Question 1

In cats, black fur color is caused by an X-linked allele; the other allele at this locus causes orange color. The heterozygote is tortoiseshell. What kinds of offspring would you expect from the cross of a black female and an orange male?

Accepted Answer

A)  Tortoiseshell females; tortoiseshell males
B)  Black females; orange males
C)  Orange females; orange males
D)  Tortoiseshell females; black males
E)  Orange females; black malesF) All of the above
G) C) and D)

Question 2

The frequency of crossing over between any two linked genes will be which of the following?

Accepted Answer

A)  Higher if they are recessive
B)  Dependent on how many alleles there are
C)  Determined by their relative dominance
D)  The same as if they were not linked
E)  Proportional to the distance between themF) A) and C)
G) C) and D)

Question 3

The frequency of Down syndrome in the human population is most closely correlated with which of the following?

Accepted Answer

A)  Frequency of new meiosis
B)  Average of the ages of mother and father
C)  Age of the mother
D)  Age of the father
E)  Exposure of pregnant women to environmental pollutantsF) B) and C)
G) C) and E)

Question 4

Cinnabar eyes is a sex-linked recessive characteristic in fruit flies. If a female having cinnabar eyes is crossed with a wild-type male, what percentage of the F1 males will have cinnabar eyes?

Accepted Answer

A)  0%
B)  25%
C)  50%
D)  75%
E)  100%F) A) and C)
G) All of the above

Question 5

SRY is best described in which of the following ways?

Accepted Answer

A)  A gene region present on the Y chromosome that triggers male development
B)  A gene present on the X chromosome that triggers female development
C)  An autosomal gene that is required for the expression of genes on the Y chromosome
D)  An autosomal gene that is required for the expression of genes on the X chromosome
E)  Required for development, and males or females lacking the gene do not survive past early childhoodF) B) and C)
G) A) and D)

Question 6

Why did the improvement of microscopy techniques in the late 1800s set the stage for the emergence of modern genetics?

Accepted Answer

A)  It revealed new and unanticipated features of Mendel's pea plant varieties.
B)  It allowed the study of meiosis and mitosis, revealing parallels between behaviors of genes and chromosomes.
C)  It allowed scientists to see the DNA present within chromosomes.
D)  It led to the discovery of mitochondria.
E)  It showed genes functioning to direct the formation of enzymes.F) A) and B)
G) A) and E)

Question 7

Morgan and his colleagues worked out a set of symbols to represent fly genotypes. Which of the following are representative?

Accepted Answer

A)  AaBb × AaBb
B)  46, XY or 46, XX
C)  vg+vgse+se × vgvgsese
D)  +2 × +3E) B) and C)
F) A) and C)

Question 8

In another cross, a wild-type fruit fly (heterozygous for gray body color and red eyes)is mated with a black fruit fly with purple eyes. The offspring are as follows: wild type, 721; black-purple, 751; gray-purple, 49; black-red, 45. What is the recombination frequency between these genes for body color and eye color?
 Using information from problem 4, what fruit flies (genotypes and phenotypes)would you mate to determine the sequence of the body-color, wing-size, and eye-color genes on the chromosome?

Accepted Answer

6%. Wild type (heterozygous fo...

Question 9

You design Drosophila crosses to provide recombination data for gene a, which is located on the chromosome shown in Figure 15.12 in the textbook. Gene a has recombination frequencies of 14% with the vestigial-wing locus and 26% with the brown-eye locus. Where is a located on the chromosome?

Accepted Answer

About one-third of t...

Question 10

What is the mechanism for the production of genetic recombinants?

Accepted Answer

A)  X inactivation
B)  Methylation of cytosine
C)  Crossing over and independent assortment
D)  Nondisjunction
E)  Deletions and duplications during meiosisF) A) and E)
G) None of the above

Question 11

Bananas plants, which are triploid, are seedless and therefore sterile. Propose a possible explanation.

Accepted Answer

Because bananas are triploid, homologous...

Question 12

What pattern of inheritance would lead a geneticist to suspect that an inherited disorder of cell metabolism is due to a defective mitochondrial gene?

Accepted Answer

The disorder would a...

Question 13

What is the chromosomal system for determining sex in mammals?

