Homologous recombination can be used in the lab to replace a gene of interest with a selection marker. To confirm that the selection marker is integrated into the correct place in the genome, sometimes a negative selection is used in addition to the standard positive selection marker. Which of the following would act as a negative selection marker? a. Transformation of a different gene, which does not act as a selection marker, to replace the gene of interest.â
b. A second marker in the knock out cassette, that if inserted into the genome results in cell death when plated on selective media.
c. Transforming the cells with two different knock out cassettes, each containing the same selection marker3. â