Question 1

Two pure lines of Nicotianum (tobacco)have significantly different corolla lengths.In line 1,the average length is 30 mm,ranging from 25 mm to 35 mm with a variance of 10.In line 2,the average corolla length is 60 mm,ranging from 45 mm to 65 mm with a variance of 12.The F₁ has a corolla length of 45 mm,ranging from 40 to 50,and the variance is 9.Upon selfing,an F₂ is produced that has an average flower length of 45 mm,but ranges from 10 mm to 80 mm with a variance of 55. a)Provide a general explanation of these results. b)Calculate the broad-sense heritability (H²)for corolla length in this study.

Accepted Answer

The answer of Two pure lines of Nicotianum (tobacco)have significantly...

Question 2

An individual plant is heterozygous for loci that affect height and have a strictly additive mode of action.If this plant is selfed,:
a)how many height classes will there be among the progeny? (Assume no environmental effects.)
b)what will be the frequency of the tallest class of progeny? (Assume no environmental effects.)

Accepted Answer

The answer of An individual plant is heterozygous for loci...

Question 3

In an experiment carried out in a chicken population,measurements of fat content reveal that the genetic variance for this trait is 120 g2,the environmental variance is 80 g2 and the variance due to dominance is 38 g2.The narrow-sense heritability (h2)of fat content in these chickens is:

Accepted Answer

A) 0.24. 
B) 0.41. 
C) 0.52. 
D) 0.74. 
E) 0.90 .

Question 4

The variance in tail length in a large population of genetically diverse mice is found to be 21.30.The broad-sense heritability for this trait in an identical population was found to be 0.8.Based on this information,what is the predicted genetic variance (Vg)for these mice?

Accepted Answer

A) 4.26 
B) 17.04 
C) 20.50 
D) 21.30 
E) 26.62

Question 5

In the course of estimating the degree of linkage of a marker and a quantitative trait of interest,researchers announced that they obtained a LOD score of 4.5.This finding indicates that:

Accepted Answer

A) there is a 4.5% chance that an individual with the marker will also show the trait of interest. 
B) the marker is 4.5 map units away from the QTL controlling the trait of interest. 
C) the marker is most likely not linked to the QTL controlling the trait of interest. 
D) the odds that the marker is linked to the QTL controlling the trait of interest are 4.5:1. 
E) the odds that the marker is linked to the QTL controlling the trait of interest are 4500:1.

Question 6

Consider a diploid fish in which tail length is solely controlled by the additive action of two unlinked loci,F (f)and G (g),without any effect of the environment.A female of genotype F/F;G/G,with a 3 cm long tail,is crossed to a male of genotype f/f;g/g,with a 2 cm long tail.All the F1 fish have 2.5 cm long tails. a)If the F1 fish are crossed to each other,how many different tail length phenotypes will be present in F2?

Accepted Answer

A) 16 
B) 5 
C) 4 
D) 3 
E) 2

Question 7

Which of the following statements is/are a central assumption of the multifactorial inheritance hypothesis?

Accepted Answer

A) Only one locus is associated with the trait. 
B) Several loci are associated with the trait. 
C) Environment plays no role in the final phenotype. 
D) Only one locus is associated with the trait,and environment interacts with this locus to produce the final phenotype. 
E) None of the answer options are correct.

Question 8

Loppins (fictitious diploid invertebrates)have variable numbers of dots on their abdomen.This variability is entirely due to genetics,with no influence of the environment,so the broad-sense heritability for this trait is 1.The mean number of dots per individual in a large population is 37.A breeder crosses the two animals with the highest number of dots,45.In the progeny,the mean number of dots is 43.4.These results suggest that the phenotype of interest is controlled:

Accepted Answer

A) at least partly by genes that have an additive mode of action. 
B) at least partly by genes that have a dominant mode of action. 
C) by genes that have both an additive and a dominant mode of action. 
D) only by genes that have an additive mode of action. 
E) only by genes that have a dominant mode of action.

Question 9

In a natural population of outbreeding annual plants,the variance of the total number of seeds per plant is 16.From the natural population,20 plants are taken into the laboratory and each selfed for 10 generations.The average variance in the tenth generation in each of the 20 sets is about equal,and averages 5.8 across all the sets.Estimate the broad-sense heritability (H²)of seed number in this population.

Accepted Answer

The answer of In a natural population of outbreeding annual...

Question 10

a)What is the role of marker genes for the identification of quantitative trait loci?
b)How do they differ from candidate genes?

Accepted Answer

The answer of a)What is the role of marker genes...

Question 11

Two different pure-breeding lines of tobacco were crossed and their F1 showed a variance in flower length of 8.76.The total variance in flower length in the F2 was 40.96.The F1 and the F2 plants were bred,grown,and kept in identical environments.

a)What is the broad-sense heritability of flower length in tobacco in this experiment?

Accepted Answer

A) 8.76% 
B) 21.38% 
C) 32.20% 
D) 78.61% 
E) The broad-sense heritability cannot be calculated based on these data.

