Download Biol207 Final Exam

Locke-Biol207 Final Exam
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Student Name _____________ _______________
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9:00 AM Tuesday Apr. 23, 2002
Biol207 Final Exam
Dr. Locke's Section - Lec B1 (MWF 9:00 AM)
Copyright © 2002 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.
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 70 marks and is worth 40% of the final grade.
10. Put only your student I.D. number at the top of each page.
11. You may use coloured pens/pencils, rulers and a simple calculator.
12. You are encouraged to use diagrams, where appropriate, in your answers.
Note:
13. For hypothetical (imaginary) organisms or people, assume that real world genetic principles
apply.
Good luck!
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Locke-Biol207 Final Exam
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1. What is a gene? (3 marks)
2. Differentiate between the terms epistasis and dominance. (2 marks)
3. What is the pseudo-autosomal region of the human Y-chromosome and why is it called this? (2 marks)
4. In eukaryotes, what is the difference between somatic and germline mutations?. (2 marks)
5. Distinguish between trisomy and triploidy. (2 marks)
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Locke-Biol207 Final Exam
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6. Distinguish between a crossover and a translocation. (2 marks)
7. Lambda bacteriophage vectors have been used for cloning genomic DNA. How large a fragment is the typical
lambda bacteriophage insert? How many different recombinant lambda clones must be present in a human
genomic library (human haploid genome size =3,000 Mbp) to have a 99% chance that any given DNA sequence will
be represented at least once? (2 marks)
8. For an Aa Bb Dd Ee diploid individual, write down the expected frequency of all the possible
combinations of alleles in the gametes if the D/d and E/e loci are absolutely linked (A/a assorts
independently) and their dominant alleles (D, E) are present in replusion. Furthermore B/b is 20 mu from the A/a
locus and in coupling phase and also assorts independently of D/d. (3 marks)
Types:
Frequencies:
9. Draw a diagram of a double heterozygote eukaryote cell (2N=4) at metaphase of mitosis showing the
chromosomes and alleles where the cell has one locus A/a, on an acrocentric chromosome, and B/b on a
telocentric chromosome and they are present in repulsion phase. (2 marks)
10. In a population of diploid individuals from a species there are four alleles, z1, z2, z3, z4. Draw a diagram of a pair
of homologous metaphase chromosomes at G2 stage of the cell cycle that is heterozygous for this locus. (2 marks)
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Locke-Biol207 Final Exam
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11.- Frodo Baggins was interested in the genetics of magical plants. In one especially magical plant, a diploid
eukaryote, Frodo found a new dominant mutation, called Anvil (A) for an Anvil phenotype (eating the plant made
one as resistant to hammer blows as an anvil) versus the wild type, a , (non-anvil - no extra resistance). Frodo
decides to see if the Anvil locus is genetically linked to the recessive mutation b, for bruiser (vs. wild type: B nonbruiser), or the dominant mutation D, for Dasher(vs wild type d, non-dasher). Eating plants with a bruiser mutation
makes one's punches always cause severe bruises, while eating plants with a Dasher mutation makes one always
run away from fights. Frodo, in his first cross (cross#1), crosses true breeding Anvil pollen to a true breeding
bruiser, Dasher flower and collects the F1 progeny. In the second cross (cross#2) the F1 plants are test-crossed to
generate the progeny below in part “c”.
a.- Using the conventional notation described above, draw a diagram to show the parents of cross#1 and #2,
indicating clearly the full genotype of each individual in the scheme. (2 marks)
cross#1
cross#2
b.- Describe the phenotype(s) of the progeny from cross#1? (1 mark)
c.- Results from Cross#2 showing phenotype and frequency from 8 classes of progeny:
Fill in the "Diploid Genotype" column in the table below for each of the phenotypic classes listed. (2 marks)
Phenotype
Frequency
Diploid G e n o t y p e A/a
B/b
D/d locus
Anvil,
bruiser,
Dasher
13 %
/
/
/
non-Anvil,
non-bruiser,
non-Dasher
11 %
/
/
/
Anvil,
non-bruiser,
non-Dasher
27 %
/
/
/
non-Anvil,
bruiser,
non-Dasher
6%
/
/
/
non-Anvil,
non-bruiser,
Dasher
2%
/
/
/
non-Anvil,
bruiser,
Dasher
29 %
/
/
/
Anvil,
non-bruiser,
Dasher
8%
/
/
/
Anvil,
bruiser,
non-Dasher
4%
/
/
/
100 %
d.- Put a "P" next to the classes above that show the parental combinations of the three alleles?( 2 marks)
e.- Is Anvil linked to bruiser and if so what is the map distance? Show how you arrived at your answer. (2 marks)
f.- Is bruiser linked to Dasher and if so what is the map distance? Show how you arrived at your answer. (2 marks)
g- Is Anvil linked to Dasher and if so what is the map distance?
