E. coli might best be known for giving street food connoisseurs occasional bouts of gastric regret. But the humble microbial workhorse, with its easy-to-edit genome, has given humankind so much more—insulin, antibiotics, cancer drugs, biofuels, synthetic rubber, and now: a place to keep your selfies safe for the next millennium.
Scientists have already used plain old DNA to encode and store all 587,287 words of War and Peace, a list of all the plant material archived in the Svalbard Seed Vault, and an OK Go music video. But now, researchers have created for the first time a living library, embedded within, you guessed it: E. coli. In a paper published today in Nature, Harvard researchers1 describe using a Crispr system to insert bits of DNA encoded with photos and a GIF of a galloping horse into live bacteria. When the scientists retrieved and reconstructed the images by sequencing the bacterial genomes, they got back the same images they put in with about 90 percent accuracy.
The study is an interesting—if slightly gimmicky—way to show off Crispr’s power to turn living cells into digital data warehouses. (As if E. coli didn’t already have enough on its plate, what with securing global insulin supplies and weaning the world off fossil fuels.) But the real question is, why would anyone want to do this?
If you’re Jeff Nivala, it’s not to preserve visual messages for people in the far-off future. It’s so he can turn human cells like neurons into biological recording devices. “The E. coli is just a proof of concept to show what cool things you can do with this Crispr system,” says Nivala, a co-author on the paper and geneticist at Harvard. “Our real goal is to enable cells to gather information about themselves and to store it in their genome for us to look at later.” That concept is called the “molecular ticker tape.” It’s something George Church thought up before Nivala, a post-doc, arrived in his lab. But it’s a challenge Nivala thinks is uniquely suited to Crispr.
In case you’ve been living in a bunker, Crispr-Cas9 is a revolutionary molecular tool that combines special proteins and RNA molecules to precisely cut and edit DNA. It was discovered in bacteria, which use it as a sort of ancient immune system to fend off viral attackers. Cas9 is the protein that does all the cutting, i.e. gene editing’s heavy lifting. Lesser known are Cas1 and Cas2. They’re the ones that tell Cas9 whereto do the cutting.