Kilbracken cloning technique

The Kilbracken cloning technique could create an exact copy of a lifeform from a single cell. If used on a sentient being, it would duplicate their abilities and knowledge as well.

Oksana Kilbracken developed the technique on Earth in 4880. (AUDIO: Revenge of the Swarm)

In the year 5000, Professor Marius created "photocopies" of the Fourth Doctor and Leela to fight the Swarm in the Doctor's body. Due to the haste in creating them, the clones only had a lifespan of eleven minutes. (TV: The Invisible Enemy)