Selective growth medium
From Wikipedia, the free encyclopedia
Selective growth media are used in cell culture to ensure proliferation and/or survival of cells carrying a certain property, such as antibiotic resistance or the ability to synthesise a certain metabolite. Normally, the presence of a specific gene or an allele of a gene confers onto the cell the ability to grow in the selective medium. In such cases the gene is termed a marker.
In bacterial culture it is common to include antibiotics, such as ampicillin or tetracycline, in the agar or liquid medium to prevent proliferation of cells that do not carry the antibiotic resistance gene. Media lacking an amino acid such as proline in conjunction with E. coli unable to synthesise it were commonly used by geneticists before the emergence of genomics to map bacterial chromosomes.
Selective growth media for eukaryotic cells commonly contain neomycin to select cells that have been successfully transfected with a plasmid carrying the neomycin resistance gene as a marker. Gancyclovir is an exception to the rule as it is used to specifically kill cells that carry its respective marker, the Herpes simplex virus thymidine kinase (HSV TK).