Download Biol 207 Final Exam

Locke-Biol207 Final Exam
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Student Name ______________ ________________
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last
2:00 - 5:00 PM, Wednesday Dec. 15, 2010
Biol 207 Final Exam
Dr. Locke's Section - Lec A2 (MWF 12:00 Noon)
Copyright © 2010 John Locke
Instructions:
1. Please answer all questions concisely in the space provided or
on the corresponding position on the back of that page (if needed).
2. Part marks will be given for partly correct answers.
3. Within a question, marks may be lost (only from those already gained) for
incorrect answers or statements.
4. Illegible answers will be marked as incorrect.
5. Make sure you have all 7 pages containing 17 questions, plus a bonus.
6. Note the value of each question (in brackets) and spend your time accordingly.
7. If any question is unclear, please clarify the uncertainty with the instructor.
8. You have up to 3 hours to finish the exam.
9. The exam has a total of 58 marks and is worth 40% of the final grade.
10. Put your student I.D. number at the top of each page.
11. You are encouraged to use diagrams, where appropriate, in your answers.
12. You are encouraged to use coloured pens/pencils and rulers, but only a simple calculator.
Note:
13. For hypothetical organisms or people assume that real world genetic principles apply.
Good luck!
Final Mark ________/58 marks
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Locke-Biol207 Final Exam
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1.- Define a gene: (2 marks)
2.- Most strains of cultivated table grapes (for eating) are seedless and the plants are propagated vegetatively.
Describe two (2) genetic mechanisms that could possibly produce seedless grapes. (2 marks)
a-
b-
3.- This question deals with a genetic mapping cross. There are three mutant characteristics: C (C, vs. c), W (W,
vs. w), and T (T, vs. t). Are any of these traits linked? In the first cross (cross#1), a homozygote for all dominant
mutant alleles is crossed to a individual with no dominant mutations and the F1 progeny are grown up. In the
second cross (cross#2) one of these F1 was test-crossed to generate the progeny below.
Table of the phenotypic classes.
Phenotype
C, W, T
C, W
W, T
C, T
C
W
T
normal
total
Frequency
38
1
12
8
6
10
3
22
100
a.- In the table above, circle the two classes that are the parental combinations for the three loci. (1 mark)
b.- Is C/c linked to W/w and if so what is the map distance? Show how you arrived at your answer. (1 mark)
c.- Is W/w linked to T/t and if so what is the map distance? Show how you arrived at your answer. (1 mark)
d- Is T/t linked to C/c and if so what is the map distance? Show how you arrived at your answer. (1 mark)
e-. Draw a genetic map(s) of these 3 loci representing all possible arrangements. (1 mark)
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Locke-Biol207 Final Exam
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4. In a strain of chickens the mutant Barred allele is dominant, and sex-linked, and gives
feathers a black & white striped (Barred) pattern rather than the normal all black colour (b).
Also, there is a white mutation, which is an autosomal, recessive mutation. It is also epistatic
to all other mutations at feather colour loci (including B). A Barred (B) mutant female (from a
true breeding - homozygous - population), was crossed to a white (c) mutant male (from a
true breeding - homozygous – population known to be non-barred).
a)-What is the genotype & phenotype of the F1 female and male progeny? (2 marks)
b)- A grown up F1 daughter was crossed to a tester rooster. What are the expected phenotypes and frequencies of
their progeny? (2 marks)
5- Hypothetically, in humans, there is a polymorphic locus that has four different alleles with restriction sites for
BamH I as shown in the diagram (below, left). Sizes between each restriction site are given in kilobasepairs (kbp).
2.5
Morph A1
0.5
2
C
P
S
3.5
Morph A2
1
Morph A3
1
Morph A4
1
1.5
0.5
2
2.5
3.5
1.5
3
0.5
2
1.5
2.5
1
0.5
Probe
You design a probe for this locus (see diagram, above left) and probe a genomic Southern blot. On the Southern
blot is genomic DNA, that has been digested with BamH I, from three different individuals labeled: P, C, and S.
a) Determine the genotypes (alleles) of the three people based on the data you obtained. (Autoradiogram is shown
(above, right) with numbers along the side as sizes in kbp). (1 mark)
P=
C=
S=
b) Could P and S be the parents of C? Explain. (1 mark)
c) Could P, S, and C be siblings? If so, what are the parent genotypes? If not, why not? (2 marks)
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Locke-Biol207 Final Exam
6. Distinguish
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“reverse transcription” from a “reverse mutation”. (2 marks)
7. List three reasons why PCR detection of VNTRs is more useful today than Southern Blot detection of RFLPs in
decreasing order of significance. (i.e. most important first). (3 marks)
1-
2-
3-
8. Below is a diagram of a 9 kbp stretch of DNA from a haploid strain of yeast. It is subcloned from a cosmid clone
that was ~40 kbp long. The restriction map, shown below, is composed of several EcoR I (E) restriction fragments
and includes one BamH I site (B). The number and location(s) of the genes in the fragment are unknown; it is your
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job to map them. Six fragments (labeled probe A to F) are outlined and have been made into label P probes.
These probes were individually hybridized to 6 Northern blots. The Northern blots contained poly(A+) RNA isolated
from purified nuclei only (N) or cytoplasm only (C) from cells that are expressing the genes in this region.
