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Multiple Alleles

Prompt

  1. One parent in heterozygous for type A blood and one patent is heterozygous for B blood. What are all the possible blood types for their children?

  2. A child has type O blood. List all possible parental genotypes

  3. Suppose a father and mother claim that they have been given the wrong baby at the hospital. Both parents ate group A. The baby they have been given is group O. Could the baby be theirs? If the baby had been group B, could the baby be theirs?

  4. Suppose a child is blood group A, and the mother is blood group O. What group or groups may the father belong to

  5. If one parent has type AB blood and the other has type A blood, is it possible for them to have a child with type B blood. Is it possible for them to have a child with type O blood?

  6. A man has type A blood and his wife has type B blood. A physician types the blood of their four children and is amazed to find one of each of the four blood types among them. He is not familiar with genetics and calls upon you to explain how such a thing could happen. What would you tell him? Diagram and explain your answer.

  7. A couple preparing for marriage has their blood typed along with the other required blood tests. Both are AB. They ask you what types of blood their children may have. What would you tell them and how would you explain your conclusions.

  8. A woman sues a man for the support of her child. She has type A blood, her child has type O, and the mas has type R. Could the man be the father? Explain your answer

  9. A wealthy, elderly couple dies together in an accident. Soon a man shows up to claim their fortune, contending that he is their only son who ran away from home when he was a boy. Other relatives dispute this claim. Hospital records show that the deceased couple was blood types AB and O. The claimant was of blood type O. Do you think that the claimant was an imposter? Explain. If he had blood type A would your answer be the same?

  10. A man of blood type A marries a woman of type B. They produce one child of type A and another of ty O. Last the genotype for each of these four people. What are the chances that their next child will be blood type AB?

  11. A common protein found in the blood of some people is called Rhesus factor (named after the Rhesus monkey in which it was first found) and it is usually designated as the Rh factor. People who have this protein are said to be Rh positive (Rh+) and those who do not are said to be Rh negative (Rh). Rh+ dominant and Rh- is recessive. If an Rh- woman has an Rh+ child, there is a chance that the child could have the condition known as ERYTHROBLASTOSIS. The first Rh+ baby is usually unaffected, but the chances increase with each succeeding Rh+ child. What are the chances of a couple having an Rh+ child if:

    1. The mother is Rh- and the father is Rh+ (heterozygous)?
    2. both parents are heterozygous for Rh+?

Response

  1. One parent is heterozygous for type A blood and one parent is heterozygous for type B blood. What are all the possible blood types for their children?

    The genotypes for the parents are \(I^A i\) and \(I^B i\). The possible blood types for their children are:

    • \(I^A I^B\) (Type AB)
    • \(I^A i\) (Type A)
    • \(I^B i\) (Type B)
    • \(i i\) (Type O)

    Therefore, the possible blood types for their children are: A, B, AB, and O.

  2. A child has type O blood. List all possible parental genotypes.

    For a child to have type O blood, both parents must have at least one recessive allele (i). The possible genotypes for the parents are:

    • \(I^A i\) (Type A)
    • \(I^B i\) (Type B)
    • \(i i\) (Type O)
    • \(I^A I^B\) (Type AB)

    The combinations can be:

    • \(I^A i\) and \(I^B i\)
    • \(I^A i\) and \(i i\)
    • \(I^B i\) and \(i i\)
    • \(i i\) and \(i i\)

  3. Suppose a father and mother claim that they have been given the wrong baby at the hospital. Both parents are group A. The baby they have been given is group O. Could the baby be theirs? If the baby had been group B, could the baby be theirs?

    • Both parents being group A means their genotypes could be \(I^A I^A\) or \(I^A i\). For the baby to be group O (genotype \(i i\)), both parents must be heterozygous \(I^A i\). So yes, the baby could be theirs.

    • If the baby had been group B, the baby could not be theirs because parents with type A blood (genotype \(I^A I^A\) or \(I^A i\)) cannot produce a type B (genotype \(I^B i\) or \(I^B I^B\)) child.

  4. Suppose a child is blood group A, and the mother is blood group O. What group or groups may the father belong to?

    • The mother has genotype \(i i\).
    • The child has genotype \(I^A i\).

    Therefore, the father must have at least one \(I^A\) allele. The father could be:

    • Type A (genotype \(I^A I^A\) or \(I^A i\))
    • Type AB (genotype \(I^A I^B\))

  5. If one parent has type AB blood and the other has type A blood, is it possible for them to have a child with type B blood? Is it possible for them to have a child with type O blood?

    • One parent with type AB blood has genotype \(I^A I^B\).

