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Zoo/Bot 3333
Genetics
11/23/09
Quiz 4
For Answers to the quiz, click here:
1. True or false. One useful property of plasmid vectors used in molecular cloning is their ability to
integrate into the E. coli chromosome.
2. The restriction enzyme, ApoI has the six base recognition sequence PuAATTPy, where Pu stands for a
purine, and Py stands for a pyrimidine). On average, this enzyme might be expected to cut a random DNA
sample every ____________bp.
a) 64; b) 256; c) 1024; d) 2048; e) 4096.
3. The recognition sites for the restriction enzymes BamHI, XbaI and BglII are
5’-GGATCC-3’, 5’-TCTAGA-3’ and 5’-AGATCT-3’, respectively, where the arrows represent the
cut locations for each strand of the palindromic site. Which enzymes leave compatible ends that will
facilitate ligation by base-pairing?
a) All of these enzymes leave ends that are compatible with ends generated by the others; b) None of the
enzymes produce compatible ends; c) Only BamHI and BglII fragments are compatible; d) Only BamHI
and XbaI fragments are compatible; e) only BglII and XbaI fragments are compatible.
Questions 4-5 pertain to the following. DNA was
prepared from liver cells isolated from a large human
population. These DNAs were individually digested
with HindIII, subjected to electrophoresis and
Southern blotting, and the blot was probed with a
radioactively labeled cloned DNA sequence. Fifteen
different restriction patterns were observed among
these samples. The figure to the right indicates the
different patterns observed in these 15 individual
samples:
1
2
3 4 5
6 7 8 9 10 11 12 13 14 15
15 kb
13 kb
9 kb
7 kb
6 kb
4 kb
2 kb
4. In the following diagrams, the vertical lines represent HindIII restriction sites. An asterisk over the site
represents a polymorphism (presence or absence of the site in individuals) in the population. The double
arrow represents the boundaries of the cloned DNA used in the Southern blot analysis. Which of the
following is consistent with the arrangement of these HindIII restriction sites in human genomic DNA?
*
a)
*
2
*
b)
3
*
2
*
*
4
*
d)
6
2
4
*
c)
*
3
4
3
*
*
e)
6
2
4
2
4
6
*
3
6
*
3
6
5. Suppose individuals 1 and 5 married. Assuming no recombination occurs within the region in question,
how many potentially different patterns would be observed among their progeny on Southern blot analysis?
a) only 1; b) 2; c) 3; d) 4 e) 6.
Question 6-7 pertains to the following. This region of the genome is known to contain a particular gene,
which encodes a very large protein of 1600 amino acids. A cDNA library primed with oligo dT was made
and a clone derived from that library hybridized to the 2 kb, 6 kb, and 9 kb restriction fragments only.
When sequenced, this cDNA clone was 720 nucleotides in length and therefore incomplete. The amino
terminal sequence of the protein encoding this gene was known, however, and a synthetic oligonucleotide
that corresponded to amino acids 1 through 10 of this protein was produced and labeled; it hybridized only
to the 9 kb, 13 kb and 15 kb fragments.
6. True or false. The 3’ end of the mRNA made from this region would be located in the 2 kb restriction
fragment.
7. True or false. These data indicate that there must be an intron interrupting the coding sequence for this
gene within the genomic DNA.
Questions 8-9 pertain to the following diagram, which
represents a region of a DNA sequencing gel produced
using the Sanger chain termination method. The
individual lanes represent the reaction products from the
four separate labeling reactions (A,G,C,T) which were
loaded at the top of the gel.
8. As deduced from this experiment, the sequence
of the strand being copied (template) in this reaction is:
a) 5’-TCGACGTGCGTA-3’
b) 5’-TACGCACGTCGA-3
c) 5 -AGCTGCACGCAT-3’
d) 5- ATGCGTGCAGCT-3’
e) 5- TTTCCCGGGGAA-3’
A
G
C
T
9. Which of the following was NOT present in the test tube during the ‘A’ DNA synthesis reaction?
a) dATP; b) dGTP; c) ddATP; d) dCTP; e) all of the above were present in the reaction.
Question 10 pertains to the following. Six independently derived mutants are recovered in Neurospora which
are all unable to grow unless supplemented with compound Z. The mutants are then grown on minimal media
supplemented with one of 6 chemicals all believed to be precursors to compound Z. A summary of the ability
of the mutants to grow on media containing these chemicals is indicated below, where a “+” sign indicates
growth and a “-” sign indicates no growth.
mutant number
precursors added to minimal medium
A
B
C
D
E
F
Z
1
+
+
+
-
-
-
+
2
+
+
+
+
-
-
+
3
+
+
+
+
+
-
+
4
-
-
+
-
-
-
+
5
-
-
-
-
-
-
+
6
-
+
+
-
-
-
+
10. From the above chart, the enzyme that catalyzes the production of compound D appears to be mutant in
strain:
a) 1; b) 2; c) 3; d) 4; e) none of the above.