Dune knew high energy physics and quantum mechanics. He was to have been one of the first humans revived, but the Wirrn Queen laid her eggs inside his body while he was still in cryogenic suspension. The Queen's larvae consumed his body and his intellect, absorbing all of his knowledge, enabling them to operate and sabotage systems aboard the Ark.
When his body was found missing by Vira, commander Noah blamed the Fourth Doctor and his party. As the alien presence inside Noah's mind grew stronger, the commander claimed that he was Dune. He later revealed that he had been given all Dune's knowledge. (TV: The Ark in Space)