Race bank

Race banks were collections of usually biological materials that preserved the genetic structure of a species. They took different forms depending upon the race preserved and the technology of the society that constructed them.

Minyan
The Minyan approach to the concept was extremely compact. All the vital information was stored in two golden cylinders aboard the P7E. Because Minyos and all her inhabitants were destroyed, Captain Jackson of the R1C led a hundred-century quest to find the P7E and retrieve the race banks. With the help of the Fourth Doctor, Leela, and K-9, he was ultimately successful. However, he also discovered that his crew were not, in fact, the last survivors of his race. Instead, the "Trogs" and other inhabitants of the planet which had coalesced around the P7E were in fact descendants of the original crew. Thus, although his quest was successful, Jackson ultimately discovered that the contents of the race bank were not strictly necessary for the perpetuation of his race. (DW: Underworld)

Kastrian
The Kastrian race bank was contained within a room in the on the planet Kastria. It was devised by Eldrad and contained memory crystals for Kastrain regeneration. Many of these crystals were ready for immediate use by the operator. Although Eldrad was supposedly destroyed, the Kastrians feared his possible return so much, that they decided to commit an act of voluntary genocide. Not only did they kill themselves, but they deleted the entire contents of the race bank. Only in this way could they be completely assured that Eldrad's evil influence would never again control them and threaten others. Their decision, while extreme, did prove wise. When Eldrad ultimately returned, he was without the ability to regenerate and enslave his race. Eldrad thus survived for thousands of years, only to become the last of his species. (DW: The Hand of Fear)