Signal - February 2017

Bachand and his team are not the only ones exploring
DNA data storage. He notes that Microsoft has purchased
synthetic DNA from Twist Bioscience in San Francisco,
specifically for data storage. In an April press release, Twist
officials say they have successfully encoded and recovered
100 percent of the digital data in DNA. The company also
indicated, however, that it is “still years away from a com-
mercially viable product.”
Bachand’s approach differs from some commercial
research in that his team has limited the data to text. Many
others, he reports, are attempting to translate binary lan-
guage into DNA language, which would allow encoding
of music, images and other more complex types of data.
“Because we’re only focusing on text, we actually can have a
higher density. We don’t have to have as many DNA letters
to encode our information,” he says. “With our approach,
there really is no limitation on the ability to take text and
convert it into DNA language.”
The project included two demonstrations in which DNA
was used to encode historic documents: a letter from Presi-
dent Harry S Truman and a part of Martin Luther King Jr.’s
“I Have a Dream” speech. The team completed the King
effort shortly before the project ended. “There is a lot of
repetition of words and a certain pattern to the speech that
actually presents a lot of unique challenges for doing the
DNA synthesis. Having repeats of the same sequences is
very problematic,” Bachand states.

The team tweaked its algorithms to increase efficiency from around 5 percent to about 80 percent. The project involved 3,300 characters, and the DNA was close to 10,000 base pairs in length. The biggest limitations, he indicates, are associated with creating the synthetic DNA itself. “The field, in general, that’s looking at doing storage of information in DNA is limited primarily right now on our ability to synthesize long stretches of DNA,” he says, pointing out that his project did not address that particular issue. “There is a lot of push and pull from the community for this type of development, so those of us doing DNA information storage can piggyback on that.”