Lecture 4 Flashcards
What determines the development of adult form?
Interactions of genes, gene products and the environment.
What happens when the dominant female anenome fish dies?
The dominant male changes sex to replace her.
What causes similarities and differences between organisms.
Similarities are due to common ancestors and differences result from natural selection which has adapted them to different environments.
What did Darwin recognise about development?
Relationships among organisms can be deduced from embryonic similarities (even though adult forms are much more different).
What is evolutionary development (evo-devo) biology?
How changes in developmental genes over time affect adult form and how they influence evolution.
What is an example of a conserved developmental gene?
Pax6 gene triggers eye development wherever it is present in both mice and drosophila.
What’s another example of a conserved developmental gene?
Same set of hox genes provide anterioir-posterior in both mammal and insect embryos. Temporal and spatial expression is similar in the 2 groups.
Why can it be assumed that it’s more than just genetics which controls development?
Because the conserved developmental genes generate so many different forms so other factors must affect developmental.
What are the 3 ways morphological changes can result from the same developmental genes?
Mutations in developmental genes.
Changes in spatial expression.
Changes in temporal expression.
What’s an example of a mutation in a developmental gene?
Insect Ultrabithorax gene is mutated in insects represses distal-less gene which is essential for leg formation. This prevents leg forming on the abdomens while spiders etc. do.
What’s an example of changes in spatial expression of developmental genes?
In birds bone morphogenic protein 4 (BMP4) is expressed between the toes to apoptose the webs in the feet. Gremlin protein in ducks inhibits BMP4 so maintain webbed feet.
How is evolution of development made easier?
Because of its modularity.
Define heterochrony.
Timing of developmental processes can shift independently thanks to the modularity of development.
Give an example of differences in temporal expression of development genes.
Salamanders delay the expression of genes that apoptose webs inbetween feet to allow juvenile webbed feet.
What are the 2 types of environmental cues that determine development.
- Cues necessary for normal development that organisms have an adaptive response to.
- Signals correlated to future conditions that organisms will respond differently to.
