Deck 4: Extensions of Mendelian Inheritance

Question 1

If a geneticist describes a trait as being 70% penetrant, what would they mean?

A) Individuals with the trait show variation in expression.
B) It is lethal in 30% of the individuals who have the trait.
C) Only 70% of the individuals who carry the allele(s) for a trait express the trait.
D) The trait is present in 70% of the population.

Answer 1

C

Question 2

If an allele is dominant in one sex and recessive in another, it is an example of ________.

A) sex-limited inheritance
B) sex-influenced inheritance
C) incomplete dominance
D) simple Mendelian inheritance

Answer 2

B

Question 3

The coat characteristics of arctic foxes and Siamese cats, where proteins in the extremities function differently than in other parts of the body, is an example of ________.

A) incomplete dominance
B) multiple allele systems
C) semilethal alleles
D) temperature-sensitive allele
E) None of the answers are correct

Answer 3

D

Question 4

Huntington disease in humans is an example of ________.

A) lethal alleles
B) epistasis
C) semilethal alleles
D) recessive inheritance
E) environmental effects

Question 5

An individual carries the allele for polydactyly, but is normal. This is an example of ________.

A) simple Mendelian inheritance
B) incomplete dominance
C) incomplete penetrance
D) codominance
E) gene dosage

Question 6

A heterozygote possesses a phenotype that is intermediate between the homozygous dominant and homozygous recessive phenotypes. This is most likely an example of ________.

A) lethal alleles
B) incomplete dominance
C) gene dosage
D) sex-influenced inheritance

Question 7

Phenylketonuria in humans is an example of ________.

A) incomplete penetrance
B) codominance
C) an environmentally-influenced trait
D) incomplete dominance

Question 8

A paralog ________.

A) is found for every gene in mammals
B) is only found on the X but not the Y chromosome
C) can explain the lack of phenotype for a gene knockout
D) cannot be mutated
E) has the same DNA sequence as the original duplicated gene

Question 9

Humans homozygous for the sickle cell allele have sickle cell anemia. A human that is heterozygous for the sickle cell allele is an example of ________.

A) codominance
B) incomplete penetrance
C) heterozygous advantage
D) multiple allele systems

Question 10

In human blood groups, the fact that an individual can have an AB blood type is an example of ________.

A) incomplete dominance
B) incomplete penetrance
C) sex-influenced trait
D) temperature-sensitive conditional allele
E) codominance

Question 11

At the molecular level, type A and type B blood differ in which of the following characteristics?

A) The antigens present on the surface of the red blood cells
B) The type of sugar found in each type
C) The antibodies that are generated against the other type of blood
D) All of the answers are correct

Question 12

For a certain trait, a heterozygous individual has a selective advantage as compared to a homozygous dominant or homozygous recessive individual. This is called ________.

A) codominance
B) incomplete dominance
C) overdominance
D) incomplete penetrance
E) multiple allele systems

Question 13

At the molecular level, which of the following best explain heterozygous advantage and overdominance?

A) A heterozygous individual can produce more varieties of homodimer proteins
B) The alleles produce two different proteins with slightly different functions
C) The proteins produced by the alleles may provide a broader range of environmental tolerance, such as temperature ranges
D) Infectious organisms may recognize only a specific functional protein
E) All of the answers are possibilities

Question 14

In rabbits, full coat color (c) is the dominant trait. A second allele, chinchilla (cch) is recessive to full coat color. Himalayan coat color (ch) is recessive to chinchilla and full coat colors and albino (c) is recessive to all coat colors. If two chinchilla rabbits mate, what coat color is not possible in their offspring?

A) Full coat color
B) Chinchilla coat color
C) Himalayan coat color
D) Albino coat color
E) All coat colors are possible

Question 15

Genes that are not required for survival, but are likely to be beneficial to the organism, are called ________.

A) essential genes
B) lethal alleles
C) semilethal alleles
D) nonessential genes
E) conditional lethal alleles

Question 16

A woman who is heterozygous for an allele that results in X-linked pattern baldness marries a man who is nonbald. Which of the following would be true of their offspring?

A) All would be bald
B) All of the females would be nonbald, all males would be bald
C) All of the females would be nonbald, ½ of the males would be bald
D) ½ of females would be bald, and ½ of the males would be bald
E) All would be nonbald

Question 17

An individual with type A blood and an individual with type B blood mate and have offspring. What blood type is not possible in their offspring?

A) Type O blood
B) Type A blood
C) Type B blood
D) Type AB blood
E) All blood types are possible

Question 18

Temperature-sensitive alleles that kill an organism only in a particular temperature range are examples of ________.

A) essential genes
B) lethal alleles
C) semilethal alleles
D) nonessential genes
E) conditional lethal alleles

Question 19

In four-o'clock plants, red flower color is dominant to white flower color. However, heterozygous plants have a pink color. If a pink-flowered plant is crossed with a white-flowered plant, what will be the phenotypic ratios of their offspring?

A) ¼ red, ½ pink, ¼ white
B) All pink
C) All white
D) ½ pink, ½ white
E) ½ red, ½ pink

Question 20

Male-pattern baldness is only an autosomal dominant trait in humans.

Question 21

The trait of cream-colored eyes in Drosophila is an example of ________.

A) simple recessive alleles
B) incomplete penetrance of red eyes
C) a gene modifier effect in eye color
D) gene dosage
E) a spontaneous mutation

Question 22

In an epistatic interaction, the genes must be located on the same chromosome.