    • The other parent with type A blood could have genotype \(I^A I^A\) or \(I^A i\).

    • It is possible for them to have a child with type B blood if the type A parent is heterozygous \(I^A i\), resulting in the following possibilities for the child's genotype: \(I^A I^A\), \(I^A I^B\), \(I^A i\), or \(I^B i\).

    • It is not possible for them to have a child with type O blood because neither parent has an \(i i\) genotype.

  6. A man has type A blood and his wife has type B blood. A physician types the blood of their four children and is amazed to find one of each of the four blood types among them. He is not familiar with genetics and calls upon you to explain how such a thing could happen. What would you tell him? Diagram and explain your answer.

    • The man with type A blood could be \(I^A i\).
    • The woman with type B blood could be \(I^B i\).

    The possible combinations for their children:

    \(I^A\) \(i\)
    \(I^B\) \(I^A I^B\) (AB) \(I^B i\) (B)
    \(i\) \(I^A i\) (A) \(i i\) (O)

    Therefore, they could have children with types A, B, AB, and O.

  7. A couple preparing for marriage has their blood typed along with the other required blood tests. Both are AB. They ask you what types of blood their children may have. What would you tell them and how would you explain your conclusions.

    • Both parents have genotype \(I^A I^B\).

    The possible combinations for their children:

    \(I^A\) \(I^B\)
    \(I^A\) \(I^A I^A\) (A) \(I^A I^B\) (AB)
    \(I^B\) \(I^A I^B\) (AB) \(I^B I^B\) (B)

    Therefore, their children could have blood types A, B, or AB. They cannot have type O.

  8. A woman sues a man for the support of her child. She has type A blood, her child has type O, and the man has type B. Could the man be the father? Explain your answer.

    • The woman has type A blood, genotype could be \(I^A i\).
    • The child has type O blood, genotype \(i i\).
    • The man has type B blood, genotype could be \(I^B i\).

    The child could have inherited the \(i\) allele from both parents. Therefore, the man could be the father.

  9. A wealthy, elderly couple dies together in an accident. Soon a man shows up to claim their fortune, contending that he is their only son who ran away from home when he was a boy. Other relatives dispute this claim. Hospital records show that the deceased couple was blood types AB and O. The claimant was of blood type O. Do you think that the claimant was an imposter? Explain. If he had blood type A would your answer be the same?

    • One parent is AB (\(I^A I^B\)), the other is O (\(i i\)).
    • The possible blood types for their child: A (\(I^A i\)) or B (\(I^B i\)).

    A child cannot have type O blood if one parent is AB. Therefore, the claimant with type O blood is an imposter.

    If the claimant had type A blood, it would be possible for the child to be theirs (\(I^A i\)).

  10. A man of blood type A marries a woman of type B. They produce one child of type A and another of type O. List the genotype for each of these four people. What are the chances that their next child will be blood type AB?

    • Man (type A): \(I^A i\)
    • Woman (type B): \(I^B i\)
    • Child (type A): \(I^A i\)
    • Child (type O): \(i i\)

    The possible combinations for their next child:

    \(I^A\) \(i\)
    \(I^B\) \(I^A I^B\) (AB) \(I^B i\) (B)
    \(i\) \(I^A i\) (A) \(i i\) (O)

    The chance of their next child being type AB is \(1/4\) or 25%.

  11. A common protein found in the blood of some people is called Rhesus factor (named after the Rhesus monkey in which it was first found) and it is usually designated as the Rh factor. People who have this protein are said to be Rh positive (Rh+) and those who do not are said to be Rh negative (Rh-). Rh+ dominant and Rh- is recessive. If an Rh- woman has an Rh+ child, there is a chance that the child could have the condition known as ERYTHROBLASTOSIS. The first Rh+ baby is usually unaffected, but the chances increase with each succeeding Rh+ child. What are the chances of a couple having an Rh+ child if:

    1. The mother is Rh- and the father is Rh+ (heterozygous)?

      • Mother: \(rr\)
      • Father: \(Rr\)

      The possible combinations for their child:

      \(R\) \(r\)
      \(r\) \(Rr\) (Rh+) \(rr\) (Rh-)
      \(r\) \(Rr\) (Rh+) \(rr\) (Rh-)

      The chance of having an Rh+ child is 50%.

    2. Both parents are heterozygous for Rh+?

      • Parents: \(Rr\) and \(Rr\)

      The possible combinations for their child:

      \(R\) \(r\)
      \(R\) \(RR\) (Rh+) \(Rr\) (Rh+)
      \(r\) \(Rr\) (Rh+) \(rr\) (Rh-)

      The chance of having an Rh+ child is 75%.