our trait (phenotype) in predictable ways. Some alleles are dominant, some are recessive. Dominant genes show their trait and ‘cover up’ recessive genes. IA (A) and IB (B) are dominant to i (O). D (+) is dominant to d (–) Some alleles are codominant. This means both alleles fully express their trait. IA and IB are codominant with each other.

Genotype to Phenotype IAiDD iidd IB IB Dd IA IB dd IB iDd What blood type will result from each genotype? IAiDD iidd IB IB Dd IA IB dd IB iDd

Genotype to Phenotype IAiDD A+ iidd O- IB IB Dd B+ IA IB dd AB- What blood type will result from each genotype? IAiDD A+ iidd O- IB IB Dd B+ IA IB dd AB- IB iDd B+

Phenotype to Genotype A+ AB- O- B+ What are the possible genotypes for each blood type? A+ AB- O- B+

Phenotype to Genotype A+ IAIADD, IAiDD, IAIADd, IAiDd AB- IAIBdd What are the possible genotypes for each blood type? A+ IAIADD, IAiDD, IAIADd, IAiDd AB- IAIBdd O- iidd B+ IBIBDD, IBiDD, IBIBDd, IBiDd Other important vocab – Homozygous – both alleles for one gene are the same (e.g. ii) Heterozygous – the two alleles for one gene are different (e.g. Iai)

Punnett Squares Punnett Squares are a tool for predicting the traits that will result from crossing certain genotypes.

Monohybrid (One gene) Crosses We do …. Iai X ii IBIB X Iai You do … 3. Dd X dd 4. IAIB X ii

Dihybrid (Two gene) Crosses We do … IAiDd X iiDd AB- X iiDD You do … IBiDd X IAiDD IAidd X IBiDd

Closure, Exit Ticket, HW Closure – Exit Ticket – Homework– Unit question? Something new? LP? TOK? Exit Ticket – Pick a blood type. For that type, list Antibodies Antigens Blood typing test results To whom can it donate? From whom can it receive? Genotype Homework– Homework sheet due next class. Major quiz in two classes.