Question 1

Once a chromosomal position for a putative gene associated with Parkinson disease is verified, which of the following is a next step?

Accepted Answer

A) developing a FISH screening test to identify pre-Parkinson patients 
B) determining whether this locus is mutated in all Parkinson patients 
C) using a genome-wide linkage SNP panel to identify more minor genes 
D) ascertaining all living and at-risk individuals who are family members of the affected test subjects 
E) fine mapping of the linkage region to identify particular variants for influencing risk

Question 2

As an H2 value approaches 0.0, which of the following must be true?

Accepted Answer

A) Almost all of the variation in phenotype is VG. 
B) Almost all of the variation in phenotype is VE. 
C) Identical (MZ)twins are virtually all discordant. 
D) Fraternal (DZ)twins are virtually all concordant. 
E) h2 = VA/VP.

Question 3

Which of the following best predicts the response of a trait to artificial selection?

Accepted Answer

A) VA 
B) VG 
C) H2 
D) h2 
E) standard deviation

Question 4

For a specific desirable trait in a breed of sheep, V_P is 28.6, V_C is 11, and V_A is 7.2. What is its broad sense heritability?

Accepted Answer

The answer of For a specific desirable trait in a...

Question 5

A GWAS tests for a strong association of genotype (using DNA markers)and phenotype in natural populations. Therefore, which of the following would be true of linkage disequilibrium?

Accepted Answer

A) There is a significant correlation between phenotype and genotype. 
B) The P value is > 0.05. 
C) The lod score is negative. 
D) There is evidence of inbreeding. 
E) There is a deviation from Hardy-Weinberg equilibrium.

Question 6

While most additive polygenic traits show continuous distribution, some can be divided into two or more categories based on their contribution to genetic liability. Such traits are said to have what separation between affected and unaffected members of a population?

Accepted Answer

The answer of While most additive polygenic traits show continuous...

Question 7

An increased number of patients have recently been diagnosed with celiac disease, which you may know of as gluten sensitivity (OMIM 212750). It is a multifactorial disorder of the small intestine influenced by genes and environment, and it is characterized by malabsorption due to inflammation of the mucosa after eating wheat gluten or related proteins. It is now thought to occur in 1 out of 120 to 300 people. Genes found to be associated with it are in the HLA region of chromosome 6, namely DR3 and DQw2. Which of the following is more probable?

Accepted Answer

A) It is an autoimmune disorder. 
B) It is caused by exposure to gluten in infancy. 
C) It has high broad-sense heritability. 
D) Its frequency varies greatly by population. 
E) It is found primarily in inbred populations.

Question 8

A strain of a cereal grain can be either dark tan, medium-dark tan, medium tan, light tan, or cream colored. When a dark tan and a cream plant are crossed, all F₁ are medium tan. The F₂ are distributed in a ratio of 1:4:6:4:1 from darkest to lightest. How many genes are involved in this coloration?

Accepted Answer

The answer of A strain of a cereal grain can...

Question 9

In some traits, different phenotypes result from genes whose alleles each contribute a specific increment to the whole. The phenotypes then have a ________ phenotypic distribution.

Accepted Answer

The answer of In some traits, different phenotypes result from...

Question 10

Sometimes the DNA marker allele and a QTL occur together more frequently than would otherwise be expected, either because they interact or because of natural selection. What term describes this?

Accepted Answer

The answer of Sometimes the DNA marker allele and a...

Question 11

Alterations in the ratio of CD4:CD8 lymphocytes are associated with risk of HIV infection progressing to AIDS, of autoimmune diseases, and of progression of some cancers. In searching for predictors of these effects in normal individuals, researchers have found two independent QTLs in the region of the genome known as the major histocompatibility complex (MHC), one in a region regulating CD8 and the other in a region regulating CD4. What does this indicate for the general population?

Accepted Answer

A) Mutation in one or both of these genes causes HIV and AIDS. 
B) Autoimmune diseases such as type 1 diabetes are caused by one of these genes. 
C) Variation in linkage disequilibrium with one or both of these mutations may increase the risk of autoimmune disease. 
D) Only one mutation can be the cause of rheumatoid arthritis. 
E) The probability of an autoimmune disease demonstrates that additive genes are involved.

Question 12

Which of the following is most typical of a case of quantitative inheritance?

Accepted Answer

A) a ratio of 9:3:3:1 
B) continuous variation in phenotypes 
C) discontinuous variation in genotypes 
D) lack of a clearly dominant phenotype 
E) a trait with little to no genetic influence

Question 13

What two measures describe the distribution of a trait in a sample?

Accepted Answer

The answer of What two measures describe the distribution of...

Question 14

An animal breeder asks your advice about which of a number of traits could most effectively be selected for in his herd. Which would you most correctly suggest?

Accepted Answer

A) a trait with high VE 
B) a high VA relative to VP 
C) a high VP relative to VG 
D) a low h2 value 
E) a low selection coefficient

Question 15

If the odds ratio for a particular QTL/DNA marker pair (e.g., Q₁₀M₁₀)is 2.2, this indicates that the organism is how many times more likely to get Q₁₀M₁₀ gametes?

Accepted Answer

The answer of If the odds ratio for a particular...

Question 16

Many human behavioral traits have both genetic and environmental components. Bipolar disorder has long been known to be familial, and more recently a number of genes and/or SNPs have been found to be involved. What are three or more reasons that this research has been hampered?

Accepted Answer

The answer of Many human behavioral traits have both genetic...

