Genetics Discussion Practice

Discussion 4 – Blood Types and ABO Incompatibility Name: Wesley Beals Directions: 1. Read the article: “Blood Types and ABO Incompatibility” 2. Answer the Basic Questions using the information in the article. All the information you need for this section will come from the article, lecture, or your textbook. 3. Take the lecture quiz for this topic. 4. Complete the Thinking Problems using the information you have about genetics and blood types to try and figure out the family relationships. 5. Come to class and participate in the discussion for points. 6. After the in-class discussion, complete the post discussion review on Canvas. Updated Information: The article above was published in 2011. As we learn more about genetics and cell biology, we identify more blood types and we add to the body of scientific knowledge about blood types. In addition, when teaching genetics, we often refer to polygenetic systems as if they were monogenetic. This is done to help students learn basic genetic concepts and develop critical thinking skills about genetics before learning the more complicated aspects of genetics. The following resources are here For Your Information (FYI) purposes only. The big take away is that, while we simplify blood typing to teach the basic concepts of blood types and genetics, there is a lot more going on in real world scenarios.    The Red Cross offers basic information on blood types: https://www.redcrossblood.org/donate-blood/blood-types.html D. Joe Chaffine, MD, hosts the Blood Bank Guy Podcast and has many detailed videos on YouTube. His website is: https://www.bbguy.org/ The International Society for Blood Transfusion (ISBT) publishes a science series with updated information. The 2020 publication offers more detail on various systems. https://onlinelibrary.wiley.com/doi/epdf/10.1111/voxs.12593 Basic Questions: 1. What characteristics might you see in a new born infant that would indicate blood type incompatibility? The newborn infant would have a couple of symptoms that would indicate a blood type incompatibility. The symptoms would include things such as jaundice, lower red blood cell counts, positive antibody tests and raised bilirubin levels that each could potentially lead to an infant’s death in the womb or after birth. 2. Why are mothers who have type O blood more likely to have infants that show ABO incompatibility? This higher probability stems from the fact that moms with O blood produce the antibodies for both A and B type blood and even though the immune system is suppressed a little during pregnancy, the food that a woman eats during pregnancy can potentially lead to those antibodies being in the bloodstream. This presence of antibodies can even lead to the production of more which leads to greater attack of the babies red blood cells. 3. Why are ABO incompatibilities usually milder than Rh incompatibility? The reason for the milder nature of the ABO incompatibility is that the antigen for A and B is also present on other fetal tissue so that it dilutes the presence of the antibodies attaching to the red blood cells and causing hemolysis leading to a milder reaction as compared to Rh incompatibility. 4. Describe hemolysis and what will happen due to hemolysis. Hemolysis is the destruction of red blood cells that causes them to lyse and die and is part of the normal life cycle of blood cells. When blood incompatibility occurs, the hemolysis can happen on normal cells and lead to lower rbc counts. With the death of all these cells, the effects can lead to higher than normal bilirubin levels, anemia, and potentially lead to things such as jaundice and other problems related to the blood that could lead to either miscarriage or death of the infant. Thinking Problems: NOTE: The pedigrees are showing the phenotype or what a blood type test would show. The question marks indicate unknown phenotypes. Directions: Refer to the Case Studies and Punnett Squares in the article for help in figuring out the pedigrees. Attempt to answer all these before coming to class. Then when in class you can confer with your group members to get a consensus. Family 1: 1. Determine the blood type for the individuals with a question mark. Fill them in on the tree. a. Determine the genotypes for each person as well. Gen 1 1? Is type A blood and AO 2 is BO Gen 2 1 is A0 2 is BO 3 is AB 4 is OO 5 is AO 6 is AA 7 is AO Gen 3 1 is OO 2 ? is either A, B, AB, or O blood with each of their respective genotypes of AO, BO, AB, or OO 3 is either AO or AA 4 is BO 2. There is a non-paternity (i.e. somebody is not the daddy) scenario in this family tree. Where is it? How do you know? Non- paternity is happening in the gen II 5 and 6 couple with child 4 in the III generation. The reason that is the non-paternity case happen in that couple with child 4 is the fact that child 4 has B blood which is not possible because the two parent are A and A and B are