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Selectable genetic markers are extraneous genes that are introduced into a cell, conferring a previously absent resistance. These markers are primarily used to "mark" the successful transformation of DNA into a plasmid. Oftentimes, selectable markers are accompanied by other extraneous genes that is the primary gene of interest; the marker simply serves to distinguish between successful transformations, and unaltered cells. It is not atypical to witness transformation efficiencies as low as .05%, making it difficult to pick correct cellular colonies without additional techniques. | Selectable genetic markers are extraneous genes that are introduced into a cell, conferring a previously absent resistance. These markers are primarily used to "mark" the successful transformation of DNA into a plasmid. Oftentimes, selectable markers are accompanied by other extraneous genes that is the primary gene of interest; the marker simply serves to distinguish between successful transformations, and unaltered cells. It is not atypical to witness transformation efficiencies as low as .05%, making it difficult to pick correct cellular colonies without additional techniques. | ||
For instance, selectable genetic markers can be used to confer ampicillin resistance to E. coli. These newly resistant E. coli can then be grown on culture plates with ampicillin, allowing only E.coli with successfully transformed DNA to proliferate. | This is where the selectable genetic markers prove their usefulness. For instance, selectable genetic markers can be used to confer ampicillin resistance to E. coli. These newly resistant E. coli can then be grown on culture plates with ampicillin, allowing only E.coli with successfully transformed DNA to proliferate. | ||
selectable | In addition to selectable genetic markers are screenable genetic markers. Screenable genetic markers function in a similar manner in that they are extraneous genes that are transformed into a cell; however, they do not confer any new sort of resistance to the cell. Instead, they cause the cell to respond differently to environmental conditions in such a way as to distinguish transformed cells from untransformed cells. This can be useful when determining the transformation efficiency of a cell, or when carefully monitoring the activity of proteins. | ||
screenable | |||
==Types of Selectable Markers== | ==Types of Selectable Markers== | ||
==Screening== | ==Screening== | ||
