Lecture 34: Evolution of Development: Genes & Form Flashcards
Natura non facit saltus
Nature does not make leaps
Point mutation altering protein sequences have what type of affects?
They alter the phenotype, but have a slow evolutionary change
Point mutations altering the protein and regulatory sequence have what type of affects?
They alter the regulatory networks (which could also alter the phenotype)
fast evolutionary change
New cell types, or new cell positions?
Is it that new cells have evolved or that have been some change to already existing cells?
define exoskeleton
a rigid external covering for the body in some invertebrate animals, especially arthropods, providing both support and protection.
What are developmental events?
They are robust synapomorphies that define monophyletic groups
Define homeotic genes
are genes which regulate the development of anatomical structures in various organisms such as insects, mammals, and plants.
- linear sequence on chromosome = anterior posterior body axis
- temporal expression follows chromosomal location
What is the Homeobox region?
60 amino acid sequence found in homeotic genes, turn on a cascade of other genes
What are homeotic mutation?
They transform one structure into the fate of another structure.
(genes defined by the structure they alter when gene is mutated)
Biothorax complex
transforms thorax segment 3 into 2
What are the 4 dimensions of development?
X, Y, Z and time
cells in developing embryos get information from adjacent cells
Define orthology
homology due to speciation events
Define paralogy
homology due to gene duplication events
Different patterns of gene expression can lead to morphological diveristy
Ex. HOX genes
