Genetics Through Family Pedigrees

What does the pedigree diagram show?

• The presence or absence of a trait through multiple generations of a family.

• The genetic makeup of a single individual.

• The environmental factors affecting a family.

• The dietary habits of a family.

What is the probability for an unaffected female to have a male offspring who is color blind?

• The probability cannot be determined without knowing the genotype of the father.

• The probability is 0% because the male will inherit an unaffected X-chromosome from his mother.

• The probability is 50% because the male will inherit an unaffected X-chromosome from his mother and an unknown X-chromosome from his father.

• The probability is 100% because the male will inherit the dominant gene on his X-chromosome.

If a male with color blindness produced offspring with a female who was a carrier for the color blindness trait, what is the probability their daughter would be affected by the color blindness trait?

• 0%

• 25%

• 50%

• 100%

Which BEST describes the color blindness trait?

• It is a recessive trait because a person who has the gene for color blindness will express the trait.

• It is a dominant trait because a person who has the gene for color blindness will express the trait.

• It is a dominant trait because a person can have the gene for color blindness without expressing the trait.

• It is a recessive trait because a person can have the gene for color blindness without expressing the trait.

A cross between an unaffected female and an affected male is shown in the incomplete Punnett square. Drag and drop the genotypes produced into the appropriate boxes in the Punnett square.

• XbY

• X^BY

• XBXb

• X^BX^b

• XBY

• X^BX^B

• XBXB

• X^bY

Read the passage - 'Passage 5307' - and answer the following question(s). Directions: The table lists the hair color and genotype of six individuals where black hair is dominant over blond. Use the table to answer any questions that follow.

• What is the dominant hair color according to the table?

• How many individuals have blond hair according to the table?

• What is the genotype of individuals with black hair according to the table?

• Which hair color is recessive according to the table?

If Mr. and Mrs. Johnson had four children together, what color of hair would the children likely have?

• All 4 of the children would have black hair.

• Only 3 of the children would have black hair, and 1 child would have blond hair.

• All 4 of the children would have blond hair.

• Only 2 of the children would have black hair, and 2 of the children would have blond hair.

If Mr. and Mrs. Ellwood had four children together, which of the following would likely represent the children's genotypes?

• Only 2 of the children would be heterozygous Bb, and 2 of the children would be homozygous bb.

• All 4 of the children would be heterozygous Bb.

• Only 3 of the children would be heterozygous Bb, and 1 child would be homozygous bb.

• All 4 of the children would be homozygous bb.

Using a Punnett square, which ratio shows the probability that Mariana's future sibling will have blue eyes?

• 1:4

• 1:2

• 3:4

• 1:1

Using a Punnett square, what is the percent probability that Mariana's future sibling will have a homozygous dominant genotype for brown eyes?

• 25%

• 50%

• 75%

• 0%