Bar is a gene often used in recombination study. Which of the following is true for the Bar gene?
a) It is normally present in two copies
b) Three copies of bar are called ultra bar
c) Heterozygous bar females have a less severe effect than homozygous bar female
d) Homozygous bar are of common occurrence
Q.2.
Consider that recombination occurs in 2 strand stage of meiosis. If a Drosophila is heterozygous for the bar locus what will be the result of recombination?
a) The recombination will make them homozygous
b) It will produce ultra bar phenotype
c) It will be heterozygous
d) No exchange
Q.3.
Chiasmatype theory states recombination occurs before chiasma formation. State whether it is true or false.
a) True
b) False
Q.4.
How many rounds of replication in BrdU will be needed to visualize Harlequin chromosome?
a) Single
b) Two
c) Three
d) Four
Q.5.
If two genes are unlinked the recombination frequency will be?
a) 25%
b) 50%
c) 75%
d) 100%
Q.6.
Is two crossovers occur between same two strands, this will result in__________
a) All recombinant strands
b) Three recombinant strands with different loci exchanged
c) Exchange of middle portion between two strands
d) Exchange of ends
Q.7.
Double cross over involving ________ strands result inrecombinant strands.
a) 1
b) 2
c) 3
d) 4
Q.8.
If a recombination event of three points crossing produces 6 DCO,SCO andNCO. What will be the percentage cross over between the terminal genes.
a) 10%
b) 20.8%
c) 14.8%
d) 30.8%
Q.9.
If single cross over frequency between two genes r and q and q and s in 3 point mapping is 0.6 and 0.2 respectively. What will be the expected double cross over frequency?
a) 0.012
b) 0.010
c) 0.022
d) 0.024
Q.10.
In an experiment you calculate the expected DCO frequency to be 0.but in reality you observe that only 0.recombination frequency. What is the phenomenon resulting in this?
a) Coincidence
b) Interference
c) Penitence
d) Expressivity
Q.11.
Which of the following will result in parental phenotype?
a) DCO in between two genes considering four strands
b) Even number of DCO between two genes
c) Odd number of DCO between two genes
d) Single cross over at 4 strand stage between two genes
Q.12.
What will be the nature of curve with map distances plotted in X axis and percentage recombination in Y axis?
a) Parallel to X axis
b) Increasing in a straight line
c) Parabolic
d) Exponential
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