Scientists unlocked a new storage bank for digital information, including a motion picture — inside the genome of living cells.
In the groundbreaking study, researchers from Harvard University found a way to encode information in bacteria cells, which they could then retrieve and piece back together — much like they would do with a USB stick or hard drive.
Using a system known as CRISPR, which can edit, cut and stitch together microscopic materials comprising cell DNA, the researchers successfully loaded one of the first-ever moving pictures — Eadweard Muybridge’s film of a horse galloping against a white backdrop — into the genome of a living cell.
The new work builds off a previous study at Harvard, during which researchers had used CRISPR to install a short sequence of data inside a cell. However, that study left other questions to be answered.
“As promising as this was, we did not know what would happen when we tried to track about 100 sequences at once, or if it would work at all. This was critical since we are aiming to use this system to record complex biological events as our ultimate goal,” said lead author Seth Shipman, a Harvard postdoctoral fellow.
Previous research has focused mainly on a single protein, Cas9, used within the CRISPR system, which was originally used to help bacteria fight off viruses. For the new study, the researchers turned to other, lesser-studied proteins.
“In this study, we show that two proteins of the CRISPR system, Cas1 and Cas2, that we have engineered into a molecular recording tool, together with new understanding of the sequence requirements for optimal spacers, enables a significantly scaled-up potential for acquiring memories and depositing them in the genome as information that can be provided by researchers from the outside, or that, in the future, could be formed from the cells natural experiences,“ said George Church, the Robert Winthrop Professor of Genetics at Harvard Medical School and a Professor of Health Sciences and Technology at Harvard and MIT.
“Harnessed further, this approach could present a way to cue different types of living cells in their natural tissue environments into recording the formative changes they are undergoing into a synthetically created memory hotspot in their genomes,” said Church.
The researchers opted for images, both still and moving, because they have a clear idea of the size of a piece of such data. They also chose a moving image because they could essentially feed it to the bacteria frame by frame.
“We designed strategies that essentially translate the digital information contained in each pixel of an image or frame as well as the frame number into a DNA code, that, with additional sequences, is incorporated into spacers. Each frame thus becomes a collection of spacers,” Shipman said.
After that, the CRISPR system encoded the images — and the researchers could retrieve the pieces of information and achieve virtual playback of the movie.
“We then provided spacer collections for consecutive frames chronologically to a population of bacteria which, using Cas1/Cas2 activity, added them to the CRISPR arrays in their genomes. And after retrieving all arrays again from the bacterial population by DNA sequencing, we finally were able to reconstruct all frames of the galloping horse movie and the order they appeared in,” said Shipman.
The researchers plan to expand their work on creating storage devices on other types of cells.
The study appeared in the journal Nature.
Richard Scott is a health care reporter focusing on health policy and public health. Richard keeps tabs on national health trends from his Philadelphia location and is an active member of the Association of Health Care Journalists.