Evolutionary Development – Lecture 7 – Model organisms in
evolutionary development biology
Importance of models
Study of mammalian embryology is difficult due to placentation
Use of vertebrate animal experiment should be limited for ethical reasons
Principles of developmental biology hold equally well for invertebrates and
vertebrates
Comparative embryology shed light on alterations of developmental pathways
underlying evolutionary change
Body plan of animal
General organization according to anterior/ventral-posterior/dorsal axis
Symmetry of the body, subdivision, sense organs, appendages (aanhangsels)
Relative position and organization of the main biological systems
Zygote contains all information on adult body plan – body plans enroll step by step
throughout development (cleavages, proliferation, apoptosis, cell migration etc.)
Large variability in body plans
Despite the variability in body plans there is:
A limited number of organizational principles
A limited number of molecular tools
This allows:
Reconstruction of evolutionary patterns
Extrapolation (uitbereiden) across species
The 6 model organisms
Invertebrates: C. elegans and Drosophilia
Vertebrates: Mouse, Chicken, Xenopus, Zebrafish
C. elegans (roundworm): phylum -- nematode
One of two first organisms whose entire genome was sequenced
Easy to grow
Genetically manipulated
Short generation time
Produce many offspring
Free living non-parastic nematode
1,5 mm by 80 um
959 cells
±20.000 genes
Hermaphroditic; they are male and female (First male
and then becomes female) (Male during larval stage 4.
In adult stage female use sperm from L4 to fertilize eggs)
Essential biological functions shared with human:
development, behaviour, neurobiology, aging
40% of protein-coding genes of C.elegans have
homologous gene in human being
o Model for Parkinson’s disease:
evolutionary development biology
Importance of models
Study of mammalian embryology is difficult due to placentation
Use of vertebrate animal experiment should be limited for ethical reasons
Principles of developmental biology hold equally well for invertebrates and
vertebrates
Comparative embryology shed light on alterations of developmental pathways
underlying evolutionary change
Body plan of animal
General organization according to anterior/ventral-posterior/dorsal axis
Symmetry of the body, subdivision, sense organs, appendages (aanhangsels)
Relative position and organization of the main biological systems
Zygote contains all information on adult body plan – body plans enroll step by step
throughout development (cleavages, proliferation, apoptosis, cell migration etc.)
Large variability in body plans
Despite the variability in body plans there is:
A limited number of organizational principles
A limited number of molecular tools
This allows:
Reconstruction of evolutionary patterns
Extrapolation (uitbereiden) across species
The 6 model organisms
Invertebrates: C. elegans and Drosophilia
Vertebrates: Mouse, Chicken, Xenopus, Zebrafish
C. elegans (roundworm): phylum -- nematode
One of two first organisms whose entire genome was sequenced
Easy to grow
Genetically manipulated
Short generation time
Produce many offspring
Free living non-parastic nematode
1,5 mm by 80 um
959 cells
±20.000 genes
Hermaphroditic; they are male and female (First male
and then becomes female) (Male during larval stage 4.
In adult stage female use sperm from L4 to fertilize eggs)
Essential biological functions shared with human:
development, behaviour, neurobiology, aging
40% of protein-coding genes of C.elegans have
homologous gene in human being
o Model for Parkinson’s disease:
