The researchers claim that the cost of DNA coding is dropping so quickly that within five to 10 years it could be cheaper to store information using this method than in conventional digital devices.

Deoxyribonucleic acid or DNA – the chemical that stores genetic instructions in almost all known organisms – has an impressive data capacity. One gram can store up to 455bn gigabytes: the contents of more than 100bn DVDs, making it the ultimate in compact storage media.

A three-strong team led by Professor George Church of Harvard Medical School has now demonstrated that the technology to store data in DNA, while still slow, is becoming more practical. They report in the journal Science that the 5.27 megabit collection of data they stored is more than 600 times bigger than the largest dataset previously encoded this way.

Writing the data to DNA took several days. "This is currently something for archival storage," explained co-author Dr Sriram Kosuri of Harvard's Wyss Institute, "but the timing is continually improving."

DNA has numerous advantages over traditional digital storage media. It can be easily copied, and is often still readable after thousands of years in non-ideal conditions. Unlike ever-changing electronic storage formats such as magnetic tape and DVDs, the fundamental techniques required to read and write DNA information are as old as life on Earth.

The researchers, who have filed a provisional patent application covering the idea, used off-the-shelf components to demonstrate their technique.

To maximise the reliability of their method, and keep costs down, they avoided the need to create very long sequences of code – something that is much more expensive than creating lots of short chunks of DNA. The data was split into fragments that could be written very reliably, and was accompanied by an address book listing where to find each code section.