Exam 3 - Biotech & Genetics

Question 1

enzymes that serve as scissors and paste

Answer 1

restriction endonucleases as scissors
DNA ligase as paste

Question 2

transformation technique

Answer 2

uptake of exogenous DNA into host cells, mix with E.coli, select on antibiotic plates

Question 3

fundamental utility of PCR

Answer 3

amplification of specific sequences of DNA

Question 4

what is thermal cycling

Answer 4

temperature changes for various steps of PCR - denaturation, primer annealing, primer extension

Question 5

steps of PCR

Answer 5

1. heat denaturation into two ssDNA
2. primer annealing
3. primer extension w/ DNA polymerase
4. two copies of dsDNA to amplify
5. repeat

Question 6

PCR for a virus (african swine fever) vs DNA testing for bull/calf relationship

Answer 6

qPCR for matrix gene (flu viruses)
qPCR for H gene if matrix is positive

DNA polymorphism, a PCR of short tandem repeats, to compare parentage

Question 7

what protein is useful for WNV vaccine and why

Answer 7

enveloped “E” glycoprotein because virus will not bind to host cells

Question 8

analogous protein from rabies virus

Answer 8

rabies glycoprotein

Question 9

principle of DNA vaccine

Answer 9

subclone gene for immunogenic protein into plasmid –> transformation into E.coli –> many E.coli –> purify plasmid DNA from lysed bacteria –> inject DNA into population

Question 10

principle of mRNA vaccine

Answer 10

mRNA encoding the protein is injected –> taken up by cells –> translated –> protein antigen presented to immune system

Question 11

What is the fundamental reason that these short tandem repeats of DNA are useful for DNA testing?

Answer 11

DNA polymorphisms, STR vary between individual genomes

basic science, crime forensics, parentage, wildlife tracking/poaching, superbowl footballs

Question 12

recombitek west nile virus vaccine

Answer 12

aka canary pox vectored vaccine
canarypox w/ low pathogenicity recombined with recombinant WNV (canary pox carrying WNV E glycoprotein)

vectored vx

Question 13

prevenile vaccine

Answer 13

aka yellow fever virus chimera
yellow fever 17D expresses WNV preM and E glycoprotein
combination of two similar flaviviruses
chimeric vx

Question 14

innovator WNV

Answer 14

aka formalin inactivated vx
DNA vx
rationally attenuated

Question 15

vaccinia rabies glycoprotein

Answer 15

vectored vx
vaccinia (poxvirus, similar to smallpox) carrying rabies-glycoprotein
vaccinia-rabies glycoprotein in baits, dropped out of planes

Question 16

subunit vx for WNV

Answer 16

immunogenic proteins produced through recombinant DNA technology
purified proteins

Question 17

is prevenile or recombitek a DIVA vx?

Answer 17

yes, both of them

Question 18

why is E.coli not a good host to produce a vaccine composed of rabies glycoprotein but is used to produce bovine growth hormone in large quantities

Answer 18

E.coli doesn’t have the capacity to glycosylate anything, thus why it is not good for rabies glycoprotein

Question 19

who invented PCR

Answer 19

kary mullis

Question 20

how PCR can be used to readily determine the repeat lengths of a specific short tandem repeat locus.

Answer 20

1. primers match flanks of loci
2. PCR
3. one fragment with 5 repeats and one fragment with 9 repeats
4. differentiate

Question 21

transgene

give an example

Answer 21

(promotor + coding region) integrated into genome of host (e.g. promotor - GFP)
microinjection into pronuclei
heritable, stable phenotype

e.g. casein promotor + valuable protein gene

Question 22

euploidy definition

Answer 22

normal

Question 23

aneuploidy definition

Answer 23

deviation from normal

Question 24

monosomy

Answer 24

lacking one of a homologous pair
missing one chromosome

Question 25

trisomy

Answer 25

three instead of two chromosomes (e.g. down syndrome in humans 3 chromosome 21)

Question 26

triploidy

Answer 26

3 haploid sets

Question 27

chimeras

Answer 27

two cell populations arise from more than one embryo

Question 28

mosaics

Answer 28

two cell populations arise from single embryo

Question 29

X chromosome inactivation rules (3)

Answer 29

1. all but one X chromosome is functionally inactivated early in gestation
2. inactivation is random w/ regard to parental origin
3. X inactivation is permanent except in cells that become gametes

Question 30

how does X chromosome inactivation relate to hemophilia

Answer 30

X linked recessive disorder
more likely in males w/ only one X
females usually carriers unless X inactivation occurs and X w/ hemophilia activated

Question 31

why tortoiseshell and calico cats are popular examples of X inactivation and how that coat color applies to that process.

Answer 31

different X inactivation patterns
most are females - half black are inactivated, half orange are inactivated = black/orange mosaics

Question 32

So what is the most frequent problem with translocations in veterinary medicine (especially well studied in cattle and sheep).

reciprocal translocation vs centric fusions infertility rates

Answer 32

infertility due to unbalanced gametes

translocations higher 50%+
centric fusions 5-15%

Question 33

Turner’s syndrome is not uncommon in mares. Describe the chromosome complement of an affected mare and the typical clinical presentation.

Answer 33

63 XO (monosomy)
failure to cycle (no estrus)
small ovaries
small uterus
no treatment
important to diagnose bc wasting time breeding

Question 34

Give an example of a situation that we discussed where different mutations in the same gene result in very different phenotypic manifestations.

Answer 34

point mutations (single nucleotide is altered)
TAT –> CAT (hist)
TAT –> GAT (asp)

Question 35

Why is Dexter dwarfism in cattle or double muscling in whippets a good example of an incompletely dominant mutation?

Answer 35

incompletely dominant = intermediate phenotype = heterozygous advantage
heterozygous = muscle dog, dwarf cow
homozygous = fat dog, fatal cow

Question 36

examples of founder effect

Answer 36

bovine leukocyte adhesion deficiency (BLAD)

equine hyperkalemic period paralysis (EHPP)

Question 37

multifactorial diseases
liability
threshold
examples

Answer 37

multiple factors affecting disease; gene interacting with environment to give phenotype

sum of all factors (genetic and environment) that render animal more/less likely to manifest disease

level of liability where disease occurs

canine hip dysplasia or PDA