Mutations Part 2

Question 1

Segments of DNA that have the capacity to move in the genome

Answer 1

Transposable Elements

Question 2

• “Copy and Paste” –increase C value
• Transposable element is duplicated; TE is made in to RNA and then reverse transcipted to DNA; DNA is transposed into genome

Answer 2

Replicative transposition

Question 3

• “Cut and paste”

- Transposable element is cut out of chromosome and inserted elsewhere

Answer 3

Conservative transposition

Question 4

Endonuclease that cuts DNA

Answer 4

Transposase

Question 5

Features found in transposable elements

Answer 5

• Enzyme to paste gene back in
• Reverse transcriptase
• Terminal repeats: repeats at ends of TE

Question 6

Transposable elements can reorganize the genome in several ways:

Answer 6

1. Disrupt reading frame
   - interrupt intron by:
   * enhancers, splice site, repressors
   - Insert into a regulatory sequence:
   * enhancer: decrease transcription
   * new expression pattern: can fuse segments together or “messy” transposition can remove DNA and cause deletions

Question 7

Two kinds of transposable elements

Answer 7

1. Autonomous

2. Nonautonomous

Question 8

Can move by themselves, encode transposase

Answer 8

Autonomous

Question 9

Requires autonomous element for movement; lack transposase gene; cannot move by themselves

Answer 9

Nonautonomous

Question 10

Which of the following is a potential effect of transposons in the genome?

a. Gene inactivation by insertional mutagenesis
b. Change in gene regulation by epigenetic change in nearby chromatin
c. Alterin splice sites of genes
d. Deletion of genetic material due to sloppy transposition
e. All of the above

Answer 10

e. All of the above