Question 1

Which of the following best describes incomplete dominance?

Accepted Answer

The heterozygote has a phenotype that is intermediate between the two homozygotes.

Question 2

A cat with genotype $w^s w^s$, $CC$ will have which of the following fur phenotypes?

Accepted Answer

Pigmented (has color everywhere)

Question 3

In the case of snapdragon flower color, $C^R$ encodes an enzyme that makes red pigment, and $C^I$ encodes no enzyme activity. What is the expected phenotype of a $C^R C^I$ plant?

Accepted Answer

Pink flowers

Question 4

Which of the following is an example of co-dominance?

Accepted Answer

A heterozygote expressing both alleles' phenotypes simultaneously, such as AB blood type in humans

Question 5

A loss of function (LOF) mutation that results in no functional protein product is called:

Accepted Answer

Null

Question 6

Which of the following best describes a dominant negative mutation?

Accepted Answer

A mutation that results in a protein that interferes with the function of the wild-type protein

Question 7

A cat with the genotype $w^+ w^s$, $cc$ will have what fur phenotype?

Accepted Answer

Completely white

Question 8

Which of the following statements about gain of function (GOF) mutations is correct?

Accepted Answer

GOF mutations result in a protein with increased or new activity and are usually dominant.

Question 9

A person with genotype $I^A I^B$ for the ABO blood group will have which blood type?

Accepted Answer

Type AB

Question 10

Which of the following best explains why most loss of function (LOF) mutations are recessive?

Accepted Answer

Because one functional copy of the gene is usually sufficient for a normal phenotype

Question 11

A yeast strain with genotype $nn$ for a transporter gene is exposed to canavanine. What is the expected outcome?

Accepted Answer

The yeast will survive because it is resistant to canavanine.

Question 12

Which of the following is an example of pleiotropy?

Accepted Answer

A gene that affects both fur color and hearing in cats

Question 13

A mutation in the lactase gene promoter causes lactase to be expressed into adulthood. This is an example of which type of mutation?

Accepted Answer

Gain of function (GOF)

Question 14

Which of the following best describes haploinsufficiency?

Accepted Answer

A single functional copy of a gene is not sufficient to produce a normal phenotype.

Question 15

A temperature-sensitive allele of tyrosinase in Siamese cats results in pigment production only in cooler areas of the body. This is an example of:

Accepted Answer

A conditional loss of function mutation

Question 16

Which of the following is true about penetrance?

Accepted Answer

Penetrance refers to the proportion of individuals with a genotype who actually display the expected phenotype.

Question 17

A mutation that results in a protein with a new function not found in the wild-type protein is called:

Accepted Answer

Neomorphic

Question 18

If a trait is fully penetrant, what does this mean?

Accepted Answer

All individuals with the genotype express the phenotype.

Question 19

Which of the following best describes a hypomorphic mutation?

Accepted Answer

A mutation that results in a protein with reduced function

Question 20

A Drosophila mutant expresses the Antennapedia gene in the head, resulting in legs growing where antennae should be. This is an example of:

Accepted Answer

A gain of function mutation

Genetic Interactions and Functional Consequences of Mutations

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