Lecture Notes on Evolutionary Developmental Biology (Evo-Devo)

Introduction to Kids' Perception of Scientists

• Kids often think of scientists as:
  • Blowing things up in labs.
  • Becoming superheroes by getting bitten by radioactive creatures.
  • Creating bizarre creatures like flies with eyeballs on their butts.
• Reality is different; scientists work in controlled environments.

What is Evolutionary Developmental Biology (Evo-Devo)?

• A new science studying genes to understand body formation and evolution.
• Reveals that all animals are genetically more similar than previously thought.

Genetic Similarity

• Humans and chimps are 98.6% genetically similar.
• Surprisingly, humans and mice are 85% genetically similar.
• Differences arise from developmental regulatory genes.

Developmental Regulatory Genes

• Control the activation of genes that build body parts.
• Do not instruct how to build, only when or if to build.
• Types of regulatory genes:
  • Gap genes: Decide basic structure during early development.
  • Homeobox genes (Hox genes): Control body part identity and organization.
• Hox genes act like architects, giving plans but not building.

Gene Hierarchy

• Rigid hierarchy in gene activation:
  • Hox genes at top, followed by layers of regulatory genes.
  • Each layer adds specificity to the gene instructions.
• A gene does nothing until activated by another gene.

Activation of Regulatory Genes

• Exact activation mechanisms unknown; a subject for future research.
• Some regulatory genes might be "junk DNA"; recently thought to have purposes.

Inheritance and Consistency of Regulatory Genes

• Inherited like other genes, but very consistent within a species.
• Everyone in a species shares the same regulatory gene sequences.

Experimental Evidence: Fruit Fly Experiment

• Mouse hox gene inserted into fruit fly led to a fruit fly eye on the leg.
• Demonstrates genes instruct "to build" rather than "how to build."

Evo-Devo and Evolution

• Evo-Devo aids in understanding rapid evolution.
• Evolution via genetic mutation vs. regulatory gene changes.
• Small changes in top-tier regulatory genes can lead to significant evolutionary changes.

Example: Bird Evolution from Dinosaurs

• Traditional view: slow mutation rate.
• Evo-Devo suggests regulatory genes turning off/on traits rapidly.
• Chickens (birds) found to have dormant genes for teeth.

Conclusion and Further Learning

• Evo-Devo provides insights on both evolution and genetic expression.
• Fascinating new science with ongoing research opportunities.
• Encourages further exploration and study in this promising field.