What are selectable markers? Give two examples.

Selectable markers are genes used in genetic engineering to identify cells that have received new DNA. When scientists insert new genes into a cell, they also add a selectable marker. This marker helps to find out which cells have taken up the new gene. 

Selectable markers usually give the cell resistance to an antibiotic or allow it to grow on a specific medium.

Examples of selectable markers:

• ampR – gives resistance to ampicillin
• kanR – gives resistance to kanamycin

When grown on media with the antibiotic, only the cells with the marker gene survive. This makes it easy to identify successful transformation.