Which biomolecule is analyzed to determine if a transgene is present in an animal's cells?

• A. RNA
• B. DNA
• C. Protein
• D. Mitochondria

Answer: (B)

The main idea is to confirm the presence of a transgene by checking the genetic material that actually carries the gene. Transgenes are written into DNA and become part of the organism’s genome, so analyzing DNA directly provides definitive evidence that the transgene is present. Techniques like PCR or Southern blot target the transgene’s DNA sequence to show its presence and, in some cases, copy number.

If you looked at RNA, you’d be assessing whether the gene is being expressed, not whether the transgene is physically present. Protein analysis would tell you if the gene is produced as a product, which depends on transcription and translation and cellular regulation. Mitochondrial DNA isn’t the usual repository for a transgene, which is typically integrated into nuclear DNA. So DNA analysis is the most direct and reliable way to determine presence.