In 1878, British photographer Eadweard Muybridge created the first motion picture of a trotting horse by setting up 12 cameras to capture photos in succession. Muybridge’s stop-motion technique is considered to be an early form of animation that later gave birth to the motion-picture industry. Now, the clip of the galloping thoroughbred mare, named Annie G., is making history once again after Harvard Medical School researchers encoded it into the DNA of a living cell.
The researchers, who published their work in the journal Nature, encoded the frames in genetic material and stored them in living bacteria. It is there that the five-frame animation can be retrieved. It can also be multiplied as the host cell divides and grows.
“DNA has a lot of properties that are good for archival storage,” Seth Shipman, a postdoctoral fellow in genetics at Harvard Medical School and the study’s lead author, told the Los Angeles Times. “It’s much more stable than silicon memory if you wanted to hold something for thousands of years.”
Storing content in DNA is not entirely new. Harvard geneticist and molecular chemist George Church, another author of the Nature study, encoded his book Regenesis in 2012 and made 90 billion copies of the text. Ewan Birney and Nick Goldman of the European Bioinformatics Institute encoded in DNA all 154 of Shakespeare’s sonnets back in 2013. They also encoded an audio clip of Martin Luther King Jr.’s “I Have a Dream” speech along with a picture of their office.
Shipman, Church and their Harvard colleagues created synthetic DNA encoded with the four basic building blocks found in a double helix: adenine, guanine, thymine and cytosine. They started by taking each frame and breaking it down into a grade of 36 pixels by 26 pixels. They then color-coded each pixel using the four DNA molecules. Each frame ended up with 104 DNA sequences.
The team also encoded where each pixel belonged within the frame, but intentionally abstained from encoding the order of the frames.
“That was important to us,” Shipman told the Times. “We wanted to see if when the bacterial DNA captures the new information, it captures it in order.”
The DNA was fed to E. coli bacteria using a technique called electroporation, which placed the DNA pieces in the bacteria cells. Then the team used a CRISPR system-based technology — CRISPR is a gene-editing system — to add the pixel codes into the bacteria’s genomes.
After sitting in a dish in a lab for a week, the cells grew by dividing into new bacteria cells. After looking at the genome of the new cells, researchers found the synthetic DNA containing the trotting horse was in the genetic code with 90% accuracy.
“What this shows us is that we can get the information in, we can get the information out, and we can understand how the timing works, too,” Shipman said.
The goal is to one day create molecular recorders that can store human body data for doctors to retrieve when a person gets ill. Think of it like the black boxes on airplanes that gather flight data. Molecular recorders would gather an individual’s biological data and could lead the way to improve existing methods for “generating cells for regenerative therapy, disease modeling and drug testing.”
“We encoded images and a movie into DNA in a living cell which is fun, but it’s not really the point of the system,” Shipman told the Guardian. “What we’re trying to develop is a molecular recorder that can sit inside living cells and collect data over time.”