codominant with one another which means that 5 in gen II is not the father of child 4 in gen III Family 2: 3. Determine the blood type for the individuals with the question mark. Fill them in on the tree. a. Determine the genotypes for each person as well. Gen I 1? Has B blood and has a high likelihood of being BB or a smaller percent is BO 2 is OO 3 either had A blood with AO or B blood and BO 4 is that same as 3 Gen II 1 is BO 2 is OO 3 is BO 4 is AO 5 is BO 6 is BO 7 is OO 8 is AO 9 is OO 10 is AB Gen III 1 is OO 2 is BO 3 is OO 4? Has AB blood and is AB or is AO with A blood 5 is OO 6 is BO 7 is either AA or AO 8? has B blood and is BO 9? Has A blood and is AO 10? Has either B blood or O with the genotype of BO or OO 11 is AO 12 is BO 13 is AO 14 is OO Gen IV 1 is BO 2 is either AO or AA 3 is AB 4 is BB or BO 5 is AA or AO 6 is AB 7 is AB 8 is BO 9 is OO 10 is OO 11 is OO 12 is AB Gen V 1 is AB 2? Is either B blood with BO or O blood with OO 4. For Person V.1, highlight or trace the inheritance of their B antigen. Which person in generation I did they get it from? Person V.1 was able to get it’s B antigen all the way from the person I.1 who had a high likelihood of being homozygous for the B antigen and even less likely they could have been BO 5. Which individuals were you able to figure out the blood type for with 100% certainty? Why? a. Could you also figure out their genotypes with 100% certainty? Why or why not? I was able to determine the blood type with 100% certainty along with genotype for most of the people in the pedigree. With each of the people that I was able to determine blood type and genotype, what helped is that they had a bigger sample of children to look at with a confirmed spouse or confirmed parents. Overall, I think the variety of the kids with different blood types and siblings helped pin down blood types. I think it also gets easier with things like AB or OO which are easier to determine genotype. 6. Which individuals were you unable to figure out blood types for with 100% certainty? Why? I couldn’t figure out the genotype or blood type for the following people: person I.3 , I.4, III.4, III.7, III.8, III.9, III.10, IV.2 , IV.4, IV.5, and V.2. In each of these cases I did not have enough information whether it was the fact that they didn’t have a lot sibling or a few or no children so and their parents were heterozygous for the different blood types that made it really difficult to come to a certain conclusion. Family 3: 7. Number each individual in the tree above. See the other two trees for reference. For each generation, starting from 1 on the leftmost parent and numbering them until I hit the rightmost parent 8. Determine the blood type for the individuals with the question mark. Fill them in on the tree. a. Determine the genotypes for each person as well. GEN I 1? Has B blood with BO 2 is AO 3 is OO 4? is most likely O with OO 5? is A with AO 6 and 7? Are a combo of AO and BO but as for which is which I’m not sure GEN II 1 is OO 2? Is A blood with AO 3 is AB 4 is OO 5? Is AO with A blood 6 is OO 7 is OO 8 is OO 9 is AO 10 is BO 11 is OO 12 is AB 13? is either A, B, AB, or O with each of the respective genotypes GEN III 1? Is either A with AO or O with OO 2? Is B with BO 3 AO 4 BO 5 AO 6? is either AO or OO 7 is AO 8 is OO 9? Is OO with O blood 10? Is OO with O blood 11 is AB 12 is OO 13 is BO 14 is BO 15 AO 16? Has B blood that is either BO or BB GEN IV 1? Is either OO, AO, or BO with each respective blood types 2 is OO 3 is BO 4 is AO 5 is OO 6? Is either A or B with AO or BO 7 is either BO or BB 8 is BO 9 is BO 10 is either AO or BO with their respective blood type GEN V 1 is OO 2 is OO 3 is AB 4 is OO 5 is AO 6 is either AO or AA 7? Is either B or O with BB ,BO or OO 8? Is either A, B, AB, or O 9. Which individuals were you able to figure out the blood type for with 100% certainty? Why? a. Could you also figure out their genotypes with 100% certainty? Why or why not? I was able to figure out a lot of the people on the trees’ blood type and respective genotype with a lot of accuracy. It was like the last tree in which the determination of blood type was helped by having both parents and siblings with confirmed blood types or being a homozygous cross in the case of many of the O blood people. In addition, if it was harder to determine the blood type and genotype based on the parents, the kids of each of these people are helpful in determining the blood type and genotype of the people. 10. Which individuals were you unable to figure out blood types for with 100% certainty? Why? The following people were hard to figure out their blood type or genotype definitely: person I.6, I.7, II.13, III.6, III.16, IV.1, IV.6, IV.9, V.6, V.7, V.8. With each of these, there were many that were only children that made it difficult to determine whether a child was a hybrid from some of the parents that married into the family tree. In addition, some did not have children themselves, which makes it difficult in Gen V because of many of the Gen V kids their parents lead to many possibilities. Also, in Gen I person 6 and 7, I can determine what the cross was to get the children of 6 and 7 but without their parents, I am unable to determine which blood type and genotype goes to which parent. 