Question

Aniridia, a type of blindness, occurs in humans and is due to a dominant allele, A. Normal vision is due to the allele, a. Migraine headaches are due to the dominant allele, M. Normal headaches are due to the allele, m. A man with normal vision and without migraines marries a woman with normal vision and migraines. The man's father had aniridia. The women's father had normal headaches but never a migraine.
Required:
1. What was the genetics of the man's father for aniridia?
2. Did the woman’s mother suffer from migraines?
3. What is the probability of this couple producing a child who is normal for both traits?
4. What is the probability of this couple producing a child who is afflicted by both traits?
5. What is the probability that a child of this couple will have normal vision and migraines?

Answer 1

Answer:

1. What was the genetics of the man's father for aniridia? his genotype for the trait is Aa

2. Did the woman’s mother suffer from migraines? Yes, the women  inherited from her the dominant allele for migraines, M

3. What is the probability of this couple producing a child who is normal for both traits? 1/2 aamm

4. What is the probability of this couple producing a child who is afflicted by both traits? 0% of the progeny will be affected by both traits at the same time

5. What is the probability that a child of this couple will have normal vision and migraines? 1/2 aaMm

Explanation:

Available data:

• Aniridia is due to a dominant allele, A.

• Normal vision is due to the allele, a.

• Migraine headaches are due to the dominant allele, M.

• Normal headaches are due to the allele, m.

A man with normal vision and without migraines marries a woman with normal vision and migraines.

• The genotype of the Man with normal vision and without migraines is  aamm

• The genotype of the woman with normal vision and migraines is aaM-

The man's father had aniridia. This means that his genotype for the trait is Aa. We know that his son is homozygous for the recessive trait and that he must have inherited one recessive allele from the mother and the other recessive allele from his father. So, the man´s father must be heterozygous for the trait. If he was homozygous, the son would be heterozygous and would express aniridia.

The women's father had normal headaches but never a migraine. This means that his genotype is mm, recessive homozygous for the trait, which tells us that the women´s mother inherited her the dominant allele for migraines, and her father inherited her the recessive allele for the trait.

Cross:

Parental) aamm    x    aaMm

Gametes) am  am  am  am

                aM  aM  am  am

Punnet square)   aM       aM       am       am

                  am   aaMm  aaMm  aamm  aamm

                  am   aaMm  aaMm  aamm  aamm

                  am   aaMm  aaMm  aamm  aamm

                  am   aaMm  aaMm  aamm  aamm

F1) 8/16=1/2 of the progeny will have normal vision and migraines, aaMm

     8/16=1/2 of the progeny will have normal vision and will not have migraines, aamm

1. What was the genetics of the man's father for aniridia? his genotype for the trait is Aa

2. Did the woman’s mother suffer from migraines? Yes, the women  inherited from her the dominant allele for migraines, M

3. What is the probability of this couple producing a child who is normal for both traits? 1/2 aamm

4. What is the probability of this couple producing a child who is afflicted by both traits? 0% of the progeny will be affected by both traits at the same time

5. What is the probability that a child of this couple will have normal vision and migraines? 1/2 aaMm