Scientists have used CRISPR to store a GIF inside the DNA of a living cell
Eadweard Muybridge was a pioneer of both early cinema and scientific observation. His iconic clip of a galloping horse was famously used to settle a bet over whether the animal lifted all four hooves from the ground when in motion.
More than 130 years after this breakthrough, Muybridge is at the centre of another as scientists have successfully encoded this iconic film into the DNA of living cells. The result is a so-called organic GIF, and is the first step in what researchers are referring to as a “molecular recorder”, able to exist, observe and capture information within living cells.
“We want to turn cells into historians,” explained neuroscientist Seth Shipman, a geneticist at Harvard Medical School. “We envision a biological memory system that’s much smaller and more versatile than today’s technologies, which will track many events non-intrusively over time.”
Using the gene editing technology CRISPR, scientists funded by the National Institutes of Health (NIH) set out to prove that any arbitrary sequential information – not just genetic information – could be encoded into a genome. They first did this with a single image, of a human hand, and with the help of a bacteria’s immune defences.
(Above: To the left is an image of a human hand, which was encoded into nucleotides and captured by the CRISPR-Cas adaptation system in living bacteria. To the right is the image after multiple generations of bacterial growth, recovered by sequencing bacterial genomes. Credit: Seth Shipman)
When a bacteria is attacked by a virus, its cells produce enzymes to cut and process the virus’s genetic code. It does this to remember the invader, taking a portion of the virus’s genetic code and adding it to its own genome, like putting heads on pikes. As time passes, the bacteria’s genome grows, more genetic code from viruses are added, and more heads are stacked on the pike.
Shipman and his colleagues hacked this process using the CRISPR system. CRISPR-Cas9 is the protein in the bacteria’s immune system that cuts the virus’s genetic code, while Cas1 and Cas2 are the proteins that insert the viral DNA into the genome. Crucially, these proteins add the DNA in the order it is encountered, meaning the scientists could feed the E.Coli synthetic strands of DNA, specially designed with sequential information – which can then be decoded and turned into a picture, or a series of frames in an animation. For more information, read our full explainer on CRISPR.
While encoding a short film into DNA is impressive, the scientists aren’t planning to create some type of cellular-level Netflix app. The Muybridge clip is intended to show the scope for the CRISPR system to turn living cells into recording devices, pulling information from their surroundings and keeping a sequential record within their genome. This could be used in everything from modeling diseases to monitoring the level of pollutants in soil.
One particularly exciting application is neurology. Shipman trained as a neurologist and he believes the technology could play an important part in how researchers unlock the mysteries of the brain – by recording brain activity and development from within the brain. While Muybridge’s cinematic techniques allowed humans to see what was imperceptible to the human eye, so too could “molecular recorders” give us a glimpse what has up to now been hidden.
“We want to use neurons to record a molecular history of the brain through development,” said Shipman. “Such a molecular recorder will allow us to eventually collect data from every cell in the brain at once, without the need to gain access, to observe the cells directly, or disrupt the system to extract genetic material or proteins.”
While the Muybridge GIF is the first time a movie has been encoded in the DNA of living cells, other scientists have already treated genetic circuitry like organic ZIP files. In March, a pair of researchers at the New York Genome Centre published a report in the Science journal, detailing methods for storing compressed files in DNA molecules.
With the help of an algorithm for translating the files into a binary code that can be mapped onto the DNA’s nucleotide bases, the researchers were able to encode the total of six files: a 1948 academic paper, a Pioneer plaque, an operating system, a virus, the 1895 film L’Arrivée d’un train en gare de La Ciotat…and a $50 Amazon giftcard.