Pedigree Chart Analysis (GF)

by Kathy Egbert

| 10 Questions
Queen Victoria's Family

1

1

Victoria's youngest child, Beatrice, had one daughter, one normal son, and two
sons with hemophilia. Beatrice's daughter, Eugenie, married King Alfonso XIII of
Spain. They had six children, one of whom was the father of Juan Carlos, King of
Spain. What is Juan Carlos's phenotype?

A normal

C hemophilic

B carrier

2

1

Victoria's daughter, Alice, had a daughter, Alix, who carried the defective
allele into the royal Russian family when she married Tsar Nicholas II. They had
four daughters and one son, Alexis. Alexis had hemophilia. The entire family was
murdered during the Russian Revolution. What is the probability that one of
Alexis's sisters was a carrier?

C 4:0 or 100%

D None of his sisters can be carriers.

A 3:1or 25%

B 1:1 or 50%

3

1

What is the probability that all four of Alexis's sisters are carriers?

Finding probability for sequential events - multiply the probability for one
sister by the probability for the next sister and so forth

D None of Alexis's sisters are carriers.

A 1 in 4

C 1 in 16

B 1 in 8

4

1

If Alexis had lived and married a normal woman and they had a daughter, what is
the probability that his daughter would have hemophilia?

Remember that the hemophilia gene is on the "X" chromosome. Alexis would
contribute his "X" chromosome to his daughters. His wife, normal and not a
carrier, would also contribute an "X" chromosome to their daughter. With two "X"
chromosomes, a deleterious allele can be masked by an allele that isn't
deleterious.

C 50% chance

D 75% chance

B 25% chance

A None of his daughters would have hemophilia.

5

1

If Alexis had lived and married a normal woman and they had a son, what is the
probability that a son would have hemophilia?

Remember that the hemophilia gene is on the X chromosome. Alexis would
contribute a "Y" chromosome for his sons. Sons "X" chromosome would come from
their mother who is normal (not a carrier).

D All of his sons would have hemophilia.

B 25% chance

A None of his sons would have hemophilia.

C 50% chance

6

1

Is it possible for a female to have hemophilia?

Before modern-day drugs, she would probably have had difficulty surviving
puberty when she began monthly menstruation. Modern day drugs can provide
considerable assistance to those with hemophilia and improve their chances of
living a relatively normal life.

B False

A True

7

1

The next generation of the present British royal family--William and Harry--are
carriers for hemophilia.

If a male has the hemophilia gene on his "X" chromosome then it is expressed and
he has hemophilia. William and Harry's squares are not shaded in on the pedigree
chart so they don't have hemophilia.

B False

A True

8

1

The sex chromosome(s) in male mammal's gametes (sperm) is/are

A only X

B only Y

C either an X or a Y

9

1

The sex chromosome(s) in a female mammal's gamete (egg) is/are

A only X

B only Y

C either an X or a Y

10

1

The half shaded in circles represents a

D female who has hemophilia.

A male carrier for hemophilia.

C male who has hemophilia.

B female carrier for hemophilia.

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