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Auxotrophic genetic markers are often used in molecular genetics; they were famously used in Beadle and Tatum's Nobel prize-winning work on the one gene-one enzyme hypothesis, connecting mutations of genes to protein mutations. This then allows for biosynthetic or biochemical pathway mapping that can help determine which enzyme or enzymes are ...
A selectable marker is a gene introduced into cells, especially bacteria or cells in culture, which confers one or more traits suitable for artificial selection.They are a type of reporter gene used in laboratory microbiology, molecular biology, and genetic engineering to indicate the success of a transfection or transformation or other procedure meant to introduce foreign DNA into a cell.
The mixture of treated cells is cultured on media that contain the antibiotic so that only transformed cells are able to grow. Another method of selection is the use of certain auxotrophic markers that can compensate for an inability to metabolise certain amino acids, nucleotides, or sugars. This method requires the use of suitably mutated ...
Auxotrophic selection markers that allow an auxotrophic organism to grow in minimal growth medium may also be used; examples of these are LEU2 and URA3 which are used with their corresponding auxotrophic strains of yeast. [7] Another kind of selectable marker allows for the positive selection of plasmid with cloned gene.
Early attempts at mutagenesis using radiation or chemical mutagens were non-site-specific, generating random mutations. [2] Analogs of nucleotides and other chemicals were later used to generate localized point mutations, [3] examples of such chemicals are aminopurine, [4] nitrosoguanidine, [5] and bisulfite. [6]
It is used as a fluorescent marker for DNA in fluorescence microscopy and flow cytometry. It intercalates in double-stranded DNA, with a high affinity for GC-rich regions, [ 2 ] making it useful for chromosome banding studies.
Complementation tests can also be carried out with haploid eukaryotes such as fungi, with bacteria, and with viruses such as bacteriophage. [1] Research on the fungus Neurospora crassa led to the development of the one-gene-one-enzyme concept that provided the foundation for the subsequent development of molecular genetics.
Mammalian cells, yeast, and other eukaryotes acquire resistance to geneticin (= G418, an aminoglycoside antibiotic similar to kanamycin) when transformed with a kanMX marker. In yeast, the kanMX marker avoids the requirement of auxotrophic markers. In addition, the kanMX marker renders E. coli resistant to kanamycin.