Bioengineers used enzymes from bacteria to flip sequences of DNA one direction, then another. The back and forth represent the ones and zeros of digital information. By coding a section of DNA that determines if the cells fluoresce red or green, the researchers easily visualized the switch (see photo).
Programmable data storage within the DNA of living cells would seem an incredibly powerful tool for studying cancer, aging, organismal development and even the natural environment.
In developing the system, researchers had to control the precise dynamics of two opposing proteins, integrase and excisionase, within the microbes. The team found it was fairly simple to flip a section of DNA in either direction but needed to repeatedly and reliably flip the sequence back and forth to create a fully reusable binary data register. Getting the balance of protein levels right took researchers three years and 750 tries. As explained further down the release:
[First author Jerome Bonnet, PhD] has now tested RAD modules in single microbes that have doubled more than 100 times and the switch has held. He has likewise switched the latch and watched a cell double 90 times, and set it back. The latch will even store information when the enzymes are not present. In short, RAD works. It is reliable and it is rewritable.
For Endy and the team, the future of computing then becomes not only how fast or how much can be computed, but when and where computations occur and how those computations might impact our understanding of and interaction with life.
“One of the coolest places for computing,” Endy said, “is within biological systems.”
A paper on the device was published today in the Proceedings of the National Academy of Sciences. The team’s next goal is to scale up to a byte – equivalent to eight bits of programmable DNA.
Previously: Drew Endy contemplates new modes of computing in medical research
Photo by Norbert von der Groeben