Imagine that you are working in a blood bank of a hospital where you test blood types from patients and make sure that they receive the proper blood type when they need a blood transfusion. Blood types are determined by antigen (special glycoproteins) on the surface of red blood cells. ABO blood groups are an example of a trait that is controlled in a codominant manner and involves multiple alleles. We typically use the symbols below to represent the alleles of the gene that control the ABO blood group antigens: IA = Type A antigen IB = Type B antigen i = neither antigen Note that the IA and IB alleles are codominant, but the i allele is recessive to both. a. What would be the genotype of a person with type B blood who has a parent with type O blood? (1 pt) b. Describe the phenotype of someone whose genotype is IAIB. Don’t just list what their blood type would be—describe what antigens would be present on the surface of their red blood cells. (1 pt)
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Type O blood has the genotype "ii" (homozygous recessive), meaning it does not have either A or B antigens. Show more…
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The ABO blood groups in humans are expressed as the IA, IB, and i alleles. The IA allele encodes the A blood group antigen, IB encodes B, and i encodes O. Both A and B are dominant to O. If a heterozygous blood type A parent (IAi) and a heterozygous blood type B parent (IBi) mate, one quarter of their offspring are expected to have the AB blood type (IAIB) in which both antigens are expressed equally. Therefore, ABO blood groups are an example of codominance.
Adi S.
10. [Multiple Alleles] In people, blood type (A, B, AB, or O) is a gene with multiple alleles. There are three allele types. IA and IB are co-dominant, but i is recessive. The IA allele puts A-markers on your red blood cells' surface. The IB allele puts B-markers on your red blood cells' surface. The i allele doesn't put any markers. These markers act like flags on the surface of your cells. Your immune system learns to recognize the flags from your cells as "okay" so it doesn't attack them. Any flags your immune system doesn't recognize it will attack. This is why getting the wrong blood types at a hospital can kill you. Your body doesn't recognize the different blood as "okay" and it attacks it. IA IA or IA i = Type A blood IA IB = Type AB blood IB IB or IB i = Type B blood ii = Type O blood Jackie has type A blood, heterozygous. Zeke has type O blood. Their baby needs a blood transfusion fast or she won't survive. They don't have time to test the baby's blood. If they find Type AB blood, should they use it? If they find Type A blood, should they use it? Why? Jackie = genotypes: phenotypes: Zeke =
Anand J.
The major blood groups in humans are determined by multiple alleles. In this ABO blood group system a single gene can exist in any of three allelic forms: I^A, I^B, or i. Alleles A and B are codominant, while allele 'i' is recessive. Four blood groups (phenotypes) are possible from combinations of these alleles: Table 6: The ABO Blood Groups Blood type | Antigens Present | Antibody Present | Genotype O | Neither A nor B | A and B | ii A | A | B | I^AI^A or I^Ai B | B | A | I^BI^B or I^Bi AB | AB | Neither A nor B | I^AI^B a. What is the possibility of two AB parents producing a child with type O blood? Explain (1 pt): b. In a case of disputed paternity, the child is type O, the mother type A. What are all the possible blood types the father of this child could be (1 pt)
Madhur L.
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