Question

What is the role of markers in a plasmid?

• A. To help in selecting the cells that are transformed
• B. To mark the proteins synthesized by the gene of interest
• C. To mark the location from where the replication starts
• D. To mark the location of transgene in the plasmid

Answer 1

The correct option is A To help in selecting the cells that are transformed

Markers are genes in the plasmid that helps in selection of the cells that have been successfully transformed. Usually markers are antibiotic resistance genes.

Normal cells will not survive in a medium containing antibiotics. However, successfully transformed cells are expected to contain the antibiotic resistance gene that will enable them to survive in media containing that particular antibiotic, therefore indirectly indicating that the cells that survive in the antibiotic media, are transformed cells.