Question 1

Which of the following statements correctly describes linkage?

Accepted Answer

A)  The closer two genes are on a chromosome, the lower the probability that a crossover will occur between them. 
B)  The observed frequency of recombination of two genes that are far apart from each other has a maximum value of 100%. 
C)  All of the traits that Mendel studied-seed color, pod shape, flower color, and others-are due to genes linked on the same chromosome. 
D)  Linked genes are found on different chromosomes. 
A)  The closer two genes are on a chromosome, the lower the probability that a crossover will occur between them. 
B)  The observed frequency of recombination of two genes that are far apart from each other has a maximum value of 100%. 
C)  All of the traits that Mendel studied-seed color, pod shape, flower color, and others-are due to genes linked on the same chromosome. 
D)  Linked genes are found on different chromosomes.

Question 2

Please use the following information to answer the question(s) below.
A plantlike organism on the planet Pandora can have three recessive genetic traits: bluish leaves, due to an allele (a) of gene A; a feathered stem, due to an allele (b) of gene B; and hollow roots due to an allele (c) of gene C. The three genes are linked and recombine.
A geneticist did a testcross with an organism that had been found to be heterozygous for the three recessive traits and was able to identify progeny of the phenotypic distribution (+ = wild type) shown in Figure 12.3.   Figure 12.3
-In which progeny phenotypes has there been recombination between genes A and B?

Accepted Answer

A)  1, 2, 5, and 6 
B)  1, 3, 6, and 7 
C)  2, 4, 5, and 8 
D)  2, 3, 5, and 7 
E)  in all 8 of them 
A)  1, 2, 5, and 6 
B)  1, 3, 6, and 7 
C)  2, 4, 5, and 8 
D)  2, 3, 5, and 7 
E)  in all 8 of them

Question 3

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 males 
A)  tortoiseshell females; tortoiseshell males 
B)  black females; orange males 
C)  orange females; orange males 
D)  tortoiseshell females; black males 
E)  orange females; black males

Question 4

Duchenne muscular dystrophy is a serious condition caused by a recessive allele of a gene on the human X chromosome. The patients have muscles that weaken over time because they have absent or decreased dystrophin, a muscle protein. They rarely live past their 20s. How likely is it for a woman to have this condition?

Accepted Answer

A)  Women can never have this condition. 
B)  One-half of the daughters of an affected man would have this condition. 
C)  One-fourth of the daughters of an affected father and a carrier mother could have this condition. 
D)  Very rarely: it is rare that an affected male would mate with a carrier female. 
E)  Only if a woman is XXX could she have this condition. 
A)  Women can never have this condition. 
B)  One-half of the daughters of an affected man would have this condition. 
C)  One-fourth of the daughters of an affected father and a carrier mother could have this condition. 
D)  Very rarely: it is rare that an affected male would mate with a carrier female. 
E)  Only if a woman is XXX could she have this condition.

Question 5

Which of the following is known as a Philadelphia chromosome?

Accepted Answer

A)  a human chromosome 22 that has had a specific translocation 
B)  a human chromosome 9 that is found only in one type of cancer 
C)  an animal chromosome found primarily in the mid-Atlantic area of the United States 
D)  an imprinted chromosome that always comes from the mother 
A)  a human chromosome 22 that has had a specific translocation 
B)  a human chromosome 9 that is found only in one type of cancer 
C)  an animal chromosome found primarily in the mid-Atlantic area of the United States 
D)  an imprinted chromosome that always comes from the mother

Question 6

When Thomas Hunt Morgan crossed his red-eyed F1 generation flies to each other, the F2 generation included both red- and white-eyed flies. Remarkably, all the white-eyed flies were male. What was the explanation for this result?

Accepted Answer

A)  The gene involved is on the Y chromosome. 
B)  The gene involved is on the X chromosome. 
C)  The gene involved is on an autosome, but only in males. 
D)  Eye color in flies is a multifactorial trait. 
A)  The gene involved is on the Y chromosome. 
B)  The gene involved is on the X chromosome. 
C)  The gene involved is on an autosome, but only in males. 
D)  Eye color in flies is a multifactorial trait.

Exam 12: The Chromosomal Basis of Inheritance

Which of the following statements correctly describes linkage?

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?

Which of the following is known as a Philadelphia chromosome?

When Thomas Hunt Morgan crossed his red-eyed F1 generation flies to each other, the F2 generation included both red- and white-eyed flies. Remarkably, all the white-eyed flies were male. What was the explanation for this result?

Introduction: Evolution and the Foundations of Biology

The Chemical Context of Life

Carbon and the Molecular Diversity of Life

A Tour of the Cell

Membrane Transport and Cell Signaling

An Introduction to Metabolism

Cellular Respiration and Fermentation

Photosynthesis

The Cell Cycle

Meiosis and Sexual Life Cycles

Mendel and the Gene Idea

The Molecular Basis of Inheritance

Gene Expression: From Gene to Protein

Regulation of Gene Expression

Development, Stem Cells, and Cancer

Viruses

Genomes and Their Evolution

Descent With Modification

Phylogeny

The Evolution of Populations

The Origin of Species

Broad Patterns of Evolution

Early Life and the Diversification of Prokaryotes

The Origin and Diversification of Eukaryotes

The Colonization of Land by Plants and Fungi

The Rise of Animal Diversity

Plant Structure and Growth

Resource Acquisition, Nutrition, and Transport in Vascular Plants

Reproduction and Domestication of Flowering Plants

Plant Responses to Internal and External Signals

Homeostasis and Endocrine Signaling

Animal Nutrition

Circulation and Gas Exchange

The Immune System

Reproduction and Development

Neurons, Synapses, and Signaling

Nervous and Sensory Systems

Motor Mechanisms and Behavior

Population Ecology and the Distribution of Organisms

Species Interactions

Ecosystems and Energy

Global Ecology and Conservation Biology

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