Lecture 21 - Transposable Elements

Question 1

What is a transposable element?

L21 S3

Answer 1

Sequences that are able to move around in the genome

Question 2

What repeated sequences are characteristic of transposons?

L21 S5-6

Answer 2

Short, flanking repeats:

• not part of transposon but found on either side
• caused by staggered cut made from insertion

Terminal, inverted repeats:
-recognition by enzyme responsible for transposition

Question 3

Differentiate between replicative transposition and non-replicative transposition?

L21 S16-20

Answer 3

Replicative:

• creates a copy of transposon that inserts elsewhere
• increases copy number
• “copy and paste”

Non-replicative:

• transposon leaves DNA and inserts elsewhere
• does not increase copy number
• “cut and paste”

Question 4

Who is Barbara McClintock?

L21 S29-30

Answer 4

Nobel prize recipient (1983) for her work on discovering that variegated corn kernels are due to transposable elements that interrupt pigment genes

Question 5

In what way does p53 regulate transposons?

L21 S40

Answer 5

p53 suppresses mobile elements, such as transposons.

Transposition is greatly increased when p53 is inactivated, such as in cancer.