Lecture 14- Evolution and development

Question 1

specialisation vs organisation

Answer 1

specialisation involves controlling the distribution of cell types, organisation involves getting the right cells in the right place at the right time

Question 2

examples of ‘developmental gene’ types (6)

Answer 2

TFs
chromatin modifiers
enhancers
microRNAs
genes encoding signalling pathways
genes controlling cell movement

Question 3

3 types of mutation important in changes to development

Answer 3

changes in protein sequences
changes in regulatory mechanisms
gene/genome duplication

Question 4

examples of a change in regulatory regions leading to evolutionary change

Answer 4

threespine sticklebacks (fish)- reduction in the pelvis and spine as an adaptation to less salty water
Hox gene Pitx1 is responsible, expressed in different places in both populations- there is an enhancer driving pelvic expression in the saltwater fish

Question 5

4 mechanisms of new genes emerging

Answer 5

de novo from a non-gene sequence
horizontal transfer
reassembly from other genes
gene duplication

Question 6

how many clusters in a Hox complex

Answer 6

4

Question 7

mechanism of Hox gene evolution

Answer 7

○ Tandem duplication formed a cluster
○ Block duplication duplicated the cluster
Genes duplicated and then diversified

Question 8

where does this initial tandem duplication date to

Answer 8

early vertebrate development- most vertebrates have 2 clusters, while most invertebrates have 1