1. Blood Typing Agenda: Hand in the 3 incomplete dominance questions Spotlight Multiple Alleles How is blood type determined? Blood Transfusions Solving basic blood typing questions.

2. Review of Last Class What is the difference between incomplete and co-dominance? In co-dominance both alleles are expressed fully. Both parental phenotypes can be distinguished in the offspring In incomplete dominance, both alleles are expressed to an extent, producing an intermediate phenotype.

3. What if a woman who was heterozygous for sickle cell anemia decided to have a baby with a man, who was homozygous for sickle cell anemia? Hb S Hb N x Hb S Hb S What would the F1 generation be? What are the chances their child will have sickle cell anemia?

4. Multiple Alleles The traits we have been studying so far, have all been controlled for by one gene with two alleles (eg. eye colour or flower colour. )

5. Multiple Alleles Many traits in humans and other species are the result of the interaction of more than two alleles for one gene. These multiple forms of genes are referred to as multiple alleles An individual can only ever have two alleles for each gene. But in the population many different alleles can exist.

6. Blood Type An example of a trait controlled for by multiple alleles on one gene, is blood type. What are the possible blood types? Do you know what blood type you are? How do you know this?

7. What Does Blood Type Refer To? In humans, a single gene determines a person’s ABO blood type. This gene and its alleles, determine what type of antigen molecule, if any, is attached to the cell membrane of red blood cells. It is the presence of these antigens, which determine your blood type.

8. Type A blood contains A antigen Type B blood contains B antigen Type AB blood contains both A and B antigens Type O blood contains neither antigen

9. There are three alleles coding for antigens on the red blood cell membrane. The alleles can be represented by I A, I B and I i Recall from last class, the big letter represents the gene coding for the trait While the superscript letters represent the alleles.

10. What can you conclude about the A, B and i alleles? Which ones are recessive, dominant and co-dominant to each other? Type A blood has these genotypes: I A I A, I A I i Type B blood has these genotypes: I B I B, I B I i Type AB blood has this genotypes: I A I B Type O blood has this genotype: I i I i

11. I A and I B alleles are dominant over I i allele. I A and I B alleles are co-dominant because both alleles are expressed simultaneously.

12. Practice Problem Imagine a mom, who is heterozygous for blood type A had a child with her husband, who is homozygous for blood type B. What would the probability of having a child with blood type A? With blood type AB? With blood type B?

13. What is an antigen? An antigen is a substance or molecule that when introduced into the body triggers the production of an antibody by the immune system. An antigen acts a marker for cells. The antibody, will then kill or neutralize the antigen that is recognized as a foreign and potentially harmful invader.

14. Antibodies Take the next minute to read the chart and fill in the blanks

15. What Do Antibodies Do?

16. What would you do? Imagine you are on a hiking trip and you cut yourself very badly. You are losing a large amount blood very quickly. Your friend suggests to transfuse (donate) some blood to you (so you do not pass out or DIE), while you are both waiting for help. You are blood type A and your friend has a blood type of B. Should you accept your friend’s generous offer? Take a minute and discuss with a partner

17. Blood Transfusions If you went ahead with the blood transfusion. Your anti-B antibodies would react with the B antigens from your friend’s blood. Causing the red blood cells to burst and/or clump together and block vessels. Incorrect transfusions can be fatal!

18. Test Your Understanding of blood groups by completing the table below: With a partner take 2 minutes to complete the table What blood type would be considered the universal donor? What blood type would be considered the universal recipient?

19. Therefore, blood type AB are universal recipients Blood type O are universal donors!

20. Practice Problem From our earlier problem, what percentage of the mother’s children would be able to donate blood to her? What about the father?

21. Summary Blood type is controlled for by one gene and the interactions between 3 alleles Blood type refers to the antigen present on the membrane of red blood cells. Your body produces antibodies to antigens, not present inside of you. These antibodies clot red blood cells.