Question 23

The presence of a group of antigens that determine blood type is an example of a(n) ________.

A) semilethal allele
B) sex-linked trait
C) multiple allele system
D) incomplete dominance

Question 24

Which of the following is not correct concerning epistatic interactions?

A) They can be associated with enzymatic pathways.
B) They produce variations in the expected 9:3:3:1 ratio of a dihybrid cross.
C) They can result when a gene at one locus masks the expression of a gene at a different locus.
D) They always result in a 9:7 ratio of a dihybrid cross.
E) They are due to gene interactions.

Question 25

Variable expressivity means that the phenotype of a trait can vary between individuals.

Question 26

Incomplete dominance is an example of blending of phenotypes, not genotypes.

Question 27

How did Bateson and Punnett's work with comb morphology in chickens differ from the dihybrid work of Mendel?

A) They were working with sex-limited traits.
B) Their F2 offspring displayed 4 unique phenotypes, not the four combinations of two phenotypes expected in a Mendelian cross.
C) ½ of their combinations were lethal.
D) The expression of their trait varied by the environment in which the chickens were raised.

Question 28

When wild-type offspring are produced from a cross between parents that both display the same recessive phenotype, this illustrates the genetic phenomenon of ________.

A) simple recessive alleles
B) incomplete penetrance
C) complementation
D) gene dosage
E) a spontaneous mutation

Question 29

A ________ allele is the most prevalent allele in a population and usually encodes a protein that is made in the proper amount and functions normally.

A) loss-of-function
B) mutant
C) wild-type
D) gain-of-function
E) lethal

Question 30

Paralogs are often functionally redundant and can compensate for the loss of either of the paralogs in a set.

Question 31

The interaction of two genes to produce a phenotype was first described by ________.

A) Morgan and Bridges
B) Mendel
C) Darwin
D) Bateson and Punnett
E) None of the answers are correct

Question 32

In a dihybrid cross of two heterozygous individuals, you expect a 9:3:3:1 phenotypic ratio in the offspring, but observe a ratio of 9:7. What is the most likely explanation?

A) Codominance
B) It is a sex-limited trait
C) Simple Mendelian inheritance
D) Incomplete penetrance
E) Epistatic interaction of the two genes

Question 33

If a combination of two or more genes is required to produce a specific trait, it is called a(n) ________.

A) overdominance
B) simple mendelian trait
C) sex-influenced trait
D) sex-linked trait
E) gene interaction

Question 34

The multiple effects of a single gene on the phenotype of an organism is called ________.

A) epistasis
B) penetrance
C) expressivity
D) overdominance
E) pleiotropy

Question 35

Human blood groups are determined by antigens on the surface of red blood cells.

Question 36

In cattle, the presence or absence of scurs follows a sex-influenced pattern of inheritance. A heterozygous male has ________ and a heterozygous female has ________.

A) Y-linked, X-linked
B) no scurs, scurs
C) X-linked, Y-linked
D) scurs, no scurs

Question 37

Epistasis is ________.

A) another term for overdominance
B) when one gene can mask the expression of a second gene
C) a trait that is only expressed in one sex of the species
D) when two dominant alleles can be expressed in the same individual
E) None of the answers are correct

Question 38

Incomplete penetrance indicates that individuals who possess a dominant trait always express the trait.

Question 39

Typically, a recessive allele increases the expression of a functional protein.

Question 40

In overdominance, the ________ genotype is beneficial over the ________ genotypes.

A) heterozygous, homozygous
B) homozygous, heterozygous
C) homozygous dominant, homozygous recessive
D) homozygous recessive, homozygous dominant
E) incomplete dominant, codominant

Question 41

The pedigree below shows the inheritance pattern of a rare X-linked allele for one family. The filled in circles and squares show affected individuals. What is the probability of individual III-2 being born male and affected?

A) 1/2
B) 1/3
C) 1/4
D) 0

Question 42

Filled in circles and square show affected individuals. Select the mode of inheritance for individual III-3.

A) Incomplete dominance
B) Codominance
C) Pseudoautosomal inheritance
D) X-linked inheritance

Question 43

The pedigree below shows the inheritance pattern of a rare X-linked allele for one family. The filled in circles and squares show affected individuals. What is the probability of individual III-2 being born female and affected?

A) 1/2
B) 1/3
C) 1/4
D) 0

Question 44

A male Manx cat and a female Manx cat produce kitten. What is the probability that kitten has a non-manx tail?

A) 1/3
B) 1/2
C) 1/4
D) 2/3

Question 45

If a light-eosin eye male Drosophila is crossed to a homozygous red eyed female, what will be the phenotype of their offspring?

A) All offspring will have red eyes.
B) All males will have light-eosin eyes and all females will have eosin eye
C) All females will have red eyes, all males will have light-eosin eyes.
D) All flies will have white eyes.

Question 46

Heavy metals, such as copper, are required for proper development. However, if too much copper is present it can lead to developmental defects. A scientist was interested in studying the developmental defects that could occur at various concentrations of copper. Genetically identical organisms were grown in 6 different concentrations of copper. This experiment evaluates a(n) ________.

A) epistasis
B) dominant trait
C) recessive trait
D) norm of reaction

Question 47

In sex influenced traits, both sexes can express the trait, depending on their genotype, but in sex limited inheritance a particular sex can only have one phenotype for the trait in question.

Question 48

In codominance, both alleles make functional gene products which are expressed simultaneously.