Download Biol207 Final Exam

Locke-Biol207 Final Exam
Student ID#
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Student Name _____________ _______________
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9:00AM-12:00Noon Monday Dec. 20, 2004
Biol207 Final Exam
Dr. Locke's Section - Lec A1 (MWF 11:00 AM)
Copyright © 2004 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 8 pages containing 19 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 your student I.D. number at the top of each page.
11. You are encouraged to use coloured pens/pencils, rulers and only 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!
Note: No reindeer or elves were harmed in the writing of this exam.
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Locke-Biol207 Final Exam
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1a.)- An elf couple (same genetics as humans) are both heterozygous for an autosomal recessive disease (e.g.
both D/d) and have one unaffected child. What is the probability that this child is a heterozygote (carrier)?
(1 marks)
1b.)- A different elf couple (both homozygous normal) has two children. What is the probability that both are girls?
(1 marks)
1c.)- Another, different, normal elf couple has two children. If at least one is a boy, what is the probability that the
other is a girl? (1 marks)
2. Distinguish between tetrasomy and tetrads? (2 mark)
3. An Aa Bb Dd Ee diploid individual, where the A/a and B/b loci are absolutely linked and their recessive alleles
(a, b) are present in repulsion. Furthermore D/d is 15 mu from the E/e locus and in coupling phase and also
assorts independently of A/a. (2 marks)
Parental combinations: _______________________________ & _________________________________
Frequency of gamete with
ABDe
______________ AbdE _____________________
abDE
______________ aBdE _____________________
4. In multi-cellular, diploid eukaryotes, what is the difference between somatic and germline mutations? (2 marks)
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Locke-Biol207 Final Exam
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5. In Drosophila, a true breeding white mutant female was crossed to a true breeding sepia mutant male. (2 marks)
What is the phenotype of the F1 females?.
An F1 female was crossed to a tester male. What are the expected phenotypes and frequencies of the progeny?
6. What is pseudo-dominance and why is it called this? (2 marks)
7. Distinguish a
crossover
from a
translocation. (2 marks)
3
8. J. Cairns (1963) used the incorporation of H-thymidine to follow the replication of the E. coli chromosome. In
this experiment, he added the label half way through the first round of replication and harvested the cells for DNA
half way through the second round of replication. Draw a diagram of the pattern(s) of silver grains that would be
expected in this labeling experiment and how Cairns would interpret them? (2 marks)
Warning: think this one through BEFORE you start drawing!
Autoradiogram pattern
Interpretation
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Locke-Biol207 Final Exam
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9.-. The adjacent diagram shows a Southern blot of
restriction digested genomic DNA from an elf Mother (M)
and elf Father (F) and four potential elf children (C1 to C4)
probed with a VNTR DNA sequence. The restriction
enzyme used was Not I. Another elf (F2) is claiming to be
the father of child C4. We will not get into the details
behind this claim but you need to interpret the genetic
evidence presented here concerning the biological
relatedness of these children in this family. Assume the
mother, M, is the real mother of these four children.
a.-. What can you say about who is the father of each of the
children. Explain concisely! (3 marks)
Child C1:
M
F
C1
C2
C3
C4
F2
Markers
a
b
c
d
e
f
g
h
i
j
k
l
m
n
o
p
q
r
t
v
Child C2:
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s
u
w
x
y
Child C3:
Child C4:
b.- Does elf F2's claim have merit? Explain? (1 mark)
10. A human male with Klinefelter syndrome has 2N=47, XXY. Draw clear and unambiguous diagrams that show
the genetically important events (in the boxes) as you would expect a G1 cell goes through Meiosis. For the
autosomes, don't try to draw them all, just show one autosome pair to represent the events of all the others. Don’t
show crossing over in your diagrams. Use coloured pens to distinguish chromosomes effectively. (4 marks)
Prophase II
G1
Replication
G2
Metaphase II
Prophase I
Products
Metaphase I
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Locke-Biol207 Final Exam
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11.- Santa was interested in the genetics of reindeer, Rangifer tarandus, a diploid
eukaryote, 2N=70. In one strain, Santa found a new dominant mutation, called Flyer (F) for a
Flying phenotype (reindeer can fly) versus the wild type, f , (can’t fly). Santa decides to see if
the Flyer locus is genetically linked to the dominant mutation Red (R), for Red-nosed (vs. wild
type: r black-nosed), or the dominant mutation Talking (T), for able to talk (vs wild type t,
silent). Santa, in his first cross (cross#1), crosses true breeding Flyer male to a true breeding
Red, Talking female and collects the F1 progeny. In the second cross (cross#2) the F1
females were test-crossed to generate the progeny below in part “c”.
a.- Using the conventional notation described above, draw a cross-scheme to show the parents
in cross#1 and #2, indicating clearly the full genotype of each individual in the scheme.
