Download Genetics Questions

Genetics Assignment
Indicate the correct answer, explain your answer and show your work. 3 points each.
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1. Assume that the genes for dark eyes (black or brown) are dominant over light eyes
(blue). A man with blue eyes marries a woman with brown eyes. They have two children,
a boy with blue eyes, and a girl with brown eyes.
Which of the following is true?
A) The girl is heterozygous and the boy is homozygous dominant
B) The girl is heterozygous and the boy is homozygous recessive
C) The girl is homozygous dominant and the boy is heterozygous
D) The father is homozygous recessive and the mother is homozygous dominant
E) The next child, if it is a girl, will have a 100% chance of having blue eyes
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2. A dark eyed man marries a dark eyed woman, but they have a blue eyed child.
What is the probability that their second child will have blue eyes?
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A) 0
B) 1/4
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C) 1/2
D) 3/4
E) 4/4
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3. Albinism is an autosomal (not sex-linked trait) recessive trait. Thus, normal
pigmentation is inherited as a dominant over albinism. A man with no albinos in his
lineage (assume he is homozygous for normal pigmentation) marries an albino woman.
Which of the following is true?
A) The genotype of their offspring is heterozygous, the phenotype of their offspring is
albino.
B) The genotype of their offspring is heterozygous, the phenotype of their offspring is
normal skin.
C) The genotype of the man is heterozygous, the phenotype of the man is normal skin.
D) The genotype of the woman is heterozygous, the phenotype of the woman is albino.
E) The genotype of the man is homozygous dominant, the genotype of the woman is
heterozygous.
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4. A woman has a rare abnormality of her eyes, where she cannot open them completely.
The condition depends on a single dominant gene (i.e. an autosomal dominant trait). The
woman's father had the same problem, and the father's mother had normal eyes. The
woman's mother also had normal eyes.
Which of the following is true?
A) The woman is homozygous recessive and her father is heterozygous.
B) The woman is heterozygous and her mother is also heterozygous
C) The woman is homozygous dominant and her father is homozygous recessive
D) The woman is homozygous recessive and her mother is also homozygous recessive
E) The woman is heterozygous and her father is heterozygous
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5. Palomino color in horses is an incompletely dominant trait obtained when a horse has a
red color gene AND an albino gene. If two palomino horses mate, what are the chances
that they have a palomino offspring?
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A) 0
B) 1/4
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C) 1/2
D) 3/4
E) 4/4
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6. A man with blood type A marries a woman with blood type B. They have a child with
blood type O.
Which of the following is true?
A) The man has a genotype of AA, the woman has a genotype of BB.
B) The man has a genotype of AA or AO, the woman has a genotype of BB
C) The man has a genotype of AO, the woman has a genotype of BO
D) The man has a genotype of AB, the child has a genotype of AO
E) The man has a genotype of OO, the child has a genotype of OO
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7. A man whose mother was type A and father was type B has type B blood. He marries a
woman with type A blood, but whose father was type O.
What is the probability that their fourth child will be blood type A?
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A) 0
B) 1/4
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C) 1/2
D) 3/4
E) 4/4
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8. Rh positive is dominant over Rh negative. An Rh positive man marries an Rh negative
woman. They have 2 Rh negative children.
What is the probability that the next child could be Rh positive?
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A) 0
B) 1/4
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C) 1/2
D) 3/4
E) 4/4
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9. Hemophilia is a recessive sex-linked disease (i.e. normal is dominant over hemophilia).
A carrier woman marries a man with hemophilia.
Which of the following is true?
A) 50% chance of their sons having hemophilia and 50% chance of their daughters
having hemophilia
B) None of their children (sons or daughters) could have hemophilia
C) 50% chance of their sons having hemophilia, but zero chance of their daughters
having hemophilia
D) 25% chance of their sons having hemophilia and 50% chance of their daughters
having hemophilia
E) Zero chance of their sons having hemophilia, but 50% chance of their daughters
having hemophilia.
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10. A homozygous normal woman marries a man with hemophilia.
Which of the following is true?
A) 50% chance of their sons having hemophilia and zero chance of their daughters
having hemophilia
B) Zero chance of their sons having hemophilia and 50% chance of their daughters
having hemophilia
C) Zero chance of sons OR daughters having hemophilia
D) 50% chance of their sons having hemophilia and 25% chance of their daughters
having hemophilia
E) 100% chance of both sons and daughters having hemophilia