Question 1

In a given mapping experiment, you expect that incidence of double crossovers is 3.5%, but you only observe 2.5%. This can be explained by ________.

Accepted Answer

A)  interference 
B)  linkage 
C)  coincidence 
D)  segregation 
A)  interference 
B)  linkage 
C)  coincidence 
D)  segregation A

Question 2

The diploid garden pea plant has 14 chromosomes. The haploid fungus Neurospora crassa has 7 chromosomes. Neither organism has separate male and female individuals. Therefore, the number of linkage groups in these two organisms is

Accepted Answer

A)  Garden pea has 14 linkage groups, and Neurospora has 7. 
B)  Garden pea has 7 linkage groups, and Neurospora has 7. 
C)  Garden pea has 8 linkage groups, and Neurospora has 8. 
D)  Gardent pea has 15 linkage groups, and Neurospora has 8. 
A)  Garden pea has 14 linkage groups, and Neurospora has 7. 
B)  Garden pea has 7 linkage groups, and Neurospora has 7. 
C)  Garden pea has 8 linkage groups, and Neurospora has 8. 
D)  Gardent pea has 15 linkage groups, and Neurospora has 8. B

Question 3

If you want to determine how the alleles of different loci interact in their various combinations, it is best to have a system where you do not have to worry about dominance and recessiveness. Which of the following would represent a system where you do not have to worry about dominance and recessiveness?

Accepted Answer

A)  Homo sapiens 
B)  Garden peas 
C)  Drosophila melanogaster 
D)  Chlamydomonas reinhardtii 
A)  Homo sapiens 
B)  Garden peas 
C)  Drosophila melanogaster 
D)  Chlamydomonas reinhardtii D

Question 4

A map distance of 23.6 between two genes indicates which of the following?

Accepted Answer

A)  The genes are 23.6 millimeters apart. 
B)  There are 23.6 other genes between the two genes of interest. 
C)  23.6% of the offspring exhibit recombination between the two genes. 
D)  23.6% of the offspring do not survive. 
A)  The genes are 23.6 millimeters apart. 
B)  There are 23.6 other genes between the two genes of interest. 
C)  23.6% of the offspring exhibit recombination between the two genes. 
D)  23.6% of the offspring do not survive.

Question 5

The percentage of recombination associated with independent assortment should approximate 50%.

Accepted Answer

A) True 
 B)False

Question 6

In a mapping experiment with three linked genes, which phenotype should occur most often in the F2 offspring?

Accepted Answer

A)  Parental phenotypes. 
B)  Phenotypes of individuals with single crossover events. 
C)  Phenotypes of individuals with double crossover events. 
D)  All of the phenotypes should occur equally in the F2 generation. 
A)  Parental phenotypes. 
B)  Phenotypes of individuals with single crossover events. 
C)  Phenotypes of individuals with double crossover events. 
D)  All of the phenotypes should occur equally in the F2 generation.

Question 7

The middle gene of a three gene mapping experiment can be determined by examining the genotypes of which of the following?

Accepted Answer

A)  Offspring that resemble the parents. 
B)  Offspring that exhibit a single crossover event. 
C)  Offspring that exhibit double crossover events. 
D)  None of the answers are correct. 
A)  Offspring that resemble the parents. 
B)  Offspring that exhibit a single crossover event. 
C)  Offspring that exhibit double crossover events. 
D)  None of the answers are correct.

Question 8

Map distance is the number of recombinant offspring divided by the total number of nonrecombinant offspring.

Accepted Answer

A) True 
 B)False

Question 9

The first observational evidence that genes may be inherited together rather than by simple Mendelian inheritance was provided by ________.

Accepted Answer

A)  Mendel 
B)  Morgan and Bridges 
C)  Bateson and Punnett 
D)  Boveri and Sutton 
E)  None of the answers are correct 
A)  Mendel 
B)  Morgan and Bridges 
C)  Bateson and Punnett 
D)  Boveri and Sutton 
E)  None of the answers are correct

Question 10

Mitotic recombination occurs between homologous chromosomes. In which of the following would you not expect to encounter mitotic recombination?

Accepted Answer

A)  The fungus, Aspergillus nidulans 
B)  Tobacco plants 
C)  Homo sapiens 
D)  Drosophila melanogaster 
A)  The fungus, Aspergillus nidulans 
B)  Tobacco plants 
C)  Homo sapiens 
D)  Drosophila melanogaster

Question 11

In a mapping cross, you determine that the recombination frequency between: loci Q and P is 12%
Loci Q and L is 15%.
If locus Q is in between loci P and L, then the recombination frequency between P and L should be approximately

Accepted Answer

A)  3%. 
B)  27%. 
C)  50%. 
D)  75%. 
A)  3%. 
B)  27%. 
C)  50%. 
D)  75%.

Question 12

The number of linkage groups in a species that does not have sex chromosomes is: Where n equals the haploid number of autosomes.

Accepted Answer

A)  1n 
B)  1n + 1 
C)  2n 
D)  2n + 2 
A)  1n 
B)  1n + 1 
C)  2n 
D)  2n + 2

Question 13

If two loci are extremely linked, then no recombination is expected.

Accepted Answer

A) True 
 B)False

Question 14

Which of the following procedures may be used to map genes in a fungi with an unordered tetrad ascus?

