Selectable markers is an antibiotic resistant gene ...What is the use of this feature? How does it work..Can I get an explaination with an example.

Dear student,
Please find below the solution to the asked query
 

Selectable markers are genes introduced into the cell especially bacterium that confers a trait suitable for artificial selection. selectable markers are mostly genes encoding resistance for certain antibiotics like tetracyclin or ampicillin. In biotectionology, these are  used to separate recombinants from the non recombinants. 

How antibiotic resistance genes help in selecting recombinants?

• Suppose tet R gene has Bam HI recognition site.
• When BamHI is used for restriction, foreign DNA fragment is inserted within the tet R gene.
• Hence, tetracycline resistance is not present in the recombinants.
• Recombinants will grow on the media containing ampicillin, but will die on media containing tetracycline.
• On the other hand, non-recombinants will grow on medium containing ampicillin as well as on medium containing tetracycline.
• In this way, antibiotic resistance gene helps in selecting transformants.

Hope this information will clear your doubts about the Selectable markers.
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