Question 1

The Huntington disease (HD)allele was discovered

Accepted Answer

A) by mapping it to blood enzyme genes,based on Lod scores of -2. 
B) through pedigree analysis alone. 
C) by linkage to a DNA genetic marker,D4S10 with a Lod score of 8.53. 
D) through mapping to known homologs in other organisms such as mice. 
E) through direct sequencing of mutations identified by SNPs. 
A) by mapping it to blood enzyme genes,based on Lod scores of -2. 
B) through pedigree analysis alone. 
C) by linkage to a DNA genetic marker,D4S10 with a Lod score of 8.53. 
D) through mapping to known homologs in other organisms such as mice. 
E) through direct sequencing of mutations identified by SNPs.

Question 2

The syntenic genes A and Z are linked.A cross between two parents,AAZZ and aazz,produces F₁ progeny with the AaZz genotype.What are the possible arrangements of alleles on the F₁ progeny's chromosomes?

Accepted Answer

A) AZ/az 
B) Az/aZ 
C) Aa/Zz 
D) AZ/Az or az/aZ 
E) A/Z or a/z 
A) AZ/az 
B) Az/aZ 
C) Aa/Zz 
D) AZ/Az or az/aZ 
E) A/Z or a/z

Question 3

Crossing over occurs frequently during meiosis.Can crossing over occur during mitosis? Explain why mitotic crossing over may or may not be possible.

Accepted Answer

Mitotic crossover is a rare event.Mitoti

Question 4

Bateson and Punnett saw early evidence of gene linkage.What terms did they use to describe genes that remained together frequently and the loss of parental alleles in favor of new,nonparental phenotypes in the F₂ progeny?

Accepted Answer

coupling a

Question 5

Which type of crossover event produces all four recombinant chromosomes?

Accepted Answer

A) single-strand crossover 
B) two-strand double crossover 
C) three-strand double crossover 
D) four-strand double crossover 
E) None of the above;all crossover events produce a combination of parental and recombinant chromosomes. 
A) single-strand crossover 
B) two-strand double crossover 
C) three-strand double crossover 
D) four-strand double crossover 
E) None of the above;all crossover events produce a combination of parental and recombinant chromosomes.

Question 6

Which type of crossover event produces no recombinant chromosomes?

Accepted Answer

A) single-strand crossover 
B) two-strand double crossover 
C) three-strand double crossover 
D) four-strand double crossover 
E) None of the above;all crossover events produce recombinant chromosomes. 
A) single-strand crossover 
B) two-strand double crossover 
C) three-strand double crossover 
D) four-strand double crossover 
E) None of the above;all crossover events produce recombinant chromosomes.

Question 7

If too little time has passed for crossing over to randomize haplotypes or if natural selection favors certain haplotypes,what type of linkage would you expect to see?

Accepted Answer

linkage di

Question 8

Which type of crossover event produces two parental and two recombinant chromosomes in gametes?

Accepted Answer

A) single-strand crossover 
B) two-strand double crossover 
C) three-strand double crossover 
D) four-strand double crossover 
E) None of the above;all crossover events produce only recombinant chromosomes. 
A) single-strand crossover 
B) two-strand double crossover 
C) three-strand double crossover 
D) four-strand double crossover 
E) None of the above;all crossover events produce only recombinant chromosomes.

Question 9

What organism exhibits complete genetic linkage,meaning there is no recombination between homologous chromosomes?

Accepted Answer

male Droso

Question 10

Tetrad analysis can be used to identify genetic linkage in haploid eukaryotes. Parental and recombinant gametes contained in an ascus can be analyzed to map genes.
-What ratios of these three tetrads would you expect to see if two genes are linked or unlinked? Why is one type of tetrad more or less common?

Accepted Answer

If two genes are linked,you will see tha

Question 11

Describe the three types of tetrads.

Accepted Answer

Parental ditypes (PD)contain four haploi

Question 12

What type of test would you use to determine whether observed data constitute evidence of genetic linkage or are simply a case of chance variation from expected values?

Accepted Answer

A) test cross 
B) two-point test-cross 
C) three-point test-cross 
D) chi-square analysis 
E) recombination frequency (r)calculation 
A) test cross 
B) two-point test-cross 
C) three-point test-cross 
D) chi-square analysis 
E) recombination frequency (r)calculation

Question 13

In early genetic analysis,5% recombination is equal to ________ map unit(s)(m.u.)or centimorgan(s)(cM)of distance between linked genes.

Accepted Answer

The answer of In early genetic analysis,5% recombination is equal...

Question 14

If there is a maximum Lod score of 4.2 at = 0.31,what can you say about the linkage and the distance between two genes?

Accepted Answer

linked and

Question 15

The alleles of syntenic genes can be reshuffled by crossing over between homologous chromosomes to produce ________.

Accepted Answer

recombinan

Question 16

Assuming three genes are linked,how many recombinant genotypes would you expect and at what frequency?

