Evo-devo Flashcards
(46 cards)
Evolution refers to changes on which 4 scales?
- Genomic
- Morphological
- Physiological
- Behavioural
The same species can have highly different morphologies. Give 2 examples.
- Breeds of dog.
2. Races of human.
What does ‘evo-devo’ mean?
Evolution arises from changes to development.
What do exons do?
Code for proteins.
What do introns do?
Control gene expression.
What do enhancer regions do?
Control transcription and thus protein synthesis.
What is a DNA binding motif and why do enhancer regions each have unique ones?
A specific sequence for a TF to bind to. Enhancer regions all have different TFs so DNA binding motifs are unique.
What does an activator do?
Bind to an enhancer region and stimulate transcription.
What does a repressor do?
Bind to an enhancer region and suppress transcription.
Give 3 examples of cytoplasmic determinants (CDs).
Proteins, mRNA and morphogens.
Cytoplasmic determinants are asymmetrically distributed. What does this mean during cell division?
The resultant daughter cells will have different compositions of CDs and thus differentiate independently.
Why are gap junctions important for the control of cell signalling?
CDs have to diffuse through gap junctions, which can affect speed and distribution.
Many cell-signalling pathways are ligand-gated. Give an example.
Wnt signalling.
What is the main point of Wnt signalling?
Dsh inhibits GSK3-beta so it can no longer degrade beta-catenin. Beta-catenin then moves into the nucleus to activate the hedgehog pathway.
What does pax6 control?
The eye.
Pax6 can be moved between species and still produce the same result. Give an example of this.
Mouse pax6 can be inserted into drosophila. Mice have camera eyes and drosophila has a compound eye. Insertion of mouse pax6 still produces a compound eye in drosophila.
What do transplant experiments in pax6 show?
It activates the same signalling pathway in all organisms, showing it is highly conserved.
If pax6 can be transplanted between animals, what does this say about gene expression?
The coding sequence is the only part that needs to be conserved - what creates differences between species is the non-coding, regulatory regions.
Define microevolution.
Comparing differences between populations of the same species, e.g. races of human.
Define macroevolution.
Comparing different species.
Define comparative embryology.
Studying the differences in gene regulation and expression between species.
Define experimental embryology.
Testing gene regulation and expression by experimental manipulation of embryos.
Which signalling pathway is upregulated in Darwin’s finches with long, pointed beaks?
Calmodulin-dependent.
What role does BMP4 expression play in Darwin’s finches?
Control beak size: lots of BMP4 produces a large beak.