Accepted Answer

A)  Haploid-diploid
B)  X-0
C)  X-X
D)  X-Y
E)  Z-WF) B) and D)
G) A) and D)

Question 14

In humans, male-pattern baldness is controlled by an autosomal gene that occurs in two allelic forms. Allele Hn determines nonbaldness, and allele Hb determines pattern baldness. In males, because of the presence of testosterone, allele Hb is dominant over Hn. If a man and woman both with genotype HnHb have a son, what is the chance that he will eventually be bald?

Accepted Answer

A)  0%
B)  25%
C)  33%
D)  50%
E)  75%F) A) and D)
G) C) and D)

Question 15

Correns described that the inheritance of variegated color on the leaves of certain plants was determined by the maternal parent only. What phenomenon does this describe?

Accepted Answer

A)  Mitochondrial inheritance
B)  Chloroplast inheritance
C)  Genomic imprinting
D)  Infectious inheritance
E)  Sex-linkageF) A) and B)
G) A) and C) B

Question 16

A man with hemophilia (a recessive, sex-linked condition)has a daughter of normal phenotype. She marries a man who is normal for the trait. What is the probability that a daughter of this mating will be a hemophiliac?
 That a son will be a hemophiliac?
 If the couple has four sons, what is the probability that all four will be born with hemophilia?

Accepted Answer

0; 1⁄2, 1/16

Question 17

Which of the following statements describes genomic imprinting?

Accepted Answer

A)  It explains cases in which the gender of the parent from whom an allele is inherited affects the expression of that allele.
B)  It is greatest in females because of the larger maternal contribution of cytoplasm.
C)  It may explain the transmission of Duchenne muscular dystrophy.
D)  It involves an irreversible alteration in the DNA sequence of imprinted genes.E) A) and B)
F) A) and C)

Question 18

Map units on a linkage map cannot be relied upon to calculate physical distances on a chromosome for which of the following reasons?

Accepted Answer

A)  The frequency of crossing over varies along the length of the chromosome.
B)  The relationship between recombination frequency and map units is different in every individual.
C)  Physical distances between genes change during the course of the cell cycle.
D)  The gene order on the chromosomes is slightly different in every individual.
E)  Linkage map distances are identical between males and females.F) A) and B)
G) All of the above

Question 19

What is the source of the extra chromosome 21 in an individual with Down syndrome?

Accepted Answer

A)  Nondisjunction in the mother only
B)  Nondisjunction in the father only
C)  Duplication of the chromosome
D)  Nondisjunction or translocation in either parent
E)  It is impossible to detect with current technologyF) A) and C)
G) B) and D)

Question 20

What is the chromosomal system of sex determination in most species of ants and bees?

Accepted Answer

A)  Haploid-diploid
B)  X-0
C)  X-X
D)  X-Y
E)  Z-WF) A) and E)
G) A) and B) A

Exam 15: The Chromosomal Basis of Inheritance

In cats, black fur color is caused by an X-linked allele; the other allele at this locus causes orange color. The heterozygote is tortoiseshell. What kinds of offspring would you expect from the cross of a black female and an orange male?

Correct Answer
verified

The frequency of crossing over between any two linked genes will be which of the following?

Correct Answer
verified

The frequency of Down syndrome in the human population is most closely correlated with which of the following?

Correct Answer
verified

Cinnabar eyes is a sex-linked recessive characteristic in fruit flies. If a female having cinnabar eyes is crossed with a wild-type male, what percentage of the F1 males will have cinnabar eyes?

Correct Answer
verified

SRY is best described in which of the following ways?

Correct Answer
verified

Why did the improvement of microscopy techniques in the late 1800s set the stage for the emergence of modern genetics?

Correct Answer
verified

Morgan and his colleagues worked out a set of symbols to represent fly genotypes. Which of the following are representative?

Correct Answer
verified

Correct Answer
verified
6%. Wild type (heterozygous fo...
View Answer

You design Drosophila crosses to provide recombination data for gene a, which is located on the chromosome shown in Figure 15.12 in the textbook. Gene a has recombination frequencies of 14% with the vestigial-wing locus and 26% with the brown-eye locus. Where is a located on the chromosome?

