L12- Evolution and Development

Question 1

What is ultrabithorax?

Answer 1

A HOX gene in which a mutation results in an ectopic set of wings

Question 2

What are HOX genes?

Answer 2

○ Important for organising nervous system, vertebral column, limbs etc
○ 4 clusters in vertebrates
○ Order of genes in genome reflects order of action in organism
○ Highly conserved

Question 3

What is heterotropy?

Answer 3

Change in location

Question 4

What is heterochrony?

Answer 4

Change in time

Question 5

What is heterometry?

Answer 5

Change in amount

Question 6

What is heterotypy?

Answer 6

Change in kind

Question 7

What are examples of heterotropy?

Answer 7

○ Cell death normally sculpts digits
○ Evolutionary changes to forelimb development in the bat compared to mouse
○ BMP signalling promotes interdigital cell death (mouse)
○ BMP inhibitors in bat (Gre, FGFs) prevent cell death in forelimb- webs

Question 8

What are examples of heterochrony?

Answer 8

○ Changes in times of development of forelimbs and jaw in marsupial mammal and placental mammal
○ MM needs to obtain milk from mother so it needs limbs and jaws earlier
○ FGF expression initiates earlier in MM forelimb/hindlimb compared to mouse

Question 9

What are examples of heterometry?

Answer 9

○ Darwins finches have different beak morphologies and structures
○ Ground finches have deep, broad beaks (elevated expression of Bmp-4)
○ Longer beak- elevated CaM

Question 10

What are examples of heterotypy?

Answer 10

○ Insects have 6 legs but they evolved from ancestors with multiple legs
○ In drosophila, Ubx gene suppresses hindlimb formation yet in Artemia Ubx is expressed in all limb bearing segments.

Question 11

What is modular control?

Answer 11

Control of developmental genes
○ Different regulatory regions control the expression of genes in different areas.
○ A mutation in one area won’t impact the expression of the gene in the other areas.