Transposons and TMDH

Question 1

What are the main features of a insertion sequence element?

Simple transposable element

Answer 1

1-2kb
-only encodes transposase (req for transposition)
-inverted repeats

Question 2

What are the main features of a transposon?

Complex transposable element

Answer 2

-encodes transposase and other genes (eg. antibiotic resistant or catabolic genes)

Question 3

What are the effects of a transposon being inserted into a genome?

Answer 3

-occurs at random sites
-may interupt coding seq/transcriptional unit ->null mutant (has downstream effects)

Question 4

What are autonomous and non-autonomous transposons?

Answer 4

Autonomous tns encode transposase
Non-autonomous tns don’t, so rely on on proteins expressed from related autonomous transposons (have the same terminal inverted repeats)

Question 5

Name examples of autonomous and non-autonomous transposons

Answer 5

Ac/Ds system in maize
-Ac (activator) is autonomous (has its own transposase)
-Ds is non-autonomous (shorter gene region so no transposase, but has same inverted repeats so can use Ac transposase)

LINEs and SINEs
-Long intersperced repeats are autonomous
-Short intersperced repeats are non-autonomous (like Ds, use LINE transposase)