Q: A population in Newfoundland shows a high frequency of a recessive disease due to genetic isolation. Which equation best describes the probability that two carriers will mate and produce an affected child?

$$P = (carrier$$requency)^2$$ \times 0.25$$

Question 1

Which inheritance pattern is most likely represented by the first pedigree image, where affected individuals appear in every generation and both males and females are affected?

Accepted Answer

Autosomal dominant

Question 2

In the second pedigree image, consanguineous mating is indicated. Which factor does consanguinity most strongly increase in a population?

Accepted Answer

Incidence of autosomal recessive traits

Question 3

A population in Newfoundland shows a high frequency of a recessive disease due to genetic isolation. Which equation best describes the probability that two carriers will mate and produce an affected child?

Accepted Answer

$$P = (carrier$$requency)^2$$ 	imes 0.25$$

Question 4

Which of the following best describes the change in red blood cell shape seen in sickle cell disease (as shown in the fifth and sixth images)?

Accepted Answer

Biconcave to sickle-shaped

Question 5

Sickle cell disease is caused by a mutation in the beta-globin gene. Which amino acid substitution is responsible for this disease?

Accepted Answer

Glutamate replaced by valine

Question 6

Referencing the sickle cell disease flowchart, which term describes the phenomenon where a single gene mutation causes multiple, seemingly unrelated symptoms?

Accepted Answer

Pleiotropy

Question 7

In an autosomal recessive pedigree, what is the expected male-to-female ratio among affected offspring?

Accepted Answer

1:1

Question 8

Which inheritance pattern is characterized by affected individuals appearing in every generation, unaffected individuals not producing affected offspring, and both sexes being equally affected?

Accepted Answer

Autosomal dominant

Question 9

A carrier female for an X-linked recessive disease mates with a normal male. What percentage of their sons are expected to be affected?

Accepted Answer

50%

Question 10

Which of the following is NOT a characteristic of X-linked recessive inheritance?

Accepted Answer

Affected fathers pass the trait to all sons

Question 11

Which equation represents the expected genotypic ratio for a monohybrid cross involving a dominant and recessive allele?

Accepted Answer

$$1:2:1$$

Question 12

Which inheritance pattern is shown in a pedigree where only males are affected and the trait is passed from father to son?

Accepted Answer

Y-linked

Question 13

A family pedigree shows affected individuals in only one generation, with siblings affected but parents unaffected. What is the most likely inheritance pattern?

Accepted Answer

Autosomal recessive

Question 14

Which mechanism can explain how a mutant allele is dominant over a wild-type allele?

Accepted Answer

Haploinsufficiency

Question 15

In X-linked dominant inheritance, what is the expected outcome for the daughters of an affected father?

Accepted Answer

All daughters affected

Question 16

Which of the following is a real-world example of an autosomal recessive disease caused by a loss of function mutation in an enzyme?

Accepted Answer

Phenylketonuria

Question 17

Which term describes the process by which one X chromosome is randomly inactivated in female embryonic cells, leading to variable expression of X-linked traits?

Accepted Answer

Dosage compensation

Question 18

A pedigree shows vertical transmission, male-to-male inheritance, and affected individuals in every generation. Which inheritance pattern is most likely?

Accepted Answer

Autosomal dominant

Question 19

Which of the following factors can increase the incidence of an autosomal recessive trait in a population?

Accepted Answer

Consanguinity

Question 20

In a Punnett square for autosomal recessive inheritance, what is the probability that two carrier parents will have an affected child?

Accepted Answer

$$\frac{1}{4}$$

Patterns of Inheritance: Pedigrees and Human Genetic Disorders

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