Replica plating

Replica plating is a technique in which multiple dishes, also known as Petri plates, containing solid (agar-based) bacteriological media, are inoculated with 10's to 1000's of colonies of organisms from a primary plate (or master dish), reproducing the original spatial pattern of colonies. The technqiue involves pressing a velvet covered disk to a primary plate, and then imprinting multiple secondary plates with cells in colonies removed by the velvet from the original plate. By using different types of selective growth media (lacking nutrients or containing chemical growth inhibitors such as antibiotics) on the different secondary plates, it is possible to rapidly screen a large number of individual isolated colonies and detect those that have different traits or mutants.