Biodata

Information: the lifeblood of modern (and likely, future) civilization.

It can be stored in analog form, in digital form, or in organic form, on an organic or even biological matrix. When the latter is used, it's frequently depicted as persons smuggling information in a biomolecular format (amino acids, for example, seem to be a common matrix for this type of information storage). Related to (real world theories of) organic and biomolecular computing. It's an emergent technology in Real Life, but it's been played straight in Speculative Fiction at least since the early nineties, and probably before that. It's present in Cyberpunk and Biopunk, but also pops up in other subgenres of Speculative Fiction like Space Opera, usually for the purpose of espionage, or as a message from an ancient race of Precursors to descendants. It's a given when dealing with Organic Technology, and Wetware CPUs. A retroviral encoding vector is another significant variation.

This does not cover the opposite, where information about a biological organism is recorded by digital computers or otherwise non-organic devices. That's a separate trope. Also does not cover inorganic storage system implants, for example in Johnny Mnemonic. A silicon memory chip in the brain is not an example of this trope; but a port implant that allows Memory Uploading from computer to brain or brain to brain would count: it all depends on the storage medium.

See also Genetic Memory, for which this is sometimes given as a Hand Wave. A staple of Cyberpunk and Biopunk, but as mentioned, common in other genres such as Space Opera.

Compare:

Neural Implanting: downloading computer files, images, databases, or abilities into a person's brain.
Neuro Vault: Burying data in a person's subconscious through post-hypnotic suggestion.
Brain Uploading: Preserving consciousness organically or inorganically for transfer to a new host.

Examples of Biodata include:

Anime And Manga

Outlaw Star: According to Gwen Khan, the information for navigating one's way to the Galactic Leyline and accessing its ability to alter the laws of probability, was contained within the "black box" data used to create Melfina. Melfina was unaware of this herself, until she reconnected with the Leyline.

Comic Books

Transmetropolitan: Data pollen. Literally, pollen from plants that's encoded with newsfeeds, advertising and other information. Breathed in, it releases the information to the nervous system. It's linked to degeneration of the synapses in the brain and goes in and out of legality several times over the series.

Literature

Iain Banks' Surface Detail provides us with the Intagliated, slaves whose bodily tattoos contain information detailing their pasts, why they're Intagliated and the markings go right down to the DNA.
In Dune, a distrans is a device for producing a temporary neural imprint on the nervous system of bats or birds. The creature's normal cry then carries the message imprint which can be sorted from that carrier wave by another distrans. In other words, it implants a message into the animal which can be later read in its normal vocalization, sort of like a modern-day telephone/radio scrambler.
The Restaurant At the End of The Universe. Earth is the computer that Deep Thought created to discover the Ultimate Question of Life, the Universe, and Everything. Because he was a part of Earth's organic matrix, the Question (or a reasonable facsimile thereof) is stored in Arthur Dent's brain wave patterns. Near the end of the book he and Ford Prefect try to discover the Question by introducing a random element that can be shaped by that pattern - drawing Scrabble tiles from a bag without looking.
Simon Illyan of the Vorkosigan Saga had a chip that recorded everything he saw and heard, using a protein-based data storage, installed into his brain. Many who got such chips installed developed schizophrenia.

Live Action Television

Lexx: Assistant Deputy Back-Up Courier Stanley Tweedle had vital data about the Divine Order's superweapon, the Lexx, encoded in amino acids stored in a false tooth.
Star Trek Enterprise: In the pilot episode, the Klingon courier Klaang carried information injected directly into his DNA, concerning the Suliban's attempts to destabilize the Empire.
Star Trek: The Next Generation: Klingons are NOT dumb. A Klingon scientist temporarily posted on the Enterprise-D modified a hyposyringe with an optical chip reader, and would use that to transform digital information from the ship's computers into amino acid sequences. Then he would inject someone without their knowledge, and the information would be carried in their bodies in their bloodstream as inert proteins, which could be extracted at any time by another spy. Damn, son!
- It seems that by the 24th century, the Klingons have actually learned a few things. This is slightly more plausible than the Enterprise example.
- The Ancient Humanoid Precursors in "The Chase" encoded a message to their descendants- us, as well as the Klingons, Cardassians, Romulans, Bolians, Yridians, Vulcans... you get the idea.
- In "Transfigurations," Data and Geordi examine a Zalkonian memory storage device from mysterious "John Doe's" escape pod that is stated to use a chemical matrix for data storage. It's basically the escape pod's Black Box.
Farscape: The Ancients inscribed knowledge of wormholes into John Crichton's brain and his DNA. Eventually he unlocked and understood it. Although the Ancients removed it from his head after he used it, his son was implied to inherit it. The Scarrans even tried to extract it from the DNA of Aeryn's unborn child.
Fringe has done this a couple of times, notably in the first season when ZFT would leave a "calling card" in the DNA of their genetically engineered weapons.
- A similar calling card was later discovered on the Nazi toxin in Season 2, in this case, the image of the seahorse, a clue that Walter Bishop's father's research had been used to create the toxin.

Real Life

This Article describes the phenomenon in RealLife. Portrayals in fiction vary considerably in their accuracy.
DNA Computing

Video Games

Ansem the Wise hides research data within Sora in Kingdom Hearts, although it is left vague on how he does this.
Mass Effect: Protheans possess Bizarre Alien Senses that allow them to read biomarkers of any living creature (and even from some inorganic objects that come into contact with the living) and store this information. This is how their Beacons work, too.
A recurring theme in the Shin Megami Tensei series - Digital Devil Saga and Devil Survivor 2 in particular - is the concept that everything ultimately boils down to data. This is implied to be how the Embryon were first reincarnated into the simulated world of the Junkyard, and linked with the notion of the Akashic Records to explain how Polaris is systematically destroying the world - and how it can be restored afterwards.