Development Flashcards
Describe Arabidopsis thaliana.
Thale cress, small and easy to grow, short lifespan, flowering plant, good for embryology and genetics.
Describe Dictyostelium discoidum.
slime mould, chemotaxis (moving due to chemicals) & genetics, multicellularity, transgenesis, social behaviour/alturism.
Describe Hydra.
Diploblastic - double bud.
radial symmetry.
sexual and asexual regeneration!
immortal.
freshwater.
Describe Planaria
high regenerative capacity.
blob looking thing.
RNAi (interference) knockdown technology,
double stranded RNA inhibits gene.
Describe Caenorhabditis elegans.
nematode worm tiny 1mm. specific no of cells ~1000. RNAi knockdown technology. males and hermaphrodites, no females. self fertilising for genetics.
Describe Drosophila melanogaster.
fruit fly.
short generation time - 1day, genetics.
Transgenesis - introducing a new gene.
imaging
Describe Stronglylocentrotus purpuratus.
A deuterostome.
its a echinodermata - spikyskin.
spiky balls.
transparent embryos.
What is a deuterostome?
Forms anus then mouth. Humans r deut.
Describe Ciona intestinalis.
sea squirts/tunicates. look like corals. embryos look like tadpoles.
transgenesis/genetics/imaging.
they are chordates - same phylum as us.
urochordate - notochord in tail.
Describe Brachiostoma lanceolatum.
invertebrate but also chordate. cephalochordate
evolution not much else
What is a cephalochordate?
Notochord all the way to the head.
Describe Danio rerio (zebrafish).
vertabrate.
useful for genetics, common.
transparent embryos, external development.
Describe Frogs.
Produce large numbers of embryos quickly, mammals usually don’t.
Mammals.
Easy to transplant, regenerative.
transparent tadpoles
Describe the Gallus gallus.
Chick embryo. transplantation experiments, imaging.
Describe Mus.
Mouse embryo.
strong genetics.
mammal.
pluripotent embryonic stem cells.
What is a protostome?
mouth forms first, anus second
What is the endoderm?
inside tissue layer.
yellow
What is the mesoderm?
Middle tissue layer.
red
What is the ectoderm?
Outside tissue layer.
blue
What is descriptive embryology?
Experiments which aim to define normal development, describing different stages etc.
What is experimental embryology?
Changing things to find out how and when cells acquire their fate.
What is gastrulation?
morphogenetic process by which the endoderm, mesoderm and ectoderm layers reach their positions in the embryo.
What is neurulation?
morphogenetic process by which the nervous system begins to form, especially the neural tube.
What is a blastomere?
A cell in the early embryo.
What is morphogenesis?
process by which form in generated (requires coordinated cell movement).
What is a fate map?
Tell you what cells will become in their normal environment.
What is a specification map?
the assessment of what a cell of tissue will form if removed from their embryonic environment.
What does competance mean?
the range of cell fates that can be achieved by a group of cells.
What does induction mean?
emitting signales to change the fate of other cells.
Describe the stages of xenopus formation.
blastulus, gastrulation, neurulation, talibud, tadpole.
Descibe mosaic development.
First looked at tunicates, they had colorations in embryos.
If a cell is removed, that cells fate is completely lost from the embryo.
Describe regulative development.
If you remove the cell, the embryo will adapt, and find ways to get it back. Mediated by cell-cell induction.
Cells haven’t decided their fate yet, depend on neighbours.
What is a homeotic mutation?
A mutation which results in the transformation of one body structure into another.
What are hox genes?
Family of genes which encode related transciption factors characterized by containing a homeobox, mutations in hox genes lead to homeotic transformations.
What are homologous genes?
Genes that share a common ancestral gene.
What are paralogous genes?
Duplicated genes within a single genome.
What are orthologous genes?
Same gene in different organisms.
Describe gene redundancy.
A situation when no phenotype is observed when a gene is mutated because an additional gene can replace or is also involved in the functinoal role of the gene.
What is determinance?
Will still develop according to its fate even if removed
What does anterior mean?
head
What does posterior mean?
tail
What do ventral and dorsal mean?
Dorsal is back, ventral is front.
What did Wilhelm Roux find out?
Destroyed half the embryo at a 2-cell stage, the other half still regulated fine.
What did Hans Spemann discover?
Used baby hair to seperate the 2 blastomeres after division. Resulted with 2 normal embryos that adjusted and regulated its development.
Fate map =/ cell state.
That each nucleus was totipotent at the 16-cell stage.
A single nucelus had the ability to form a full organism. “first cloning”
Describe what Hidle Mangold discovered.
Transplanted a partfrom the dorsal region to another region of a different embryo. Used differently pigmented embryos. Able to induce a second embryo - siamese twin.
The tissue could induce the cells around it.
What is tandem gene duplication?
unequal cross over caused by chromosome mis-pairing, possibly caused by repeat DNA sequences.
Why is subfunctionalisation neccessary?
If all the replicated genes had the same function they would have no use and would be destroyed.
What is allotetraploidy?
whole gene duplication. hybridization between two seperate species.
What is autotetraploidy?
whole genome duplication.
hybridization through improper meiosis.
What are the methods of subfunctionalization?
Changing the protein sequence.
change time/place of expression.
What is segmental duplication?
A large tandem duplication, not single gene but a large chunk.
Where are the 3’ end and 5’ end expressed in patterning?
3’ anterior.
5’ posterior
What are toolkit genes?
act directly or indirectly to control the expression of other genes. ie hox genes control the anterior-posterior patterning.
What does potency mean?
the range of cell fates availible to a cell or tissue.
What does totipotent mean?
the abillity to develop into all cells.
What does pluripotent mean?
The ability to develop into most but not all embryonic cells.
What does bipotent mean?
the ability to develop into two cell types.
What does unipotent mean?
the ability to develop into one cell type.
Describe what Briggs & Kings discovered.
First to successfully transplant nuclei from blastula stage to eggs - tadpoles/frogs.
Didn’t work past blastula stage.
Describe the Waddington landscape.
Potency decreases with time. As totipotent cells differentiate they become more restricted.
However not one way road, differentiated cells can be reprogrammed back to an embryonic pluripotent state - nucleur reprogramming.
Describe John Gurdon’s experiments.
serial nucleur transplantation, repeated lots. Got normal clones.
First to clone an animal through nucleur transplantation using a terminally differentiated nucleus.
What are embryonic stem cells?
Remain at the top of the landscape under the right conditions.
Describe Yamanaka’s experiments.
First to reprogram cells/nuclei (induce pluripotency) without nucleur transplantation.
Can remove disease using own cells, no rejection.
What is the grey crescent fated to do?
become the notocord.
what are the effects of radiation on humans?
aplastic anemia - descrease in blood count.
nausea and vomiting.
loss of hair.
how can you treat radiation?
bone marrow transplants
What are hematopoietic steam cells?
In bone marrow
Why does nausea occur?
The intestinal steam cells are lost, cant renew the intestine cells.
Why does a loss of hair occur?
stem cells in hair are lost.
What are the factors for induced pluripotency?
Klf4 Sox2 Oct4 MyC
