Replica Plating Handle 1Sterile velvet is pressed on the grown colonies on the master Velvet plate surface (sterilized) Master plate Cells from each colony are transferred from the with medium velvet to new plates containing histidine 3 Plates are Petri plate with Petri plate with incubated medium containing medium lacking histidine histidine Auxotrophic mutant Growth on plates is compared. A colony that grows on the medium with histidine but could not grow on the medium without histidine is an auxotrophic(histidine-requiring mutant) Colony missing Figure 8.21Replica Plating Figure 8.21