BIO 529 S04
Exam I
Name______________________
ID #_______________________
1. Fill in the blanks with the best answer from the list provided. (1 pt each)
epigenesis
fate map
induction
soma
determination
gastrulation
morphogen
autonomous
cloning
RNAi
specification
juxtacrine
pluripotence
commitment
nematode
enhancer
Pax6
vertebrate
epithelium
morpholino
protostome
preformation
autonomous
fate map
pluripotence
competence
syncytial
Northern blotting
FGF
gastrulation
endocrine
urochordate
imprinting
determination
instructive
chimera
cloning
In situ hybridization
embryo
notochord
preformation
metazoan
conditional
microarray
morphogenesis
blastula
totipotence
mitosis
Wnt
deuterostome
TGF-
epithelium
PCR
competence
amphibian
FGF
epiboly
diploblast
zygote
cleavage
stem cell
morpholino
germ line
imprinting
instructive
meiosis
chordate
permissive
arthropod
BMP4
endocrine
Hedgehog
differentiation
Smad
chimera
triploblast
organogenesis
larva
protostome
regulative development
in situ hybridization
mosaic development
JAK-STAT
syncytial
reverse transcription
mesenchyme
receptor tyrosine kinase
Northern blotting
paracrine
urochordate
targeted knock-out
methylation
A sheet of tightly connected cells
Chemically modified oligonucleotide used to reduce gene activity
Organism in which the mouth is the first orifice to develop
Theory that organisms develop from a miniature in the gamete
Type of specification in which individual cells develop independently
Technique to trace all the cell lineages of an organism
Ability of a cell to produce many, but not all, fates
Ability of a cell to respond to a signal from another cell
Type of specification that occurs when the nuclei of an early embryo
develop in a common cytoplasm
Hybridization technique that provides information about the total size
of a mRNA
A ligand that stimulates RTK signaling
Stage of embryogenesis during which cells are rearranged
Signaling that affects very distant cells of the body
Organism with a notochord only during embryogenesis
Selective inactivation of gene copy from only one parent
State in which a cell is irreversibly developing toward a specific fate
Type of induction that provides specific information to the responder
Organism that is comprised of cells with two different genotypes
Use of somatic cell nucleus from one organism to create a new
organism
Technique that provides the most specific information about the
spatial expression of a gene
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BIO 529 S04
Exam I
Name______________________
ID #_______________________
For all remaining questions, you must show your work or explain your reasoning to receive
any partial credit.
2. Most eukaryotic embryos are comprised of three primary germ layers.
a. Name the three germ layers and provide one example of an adult tissue derived from each.
(9 pts)
ectoderm- epidermis, nervous system, neural crest, etc.
mesoderm- notochord, bone, muscle, kidney, blood cells, etc.
endoderm- gut, pancreas, lungs, liver, etc.
b. What is the name for an organism with only two primary germ layers. (1 pt)
diploblast
3. Classify the following organisms with respect to the following features. (1 pt each)
Organism
Xenopus
Drosophila
Dictyostelium
Mouse
Arabidopsis
Animal, Plant,
or Protist
Animal
Animal
Protist
Animal
Plant
For Animals: Protostome
or Deuterostome
Deuterostome
Protostome
NV
Deuterostome
NV
For Animals:
Dipoblast or Triploblast
Triploblast
Triploblast
NV
Triploblast
NV
4. Name the three major stages of metazoan embryogenesis (after fertilization) and describe
what happens or is characteristic of each stage. (9 pts)
Cleavage- Fertilized egg divides many times without movements of the cells.
Gastrulation- Cell layers are rearranged relative to one another.
Organogenesis- Complex tissues are organized.
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BIO 529 S04
Exam I
Name______________________
ID #_______________________
5. You are given an animal whose development has never been characterized before. You note
that at the four-cell stage, one blastomere transiently shows red pigmentation. However, as
embryogenesis proceeds, the red pigmentation fades and you are unable to determine what
becomes of the blastomere in the fully-developed embryo. Describe a simple experiment you
can do to determine the fate of the red blastomere. Provide sufficient detail to show that you
understand the technique and its interpretation. (10 pts)
The simplest experiment is a cell lineage (fate mapping) analysis. One would
inject a marker (vital dye, fluorescent molecule, radioactive molecule,
enzymatic marker, immunological tag, etc.) into the red blastomere at the four
cell stage, then allow embryogenesis to proceed to completion. At that time
the tissues would be examined for the presence of the marker. Any tissue
with marker present would be derived from the red blastomere.
6. For the animal described above, you find that the red blastomere at the four-cell stage
ultimately gives rise to all of the central nervous system of the embryo. Using this
information, devise an experiment to determine whether development in this organism is
regulative or mosaic. In addition to describing the experimental procedure, describe the
possible results and how you would interpret them. (15 pts)
One could perform either an isolation or a defect experiment (or both). In the
isolation experiment, the red blastomere would be removed from the embryo
at the four-cell stage, then cultured in medium away from the rest of the
embryo. If development is mosaic, the blastomere should continue to develop
into CNS tissue. If development is regulative, the blastomere will either fail to
develop or will develop into tissues in addition to CNS (perhaps even a whole
organism).
In a defect experiment, the red blastomere would be removed at the four-cell
stage, then the remaining three cells would continue to be cultured as a
cluster. If development is mosaic, the embryo will develop lacking just the
CNS tissue. If development is regulative, the remaining cells will compensate
and produce a complete embryo.
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BIO 529 S04
Exam I
Name______________________
ID #_______________________
7. At the early gastrula stage of a Xenopus embryo, the presumptive eye tissue is transplanted
into a new embryo that in the region that gives rise to the somitic mesoderm. The resulting
transplanted tissue becomes somitic mesoderm. What does that tell you about the
presumptive eye tissue of Xenopus at the early gastrula stage? (8 pts)
The presumptive eye tissue was not yet determined. It may either have been
reversibly specified or not committed at all.
8. In birds, feathers form from the epidermis after induction by the underlying dermis. The
protein Feather Forming Factor (FFF) may be involved in this process. To determine the role
of FFF in feather induction, tissue from FFF mutants was mixed with wild-type tissue.
Indicate the anticipated results of these mixing experiments for each of the following
situations by filling in the table with “Yes” or “No” to indicate whether feathers would form.
(9 pts)
Dermis
FFFWild-type
FFF-
Epidermis
FFFFFFWild-type
FFF is Inducer
Feather Formation If…
FFF is Competence Factor
FFF is Not Required
No
Yes
No
No
No
Yes
Yes
Yes
Yes
9. The Binary Expression (GAL4) system is commonly used in Drosophila to easily misexpress
genes of interest. Using a diagram and words, explain the binary (two) DNA components of
this system and how they interact to create misexpression. (10 pts)
The system uses a GAL4 “driver” construct that expresses GAL4 under the
control of a specific promoter. The GAL4 transcriptional activator protein is
thereby produced in the cells of interest. The second construct contains the
UAS, an enhancer that binds GAL4 protein, controlling the expression of the
gene of interest. The GAL4 protein produced by expression from the first
construct binds the UAS sequence in the second construct to promote
transcription of the gene of interest.
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