Question 1

In which of the complex traits shown here is variation determined almost completely by the environment?

Accepted Answer

A) trait M 
B) trait H 
C) trait K 
D) trait L 
E) trait Q 
A) trait M 
B) trait H 
C) trait K 
D) trait L 
E) trait Q

Question 2

Heritability is a measure of the:

Accepted Answer

A) extent to which a trait is passed from parent to offspring. 
B) proportion of a trait that is determined by genes rather than by the environment. 
C) proportion of total variation in a trait that is due to genetic differences among individuals within a population. 
D) extent to which a trait exhibits regression toward the mean in a population. 
E) norm of reaction of a trait. 
A) extent to which a trait is passed from parent to offspring. 
B) proportion of a trait that is determined by genes rather than by the environment. 
C) proportion of total variation in a trait that is due to genetic differences among individuals within a population. 
D) extent to which a trait exhibits regression toward the mean in a population. 
E) norm of reaction of a trait.

Question 3

Genetic differences are always more important than environmental differences for determining phenotypic outcomes.

Accepted Answer

A) True 
 B)False

Question 4

Variation in the effects of the environment on different genotypes is known as:

Accepted Answer

A) the norm of reaction. 
B) complex variation. 
C) genotype-by-genotype variation. 
D) genotype-by-environment interaction. 
E) environment-by-environment variation. 
A) the norm of reaction. 
B) complex variation. 
C) genotype-by-genotype variation. 
D) genotype-by-environment interaction. 
E) environment-by-environment variation.

Question 5

Personalized medicine refers to the idea of:

Accepted Answer

A) using a patient's individual genotype to inform treatment for a given disease. 
B) using a patient's individual lifestyle and other risk factors to inform treatment for a given disease. 
C) using a combination of a patient's lifestyle and genotype to inform treatment for a given disease. 
D) basing treatment on an individual's long-term medical history. 
E) using a combination of a patient's lifestyle, genotype, and long-term medical history to inform treatment for a given disease. 
A) using a patient's individual genotype to inform treatment for a given disease. 
B) using a patient's individual lifestyle and other risk factors to inform treatment for a given disease. 
C) using a combination of a patient's lifestyle and genotype to inform treatment for a given disease. 
D) basing treatment on an individual's long-term medical history. 
E) using a combination of a patient's lifestyle, genotype, and long-term medical history to inform treatment for a given disease.

Question 6

Regression toward the mean is observed because of:

Accepted Answer

A) correlation between genotype and environment. 
B) breakdown of genotype-by-environment interaction. 
C) mating between relatives. 
D) segregation and recombination. 
E) variable norms of reaction. 
A) correlation between genotype and environment. 
B) breakdown of genotype-by-environment interaction. 
C) mating between relatives. 
D) segregation and recombination. 
E) variable norms of reaction.

Question 7

The concordance among monozygotic twins for epilepsy is 37% and for dizygotic twins is 10%. From this information, we can conclude that:

Accepted Answer

A) epilepsy has only a minor genetic component. 
B) epilepsy has an important genetic component. 
C) lifestyle and other environmental factors play an important role in epilepsy. 
D) epilepsy has only a minor genetic component, while lifestyle and other environmental factors play an important role. 
E) epilepsy has both an important genetic component and an important environmental component. 
A) epilepsy has only a minor genetic component. 
B) epilepsy has an important genetic component. 
C) lifestyle and other environmental factors play an important role in epilepsy. 
D) epilepsy has only a minor genetic component, while lifestyle and other environmental factors play an important role. 
E) epilepsy has both an important genetic component and an important environmental component.

Question 8

All of the genes involved in a complex trait contribute equally to the manifestation of that trait.

