Some of the earliest computers used a 鈥� literally storing information on cards with holes punched out. Now researchers have found a way to apply the same concept to DNA.
DNA sequences have often been suggested as a form of data storage but many methods for doing this are painstaking or expensive 鈥� such as synthesising new DNA in the lab.
Instead, Olgica Milenkovic at the University of Illinois at Urbana-Champaign and her colleagues have made tiny cuts in existing strands of E. coli DNA, turning them into the molecular equivalent of punch cards.
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The team nicked or partially cut the DNA strands at particular points every 25 base pairs along the sequence. A cut represents a one and the absence of a cut represents a zero, creating a binary code 鈥減unched鈥� into the DNA itself that can store any form of digital data.
鈥淲e were not sure if we could place the nicks so close together,鈥� says Milenkovic. 鈥淚t was a really, really great feeling that it worked out.鈥� Despite weakening the DNA by cutting it, she says the molecules still held together, and they could perhaps make the cuts even closer to increase the information storage density.
The team used their DNA punch cards to store the text of Abraham Lincoln鈥檚 Gettysburg Address and a picture of the Lincoln Memorial in Washington DC.
Both files were extracted with 鈥減erfect accuracy鈥�, says Milenkovic, by breaking up the DNA and sequencing the nick-severed strands. Comparing those sequences against a reference of the E.coli genome reveals the position of the nicks and, consequently, the binary code it records.
Milenkovic says using DNA extracted from E.coli makes it easy to store and read the data later. A separate project previously showed how to write data directly into DNA within the organism.
Using natural occurring DNA for storage is resourceful, says at the University of Washington. 鈥淵ou don鈥檛 need to synthesise it from scratch, that is a plus,鈥� he says.
But he adds that the steps needed to target the correct bits of DNA for nicking are still somewhat laborious. It might be possible to create a tool to automate this, he says.
Reference: biorXiv聽