Question 12

It is difficult to measure any type of heritability without the ability to perform specific crosses.However,vast population studies enable estimation of heritability for some characters in human beings.Some estimated broad-sense heritabilities include:$$\begin{array} { l l } 
\text { Character } & H ^ { 2 } \
\hline \text { stature } & 0.85 \
\text { body weight } & 0.62 \
\text { systolic blood pressure } & 0.57 \
\text { diastolic blood pressure } & 0.44 \
\text { twinning } & 0.50
\end{array}$$
Which of these characteristics is most likely to "run in families"?

Accepted Answer

A) body weight 
B) diastolic blood pressure 
C) stature 
D) systolic blood pressure 
E) twinning

Question 13

Three populations of true-breeding C.elegans larvae are each split into four subpopulations of equal sizes,and each subpopulation is grown in a different environment.The mean adult body lengths in each environment are as follows:

Based on these data,what environment has the highest environmental deviation?

Accepted Answer

A) both Environments 3 and 4 
B) Environment 1 
C) Environment 2 
D) Environment 3 
E) Environment 4

Question 14

Narrow-sense heritability (h2)is a quantification of the proportion of total variance due to:

Accepted Answer

A) additive genetic variance. 
B) dominance variance. 
C) environmental variance. 
D) phenotypic variance. 
E) total genetic variance.

Question 15

The phenotypic deviation that is transmitted from parents to their offspring is known as:

Accepted Answer

A) additive genetic variance. 
B) dominance variance. 
C) environmental variance. 
D) total genetic variance. 
E) transmissible variance.

Question 16

In a population of beetles,the total variance of body weight is 130.It is estimated that the environmental variance is 35,and dominance genetic variance is 45.Calculate the narrow-sense heritability (h²)of body weight in these beetles.

Accepted Answer

The answer of In a population of beetles,the total variance...

Exam 19: The Inheritance of Complex Traits

In an experiment carried out in a chicken population,measurements of fat content reveal that the genetic variance for this trait is 120 g²,the environmental variance is 80 g² and the variance due to dominance is 38 g².The narrow-sense heritability (h²) of fat content in these chickens is:

The variance in tail length in a large population of genetically diverse mice is found to be 21.30.The broad-sense heritability for this trait in an identical population was found to be 0.8.Based on this information,what is the predicted genetic variance (V_g) for these mice?

In the course of estimating the degree of linkage of a marker and a quantitative trait of interest,researchers announced that they obtained a LOD score of 4.5.This finding indicates that:

Which of the following statements is/are a central assumption of the multifactorial inheritance hypothesis?

a)What is the role of marker genes for the identification of quantitative trait loci? b)How do they differ from candidate genes?

Narrow-sense heritability (h²) is a quantification of the proportion of total variance due to:

The phenotypic deviation that is transmitted from parents to their offspring is known as:

In a population of beetles,the total variance of body weight is 130.It is estimated that the environmental variance is 35,and dominance genetic variance is 45.Calculate the narrow-sense heritability (h²)of body weight in these beetles.

Exam 19: The Inheritance of Complex Traits

In an experiment carried out in a chicken population,measurements of fat content reveal that the genetic variance for this trait is 120 g2,the environmental variance is 80 g2 and the variance due to dominance is 38 g2.The narrow-sense heritability (h2) of fat content in these chickens is:

The variance in tail length in a large population of genetically diverse mice is found to be 21.30.The broad-sense heritability for this trait in an identical population was found to be 0.8.Based on this information,what is the predicted genetic variance (Vg) for these mice?

In the course of estimating the degree of linkage of a marker and a quantitative trait of interest,researchers announced that they obtained a LOD score of 4.5.This finding indicates that:

Which of the following statements is/are a central assumption of the multifactorial inheritance hypothesis?

a)What is the role of marker genes for the identification of quantitative trait loci? b)How do they differ from candidate genes?

Narrow-sense heritability (h2) is a quantification of the proportion of total variance due to:

The phenotypic deviation that is transmitted from parents to their offspring is known as:

In a population of beetles,the total variance of body weight is 130.It is estimated that the environmental variance is 35,and dominance genetic variance is 45.Calculate the narrow-sense heritability (h2)of body weight in these beetles.

In an experiment carried out in a chicken population,measurements of fat content reveal that the genetic variance for this trait is 120 g²,the environmental variance is 80 g² and the variance due to dominance is 38 g².The narrow-sense heritability (h²) of fat content in these chickens is:

The variance in tail length in a large population of genetically diverse mice is found to be 21.30.The broad-sense heritability for this trait in an identical population was found to be 0.8.Based on this information,what is the predicted genetic variance (V_g) for these mice?

Narrow-sense heritability (h²) is a quantification of the proportion of total variance due to:

In a population of beetles,the total variance of body weight is 130.It is estimated that the environmental variance is 35,and dominance genetic variance is 45.Calculate the narrow-sense heritability (h²)of body weight in these beetles.