Biodata (short for biographic data) contained information on a person's history and timeline (like temporal DNA). If a person's biodata could be manipulated, his entire time stream could be altered. (PROSE: Alien Bodies) A biodata signature was also referred to as an "artron imprint." (AUDIO: The Inquiry)
On Gallifrey there were stores of all Time Lord biodata in the form of biodata extracts, called biogs (short for biodata log). Excitonics was the technology underlying its circuitry. Pratt was able to gain access to the Doctor's biodata extract to summon him to Gallifrey. (TV: The Deadly Assassin) Certain artefacts could also alter biodata, such as the Sash of Rassilon and other Presidential artefacts changing the biodata of Time Lord presidents to allow them to access certain secrets that only the President was authorized to use. (PROSE: Alien Bodies)
Faction Paradox used biodata in their rituals. They used a biodata extractor to take biodata from a subject, though blood would work, since it contained biodata. (PROSE: Alien Bodies)
A member of Faction Paradox altered the Eighth Doctor's biodata to change his origins and to remove his ability to perceive the colour violet. (PROSE: Unnatural History)
Compassion evolved into a type 102 TARDIS after a receiver given to her by the Doctor warped her biodata by processing signals from the TARDIS as Block Transfer Computations that altered her physiology. (PROSE: The Shadows of Avalon)
The Faction had developed biodata viruses that could infect potential Faction members to convert them to share the Faction's beliefs and abilities. Normally these viruses were too weak to infect Time Lords, but the virus was able to infect the Third Doctor when his history was changed and he was killed on Dust, resulting in him regenerating ahead of schedule and the virus infecting him while his immune system was in chaos during the change. (PROSE: Interference)
Braxiatel had a Biodata Archive with the biodata of every Time Lord in every regeneration, so that Gallifrey could be rebuilt should it fall to the Dogma Virus. (AUDIO: Panacea)