The data in the table below show the concordance between identical twins and same-sex fraternal twins for five complex traits. Based on these data, which of the traits shows the GREATEST effect of environment relative to heredity? \[\begin{array} { | c | c | c | } \hline \text { Trait } & \begin{array} { l } \text { Identical twin } \\ \text { concordance (\%) } \end{array} & \begin{array} { l } \text { Same-sex fraternal } \\ \text { twin concordance } \\ ( \% ) \end{array} \\ \hline \text { M } & 75 & 25 \\ \hline \text { H } & 100 & 75 \\ \hline \text { K } & 75 & 50 \\ \hline \text { L } & 50 & 50 \\ \hline \text { Q } & 75 & 50 \\ \hline \end{array}\]

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

Exam 18: The Genetic and Environmental Basis of Complex Traits

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It is a general assumption that identical twins share exactly the same DNA because they arise from the same fertilized egg. However, SNP studies show that they are only about 99% identical. Where might the 1% difference have come from?

(Multiple Choice)

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Question 21

Phenylketonuria (PKU) is a metabolic disorder that results in a mental handicap when phenylalanine is present in the diet. It was found that putting children with this genetic defect on a special diet prevented the effects of the disease. This is an example of:

(Multiple Choice)

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Question 22

Which of the following statements BEST reflects the extent to which we can distinguish the effects of genes and the environment on the expression of a complex trait?

(Multiple Choice)

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Question 23

In a hypothetical twin study, investigators identify 50 identical twin pairs in which both individuals share the trait in question. In another 50 pairs, only one member exhibits the trait while the other does not. The concordance among identical twins for this trait is:

(Multiple Choice)

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Question 24

A complex trait can be influenced by the environment.

(True/False)

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Question 25

Genetic variation that affects a hypothetical complex trait has the property that 1/2 of the genes have a relative effect of size 1, 1/4 of the genes have a relative effect of size 2, 1/8 of the genes have a relative effect of size 3, and the remaining 1/8 of the genes have a relative effect of size 4. What is the average relative effect size of the genes?

(Multiple Choice)

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Question 26

Imagine that one of your good friends comes from a tall family. You measure the height of your friend and her two brothers. What would you expect of the average height of your friend and her siblings?

(Multiple Choice)

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Question 27

Which of the following statements is TRUE regarding heritability?

(Multiple Choice)

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Question 28

Nilsson-Ehle studied the effects of a small number of genes on a particular trait and found that the Mendelian laws of inheritance did not apply.

(True/False)

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Question 29

The magnitude of heritability is an intrinsic property of a trait.

(True/False)

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Question 30

Only by studying identical twins raised in separate environments can scientists uncover the role of genes vs. environment in the development of a specific trait. Comparing the occurrence of the trait in identical vs. fraternal twins yields little usable data.

(True/False)

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Question 31

Heritability is measured as:

(Multiple Choice)

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Question 32

Which line on the graph below demonstrates Galton's concept of regression toward the mean?

(Multiple Choice)

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Question 33

Which of the following statements is TRUE regarding genes involved in determining cholesterol levels in humans?

(Multiple Choice)

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Question 34

Red coloration in wheat seeds is a complex trait influenced by three unlinked genes, each with two different alleles A and a; B and b; C and c. This Punnett square shows the results of a mating between two plants that are both heterozygous at all three loci. The recessive alleles do not contribute to the red coloration of the seed casing.

(True/False)

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Question 35

Heritability is a measure of:

(Multiple Choice)

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Question 36

The data in the table below show the concordance between identical twins and same-sex fraternal twins for five complex traits. Based on these data, which of the traits shows the GREATEST effect of environment relative to heredity? Trait Identical twin concordance (\%) Same-sex fraternal twin concordance (\%) M 75 25 H 100 75 K 75 50 L 50 50 Q 75 50

(Multiple Choice)

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Question 37

Consider a trait determined by a rare mutation in mitochondrial DNA. What is the concordance between identical twins? Between same-sex fraternal twins?

(Multiple Choice)

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Question 38

Nilsson-Ehle's studies of seed color in wheat were important because they showed that:

(Multiple Choice)

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Question 39

Personalized genome sequencing is MOST easily justified in situations in which there are:

(Multiple Choice)

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Question 40

Showing 21 - 40 of 164

Exam 18: The Genetic and Environmental Basis of Complex Traits

It is a general assumption that identical twins share exactly the same DNA because they arise from the same fertilized egg. However, SNP studies show that they are only about 99% identical. Where might the 1% difference have come from?

Phenylketonuria (PKU) is a metabolic disorder that results in a mental handicap when phenylalanine is present in the diet. It was found that putting children with this genetic defect on a special diet prevented the effects of the disease. This is an example of:

Which of the following statements BEST reflects the extent to which we can distinguish the effects of genes and the environment on the expression of a complex trait?

In a hypothetical twin study, investigators identify 50 identical twin pairs in which both individuals share the trait in question. In another 50 pairs, only one member exhibits the trait while the other does not. The concordance among identical twins for this trait is:

A complex trait can be influenced by the environment.

Imagine that one of your good friends comes from a tall family. You measure the height of your friend and her two brothers. What would you expect of the average height of your friend and her siblings?

Which of the following statements is TRUE regarding heritability?

Nilsson-Ehle studied the effects of a small number of genes on a particular trait and found that the Mendelian laws of inheritance did not apply.

The magnitude of heritability is an intrinsic property of a trait.

Only by studying identical twins raised in separate environments can scientists uncover the role of genes vs. environment in the development of a specific trait. Comparing the occurrence of the trait in identical vs. fraternal twins yields little usable data.

Heritability is measured as:

Which line on the graph below demonstrates Galton's concept of regression toward the mean?

Which of the following statements is TRUE regarding genes involved in determining cholesterol levels in humans?

Heritability is a measure of:

Consider a trait determined by a rare mutation in mitochondrial DNA. What is the concordance between identical twins? Between same-sex fraternal twins?

Nilsson-Ehle's studies of seed color in wheat were important because they showed that:

Personalized genome sequencing is MOST easily justified in situations in which there are:

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