Genome Evolution

Question 1

What is the molecular clock?

Answer 1

The change in nucleotide sequence that occurs at about 1% every 10 million years

Question 2

How is the molecular clock calibrated?

Answer 2

Using fossil records

Question 3

What are the positions in which mouse and chimps or chimps and humans share on the FOXP2 gene?

Answer 3

Mouse and chimp - 303T

Chimp and human - 80D

Question 4

What is convergent evolution?

Answer 4

Where organisms not closely related inherit similar traits as a result of having to adapt to similar ecological niches

Question 5

What are the 4 clusters that the 22 FGFs fall into based on?

Answer 5

Protein sequence alignment

Question 6

How do many FGFs arise?

Answer 6

Gene duplication

Question 7

Describe chromosome duplication

Answer 7

Duplicate genes are initially redundant. The extra copy can change in pattern of expression or structure of the protein. Small changes are caused by point mutations and big changes are caused by domain swapping.

Question 8

Enhancers are easily changed, T or F?

Answer 8

T

Question 9

What is the evidence that a new enhancer closer to the gene changes function?

Answer 9

1. C6 Hox gene expression starts posterior in chick = longer neck and less chest than mouse
2. Changing expression of a single gene creates ectopic organs. Master regulatory genes regulate whole gene networks - crustaceans have legs on abdomen, insects only have on thorax. Is this due to change in leg master regulatory gene during evolution?

Question 10

What is an example of a change in expression of a single gene leading to ectopic organs?

Answer 10

In flies Dlx specifies leg precursor cells and Ubx represses DLx. Ubx is expressed in abdomen.
In crustaceans Ubx doesn’t act as a repressor - they have a anti-repression motif that was lost in insects