Transposable Elements

Question 1

Transposable elements

Answer 1

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

Question 2

Replicative transposition

Answer 2

1. Transposable element is duplicated
2. TE is made into RNA and reverse transcribed into DNA
3. DNA is inserted into genome
   “Copy and paste”

Question 3

Retrotransposons

Answer 3

Replicative TEs

Question 4

Conservative transposition

Answer 4

TE is cut out of genome and is inserted elsewhere

“Cut and paste”

Question 5

Genes found in transposable elements

Answer 5

Transposase: endonuclease (cuts within sequence) that cuts DNA
Enzyme to paste gene back in
Reverse transcriptase
Repeats in nucleotides at the ends of TEs: terminal repeats

Question 6

Ways that transposable elements can reorganize the genome

Answer 6

1. Disrupt reading frame
2. Insertion into regulatory sequence: new expression pattern
3. Excision of TE with parts of other genes: “messy” transposition can cause deletions
4. Recombination of 2 TEs: pieces of the two genes that contain the TEs are fused together

Question 7

Autonomous transposable elements

Answer 7

Can move by themselves

Encode transposase

Question 8

Nonautonomous transposable elements

Answer 8

Lack transposes and can’t move by themselves

Require help from autonomous TEs