Question 1

Which of the following best describes polygenic inheritance?

Accepted Answer

Multiple genes independently affect a single trait.

Question 2

In Labrador retrievers, coat color is determined by two genes. If a dog has the genotype 'bb' for the pigment gene and 'Ee' for the color deposition gene, what color will the dog be?

Accepted Answer

Chocolate

Question 3

A normal distribution of phenotypes, such as human height, is most likely the result of which genetic mechanism?

Accepted Answer

Polygenic inheritance

Question 4

Which equation best represents the additive effect of multiple genes on a polygenic trait?

Accepted Answer

$P = G_1 + G_2 + G_3 + ... + G_n$

Question 5

Which environmental factor is most likely to influence the expression of a multifactorial trait such as human height?

Accepted Answer

Nutrition

Question 6

Hydrangea flowers can be pink or blue depending on soil conditions. This is an example of:

Accepted Answer

Phenotypic plasticity

Question 7

Which statement about epistasis is correct?

Accepted Answer

Epistasis occurs when the expression of one gene alters the phenotypic expression of another gene.

Question 8

If a trait is influenced by both genetic and environmental factors, it is best described as:

Accepted Answer

Multifactorial

Question 9

Which of the following is NOT a characteristic of polygenic traits?

Accepted Answer

They are always affected by environmental factors.

Question 10

In a population, the frequency of a polygenic trait can be modeled by which statistical distribution?

Accepted Answer

Normal distribution

Question 11

Which scenario best illustrates gene-environment interaction (G x E)?

Accepted Answer

A person with a genetic predisposition for tall stature grows taller with a high-protein diet.

Question 12

Which of the following best explains why identical twins can have different phenotypes?

Accepted Answer

Environmental factors and epigenetic changes can alter gene expression.

Question 13

Which of the following is an example of a Mendelian trait in humans?

Accepted Answer

Earlobe attachment

Question 14

Which of the following statements about polygenic traits is correct?

Accepted Answer

Polygenic traits are influenced by the additive effects of multiple genes.

Question 15

A population of butterflies shows a range of cold tolerance. If this trait is polygenic, which equation best describes the genetic contribution to cold tolerance?

Accepted Answer

$T = G_1 + G_2 + G_3 + ... + G_n$

Question 16

Which of the following best describes the effect of epigenetic markers?

Accepted Answer

They alter gene expression without changing the DNA sequence.

Question 17

Which of the following is a real-world example of phenotypic plasticity?

Accepted Answer

Hydrangea flowers changing color based on soil pH.

Question 18

Which of the following best explains why height in humans is not a Mendelian trait?

Accepted Answer

Height is influenced by many genes and environmental factors.

Question 19

Which of the following is NOT a polygenic trait?

Accepted Answer

Tongue rolling

Question 20

Which of the following best describes the distribution of height in a population?

Accepted Answer

Height is distributed in a normal (bell-shaped) curve.

Extensions and Exceptions to Mendelian Genetics: Polygenic Traits, Epistasis, and Environmental Effects

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