On the line below labeled “Genes”, mark in the expected structure(s)/location(s)/number of the genes,
based on the hybridization signals on the six Northern blot autoradiograms below. (6 marks)
Probe A
Probe B
Probe C
"Northern"
Autoradiogram
C
N
kb
"Northern"
Autoradiogram
C
N
kb
"Northern"
Autoradiogram
C
N
kb
"Northern"
Autoradiogram
C
N
kb
"Northern"
Autoradiogram
C
N
kb
"Northern"
Autoradiogram
C
N
kb
--6
--6
--6
--6
--6
--6
--4
--4
--4
--4
--4
--4
--2
--2
--2
--2
--2
--2
--1
--1
--1
--1
--1
--1
-0.8
-0.8
-0.8
-0.8
-0.8
-0.8
-0.5
-0.5
-0.5
-0.5
-0.5
-0.5
Probes
B = 1.1kbp
0
1
2
|
E
3
Probe F
F = 1.4kbp
C = 1.2kbp
|
E
Probe E
D = 0.9kbp
A = 1.0kbp
Restriction Map
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E
E
Probe D
E = 1.3kbp
|
E
4
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E
5
|
E
6
7
|
E
8
|
B
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E
9
kbp
Genes
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Locke-Biol207 Final Exam
9- What is the difference between a
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translocation
10. Explain the difference between epistasis and
and
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crossing over ? Explain. (2 marks)
dominance ? (2 marks)
11. A diploid individual has the genotype: Aa Bb Dd Ee. The A/a and B/b loci are very closely linked, being 1
CentiMorgan apart, and their recessive alleles (a, b) are present in repulsion. Furthermore, D/d is 10 CentiMorgans
from the E/e locus and in coupling phase and both D/d and E/e also assort independently of A/a. All are syntenic.
What is the frequency of a gamete with the genotype: (2 marks)
ABDe
_____________________%
AbdE
_____________________%
aBdE
_____________________%
abDE
_____________________%
12 – The diagram below shows three RFLP Southern transfer probings for a mother (M), child (C) and three
potential fathers( P1, P2, P3). Each RFLP is located on a different chromosome. Single thickness bands indicate
one copy, while double thickness bands indicate two.
M
a)- Who is/could be the father? Why? (2 marks)
C
P1
P2
P3
RFLP
#1
RFLP
#2
b)- If one of the fathers is actually
the father of this child, what can be said,
based on the RFLPs, about the chromosome location
RFLP
#3
of each RFLP? (3 marks)
1=
2=
3=
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Locke-Biol207 Final Exam
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13 . A new bacterial species was found and its DNA was analysed. It has a 50% G+C content. Complete the
table below by filling in the average length of restriction fragments expected from the genomic DNA (assuming
a random distribution of bases) if it were digested with the following four restriction enzymes. (4 marks)
The “/” symbol indicates the location of the cleavage site.
Assume 50% G+C
Restriction Enzyme
Sequence recognized
Msp I
C/CGG
Hinf I
G/ANTC
Sfi I
GGCCNNNN/NGGCC
Psi I
TTA/TAA
Average length of restriction fragment (base pairs)
14.- Restriction mapping. On the right is a diagram
representing an agarose gel of various restriction digests
(single and double) of four different enzymes (E, B, K, & X) of
a plasmid DNA sample. Please construct a map showing the
locations of these enzyme sites in the circle below along with
the distances between sites. A “K” site is present to get you
started. (Use the back of the page for your rough work,
please, and present your final map below.) (4 marks)
K
15. A wild type metacentric chromosome is shown below for a typical diploid organism. On a mutant chromosome
there is both an inversion, with one break between loci F&G and another break between I&J, plus this chromosome
also contains a terminal deletion of loci A & B.
A
B
C
D
E
F
G
H
I
J
a.-Draw a diagram of the mutant chromosome synapsed with a wild type homolog at prophase I of meiosis. (2
marks)
b.- Draw the resulting meiotic products if there is a single crossover between loci D & E. (2 marks)
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Locke-Biol207 Final Exam
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16. In Drosophila melanogaster there is a chromosomal mutation containing a reciprocal translocation between the
tip of the telocentric X-chromosome and the long arm of the acrocentric chromosome 4. For a male heterozygous
for this mutation, draw clear and unambiguous diagrams of the sex-chromosomes and chromosome 4 (not the
other 2 autosomes) that show the genetically important events (in the boxes) that would be expected as a G1
meiocyte goes through Meiosis to make viable, balanced gametes. Don’t show crossing-over in your diagrams.
PLEASE use coloured pens to distinguish the chromosomes effectively. (4 marks)
Prophase II
G1
Replication
G2
Anphase II
Prophase I
Products
Anaphase I
17. A researcher, here at the U of A, has an unexpected genetic observation. She works with mice and is studying
an embryonic recessive lethal mutation in an autosomal gene ( -/- mutant homozygotes die as early embryos).
She crossed +/- heterozygotes with +/+ wild types and got the expected 1:1 ratio of +/- to +/+ progeny (mouse
pups). She then took the +/- brothers and sisters and crossed them together and the viable progeny (live births)
are ALL +/- . These progeny can be crossed (brother to sister) and ALL are +/- again. The genotypes of “+” and
“-“ are determined for each mouse pup by a PCR test that permits co-dominant inheritance to be determined.
Question: This question may have several correct answers. Using your Biol 207 knowledge, identify what is
unexpected in her results. Then, provide your best (ONE ONLY) genetic description of how these unexpected
results might be explained. Use the back of this page for your rough thoughts and present only your best below,
please.
Unexpected result: (1 mark)
Explanation: (2 marks)
Bonus: Write, in the margin below, the name of a famous Canadian Geneticist and why they are famous. (1 mark)
(Profs/researchers from the U of A don’t count.)
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