Principles of Inheritance-BIOL-107

Principles of Inheritance

If T is the normal allele and t is the recessive allele, what are the possible genotypes of her eggs?

Some eggs are T and other eggs are t.
Tt

Some eggs are TT and other eggs are tt.

t

T

Use a Punnett square to answer the following three questions: If both parents are heterozygous for the Tay-Sachs gene, what is the chance their first child will have Tay-Sachs?

75%

100%

0%

25%

50%

If both parents are heterozygous for Tay-Sachs, what is the chance that their first child will be homozygous dominant?

100%

25%

50%

75%

0%

If both parents are heterozygous for the Tay-Sachs gene, what is the chance that their first child will also be heterozygous?

50%

100%

0%

25%

75%

In humans, albinism is a recessive trait. Two parents who have normal skin color have a child with albinism. What is the genotype of the mother?

Aa

AA

aa

Question 6

What is the genotype of the child with albinism?

Aa

AA

aa

Huntington’s disease is a disease with symptoms that do not begin until later in life. Huntington’s is caused by a dominant allele (H). A man who is heterozygous for the gene marries a woman who is homozygous recessive. Who will develop the disease, the man or the woman?

The woman will develop the disease

The man will develop the disease.

Neither the man nor the woman will develop the disease.

Both the man and the woman will develop the disease.

If a man who is heterozygous for Huntington’s disease and a woman who is homozygous recessive for the gene have a child, what is the chance that the child will eventually develop Huntington’s? (Use a Punnett square)

75%

25%

100%

0%

50%

What is genotype of the oldest man in this pedigree (in row I)?

Either FF or Ff

FF

ff

Ff

Question 10

Ff

ff

Either FF or Ff

FF

Question 11

Either FF or Ff

Ff

ff

FF

X-linked recessive

Autosomal recessive

Autosomal dominant

X-linked recessive

Autosomal recessive

Principles of Inheritance-Question 14

If a heterozygous offspring has a phenotype that shows the traits of both of their homozygous parents, it is an example of ____________. If instead the heterozygous offspring has a phenotype that is intermediate trait, it is an example of __________.

multifactorial traits, incomplete dominance

incomplete dominance, codominance

codominance, incomplete dominance

multifactorial traits, codominance

Assume that ^ICfor the curly hair allele and I^S for the straight hair allele.

What is the genotype of an individual who has straight hair?

I^CI^C

I^C

No answer text provided.

I^SI^S

I^S

Use a Punnett square to answer this question: If one parent has straight hair and the other has wavy hair, what is the probability that their child will have straight hair?

25%

100%

50%

75%

0%

Question 17

ii

I^AI^A

I^Ai

Since having blood group A is a dominant trait, you don’t know if she is I^AI^Aor I^Ai.

Her genotype could be either I^AI^Aor I^Ai

Suzy (blood type A) marries Joe, who is type O. Their second child has type O blood.
What is Suzy’s genotype?

She could be either I^AI^Aor I^Ai.

I^AI^A

I^Ai

ii

Many forms of colorblindness are due to an X-linked recessive allele. A colorblind man and a woman who is a carrier for colorblindness are expecting their first child. If the child is a boy, what is the chance that he will be colorblind?

50%

25%

100%

0%

A colorblind man and a woman with normal vision have a son who is colorblind. Did the son inherit the colorblind allele from his mother or his father?

mother

father

Since it is a recessive trait, he must have inherited the allele from both his mother and father.

Could have inherited it from either his mother or his father.

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Principles of Inheritance-BIOL-107