11. There is a non-paternity (i.e. somebody is not the daddy) scenario in this family tree. Where is it? How do you know? The non paternity situation happens between person II.10 and II.11 and their child III.15. The problem arises because II.10 and II.11 are type B blood and O blood respectively while their child has A blood which is impossible with this pairing because neither parent has the A allele that would be necessary to have a child with A blood. 12. Are there any individuals in generation V who you can trace their antigens back to generation I? (Hint: see question 4). If so, do this and say which person/people in generation I they got each antigen from. There are a few people that can trace their antigen back to people in GEN I. People such as person V.3 and V.4 can trace their A antigen back to person I.2 and person V.3 can trace their B antigen back to person I.6. If I could definitively prove the blood type or genotype of person V.7 and person V.8, I could be able to trace their antigens back to a person in the first generation. 13. New Information: Use this new information to reevaluate Family 3’s tree. a. Rh factor:The Rh factor is a different blood type system separate from the ABO system. People with the Rh factor are positive (+). People without the Rh factor are negative (-). People who are heterozygous for the Rh factor will have a Rh-positive phenotype. Blood types for both the ABO and Rh systems are often reported together. For example, ABO+ or O-. i. Everyone in generation V is homozygous Rh-positive and everyone in generation I is Rh-negative. Determine the where the Rh-positive genes entered the family trees. Most of the Rh-positive factors would have had to been introduced in Generation III because many of the Gen II kids save two married among one another. Thes would cause the children in Gen IV to be heterozygous for the Rh-positive factor and if these kids then married and had kids with other heterozygous or even homozygous dominant people then that would lead to the observation that all the kids in Gen V would be homozygous dominant for the trait of the Rh factor. ii. Are there any situations where you cannot determine where the Rh factor entered the family tree? Why? Not really because there the inheritance pattern for the Rh factor is straightforward and for the most part if it was not in the families originally it would need to have been brought in through marriage of outside family members of which we do not have the family trees to look at it. In addition, for everyone to be homozygous dominant by gen V, there needs to be time for the allele to be Rh negative to be bred out of the family and that would be through two breeding. b. Bombay Phenotype: In class we discussed a form of epistasis called the Bombay phenotype. In the family circled in with the dotted line in the tree above has the Bombay phenotype. i. How would this phenotype affect the family shown? This phenotype would cause the people to test and show up as having O blood despite that fact that they maybe genetically another blood type. So any people that may show up as O may not be genetically O but have the Bombay phenotype that prevents the actual phenotype from appearing ii. Which other individualsmight be affected by this phenotype? These are the following people who might have the Bombay phenotype: person I.3, I.4, II.4, II.6 II.7, II.8, III.7, III.8, III.9, IV.6 iii. Discuss with your group if the individuals you listed in the above question would be affected by the Bombay phenotype. State your position below and defend your reasoning. These people have the highest probability of having the Bombay phenotype and it started in the family through the first generation with person I.3 or I.4 being either carrier without realizing that they were or had the phenotype themselves and passed it down to each of their children. The family circle would have had to have received two recessive alleles to have the phenotype described and when looking at the tree the two parents would have had to have the allele. In addition, the sibling of the original family would have also probably had it because we do not actually know their blood type and they did not have children so it would be hard to not rule them out as another person with the phenotype. People with the Bombay phenotype show up as O in blood tests and so I would be suspicious of all the O blooded people in that family. I do not think that it passes further than that family line because after generation II, the other family lines branch off like normal and have their blood types show up as normal.