Question

which of the following most accurately describes a retrotransposon?

• A. a DNA sequence that can move from one site in the genome to another without replication
• B. a DNA sequence that can be deleted from the genome without consequences
• C. a DNA that replicates via an RNA intermediate
• D. a DNA that replicates via protein intermediate
• E. a DNA that causes base-substitution mutations at some other site on the chromosome

Answer 1

The correct option is A a DNA sequence that can move from one site in the genome to another without replication

Retrotransposons (also called transposons via RNA intermediates) are genetic elements that can amplify themselves in a genome. The first step in retrotransposition occurs when the transposable DNA is copied into RNA. The RNA segment then jumps to another location in the genome. However, in order to be inserted into the genome at the new site, the RNA must be copied back into DNA by an enzyme called reverse transcriptase. Here, the amplification of DNA takes place without replication.

So, the correct option is 'a DNA sequence that can move from one site in the genome to another without replication.