Homework answers / question archive / University of South Florida PCB 3063 Quiz 9 1)Which of the following statements best defines a linkage group? a chromosome region where crossing over cannot occur a chromosome region where crossing over occurs at maximum frequency the collection of autosomes in an organism   all of the genes that are located on the same chromosome a collection of genes that always assorts independently   2

University of South Florida PCB 3063 Quiz 9 1)Which of the following statements best defines a linkage group? a chromosome region where crossing over cannot occur a chromosome region where crossing over occurs at maximum frequency the collection of autosomes in an organism   all of the genes that are located on the same chromosome a collection of genes that always assorts independently   2

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University of South Florida

PCB 3063

Quiz 9

1)Which of the following statements best defines a linkage group?

a chromosome region where crossing over cannot occur

a chromosome region where crossing over occurs at maximum

frequency the collection of autosomes in an organism

  all of the genes that are located on the same chromosome

a collection of genes that always assorts independently

 

2. In Drosophila melanogaster, the wild-type eye color is red. White eyes is a recessive mutation. Which of the following genotypes will exhibit a white eye phenotype?

w+w+ w+w

  w w

two of the above

 all of the above

 

3. For any pair of linked genes, double crossover increases the variety of gametes produced.

True

  False

 

4. A gene distance of 1 cM is

equivalent to 1 map unit but not 1 % recombination.

equivalent to 1 % recombination but not 1 map unit.

  equivalent to 1 % recombination and 1 map unit.

not equivalent to 1 % recombination or 1 map unit.

 

 

5. Which of the following statements about crossing-over is TRUE?

It is not detectable if it occurs an odd number of times between two marker genes.

  it does not occur in Drosophila melanogaster males.

Both A and B

Neither A nor B

 

6. Assume that a cross is made between AaBb and aabb plants, and all of the offspring are either AaBb or aabb. These results are consistent with which of the following circumstances?

 incomplete linkage

  complete linkage

independent assortment incomplete dominance

two of the above

 

7. The terms cis and trans describe the

arrangement of alleles on non-homologous chromosomes.

  arrangement of alleles on homologous chromosomes.

relative position of different genes on the same chromosome.

relative position of different genes on sex chromosomes.

relative position of different chromosomes in the nucleus.

 

8. Recombination frequencies are the same for all genes.

arise from specific genetic exchange.

  increase with genetic distance

decrease with genetic distance

either C or D depending on the chromosome.

 

9. In Drosophila, the genes j and r are linked. Parental flies of genotype j+ r+/ j+ r+ and j r/ j r are crossed. What allele arrangement would the F1 flies contain?

repulsion trans

  cis

recombinant

parental

 

10. A cross of two Drosophila strains of genotypes z+ t+ and z t produced the following progeny: 126 z+ t+, 133 z t, 15 z+ t, and 18 z t+. What is the frequency of recombination between genes t and z?

9.3%

12.7%

15.2%

 

18.6%

  none of these choices

 

11. The maximum recombination frequency between two genes is 100%

75%

25%

10%

  none of these choices

 

12. You may have noticed that people who have red hair usually have freckles too. Which of the following can best describe this phenomenon?

nondisjunction at meiosis variable expressivity incomplete penetrance

  linkage

incomplete

dominance

 

13. In the organism Socnorb revned, rectangular ears require the presence of either or both of two dominant alleles, A and B. Individuals homozygous for both recessive alleles have oval ears. The two genes are on the same chromosome and recombine with a frequency of 30 percent. From the cross AB/ab X AB/ab, what is the expected frequency of individuals with oval ears in the progeny?

2.25 %

5.25 %

7.50 %

9.75 %

  12.25

 

14. Refer to the organism of question 19. From the cross Ab/aB X AB/ab, what is the expected frequency of individuals with oval ears in the progeny?

2.25 %

  5.25 %

7.50 %

9.75 % 12.25

 

15. In dragons, straight tails require the presence of either or both of two dominant alleles, Z and T. Individuals homozygous for both recessive alleles have zigzag tails. The two genes are on the same chromosome and recombine with a frequency of 24 percent. From the cross ZT/zt X ZT/zt, what is the expected frequency of individuals with zigzag tail in the progeny?

1.44 %

 

4.56 %

7.33 %

10.25 %

  14.44 %

 

16. Refer to the organism of question 28. From the cross Zt/zT X ZT/zt, what is the expected frequency of individuals with zigzag tails in the progeny?

1.44 %

  4.56 %

7.33 %

10.25 %

none of these choices

 

17. In a particular plant, genes A and B are completely linked. A plant of genotype A b/A b is crossed with one of genotype a b/a b. Which of the following is TRUE?

  All progeny will be phenotypically Ab

All progeny will be phenotypically ab

The progeny will have a phenotypic ratio of 1 Ab : 1 ab The progeny will have a phenotypic ratio of 3 Ab : 1 ab

 none of the above