Question

1. What is the major difference between simple transposons and retrotransposons?

2. How can simple transposition lead to copy number increase?

3. Briefly explain the role of reverse transcriptase and integrase in retrotransposition.

4. What damage does UV do to DNA?

5. UV damage to DNA is repaired by the Nucleotide Excision Repair Pathway. Briefly explain how UvrB and UvrC repair UV damage in E.coli.

Answer 1

1). The primary difference between transposon and retrotransposon is their mode of replication.

Transposons replicate by the common mode of DNA replication and encode an enzyme known as the transposase, which acts on the DNA sequences located at the transposon end, and makes it get inserted into another DNA site, this process repeats and keep the transposon from hopping over and over.

The retrotransposons replicate first by transcribing into RNA. They the DNA copy is produced by the reverse transcriptase. The DNA now integrates into the host genome.