To confirm that the RAD9A (first found as a gene that promotes G2 cell cycle arrest) is necessary to invoke G2 cell cycle arrest, they tested a double mutant of RAD9A with DNA repair deficient-strain, rad52, and found that the cell failed to arrest in G2, further proving that a functional Rad9 gene is needed to induce G2 arrest.
To confirm that the RAD9A (first found as a gene that promotes G2 cell cycle arrest) is necessary to invoke G2 cell cycle arrest, they tested a double mutant of RAD9A with DNA repair deficient-strain, rad52, and found that the cell failed to arrest in G2, further proving that a functional Rad9 gene is needed to induce G2 arrest.