Question 17

A strain of a cereal grain can be either dark tan, medium-dark tan, medium tan, light tan, or cream colored. When a dark tan and a cream plant are crossed, all F₁ are medium tan. The F₂ are distributed in a ratio of 1:4:6:4:1 from darkest to lightest. How many additive alleles are needed to produce the darkest phenotypes?

Accepted Answer

The answer of A strain of a cereal grain can...

Question 18

Recent work in Drosophila demonstrated that the genes known as the chromatin remodeling complex co-localize at loci for hsp genes that respond to heat shock. Outline a procedure you could use to substantiate this finding.

Accepted Answer

The answer of Recent work in Drosophila demonstrated that the...

Question 19

Describe how quantitative traits can be explained in Mendelian terms.

Accepted Answer

The answer of Describe how quantitative traits can be explained...

Question 20

Given a list of concordances (as percentages)for monozygotic and dizygotic twins for a selection of traits, describe how you would evaluate the relative input of environmental versus genetic factors for each trait.

Accepted Answer

The answer of Given a list of concordances (as percentages)for...

Exam 21: Genetic Analysis of Quantitative Traits

Once a chromosomal position for a putative gene associated with Parkinson disease is verified, which of the following is a next step?

As an H² value approaches 0.0, which of the following must be true?

Which of the following best predicts the response of a trait to artificial selection?

For a specific desirable trait in a breed of sheep, V_P is 28.6, V_C is 11, and V_A is 7.2. What is its broad sense heritability?

A GWAS tests for a strong association of genotype (using DNA markers) and phenotype in natural populations. Therefore, which of the following would be true of linkage disequilibrium?

While most additive polygenic traits show continuous distribution, some can be divided into two or more categories based on their contribution to genetic liability. Such traits are said to have what separation between affected and unaffected members of a population?

In some traits, different phenotypes result from genes whose alleles each contribute a specific increment to the whole. The phenotypes then have a ________ phenotypic distribution.

Sometimes the DNA marker allele and a QTL occur together more frequently than would otherwise be expected, either because they interact or because of natural selection. What term describes this?

Which of the following is most typical of a case of quantitative inheritance?

What two measures describe the distribution of a trait in a sample?

An animal breeder asks your advice about which of a number of traits could most effectively be selected for in his herd. Which would you most correctly suggest?

If the odds ratio for a particular QTL/DNA marker pair (e.g., Q₁₀M₁₀)is 2.2, this indicates that the organism is how many times more likely to get Q₁₀M₁₀ gametes?

Many human behavioral traits have both genetic and environmental components. Bipolar disorder has long been known to be familial, and more recently a number of genes and/or SNPs have been found to be involved. What are three or more reasons that this research has been hampered?

Recent work in Drosophila demonstrated that the genes known as the chromatin remodeling complex co-localize at loci for hsp genes that respond to heat shock. Outline a procedure you could use to substantiate this finding.

Describe how quantitative traits can be explained in Mendelian terms.

Given a list of concordances (as percentages)for monozygotic and dizygotic twins for a selection of traits, describe how you would evaluate the relative input of environmental versus genetic factors for each trait.

Exam 21: Genetic Analysis of Quantitative Traits

Once a chromosomal position for a putative gene associated with Parkinson disease is verified, which of the following is a next step?

As an H2 value approaches 0.0, which of the following must be true?

Which of the following best predicts the response of a trait to artificial selection?

For a specific desirable trait in a breed of sheep, VP is 28.6, VC is 11, and VA is 7.2. What is its broad sense heritability?

A GWAS tests for a strong association of genotype (using DNA markers) and phenotype in natural populations. Therefore, which of the following would be true of linkage disequilibrium?

While most additive polygenic traits show continuous distribution, some can be divided into two or more categories based on their contribution to genetic liability. Such traits are said to have what separation between affected and unaffected members of a population?

A strain of a cereal grain can be either dark tan, medium-dark tan, medium tan, light tan, or cream colored. When a dark tan and a cream plant are crossed, all F1 are medium tan. The F2 are distributed in a ratio of 1:4:6:4:1 from darkest to lightest. How many genes are involved in this coloration?

In some traits, different phenotypes result from genes whose alleles each contribute a specific increment to the whole. The phenotypes then have a ________ phenotypic distribution.

Sometimes the DNA marker allele and a QTL occur together more frequently than would otherwise be expected, either because they interact or because of natural selection. What term describes this?

Which of the following is most typical of a case of quantitative inheritance?

What two measures describe the distribution of a trait in a sample?

An animal breeder asks your advice about which of a number of traits could most effectively be selected for in his herd. Which would you most correctly suggest?

If the odds ratio for a particular QTL/DNA marker pair (e.g., Q10M10)is 2.2, this indicates that the organism is how many times more likely to get Q10M10 gametes?

Many human behavioral traits have both genetic and environmental components. Bipolar disorder has long been known to be familial, and more recently a number of genes and/or SNPs have been found to be involved. What are three or more reasons that this research has been hampered?

Recent work in Drosophila demonstrated that the genes known as the chromatin remodeling complex co-localize at loci for hsp genes that respond to heat shock. Outline a procedure you could use to substantiate this finding.

Describe how quantitative traits can be explained in Mendelian terms.

Given a list of concordances (as percentages)for monozygotic and dizygotic twins for a selection of traits, describe how you would evaluate the relative input of environmental versus genetic factors for each trait.

As an H² value approaches 0.0, which of the following must be true?

For a specific desirable trait in a breed of sheep, V_P is 28.6, V_C is 11, and V_A is 7.2. What is its broad sense heritability?

If the odds ratio for a particular QTL/DNA marker pair (e.g., Q₁₀M₁₀)is 2.2, this indicates that the organism is how many times more likely to get Q₁₀M₁₀ gametes?