Question 1

In the figure below,the grey boxes represent the offspring of parents that are heterozygous at locus 1 (Aa)and locus 2 (Bb).Which of the grey boxes represent repulsion double heterozygote offspring?

Accepted Answer

A) Light grey 
B) Medium grey 
C) Dark grey 
D) B and C 
E) All of the above

Question 2

If the value of linkage disequilibrium (D)is equal to -0.25,one can infer that the alleles are

Accepted Answer

A) in repulsion. 
B) in coupling. 
C) in linkage disequilibrium. 
D) A and C 
E) None of the above

Question 3

In the figure above,the population indicated by the dots

Accepted Answer

A) has a high fitness. 
B) exhibits two distinct morphs 
C) is experiencing background selection. 
D) is experiencing drift. 
E) is in equilibrium.

Question 4

Narrow-sense heritability is defined as the total

Accepted Answer

A) genetic variation divided by the total phenotypic variation. 
B) additive genetic variation divided by the total phenotypic variation. 
C) dominance genetic variation divided by the total phenotypic variation. 
D) additive genetic variation divided by the total dominance variation. 
E) epistatic genetic variation divided by the total dominance variation.

Question 5

In quantitative genetic terms,a phenotypic value can be expressed as

Accepted Answer

A) dominance and recessiveness. 
B) epistasis and pleiotropy. 
C) genotypic value and environmental deviation. 
D) A and B 
E) All of the above

Question 6

A haplotype is

Accepted Answer

A) all of the alleles at a single locus. 
B) a product of epistasis. 
C) a set of alleles at different loci along a chromosome. 
D) all of the alleles in a population. 
E) None of the above

Question 7

Which of the following can generate linkage disequilibrium?

Accepted Answer

A) Drift 
B) Selection 
C) Mutation 
D) Migration 
E) All of the above

Question 8

What two major concepts in biology were unified in the middle of the twentieth century?

Accepted Answer

A) Natural selection and drift 
B) Discontinuous and continuous variation 
C) Mutation and migration 
D) Natural selection and Mendelian genetics 
E) Population genetics and quantitative genetics

Question 9

Multiple drug-resistant Staphylococcus aureus (MRSA)is a bacterium that has developed resistance to a wide range of antibiotics.Its resistance to penicillin,methicillin,and oxacillin is a result of the serial use of these antibiotics,which created a selective environment that favored resistance to the drug being used at the time.This resistance provides the bacteria with the ability to thrive in an environment with standard antibiotics,thereby making it a dangerous human health hazard.Why would one expect MRSA to retain penicillin resistance even if this antibiotic is rarely used?

Accepted Answer

The answer of Multiple drug-resistant Staphylococcus aureus (MRSA)is a bacterium...

Question 10

Without using mathematical symbols,explain the difference between broad- and narrow-sense heritability,including why one is more relevant to evolutionary studies.

Accepted Answer

The answer of Without using mathematical symbols,explain the difference between...

Question 11

The statistical association of alleles at different loci is referred to as

Accepted Answer

A) physical linkage. 
B) haplotypes. 
C) epistasis. 
D) linkage equilibrium. 
E) linkage disequilibrium.

Question 12

The following figure demonstrates the genotypic adaptive landscape for bacteria growing in media without antibiotics.The height of the bars associated with a genotype indicates the fitness of that genotype.The R allele confers resistance to antibiotics,and the C allele compensates for the loss of fitness that the R allele confers in the absence of antibiotics.The rc haplotype lacks both compensation and resistance.Based on this landscape,why are resistance and compensation unlikely to be lost even in the absence of antibiotics?

Accepted Answer

A) A lack of mutation will prevent the haplotypes from changing. 
B) Epistasis will maintain haplotype frequencies. 
C) Haplotype frequencies do not change in Hardy-Weinberg populations. 
D) RC populations are stuck on a local maximum. 
E) Bacteria evolve slowly.

Question 13

The figure below describes the percent oil content in corn from different generations.What is the expected slope of a parent-offspring regression for corn oil content?

Accepted Answer

A) 0.69 
B) 1.6 
C) 2.1 
D) 2.5 
E) Cannot be determined based on the information provided

Question 14

Texas longhorn cattle have been bred to increase the tip to tip width of their horns,and the heritability of this trait has been well studied by Professor David Hillis at the University of Texas,Austin.In the current generation,the mean horn length is 52 inches.If only a subset of this population,with a mean horn length of 61 inches,are allowed to reproduce,and the narrow-sense heritability of this trait = 0.2,what is the expected horn length in the offspring generation?

Accepted Answer

A) ~1.8 inches 
B) ~9 inches 
C) ~54 inches 
D) ~61 inches 
E) Cannot be determined based on the information provided

Question 15

Consider two loci on a single chromosome.These loci

Accepted Answer

A) have alleles that will always segregate together. 
B) are physically linked. 
C) are in linkage disequilibrium. 
D) interact with each other. 
E) will be broken up during recombination.

Question 16

Consider two microsatellite loci (A,B)each with two alleles determined by the number of repeats of the microsatellite motif (A = 15 or 17; B = 27 or 31).You genotype an individual in this population and determine that its haplotype is 15/27 and 15/27.Are these alleles in coupling and/or repulsion? Explain your answer.

Accepted Answer

The answer of Consider two microsatellite loci (A,B)each with two...

Question 17

Assuming the value of linkage disequilibrium (D)is positive,recombination will generate

Accepted Answer

A) more repulsion pairs. 
B) more coupling pairs. 
C) no change, since recombination does not change expected haplotype frequencies. 
D) an increase in D. 
E) None of the above

Question 18

A researcher tracks the escape behavior of a population of squirrels on campus across two generations.When she plots the escape behavior of the offspring generation against the parental behavior,she notes that the offspring's behavior exactly matches the parental behavior.Nonetheless,the narrow-sense heritability equals zero.How can the heritability equal zero in this example?

Accepted Answer

A) The additive genetic variance equals zero. 
B) All the escape behavior alleles are fixed in the population. 
C) There is no phenotypic variation. 
D) A and B 
E) All of the above

Question 19

In the figure below,what does the straight line indicate?

Accepted Answer

A) The broad-sense heritability 
B) The narrow-sense heritability 
C) The norm of reaction of nocturnal restlessness 
D) None of the above 
E) All of the above

Exam 9: Evolution at Multiple Loci

In the figure below,the grey boxes represent the offspring of parents that are heterozygous at locus 1 (Aa) and locus 2 (Bb) .Which of the grey boxes represent repulsion double heterozygote offspring?

If the value of linkage disequilibrium (D) is equal to -0.25,one can infer that the alleles are