Show how you arrived at your answer (3 marks).
h. Draw a genetic map to show any linkages/distances among these 3 loci. (1 mark)
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Locke-Biol207 Final Exam
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12 . A U. of A. plant geneticist was using crosses to examine the genetics of leaf colour in a common plant. A strain
of plants from Edmonton have bright, green leaves while the strain from Calgary has red leaves.. In a cross between
true breeding Edmonton strain and a true breeding Calgary strain, the geneticist observed all the progeny had red
leaves. In hopes of understanding this result further, he self-crossed the F1 and of the 1000 progeny he scored,
561 had red leaves while 439 had green leaves. Explain this result in terms of Mendelian inheritance. (4 marks)
13.- In this pedigree of the royal family of the kingdom of the Elves, what are the possible patterns and which is the
most likely pattern of inheritance of the rare disease? Explain why.(3 marks)
D
B
A
C
b. If this disease where to be autosomal recessive then what can be said (types & probabilities) about the
genotypes of the following individuals in the pedigree? (4 marks)
A
B
C
D
14. In one of the elf villages in the kingdom above there is a married elf couple who were both albinos (albinism is
due to recessive mutations) but had four normal, non-albino, elf children. It seems impossible for them to have one
non-albino child (let alone four) and one possibility is that the children were adopted. This suggestion was quickly
denied by the albino elf parents. A second suggestion of "non-paternity" was wrong, too. Provide a simple genetic
explanation of how phenotypically normal children can come from two mutant parents with recessive mutations. (2
marks)
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Locke-Biol207 Final Exam
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15. A Biol207 Professor (not Dr. Locke) was mapping genes in a strain of yeast she uses for making beer. Below is
a diagram of a 9 kbp Xba I (X) restriction fragment subcloned from a cosmid clone that she cloned from her Yeast
genomic library. The yeast genome is ~13 Mbp. The restriction map for this fragment shows the EcoR I sites (E) and
BamH I sites (B). The locations of the only two genes (labeled A and B) in the fragment are shown relative to a kbp
scale and the restriction map. Three fragments (labeled 1, 2, & 3) are outlined and have been made into 32P
probes. These probes were individually hybridized to 3 Southern and 3 Northern blots. The Southern blots
contained total Yeast genomic DNA digested with EcoR I (E) or BamH I (B). The Northern blots contained poly(A+)
RNA isolated from purified nuclei only (N) or cytoplasm only (C) from cells that are expressing these genes.
On the diagrams below, mark in the expected location of hybridization signals (bands) this
professor would expect to see for the respective autoradiograms below. The locations of three probes are marked,
1, 2, & 3 on the restriction map. (6 marks)
Restriction Map
X
|
|
B
kbp
0
E
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E
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B
1
1
2
Genes:
2
E
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3
E
|
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B
4
3
6
5
gene A
E
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E
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E
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B
7
X
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9
8
Gene B
Probe 1
Probe 2
Probe 3
Show the location of the band(s) expected. Show the location of the band(s) expected. Show the location of the band(s) expected.
"Southern"
"Northern"
Autoradiogram Autoradiogram
kbp
15--
E
10-8-6-4-2-1-0.5--
B
N
C
kb
--8
--6
--4
--2
--1
--0.5
"Southern"
"Northern"
Autoradiogram Autoradiogram
kbp
15-10-8-6-4-2-1-0.5--
E
B
N
C
kb
--8
--6
--4
--2
--1
--0.5
"Southern"
"Northern"
Autoradiogram Autoradiogram
kbp
15-10-8-6-4-2-1-0.5--
E
B
N
C
kb
--8
--6
--4
--2
--1
--0.5
16. Explain how the ends of chromosomes are replicated without the loss of sequences predicted from the
requirement of DNA polymerases to only extend from 3' ends. Draw a diagram that explains how both ends of
one linear chromosome are completely replicated (assume one origin). Label the synthesized strands, primers, the
leading and lagging strands and the polarity of the daughter strands. (6 marks)
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Locke-Biol207 Final Exam
Student ID#
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17. Do either Part A or B (8 marks)
I am doing Part A [ ] or Part B [
]. (Check one only).
Part A: Staple your sealed envelope containing the single page of your prepared book review to the upper right
corner back page (where the staple is) of your exam.
Part B : .....In the Biol207 lab you have seen and used alleles of the sepia (se) locus of Drosophila . The se- allele is a
recessive mutation defining a locus on chromosome 3 that affects eye colour. Using what you have learned about
cloning genes in Biol 207 lectures (and labs if needed), describe a series of experiments (in point form) that would
lead to the cloning of a genomic DNA restriction fragment that contains the wild type sepia gene and how you
would establish that this fragment truly contained the complete sepia gene (regulatory regions and transcription
unit). A correct answer for this question requires that you put concepts from several lectures together to
accomplish the end goal.
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