Question 1

Which of the following best describes the dominance hierarchy for mouse coat color alleles, as shown in the images and study materials?

Accepted Answer

Ay \u003e A1 \u003e A+ \u003e a1 \u003e a

Question 2

In Cuenot’s yellow mice, why is it impossible to obtain a true-breeding yellow (YY) line?

Accepted Answer

The YY genotype is lethal, so all YY embryos die.

Question 3

Which equation best represents the probability of two carriers of a rare recessive allele producing an affected offspring?

Accepted Answer

$$P = 0.25$$

Question 4

A Labrador retriever with genotype 'bbEe' will have which coat color?

Accepted Answer

Chocolate

Question 5

Which genetic phenomenon is illustrated by the interaction between the 'E' and 'B' genes in Labrador retrievers?

Accepted Answer

Epistasis

Question 6

Human height is best described as a trait controlled by:

Accepted Answer

Polygenic inheritance

Question 7

A Siamese cat’s coat color is determined by an enzyme that is only active below $$33^\circC. $$What type of genetic effect is this?

Accepted Answer

Gene expression influenced by the environment

Question 8

In a pedigree chart, what does a half-filled symbol represent?

Accepted Answer

A carrier of a recessive allele

Question 9

Which of the following is a key feature of a pedigree showing a dominant trait?

Accepted Answer

Affected individuals appear in each successive generation

Question 10

Sickle-cell disease is caused by:

Accepted Answer

A single amino acid substitution in the hemoglobin protein

Question 11

Individuals with genotype 'Hh' for sickle-cell disease:

Accepted Answer

Are carriers but do not show symptoms

Question 12

Which equation represents the expected ratio of black:chocolate:yellow Labs from a BbEe x BbEe cross?

Accepted Answer

$$9:3:4$$

Question 13

Which inheritance pattern is more likely to be observed in males than females?

Accepted Answer

X-linked recessive

Question 14

If a female is heterozygous for an X-linked recessive disorder, what is the probability her son will be affected?

Accepted Answer

$$P = 0.5$$

Question 15

Which of the following best explains why consanguineous matings increase the risk of recessive genetic disorders?

Accepted Answer

Close relatives are more likely to carry the same rare recessive allele

Question 16

Which equation describes the probability of a child inheriting sickle-cell disease from two carrier parents?

Accepted Answer

$$P = 0.25$$

Question 17

Which of the following is true about polygenic traits?

Accepted Answer

They show continuous variation in the population

Question 18

Which genetic concept is illustrated by the inability to taste PTC, as shown in the pedigree analysis?

Accepted Answer

Recessive inheritance

Question 19

Which statement about sex-linked genes is correct?

Accepted Answer

Most genes on the X chromosome do not have counterparts on the Y chromosome

Question 20

If the SRY gene crosses over to the X chromosome, what is the most likely outcome?

Accepted Answer

An individual with XX chromosomes may develop male characteristics

Patterns of Inheritance: Extensions of Mendelian Genetics

Study Guide - Practice Questions