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GENETICS 310
EXAM 3
June 30, 2016
I. Which of the following enzymes or cloning tools would be used for the
specific steps listed bellow? Put the code(s) provided in each blank as
appropriate.
RE, restriction endonuclease, RT, reverse transcriptase H, RNAase H
L, DNA Ligase, T primer made of all Ts, B, beads with T tails,
TdT terminal deoxynucleotide transferase, P, DNA polymerase
a) cDNA clone preparation
B
Collecting eukaryotic mRNAs from ground tissue
RT
Making a cDNA copy of the messages
H, RT or P
TdT
Replacing the RNA strand with a second strand of DNA
Adding A tails to the double stranded cDNAs
b) Shotgun cloning step
RE
Fragmenting donor DNA
L
Inserting fragments into a linearized pUC vector
II Given the sequence below describe how you could make millions of copies in
a short period of time. For simplicity, use arrows to indicate primers 1 and 2
that are just 7 bases long:
5’ ACCGTCAACTGCAATGCGCGCTAGAATCGTTGCATGATGG 3’
3’TGGCAGTTGACGTTACGCGCGATCTTAGCAACGTACTACC 5’
Name of process? Polymerase Chain Reactio
Enzyme used?
TAQ polymerase
Source? Hot springs bacterium
III. Cross out the maize plants below that would not produce pollen based on
their genotype (in the nucleus)/cytotype combinations?
S
F
R_
rr_
F
S
rr
rr
R_
rr_
IV. A) RB gene defects appear to be inherited as dominant, but not everyone
who gets a defective copy develops retinoblastoma.
Tumor Suppressor
2. What is the normal function of such genes?
Turn off cell division
3. Why do some individuals with a defective RB gene escape getting
retinoblastoma? It requires a mutation in the remaining copy of a somatic cell
B) The SRC gene was originally discovered to cause sarcomas in chickens
following infection with Rous Sarcoma virus.
1. What type of gene is SRC in terms of cancer ?
Oncogene
2. What is the normal function of such genes?
Turn on cell division
3. What general type of virus is RSV?
Retrovirus
4. What is unusual about the RSV particles that cause sarcomas?
They carry an onc gene incorporated from a host genome
5. How do we know that humans also have a SRC gene?
DNA hybridization to the cloned chicken gene
C) At least 3 DNA viruses are associated with increased risk of cancer in
humans. List 2 of them.
Epstein Barr
&
Hepatitis B or HPV
V. A) Check the following that are found in or as a part of eukaryotic but not
prokaryotic chromosomes:
X
DNA
RNA
centromeres
X
X
teleomeres
histones
lipids
mitomeres
B) Why do the chromosomes in a typical human karyotype appear doubled?
They are taken from cells trapped at metaphase of mitosis
VI. Fill in affected individuals assuming a perfect segregation ratio for each trait
Mom is heterozygous for Duchene MD
Dad is colorblind, mom is heterozygous
Dad has a defect in one copy of the ‘Prader-Willi’ genes
which should remain active in sperm
MomhasMERRF,amitochondrialdefect
Momisheterozygousforcompleteandrogensensitivity
(testicularfeminization)
Whatdoesaffectedmeaninthiscase?
VII.Giveanexampleof:
Momisheterozygousforadominantsex-linkedgene
Aholandricgene
Sry=tdf,HYantigen
AvisibleconsequenceoftheLyonHypothesis calicocats
Asex-limitedtrait
hornsinsheep,patternbaldness lactation
Asex-influencedtrait
XYfemale
Amaternaleffectstrait
left/rightcoilinginsnails Whatforcealtersallelefrequenciesinsmallpopulations
drift (chance)
VIII.Placetheletterorlettersofeachofthefollowingsyndromesinallappropriateblanks:
Syndrome
Characteristic
A)Angelman's
47chromosomes,D,JK,X
C)Cri-du-chat
SomeIQlossA,CD,J,K,(T),X
D)Down's
Female(always)T,X
J)Jacobs
AbnormalsexchromosomenumberJ,K,T,X
K)Klinefelter's
NormalfertilityJ,X
T)Turner's
45chromosomesT
X)TriploX
genomicimprintingA
tallforfamilyexpectation
J,K
Deletion C
IX.IncattleC_animalsarenormalandccdevelopcataracts.ADNAbasedpolymorphism
detectedbyPCRisjust4mapunitsfromthecataractsgene.It’sallelesaredesignatedA35
orA50forthesizeoftheamplifiedproduct.Supposeabullhasthegenotype
CA35/cA50
Whatfractionofthespermheproduceswillhavethefollowinggenearrangements:
CA3548% CA50 2% cA35 2% cA50 48% ?
WhatgenotypewouldbeoptimalinthecowsifarancherwantedtousePCRteststocull
calveswiththecataractscallelefromhisherdbeforetheywereallowedtoreproduce?
CA35/CA35
X.a)Twofactorsareknowntoleadtosignificantincreaseintheriskoftrisomy21.What
arethey?
Agedmother &
Translocationof21toanother
b)1.Howaretheseedsusedtogrowseedlesswatermelonsproduced?
4NX2Ncrosses
b)2.Whyaretheyseedless?
Gameteswillnothavebalancedsetsofchromosomesandwillnotfunction
c)1.Amousehomozygousforthegenearrangement‘A B
C
•
D
E’is
crossedtoanotherwiththearrangement
‘a b
d
•
c
e’
Capitalandsmalllettersareusedjusttoaidinthefollowingdrawing.Showsynapsis(with
thegeneslabeled)inmeiosisoftheF1hybridbetweenthetwoanimals.
c)2.Whatisthenameofthechromosomalaberration? Prericentricinversion
c)3.What%fertilityisexpected
intheF1malesandfemales?Males 50% females
50% XI.Althoughothergenesmaymodifytheactualcolors,inmanybreedsofsheepwhitewool
isdominant(W_)andblackisrecessive(ww).Inalargerandommatingflock16%ofthe
lambsareblack.WhataretheallelefrequenciesofWandw?
P=f(W)=0.6;q=f(w)=0.4
Whatarethepredictedgenotypicfrequenciesintheflock?
36WW:48Ww:16ww
Supposetheshepherdsoldoffalltheblacklambsbornoneyear,andkepttheresttostarta
newflock.What‘force’wouldbeinvolvedinchangingallelefrequencies?
Selection
Iftherewere100lambsandtheblackonesweresold,whatwilltheWandwallele
frequenciesbeinthisnewflockoncetheyaregone?
F(W)=(2X36+48)/168f(w)=48/168