Intro to Development Flashcards
What three main things does development consist of?
Positional information (cell signalling)
Differentiation (differential gene expression)
Morphogenesis (growth/changes in cell shape/cell movement)
What are the advantages of using nematodes (Caenorhabditis elegans) as a model organism for development?
Transparent (can track individual cells)
Grown in large numbers
Easy to screen for novel drug effects
Useful for study of aging and neural development -> connectivity map of 302 neurons with 7000 synapses exists where functions are known and understood
What are the advantages of using fruit flies (Drosophila melanogaster) as a model organism for development?
Rapid development
Small genome size so easy to understand
Availability of developmental mutants (easy to generate mutants) (for studying gene function)
What are the advantages of using zebrafish (Danio rerio) as a model organism for development?
Small and robust
Transparent (can track individual cells)
Cheaper maintenance than mice
Can lay eggs any time, constant source of embryos (other fish more limited in laying)
->Hundreds of eggs at weekly intervals
What are the advantages of using African clawed toad (Xenopus laevis) as a model organism for development?
Large oocytes
Cell-free extracts rich in protein, DNA, RNA for study
Cell cycle synchrony
Conserved molecular mechanisms with humans
Ease in microinjection
What are the advantages of using mice (mus musculus) as a model organism for development?
99% match with human genome
Easy to generate knock-out or transgenic mice
Easy to tag proteins
Small size -> large scale cost efficient model
Good genetic/molecular toolbox available
Access to embyronic stem cells
What are the advantages of using chicks (Gallus gallus domesticus) as a model organism for development?
Easy to label, transplant and culture cells and tissues
Similar to mammalian development systems (Gestation is same timeframe as mice: 21 days)
Access to egg (by cutting top off shell) for imaging and manipulation (tissue transplants, fluorescent probes, development in-vivo)
What is the name of the pigmented part of the unfertilised Xenopus eggs?
Animal hemisphere
What is the name of the unpigmented part of the unfertilised Xenopus eggs?
Vegetal hemisphere
What stage of embryonic development follows fertilisation in Xenopus?
Cleavage
What stage of embryonic development follows cleavage in Xenopus?
Gastrulation
Describe the structure of a blastula
Epithelium surrounds a more hollow interior
Which organism is most useful for early embryo development study?
Xenopus (frog) due to large eggs
Describe cleavage 1 and 2 in Xenopus embryonic development
Cleavage 1 splits zygote into two, cleavage 2 splits zygote into four. They are perpendicular and equal holoblastic.
The nuclei are displaced and in
animal hemisphere (animal-ward)
Describe cleavage 3 in Xenopus embryonic development
Cleavage 3 is perpendicular/equatorial to 2 and 3.
It is unequal holoblastic (closer to
animal cap, in vegetal region)
What are the two main functions of gastrulation?
Form gut
Form primary germ layers
Which end of where the blastopore begins and ends becomes the mouth and anus of the organism? (Xenopus)
Begins becomes anus
Ends becomes mouth
What are the primary germ layers?
Endoderm
Mesoderm
Ectoderm
What is the blastocoel?
The cavity in the middle of the blastula
What is the blastula?
Stage after the morula, epithelium surrounding hollow interior
What is the morula?
Ball of cells after the 16 cell stage
In vertebrates, what organs does the endoderm go onto form?
Gut, liver, lungs
In vertebrates, what organs does the mesoderm go onto form?
Skeleton, muscle, kidney, heart, blood
In vertebrates, what organs does the ectoderm go onto form?
Skin, nerous system
