Chromosome theory, linkage and recombination — practice questions

Question 1 · difficulty L1 · recall

Exchange of segments between non-sister chromatids of homologous chromosomes:

• A. crossing over
• B. translation
• C. transcription
• D. segregation only

Question 2 · difficulty L1 · recall

Genes located close together on the same chromosome tend to show:

• A. independent assortment always
• B. complete dominance
• C. polyploidy
• D. linkage

Question 3 · difficulty L3 · understanding

Frequency of recombination between gene pairs on same chromosome as a measure of the distance between genes to map their position on chromosome, was used for the first time by

• A. Sutton and Boveri
• B. Alfred Sturtevant
• C. Henking
• D. Thomas Hunt Morgan

Question 4 · difficulty L3 · understanding

In meiosis, crossing over and exchange of genetic material between homologous chromosomes are catalyzed by the enzyme

• A. Polymerase
• B. Phosphorylase
• C. Recombinase
• D. Transferase

Question 5 · difficulty L3 · understanding

Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : Mendel's law of independent assortment does not hold good for the genes that are located closely on the same chromosome. Reason (R) : Closely located genes assort independently. In the light of the above statements, choose the correct answer from the options given below :

• A. Both (A) and (R) are correct and (R) is the correct explanation of (A)
• B. Both (A) and (R) are correct but (R) is not the correct explanation of (A)
• C. (A) is correct but (R) is not correct
• D. (A) is not correct but (R) is correct

Question 6 · difficulty L3 · understanding

The recombination frequency between the genes a & c 5&, b & c is 15%, b & d is 9%, a & b is 20%, c & d is 25% and a & d is 29%. What will be the sequence of these genes on a linear chromosome?

• A. a, d, b, c
• B. d, b, a, c
• C. a, b, c, d
• D. a, c, b, d

Question 7 · difficulty L3 · understanding

The chromosomal theory of inheritance was proposed by

• A. Robert Brown
• B. Thomas Morgan
• C. Sutton and Boveri
• D. Gregor Mendel

Question 8 · difficulty L3 · understanding

Now-a-days it is possible to detect the mutated gene causing cancer by allowing radioactive probe to hybridise its complimentary DNA in a clone of cells, followed by its detection using autoradiography because:

• A. mutated gene does not appear on photographic film as the probe has complementarity with it
• B. mutated gene partially appears on a photographic film
• C. mutated gene completely and clearly appears on a photographic film
• D. mutated gene does not appear on a photographic film as the probe has no complementarity with it

Question 9 · difficulty L3 · understanding

Experimental verification of the chromosomal theory of inheritance was done by

• A. Sutton
• B. Mendel
• C. Morgan
• D. Boveri

Question 10 · difficulty L4 · analysis

Two genes lie very close together on the same chromosome. Compared with genes far apart on that chromosome, what is most likely?

• A. They show a higher recombination frequency
• B. They assort independently in every meiosis
• C. Stronger linkage and less recombination
• D. They can never be inherited together