Accepted Answer

A)  Testcross 
B)  Monohybrid cross 
C)  Dihybrid cross 
D)  Chi-square analysis 
E)  Analysis of interference 
A)  Testcross 
B)  Monohybrid cross 
C)  Dihybrid cross 
D)  Chi-square analysis 
E)  Analysis of interference

Question 15

The end result of meiosis in fungi is a tetrad of spores.

Accepted Answer

A) True 
 B)False

Question 16

In a chi-square test to determine if two genes are linked or assorting independently, what is the default (null) hypothesis that is tested?

Accepted Answer

A)  The genes are linked to one another. 
B)  The genes are assorting independently. 
C)  The genes are located on the sex chromosomes. 
D)  No crossing over occurs. 
E)  The distance between the genes is very small. 
A)  The genes are linked to one another. 
B)  The genes are assorting independently. 
C)  The genes are located on the sex chromosomes. 
D)  No crossing over occurs. 
E)  The distance between the genes is very small.

Question 17

The number of linkage groups in an organism with sex chromosomes equals ________, where n equals the haploid number of autosomes.

Accepted Answer

A)  1n 
B)  2n +1 
C)  1n + 1 
D)  2n + 2 
A)  1n 
B)  2n +1 
C)  1n + 1 
D)  2n + 2

Question 18

Following crossing-over, chromosomes with genetic combinations that resemble the parents' chromosomes are called nonrecombinant.

Accepted Answer

A) True 
 B)False

Question 19

The locus B on the X chromosome of a malaria-carrying mosquito shows a 49% recombination rate with respect to the locus M. Since a recombination rate of 50% is essentially indistinguishable from independent assortment, you might be tempted to look for a locus that falls between B and M. Before you decide to do all that work, you run a chi square test to determine the P value of your experiment. Which of the following P values would be most likely to tell you that you should accept the conclusion that locus B and locus M are, indeed, 49mu apart and that another locus is not necessary?

Accepted Answer

A)  P = 0.45 
B)  P = 0.01 
C)  P = 0.005 
D)  P = 0.0007 
A)  P = 0.45 
B)  P = 0.01 
C)  P = 0.005 
D)  P = 0.0007

Question 20

You have calculated the interference value for a given mapping experiment to be 30%. What does this mean?

Accepted Answer

A)  30% more double crossovers occurred than expected. 
B)  30% fewer double crossovers occurred than expected. 
C)  70% more double crossovers occurred than expected. 
D)  70% fewer double crossovers occurred than expected. 
A)  30% more double crossovers occurred than expected. 
B)  30% fewer double crossovers occurred than expected. 
C)  70% more double crossovers occurred than expected. 
D)  70% fewer double crossovers occurred than expected.

Exam 6: Genetic Linkage and Mapping in Eukaryotes

In a given mapping experiment, you expect that incidence of double crossovers is 3.5%, but you only observe 2.5%. This can be explained by ________.

The diploid garden pea plant has 14 chromosomes. The haploid fungus Neurospora crassa has 7 chromosomes. Neither organism has separate male and female individuals. Therefore, the number of linkage groups in these two organisms is

A map distance of 23.6 between two genes indicates which of the following?

The percentage of recombination associated with independent assortment should approximate 50%.

In a mapping experiment with three linked genes, which phenotype should occur most often in the F2 offspring?

The middle gene of a three gene mapping experiment can be determined by examining the genotypes of which of the following?

Map distance is the number of recombinant offspring divided by the total number of nonrecombinant offspring.

The first observational evidence that genes may be inherited together rather than by simple Mendelian inheritance was provided by ________.

Mitotic recombination occurs between homologous chromosomes. In which of the following would you not expect to encounter mitotic recombination?

In a mapping cross, you determine that the recombination frequency between: loci Q and P is 12% Loci Q and L is 15%. If locus Q is in between loci P and L, then the recombination frequency between P and L should be approximately

The number of linkage groups in a species that does not have sex chromosomes is: Where n equals the haploid number of autosomes.

If two loci are extremely linked, then no recombination is expected.

Which of the following procedures may be used to map genes in a fungi with an unordered tetrad ascus?

The end result of meiosis in fungi is a tetrad of spores.

In a chi-square test to determine if two genes are linked or assorting independently, what is the default (null) hypothesis that is tested?

The number of linkage groups in an organism with sex chromosomes equals ________, where n equals the haploid number of autosomes.

Following crossing-over, chromosomes with genetic combinations that resemble the parents' chromosomes are called nonrecombinant.

You have calculated the interference value for a given mapping experiment to be 30%. What does this mean?

Overview of Genetics

Mendelian Inheritance

Chromosome Transmission During Cell Division and Sexual Reproduction

Extensions of Mendelian Inheritance

Non-Mendelian Inheritance

Genetic Transfer and Mapping in Bacteria

Variation in Chromosome Structure and Number

Molecular Structure of Dna and Rna

Chromosome Organization and Molecular Structure

Dna Replication

Gene Transcription and Rna Modification

Translation of Mrna

Gene Regulation in Bacteria

Gene Regulation in Eukaryotes I: Transcriptional and Translation Regulation

Gene Regulation in Eukaryotes Ii: Epigenetics

Non-Coding Rnas

Genetics of Viruses

Gene Mutation and Dna Repair

Recombination, Immunogenetics, and Transposition

Molecular Technologies

Biotechnology

Genomics I: Analysis of Dna

Genomics Ii: Functional Genomics, Proteomics, and Bioinformatics

Medical Genetics and Cancer

Developmental Genetics

Population Genetics

Complex and Quantitative Traits

Evolutionary Genetics

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