In recombinant DNA technology, the genes encoding resistance to antibiotics such as ampicillin and tetracycline in a plasmid vector primarily act as:

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In recombinant DNA technology, genes encoding resistance to antibiotics such as ampicillin, chloramphenicol, tetracycline, or kanamycin are considered useful selectable markers for E. coli. Selectable markers help in identifying and eliminating non-transformants and selectively permitting the growth of the transformants. Therefore, the genes encoding resistance to antibiotics in a plasmid vector primarily act as selectable markers. Answer: Selectable markers