Accepted Answer

A) two recombinant genotypes,more frequent than expected by chance 
B) four recombinant genotypes,more frequent than expected by chance 
C) six recombinant genotypes,more frequent than expected by chance 
D) four recombinant genotypes,less frequent than expected by chance 
E) six recombinant genotypes,less frequent than expected by chance 
A) two recombinant genotypes,more frequent than expected by chance 
B) four recombinant genotypes,more frequent than expected by chance 
C) six recombinant genotypes,more frequent than expected by chance 
D) four recombinant genotypes,less frequent than expected by chance 
E) six recombinant genotypes,less frequent than expected by chance

Question 17

When constructing a genetic map of Zea mays,Creighton and McClintock used genetic markers as well as structural differences in the homologous copies of chromosome 9 that can be seen under the microscope.What are these structural differences called?

Accepted Answer

The answer of When constructing a genetic map of Zea...

Question 18

In a dihybrid cross exhibiting complete genetic linkage,what would you expect?

Accepted Answer

A) one parental allele combination occurring more frequently than another 
B) two equally frequent gametes containing only parental allele combinations 
C) only recombinant gametes 
D) one parental allele combination occurring more frequently than another and no recombinant gametes 
E) two equally frequent gametes containing only parental allele combinations and no recombinant gametes 
A) one parental allele combination occurring more frequently than another 
B) two equally frequent gametes containing only parental allele combinations 
C) only recombinant gametes 
D) one parental allele combination occurring more frequently than another and no recombinant gametes 
E) two equally frequent gametes containing only parental allele combinations and no recombinant gametes

Question 19

For a given cross,the expected number of double recombinants is 20 and the observed number of double recombinants is 15.What is the coefficient of coincidence (c)?

Accepted Answer

A) 0.25 
B) 1.33 
C) 20 
D) 0.75 
E) 15 
A) 0.25 
B) 1.33 
C) 20 
D) 0.75 
E) 15

Question 20

Recombination frequency differs between males and females.Which sex has a higher rate of recombination,heterogametic (males)or homogametic (females)?

Accepted Answer

homogameti

Exam 5: Genetic Linkage and Mapping in Eukaryotes

The Huntington disease (HD)allele was discovered

The syntenic genes A and Z are linked.A cross between two parents,AAZZ and aazz,produces F₁ progeny with the AaZz genotype.What are the possible arrangements of alleles on the F₁ progeny's chromosomes?

Crossing over occurs frequently during meiosis.Can crossing over occur during mitosis? Explain why mitotic crossing over may or may not be possible.

Bateson and Punnett saw early evidence of gene linkage.What terms did they use to describe genes that remained together frequently and the loss of parental alleles in favor of new,nonparental phenotypes in the F₂ progeny?

Which type of crossover event produces all four recombinant chromosomes?

Which type of crossover event produces no recombinant chromosomes?

If too little time has passed for crossing over to randomize haplotypes or if natural selection favors certain haplotypes,what type of linkage would you expect to see?

Which type of crossover event produces two parental and two recombinant chromosomes in gametes?

What organism exhibits complete genetic linkage,meaning there is no recombination between homologous chromosomes?

Describe the three types of tetrads.

What type of test would you use to determine whether observed data constitute evidence of genetic linkage or are simply a case of chance variation from expected values?

In early genetic analysis,5% recombination is equal to ________ map unit(s)(m.u.)or centimorgan(s)(cM)of distance between linked genes.

If there is a maximum Lod score of 4.2 at = 0.31,what can you say about the linkage and the distance between two genes?

The alleles of syntenic genes can be reshuffled by crossing over between homologous chromosomes to produce ________.

Assuming three genes are linked,how many recombinant genotypes would you expect and at what frequency?

When constructing a genetic map of Zea mays,Creighton and McClintock used genetic markers as well as structural differences in the homologous copies of chromosome 9 that can be seen under the microscope.What are these structural differences called?

In a dihybrid cross exhibiting complete genetic linkage,what would you expect?

For a given cross,the expected number of double recombinants is 20 and the observed number of double recombinants is 15.What is the coefficient of coincidence (c)?

Recombination frequency differs between males and females.Which sex has a higher rate of recombination,heterogametic (males)or homogametic (females)?

The Molecular Basis of Heredity, Variation, and Evolution

Transmission Genetics

Cell Division and Chromosome Heredity

Gene Interaction

Genetic Analysis and Mapping in Bacteria and Bacteriophage

DNA Structure and Replication

Molecular Biology and Transcription and Rna Processing

The Molecular Biology of Translation

The Integration of Genetic Approaches: Understanding Sickle Cell Disease

Chromosome Structure

Gene Mutation, DNA Repair, and Homologous Recombination

Chromosome Aberrations and Transposition

Regulation of Gene Expression in Bacteria and Bacteriophage

Regulation of Gene Expression in Eukaryotes

Forward Genetics and Recombinant DNA Technology

Applications of Recombinant DNA Technology and Reverse Genetics

Genomics: Genetics From a Whole-Genome Perspective

Cytoplasmic Inheritance and the Evolution of Organelle Genomes

Developmental Genetics

Genetic Analysis of Quantitative Traits

Population Genetics and Evolution

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