Accepted Answer

A) True 
 B)False

Question 9

If genetic contribution to variation in a trait is negligible:

Accepted Answer

A) identical twins will be more similar to one another than fraternal twins are to one another. 
B) fraternal twins will be more similar to one another than identical twins are to one another. 
C) identical twins will be no more similar to one another than are fraternal twins. 
D) identical twins will be resemble one another more closely than do any other siblings. 
E) None of the answer options is correct. 
A) identical twins will be more similar to one another than fraternal twins are to one another. 
B) fraternal twins will be more similar to one another than identical twins are to one another. 
C) identical twins will be no more similar to one another than are fraternal twins. 
D) identical twins will be resemble one another more closely than do any other siblings. 
E) None of the answer options is correct.

Question 10

Consider a trait determined entirely by environmental risk factors for which the chance that a random individual is affected is 25%. What is the concordance between identical twins? What is the concordance between same-sex fraternal twins?

Accepted Answer

A) identical concordance = 1.0; fraternal concordance = 0.167 
B) identical concordance = 0.167; fraternal concordance = 0.167 
C) identical concordance = 0.167; fraternal concordance = 0.143 
D) identical concordance = 0.143; fraternal concordance = 0.143 
E) None of the answer options is correct. 
A) identical concordance = 1.0; fraternal concordance = 0.167 
B) identical concordance = 0.167; fraternal concordance = 0.167 
C) identical concordance = 0.167; fraternal concordance = 0.143 
D) identical concordance = 0.143; fraternal concordance = 0.143 
E) None of the answer options is correct.

Question 11

Which of the following are quantitative traits?

Accepted Answer

A) serum cholesterol 
B) blood pressure 
C) height 
D) weight 
E) skin color 
A) serum cholesterol 
B) blood pressure 
C) height 
D) weight 
E) skin color

Question 12

Single-gene traits are more likely to be influenced by the environment.

Accepted Answer

A) True 
 B)False

Question 13

Genotype-by-environment interaction means that genetic and environmental influences may interact or contribute to the phenotypic outcomes in unpredictable ways.

Accepted Answer

A) True 
 B)False

Question 14

The traits that Mendel studied are most often influenced by single genes.

Accepted Answer

A) True 
 B)False

Question 15

BRCA1 and BRCA2 are:

Accepted Answer

A) genes related to DNA repair. 
B) proteins necessary for normal breast cell division. 
C) genes related to DNA synthesis. 
D) proteins necessary for tumor suppression. 
E) genes known to cause cancer. 
A) genes related to DNA repair. 
B) proteins necessary for normal breast cell division. 
C) genes related to DNA synthesis. 
D) proteins necessary for tumor suppression. 
E) genes known to cause cancer.

Question 16

The multiple genetic and environmental factors affecting complex traits imply that different people can have the same disease for different reasons.

Accepted Answer

A) True 
 B)False

Question 17

_____ is defined as the percentage of cases in which both members of a pair of twins show the trait when it is known that at least one member shows it.

Accepted Answer

A) Concordance 
B) Discordance 
C) Epistasis 
D) Accordance 
E) Monozygocity 
A) Concordance 
B) Discordance 
C) Epistasis 
D) Accordance 
E) Monozygocity

Question 18

Heritability is the proportion of the total phenotypic variation in a trait that is the result of:

Accepted Answer

A) genetic variation among individuals. 
B) environmental variation among the individuals. 
C) variation in the degree of dominance of different genes. 
D) variation in the degree of epistasis among genes. 
E) variation in the frequency of recombination between genes. 
A) genetic variation among individuals. 
B) environmental variation among the individuals. 
C) variation in the degree of dominance of different genes. 
D) variation in the degree of epistasis among genes. 
E) variation in the frequency of recombination between genes.

Question 19

Certain forms of dwarfism are the result of mutations in the Sox9 gene. Thus, Sox9 is considered to be the major height determining gene in humans.

Accepted Answer

A) True 
 B)False

Question 20

Ten individuals of two inbred strains of mice, A and B, are fed identical diets. All have normal blood sugar as adults. The same mice are then fed diets high in sugar. Mice from strain B develop diabetes, but mice from strain A do not. Diabetes in strain B mice results from:

Accepted Answer

A) the interaction of their diet with their genotype. 
B) their genotypes, which are different from strain A mice. 
C) their diets, which are different from strain A mice. 
D) their norm of reaction to sugar in their diets. 
E) None of the other answer choices is correct. 
A) the interaction of their diet with their genotype. 
B) their genotypes, which are different from strain A mice. 
C) their diets, which are different from strain A mice. 
D) their norm of reaction to sugar in their diets. 
E) None of the other answer choices is correct.

