Final answer:
The mechanism highlighted by this question is reverse transcription, which is central to the lifecycle of retroviral-like retrotransposons and true retroviruses. (option 3)
Step-by-step explanation:
The mechanisms utilized by DNA-only transposons, retroviral-like retrotransposons, and true retroviruses include transcription, translation, reverse transcription, and replication. Specifically:
DNA-only transposons (Class II transposons) typically use a 'cut-and-paste' or replicative process that mirrors aspects of DNA replication and repair.
Retroviral-like retrotransposons (Class I transposons) and true retroviruses primarily rely on reverse transcription to convert RNA into DNA before integrating into the host genome. This process is facilitated by the enzyme reverse transcriptase, which is unique to these entities.
Once integrated, the viral or transposon DNA undergoes transcription to produce RNA, which can then be translated into proteins necessary for the formation of new virions or transposon copies.
DNA-only transposons use a 'cut-and-paste' or replicative mechanism, while retroviral-like retrotransposons and true retroviruses use reverse transcription, facilitated by the enzyme reverse transcriptase, to integrate their genetic material into the host genome.