A researcher overexpresses the full-length genomic sequence of rice GAPDH gene under a CaMV35S promoter in transgenic rice. Which one of the following options can be used to confirm transgenic lines using PCR?​

Correct option is D

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This method targets the unique junction between the CaMV35S promoter and the GAPDH gene, ensuring specific detection of the transgene. Other options could amplify endogenous sequences or unrelated regions, causing ambiguity.

Information Booster

• CaMV35S Promoter: A widely used constitutive promoter in plant genetic engineering that drives high expression of transgenes.
• Transgene Confirmation: PCR using primers spanning the junction between the CaMV35S promoter and the gene of interest ensures specific amplification of the transgenic construct, avoiding false positives from endogenous genes.

Additional Knowledge

• Option (a): Exon-specific primers would amplify both transgenic and endogenous GAPDH genes, leading to non-specific results.
• Option (b): Intron-specific primers target regions present in the endogenous gene but might be absent in the transgene, leading to unreliable confirmation.
• Option (c): Amplifying the GAPDH promoter is irrelevant because the transgene is under the CaMV35S promoter, not its native promoter.