Developmental Bio Flashcards
What is the central dogma?
DNA -> Transcription -> RNA -> Translation -> Protein
What are untranslated regions (UTRs)?
Sections before a start codon (ATG) and after a stop codon that don’t make it into the protein.
What are removed via splicing during transcription?
Introns
Why is Drosophila a good model system?
Rapid life cycle, small in size, genetically tractable & has accessible embryos.
What is homeosis?
The transformation of one body region/part so that it resembles another.
Segment differentiation in Drosophila shows examples of what 4 concepts?
Morphogenetic gradients, developmental fields, positional information and boundaries.
What determines the differentiation pathways which control positioning in Drosophila?
The Hox code
Name 4 parts of “development.”
Growth, regional specification, morphogenesis and cell differentiation.
What is potency?
The total things tissue can develop into in the appropriate environment.
What is a morphogen?
A substance with variable levels which cause different target gene activities - different responses + threshold effects.
Why is bicoid an example of a morphogen?
It has asymmetric localisation, as it induces the head and thorax.
What makes morphogen gradients so important?
Cells have the potential to develop differently depending on the concentration of them morphogen in that region.
What is an embryonic field?
An area of embryo/tissue within which a certain process occurs.
Why are Xenopus laevis useful in experimental embryology?
They produce large, amenable eggs.
What is induction in embryology?
An embryonic region interacts with another to influence its behaviour or differentiation, using chemical singles from cells or the environment.
What is specification?
When a tissue/cell develops autonomously into a particular structure after isolation from the embryo.
What is the name for the potential tissue has to respond to induction?
Competence
What is fate?
The final state of cells/tissue during normal development.
What is determination?
Irreversible commitment of a tissue/cell to develop into a particular type, regardless of surroundings.
What is mosaicism?
When the map of specified regions are determined independently and match the fate map.
What is regulation?
When the map of specified regions does not match the fate map so it is re-established on uncommitted tissue.
What are the 4 stages of lineage commitment?
- Undifferentiated
- Specified
- Determined
- Differentiated
What is lateral inhibition?
When one cell fulfils a role and a signal passes so the next cell develops into something else.
What causes stripes in every segment of anthropods?
The ‘segment polarity’ gene, expressed at the phylotypic stage.
What is the name for different genes in front and back regions of organism?
Dorsal-ventral patterning.
What are master control genes?
Genes which set in motion a chain of developments.
Give some examples of likely developmental mechanisms present in the Urbilaterian.
Pax6 gene for eyes, Distalless gene for appendages and tinnan gene for hearts.
What is the Urbilaterian?
The first bilaterian animal.
With such deep homologous, what is one way bilaterians become so diverse?
Mutations
What is subfunctionalisation of duplicated genes?
Both daughter cells remain.
What is neofunctionalisation of duplicated genes?
Daughter cells evolve new functions.
What is nonfunctionalisation of duplicated genes?
One daughter cell is lost/redundant.
What is the DDC model?
Duplication, Degeneration and Complementation.
What is the role of modular regulatory elements?
They control expression of genes in distinct contexts.
What is pleitropy?
When genes have multiple functions.
What is heterotopy?
Evolution via changing topological arrangement of structures.
What is heterometry?
Evolution via changing the size of structures, and so changing the expression levels.
What is heterotypy?
Evolution via changing types of structures.
What is the name for the recruitment of developmental networks into evolutionary novelties?
Co-option
What is heterochrony?
Evolution via changing timing of developmental events.