Exam 18: The Genetic and Environmental Basis of Complex Traits

In which of the complex traits shown here is variation determined almost completely by the environment?

Heritability is a measure of the:

Genetic differences are always more important than environmental differences for determining phenotypic outcomes.

Variation in the effects of the environment on different genotypes is known as:

Personalized medicine refers to the idea of:

Regression toward the mean is observed because of:

The concordance among monozygotic twins for epilepsy is 37% and for dizygotic twins is 10%. From this information, we can conclude that:

All of the genes involved in a complex trait contribute equally to the manifestation of that trait.

If genetic contribution to variation in a trait is negligible:

Consider a trait determined entirely by environmental risk factors for which the chance that a random individual is affected is 25%. What is the concordance between identical twins? What is the concordance between same-sex fraternal twins?

Which of the following are quantitative traits?

Single-gene traits are more likely to be influenced by the environment.

Genotype-by-environment interaction means that genetic and environmental influences may interact or contribute to the phenotypic outcomes in unpredictable ways.

The traits that Mendel studied are most often influenced by single genes.

BRCA1 and BRCA2 are:

The multiple genetic and environmental factors affecting complex traits imply that different people can have the same disease for different reasons.

_____ is defined as the percentage of cases in which both members of a pair of twins show the trait when it is known that at least one member shows it.

Heritability is the proportion of the total phenotypic variation in a trait that is the result of:

Certain forms of dwarfism are the result of mutations in the Sox9 gene. Thus, Sox9 is considered to be the major height determining gene in humans.

Ten individuals of two inbred strains of mice, A and B, are fed identical diets. All have normal blood sugar as adults. The same mice are then fed diets high in sugar. Mice from strain B develop diabetes, but mice from strain A do not. Diabetes in strain B mice results from:

Life: Chemical, Cellular, and Evolutionary Foundations

The Molecules of Life

Nucleic Acids and Transcription

Translation and Protein Structure

Organizing Principles: Lipids, Membranes, and Cell Compartments

Making Life Work: Capturing and Using Energy

Cellular Respiration: Harvesting Energy From Carbohydrates and Other Fuel Molecules

Photosynthesis: Using Sunlight to Build Carbohydrates

Cell Signaling

Cell and Tissue Architecture: Cytoskeleton, Cell Junctions, and Extracellular Matrix

Cell Division: Variations, Regulation, and Cancer

Dna Replication and Manipulation

Genomes

Mutation and Dna Repair

Genetic Variation

Mendelian Inheritance

Inheritance of Sex Chromosomes, Linked Genes, and Organelles

Genetic and Epigenetic Regulation

Genes and Development

Evolution: How Genotypes and Phenotypes Change Over Time

Species and Speciation

Evolutionary Patterns: Phylogeny and Fossils

Human Origins and Evolution

Cycling Carbon

Bacteria and Archaea

Eukaryotic Cells: Origins and Diversity

Being Multicellular

Plant Structure and Function: Moving Photosynthesis Onto Land

Plant Reproduction: Finding Mates and Dispersing Young

Plant Growth and Development

Plant Defense: Keeping the World Green

Plant Diversity

Fungi: Structure, Function, and Diversity

Animal Nervous Systems

Animal Sensory Systems and Brain Function

Animal Movement: Muscles and Skeletons

Animal Endocrine Systems

Animal Cardiovascular and Respiratory Systems

Animal Metabolism, Nutrition, and Digestion

Animal Renal Systems: Water and Waste

Animal Reproduction and Development

Animal Immune Systems

Animal Diversity

Animal Behavior

Population Ecology

Species Interactions, Communities, and Ecosystems

Biomes and Global Ecology

The Anthropocene: Humans As a Planetary Force

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