cross#1 parents(1 mark)
cross#2 parents(1 mark)
b.- Describe the phenotype(s) of the progeny from cross#1? (1 mark)
c.- Results from Cross#2 showing phenotype and frequency from 6 classes of progeny:
Fill in the "Diploid Genotype" column in this table below for each of the phenotypic classes listed. (2 marks)
Phenotype
Frequency
Diploid Genotype
R/r
F/f
T/t
locus
Flyer, Red-nosed, Talking
25
/
/
/
wildtype
15
/
/
/
317
/
/
/
Flyer, Talking
73
/
/
/
Flyer, Red-nosed
89
/
/
/
323
/
/
/
Red-nosed,
87
/
/
/
Talking
71
/
/
/
Red-nosed, Talking
Flyer,
total
1000
d.- Put a "P" next to the classes above that show the parental combinations of the three alleles. ( 2 marks)
e.- Is Red-nosed linked to Talking and if so what is the map distance? Show how you arrived at your answer. (2
marks)
f.- Is Red-nosed linked to Flyer and if so what is the map distance? Show how you arrived at your answer. (2
marks)
g- Is Flyer linked to Talking and if so what is the map distance? Show how you arrived at your answer. (2 marks)
h-. Draw a genetic map(s) to show any linkages/distances among these 3 loci. (2 mark)
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Locke-Biol207 Final Exam
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12 . Describe how you would find an RFLP
linked to the gene shown here. The S, H,
and R show the sites of restriction
enzymes. (4 mark)
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gene
H
S
R
H
S
13.- This is a pedigree of one of Santa’s elf families. What patterns of inheritance are possible and which is the
most likely for this trait? Explain why.(3 marks)
B
D
Possible:
Not possible:
A
C
Most likely:
b. If this trait were due to a rare autosomal recessive disease then what can be concluded about the genotypes
(types & probabilities) of the following individuals in the pedigree? (4 marks)
A
B
C
D
14. In lecture, we described several methods for cloning a gene. Concisely explain which method you would use
to clone the gene encoding the rat myosin-heavy-chain polypeptide? (2 marks)
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Locke-Biol207 Final Exam
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15. Santa, a closet geneticist you know, is mapping genes in a haploid strain of yeast. Below is a
diagram of a 9 kbp EcoR I (E) restriction fragment subcloned from a cosmid clone that he cloned
from his Yeast genomic library. The yeast genome is ~13 Mbp long. The restriction map for this
fragment shows the Xba I sites (X) and BamH I sites (B). The locations of the only three genes (A,
B, and C) in the fragment are shown relative to a kbp scale and the restriction map. Three
fragments (numbered 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 (X) 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 three genes.
Mark in the expected location of the hybridization signals that Santa would expect to see on the diagrams of the
respective autoradiograms below. The locations of three probes are marked, 1, 2, & 3 on the restriction map. (6
marks)
1
Restriction Map
|
E
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X
0
kbp
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X
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B
1
2
3
2
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X
Gene A
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B
3
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X
4
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X
6
5
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X
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B
7
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B
8
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E
9
Gene C
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--
X
B
N
C
"Southern"
"Northern"
Autoradiogram Autoradiogram
kb
--8
10--
kbp
15--
6--
1--
--0.5
kb
--8
--6
--4
4--
--2
2-1--
--1
0.5--
C
6--
--2
2--
N
8--
--4
4--
B
10--
--6
8--
X
--1
0.5--
--0.5
"Southern"
"Northern"
Autoradiogram Autoradiogram
kbp
15--
X
B
N
10-8-6-4-2-1-0.5--
C
kb
--8
--6
--4
--2
--1
--0.5
16. The wild type telocentric chromosome of a reindeer is shown below. Reindeer are a diploid organism with
2N=70. On one mutant chromosome there is both, an inversion with one break between loci A&B and another
break between C&D, plus a deletion of loci H & I.
A
B
C
D
E
F
G
H
I
J
a.-Draw a diagram of this mutant chromosome synapsed with a wild type homolog at prophase I of meiosis. (2
marks)
b.- Draw the four 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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17. Santa, being an amateur geneticist, kept a species of fruit flies called Drosophila jollygaster. The genetics of
these flies is the essentially the same as that in Drosophila melanogaster. Santa wanted to introduce a gene for
pure black-body-colour into his strain so he could easily see them on the snow. He read the latest genetics
journals and his elf lab technicians were able to do this by P-element transformation. He cloned a gene, called
+
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BLACK (B ), from a black fly species (from North Ontario), into a P-element vector and, using a helper P
element, transformed the B
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gene into the germline of his normal coloured Drosophila jollygaster . fly species. He
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obtained only one transformed line, which contained only one B transgene insert. This line was propagated and
the transgene, as a heterozygote, conferred a pure black colour to the body of his species. The homozyotes for the
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transgene were crossed together to make a homozygous transgene strain (B /B ), which showed the pure black+
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body phenotype. Note: the P[B ] transgene is dominant to wild type (no transgene), so B /+ will show the pure
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black-body phenotype. Santa noticed that the B /B
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homozygotes also gained a recessive vestigal (vg )
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phenotype suggesting that the P[B ] transgene had transposed into the vestigal gene.
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Santa also has the following true-breeding stocks of D. jollygaster : (1) vg /vg (2) vg /vg ; P[transposase]/
P[transposase (3) ry /ry (4) Bl / Bl and (5) +/+ (wild type). vg=vestigal wings; w=white eye colour; ry=rosy eye
colour; Bl=short bristles (a dominant mutation) P[transposase]= gene with non-mobile transposase gene. There is
no crossing over in males of this species, just like D. melanogaster.
Question: Outline a series of experiments (using only Santa’s stocks listed above and any molecular genetics
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techniques you have learned) to show that the P[B ] transgene has inserted into the vestigal locus. Define the
phenotypes and genotypes of the parents and expected progeny for any cross you undertake. Also, define the
expected frequency of each class of progeny. (5 marks).
18). What is the full name of your TA? (1 marks)
19). If one of Santa’s elves were to take Biol 207 next year, what advice would you give them to help them get a
good mark.? (Answer on the back of this page – Any reasonable effort is worth 1 mark.)
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