What is the source of the reverse transcriptase used in recombinant DNA technology?

• A. Plant cells
• B. Cultured fungal cells
• C. Cultured phage-infected mammalian cells
• D. Either retroviruses or cultured phage-infected mammalian cells
• E. Retroviruses

Answer: (E)

Verified step by step guidance

1. Understand the role of reverse transcriptase: Reverse transcriptase is an enzyme that synthesizes DNA from an RNA template, a process called reverse transcription.
2. Identify the natural source of reverse transcriptase: Reverse transcriptase is naturally found in retroviruses, which are a type of virus that uses RNA as its genetic material.
3. Consider the options provided: The options include plant cells, cultured fungal cells, cultured phage-infected mammalian cells, and either retroviruses or cultured phage-infected mammalian cells.
4. Eliminate incorrect options: Plant cells and cultured fungal cells do not naturally produce reverse transcriptase. Cultured phage-infected mammalian cells may contain reverse transcriptase if they are infected by a retrovirus, but they are not the primary source.
5. Conclude with the correct source: Retroviruses are the primary natural source of reverse transcriptase, as they require this enzyme to replicate their RNA genome into DNA within a host cell.