Question 1

Which of the following best describes incomplete dominance, as illustrated by the flower color cross shown in the images?

Accepted Answer

The heterozygote has a phenotype intermediate between the two homozygotes.

Question 2

In the F2 generation of a monohybrid cross involving incomplete dominance (as shown in the flower diagram), what is the expected phenotypic ratio?

Accepted Answer

1:2:1

Question 3

A woman with blood type O (genotype $$ii) $$and MN blood type (MM) marries a man with blood type AB (genotype $$I^A I^B) $$and MN blood type (MN). What blood types could their children have?

Accepted Answer

A, M; A, MN; B, M; B, MN

Question 4

Which genotype results in blood type O in the ABO blood group system?

Accepted Answer

$$ii$$

Question 5

In the agouti mouse coat color system, the $$A^Y$$ allele is dominant for coat color but recessive lethal. What is the expected outcome for $$A^Y A^Y$$ mice?

Accepted Answer

They do not survive.

Question 6

Which of the following best describes polygenic inheritance, as illustrated by the skin color diagrams?

Accepted Answer

Multiple genes have an additive effect on the phenotype.

Question 7

Epistasis is illustrated in the diagram where one gene masks the effect of another. Which of the following is an example of recessive epistasis?

Accepted Answer

A recessive allele at one locus masks the effect of another gene.

Question 8

In Labrador retrievers, which genotype results in a yellow coat regardless of the B gene alleles?

Accepted Answer

$$BBee or$$ $$Bbee or$$ $$bbee$$

Question 9

A cross between two heterozygous mice ($$AaCc 	imes AaCc) $$for agouti and pigment production results in which phenotypic ratio?

Accepted Answer

9 agouti : 3 solid color : 4 albino

Question 10

The Bombay phenotype in humans is an example of epistasis. Which genotype results in blood type O regardless of the ABO alleles?

Accepted Answer

$$hh$$ genotype with any ABO alleles

Question 11

Dominant epistasis is illustrated in squash color. What is the expected phenotypic ratio in the F2 generation of a heterozygous cross?

Accepted Answer

12:3:1

Question 12

Complementation analysis is used to determine whether mutations causing the same phenotype are in the same gene. If two flies with mutant wings are crossed and their offspring have normal wings, what does this indicate?

Accepted Answer

The mutations are in different genes.

Question 13

Which of the following statements about X-linked inheritance is correct?

Accepted Answer

Males are hemizygous for X-linked genes.

Question 14

A carrier mother for X-linked red–green color blindness and a normal father have children. What is the probability that a son will be color blind?

Accepted Answer

50%

Question 15

Which of the following best illustrates the effect of environment on phenotype, as seen in Himalayan rabbits?

Accepted Answer

Temperature influences fur color expression.

Question 16

Male pattern baldness is an example of a sex-influenced trait. Which genotype results in baldness in males but not in females?

Accepted Answer

$$Bb$$

Question 17

Which of the following is an example of pleiotropy?

Accepted Answer

A single gene affects multiple phenotypic traits.

Question 18

A nutritional mutation in microbes results in the inability to synthesize a certain nutrient. What is the term for microbes that require this nutrient in their diet to show a phenotype?

Accepted Answer

Auxotrophs

Question 19

Which of the following best describes a temperature-sensitive mutation?

Accepted Answer

A mutation that affects phenotype only at certain temperatures.

Extensions of Mendelian Genetics: Complex Patterns of Inheritance

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