Unit 4: Evo-Devo, Development and Evolution

Question 1

Why is development important in evolutionary biology ?

Answer 1

As commonality of body organisation and developmental patterns reflects shared ancestry

Question 2

Why is evolutionary change often due to changes in late rather than early embryonic development

Answer 2

• As early development is highly conserved and essential for survival, so changes are less likely
• Late development is more flexible and can accommodate changes in traits (e.g., size, shape, and function) without affecting survival

Question 3

How does gene regulation contribute to development ?

Answer 3

• Changes in gene regulation can lead to new traits or structures without altering the genetic code

Question 4

How does gene regulation contribute to evolution ?

Answer 4

• Small changes can cause large evolutionary changes in form and function
• Lead to adaptations

Question 5

What is the role of transcription factors in development ?

Answer 5

• Different gene expression profiles (controlled by TFs) determine cell and tissue characteristics = ultimately body features
• Temporal (timing) and spatial regulation of gene expression during development determines the features of an adult = critical for speciation processes

Question 6

What does eco-devo examine ?

Answer 6

How slight genetic divergences can become magnified into major morphological differences between species

Question 7

What are HOX genes ?

Answer 7

Regulatory genes that control the expression of other genes which control major patterns of animal architecture

Question 8

What is the number of HOX genes correlated with ?

Answer 8

The complexity of the animals anatomy .e.g. more complex= more HOX genes

Question 9

What is a homeotic mutant ?

Answer 9

A HOX gene mutant

Question 10

What happens when there are mutations in homeotic genes ?

Answer 10

They transform one segment into another

Question 11

What can changes in where HOX genes are expressed affect ?

Answer 11

Can result in different morphology and anatomy

Question 12

What are the 4 types of genes that are important in development and evolution ?

Answer 12

1) Cell adhesion proteins (control cell migration and localisation during development)
2) Cell surface receptors (critical for response to extracellular signals, such as secreted factors)
3) Secreted morphogens (attract cell to certain microenvironments, stimulate local cell response)
4) Regulator of cell death or apoptosis (regulate number of cells in certain tissue/organs)