Correct Answer
verified
About one-third of t...
View Answer

What is the mechanism for the production of genetic recombinants?

Correct Answer
verified

Bananas plants, which are triploid, are seedless and therefore sterile. Propose a possible explanation.

Correct Answer
verified
Because bananas are triploid, homologous...
View Answer

What pattern of inheritance would lead a geneticist to suspect that an inherited disorder of cell metabolism is due to a defective mitochondrial gene?

Correct Answer
verified
The disorder would a...
View Answer

What is the chromosomal system for determining sex in mammals?

Correct Answer
verified

Correct Answer
verified

Correns described that the inheritance of variegated color on the leaves of certain plants was determined by the maternal parent only. What phenomenon does this describe?

Correct Answer
verified
B

Correct Answer
verified
0; 1⁄2, 1/16

Which of the following statements describes genomic imprinting?

Correct Answer
verified

Map units on a linkage map cannot be relied upon to calculate physical distances on a chromosome for which of the following reasons?

Correct Answer
verified

What is the source of the extra chromosome 21 in an individual with Down syndrome?

Correct Answer
verified

What is the chromosomal system of sex determination in most species of ants and bees?

Correct Answer
verified
A

Exam 15: The Chromosomal Basis of Inheritance

In cats, black fur color is caused by an X-linked allele; the other allele at this locus causes orange color. The heterozygote is tortoiseshell. What kinds of offspring would you expect from the cross of a black female and an orange male?

Correct AnswerverifiedShow Answer

The frequency of crossing over between any two linked genes will be which of the following?

Correct AnswerverifiedShow Answer

The frequency of Down syndrome in the human population is most closely correlated with which of the following?

Correct AnswerverifiedShow Answer

Cinnabar eyes is a sex-linked recessive characteristic in fruit flies. If a female having cinnabar eyes is crossed with a wild-type male, what percentage of the F1 males will have cinnabar eyes?

Correct AnswerverifiedShow Answer

SRY is best described in which of the following ways?

Correct AnswerverifiedShow Answer

Why did the improvement of microscopy techniques in the late 1800s set the stage for the emergence of modern genetics?

Correct AnswerverifiedShow Answer

Morgan and his colleagues worked out a set of symbols to represent fly genotypes. Which of the following are representative?

Correct AnswerverifiedShow Answer

Correct Answerverified6%. Wild type (heterozygous fo...View AnswerShow Answer

You design Drosophila crosses to provide recombination data for gene a, which is located on the chromosome shown in Figure 15.12 in the textbook. Gene a has recombination frequencies of 14% with the vestigial-wing locus and 26% with the brown-eye locus. Where is a located on the chromosome?

Correct AnswerverifiedAbout one-third of t...View AnswerShow Answer

What is the mechanism for the production of genetic recombinants?

Correct AnswerverifiedShow Answer

Bananas plants, which are triploid, are seedless and therefore sterile. Propose a possible explanation.

Correct AnswerverifiedBecause bananas are triploid, homologous...View AnswerShow Answer

What pattern of inheritance would lead a geneticist to suspect that an inherited disorder of cell metabolism is due to a defective mitochondrial gene?

Correct AnswerverifiedThe disorder would a...View AnswerShow Answer

What is the chromosomal system for determining sex in mammals?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Correns described that the inheritance of variegated color on the leaves of certain plants was determined by the maternal parent only. What phenomenon does this describe?

Correct AnswerverifiedB

Correct Answerverified0; 1⁄2, 1/16

Which of the following statements describes genomic imprinting?

Correct AnswerverifiedShow Answer

Map units on a linkage map cannot be relied upon to calculate physical distances on a chromosome for which of the following reasons?

Correct AnswerverifiedShow Answer

What is the source of the extra chromosome 21 in an individual with Down syndrome?

Correct AnswerverifiedShow Answer

What is the chromosomal system of sex determination in most species of ants and bees?

Correct AnswerverifiedA

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
6%. Wild type (heterozygous fo...
View Answer

Correct Answer
verified
About one-third of t...
View Answer

Correct Answer
verified

Correct Answer
verified
Because bananas are triploid, homologous...
View Answer

Correct Answer
verified
The disorder would a...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
B

Correct Answer
verified
0; 1⁄2, 1/16

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
A