In standard recombinant DNA-based gene cloning, what is typically the first step in the cloning workflow?

• A. Amplify and express the cloned gene to produce large amounts of the protein product.
• B. Select transformed cells on antibiotic-containing medium and screen for correct inserts.
• C. Isolate the DNA containing the gene of interest (e.g., extract genomic DNA or prepare cDNA from mRNA).
• D. Transform competent bacterial cells with the recombinant plasmid.

Answer: (C)

Verified step by step guidance

1. Understand the overall goal of recombinant DNA-based gene cloning, which is to obtain multiple copies of a specific gene by inserting it into a vector and propagating it in host cells.
2. Identify the starting material needed for cloning, which is the DNA containing the gene of interest. This can be genomic DNA extracted from cells or complementary DNA (cDNA) synthesized from mRNA.
3. Recognize that the first practical step in the cloning workflow is to isolate this DNA, ensuring you have the target gene available for further manipulation.
4. After isolation, the gene of interest is typically inserted into a cloning vector (such as a plasmid) to create a recombinant DNA molecule.
5. Subsequent steps include transforming competent bacterial cells with the recombinant plasmid, selecting transformed cells on antibiotic-containing media, and then amplifying and expressing the cloned gene.