The technique takes advantage of the gene-editing system CRISPR. When viruses attack bacteria, the bacteria use this defense mechanism to cut parts of the virus\u2019s DNA and paste them inside its own DNA. This essentially makes the virus DNA part of the bacteria cell. Those sequences serve as a memory of the viral invasion, so that the cell can go out and cut up future versions of that virus if it\u2019s attacked again.<\/p>\n
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These virus attacks are \u201crecorded\u201d in the reverse chronology of how they occurred, so that, over time, the sequences become a living, physical record of all the different viruses that invaded. The team decided to hack this system for their own purposes, says study co-author Seth Shipman<\/a>, a neuroscience researcher at Harvard University.<\/p>\n The images and videos the researchers pasted inside E. Coli<\/em> are composed of black-and-white pixels. First, the scientists encoded the pixels into DNA. Then, they put their DNA into the E. coli<\/em> cells using electricity. Running an electrical current across cells opens small channels in the cell wall, and then the DNA can flow inside. From here, the E. Coli<\/em>\u2019s CRISPR system grabbed the DNA and incorporated it into its own genome. \u201cWe found that if we made the sequences we supplied look like what the system usually grabs from viruses, it would take what we <\/em>give,\u201d Shipman says.<\/p>\n Once the information was inside, the next step was to retrieve it. So, the team sequenced the E. coli<\/em> DNA and ran the sequence through a computer program, which successfully reproduced the original images. So the running horse you see at the top of the page is really just the computer’s representation of the sequenced DNA, since we can\u2019t see DNA with the naked eye.<\/p>\n The choice of image and video weren\u2019t random. Shipman says that the team wanted to \u201creference some of the original images that humankind ever put in the natural world,\u201d like the cave drawings of hands. Similarly, the five frames of the Muybridge movie, showing a horse galloping,was one of the first moving images ever recorded, using technology that was new in the 1870s. \u201cWe figured that we were also encoding information onto the natural world in a new way and should go with something that was tried and tested,\u201d says Shipman.<\/p>\n So far, this method can\u2019t handle a lot of information. The video is only 36 by 26 pixels, which isn\u2019t a lot considering we can encode books and longer movies<\/a> in synthetic DNA. But the new method of using live bacteria opens the door to exciting possibilities. For instance, we could make cells that record information about what\u2019s happening in the nearby environment. Shipman, as a neuroscientist, hopes that one day the system can be used to record events that happen over time, such as how neurons form in the brain. And yes, maybe one day you could embed all of Game of Thrones<\/em> in your skin.<\/p>\n