DEV2011 Lecture Notes - Lecture 4: Stem Cell, Model Organism, Zebrafish
Lecture 4 – Evo-devo and Model Organisms
Phylogeny
• Shared evolutionary – important in determining suitability of a model
organism
• Anatomy therefore reflects our long ancestry
Studying Development of Humans
• Rarely use human beings
• Use other organisms
• Developmental biology
o Animals
• Molecular biology
o Use yeast, bacterium
▪ Yeast: undergo meiosis like genomes in humans
• Physiology
o Use cow, sheep
Roundworms
• Small ~1mm in length
• Easy to cultivate
o Grown on agar plates – bacteria for food
• Short life cycle
o Egg (hermaphroditic) adult is only 3 days
• Similarity
o ~40% genes implicated in human disease have orthologues in worms
• Adult worms have 959 somatic cells
o Specific cells must die during development for it to proceed (apoptosis
– programmed cell death)
Drosophila Advantages
• Very inexpensive
• Prolific breeding rate
• Generation times are very short – breeding age of 10 days old
• Body patterning
• Stem cell biology
• Reproductive biology
• Are invertebrates
o Lack blood vessels
• Don’t generate antibodies to fight disease
Zebra Fish
• Tropical freshwater fish
o Originally from Ganges in Eastern India
• Are vertebrates
• Mutations in zebrafish genes can produce similar phenotype to human
diseases
o Easy to maintain large numbers
o Can induct mutations or test toxicity simply by adding substances to
water
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Document Summary
Phylogeny: shared evolutionary important in determining suitability of a model organism, anatomy therefore reflects our long ancestry. Studying development of humans: rarely use human beings, use other organisms, developmental biology, animals, molecular biology, use yeast, bacterium, yeast: undergo meiosis like genomes in humans, physiology, use cow, sheep. Drosophila advantages: very inexpensive, prolific breeding rate, generation times are very short breeding age of 10 days old, body patterning, stem cell biology, reproductive biology, are invertebrates, lack blood vessels, don"t generate antibodies to fight disease. Ideal for studying brain circuitry, synaptic plasticity and behaviour: body patterning, altering expression of specific genes during embryogenesis roles in fundamental developmental process can be observed, paraxial mesoderm development and somitogenesis, regeneration, regenerate heart muscle, fins, skin. Frog x. laevis: pseudotetraploid vertebrate, lives in fresh water, most essential cellular and molecular mechanisms. Incubation period of 21 days: fundamentals of early embryogenesis learned from chick, early embryonic development, body patterning, reproductive biology.