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| A gel image of the DNA of 96 horses displayed on a computer monitor at the UC Davis veterinary genetics lab in Davis, California. — Photo: AP |
Genetic material might become a suitable format to archive data in the future.
Her computer, Karin Strauss says, contains her “digital
attic” a place where she stores that published math paper she wrote in
high school, and computer science schoolwork from college.
She’d
like to preserve the stuff “as long as I live, at least,” says Ms.
Strauss, 37. But computers must be replaced every few years, and each
time she must copy the information over, “which is a little bit of a
headache.”
It would be much better, she says, if she could store it in DNA the stuff our genes are made of.
Ms. Strauss, who works at Microsoft Research in Redmond, Washington, is working to make that sci-fi fantasy a reality.
She
and other scientists are not focused on finding ways to stow high
school projects or snapshots or other things an average person might
accumulate, at least for now. Rather, they aim to help companies and
institutions archive huge amounts of data for decades or centuries, at a
time when the world is generating digital data faster than it can store
it.
It’s not that the data will disappear from the
tape. A bigger problem is familiar to anybody who has come across an old
eight-track tape or floppy disk and realised he no longer has a machine
to play it. Technology moves on, and data can’t be retrieved if the
means to read it is no longer available, Mr. Starr says.
So for that and other reasons, long-term archiving requires repeatedly copying the data to new technologies.
The difference between DNA and digital devices
Into
this world comes the notion of DNA storage. DNA is by its essence an
information-storing molecule; the genes we pass from generation to
generation transmit the blueprints for creating the human body. That
information is stored in strings of what’s often called the four-letter
DNA code. That really refers to sequences of four building blocks
abbreviated as A, C, T and G found in the DNA molecule. Specific
sequences give the body directions for creating particular proteins.
Digital
devices, on the other hand, store information in a two-letter code that
produces strings of ones and zeroes. A capital ‘A’, for example, is
01000001.
How to convert from digital to DNA?
Converting
digital information to DNA involves translating between the two codes.
In one lab, for example, a capital A can become ATATG. The idea is once
that transformation is made, strings of DNA can be custom-made to carry
the new code, and hence the information that code contains.
What are the advantages?
*
One selling point is durability. Scientists can recover and read DNA
sequences from fossils of Neanderthals and even older life forms. So as a
storage medium, “it could last thousands and thousands of years,” says
Luis Ceze of the University of Washington, who works with Microsoft on
DNA data storage.
* Advocates also stress that DNA
crams information into very little space. Almost every cell of your body
carries about six feet of it; that adds up to billions of miles in a
single person. In terms of information storage, that compactness could
mean storing all the publicly accessible data on the Internet in a space
the size of a shoebox, Mr. Ceze says.
* DNA storage
would avoid the problem of having to repeatedly copy stored information
into new formats as the technology for reading it becomes outmoded.
Developments in this area
Getting
the information into DNA takes some doing. Once scientists have
converted the digital code into the 4-letter DNA code, they have to
custom-make DNA. For some recent research Ms. Strauss and Mr. Ceze
worked on, that involved creating about 10 million short strings of DNA.
Twist Bioscience of San Francisco used a machine to
create the strings letter by letter, like snapping together Lego pieces
to build a tower. The machine can build up to 1.6 million strings at a
time.
Each string carried just a fragment of
information from a digital file, plus a chemical tag to indicate what
file the information came from.
To read a file,
scientists use the tags to assemble the relevant strings. A standard lab
machine can then reveal the sequence of DNA letters in each string.
What are the challenges?
Sri
Kosuri of the University of California Los Angeles, who has worked on
DNA information storage but has now largely moved on to other pursuits,
says one challenge for making the technology practical is making it much
cheaper.
Scientists custom-build fairly short
strings DNA now for research, but scaling up enough to handle
information storage in bulk would require a “mind-boggling” leap in
output, Mr. Kosuri says. With current technology, that would be hugely
expensive. http://www.thehindu.com/sci-tech/science/scientists-work-toward-storing-digital-information-in-dna/article8894266.ece
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