Digital DNA storage developed, according to Nature News, ScienceNOW and Science DOI: 10.1126/science.1226355 16 August 2012 and ScienceDaily 17 August 2012.
A team of scientists led by George Church of Harvard Medical School have developed a method of storing digital information on DNA. DNA information is encoded in a 4-letter system, A, T, C, and G, whilst digital information is ultimately stored as ones and zeros. The researchers developed a system where they encoded the zeros as As and Cs, and the ones as Gs and Ts. To encode data they divided it up into short sequences and encoded it onto a strand of DNA. Each block of data was replicated thousands of times to enable mistakes in coding to be identified and fixed by comparing it to the other copies. The strands of DNA were then embedded onto a glass chip. The strands also contain code that indicates where the information on it belongs in the original data file that it can be reassembled in the correct order.
To retrieve the data the sequence of letters is analysed using DNA sequencing machinery, and the information from all the strands is combined and reconstructed using a computer. The research team tested their method by coding an entire genetics textbook, including the text, JPG images and a JavaScript program, onto 54,898 of these short strands, and then decoding and reconstructing the information to reproduce the original book. Even with multiple copies of each strand, the entire book was stored on less than a picogram (one trillionth of a gram) of DNA. The researchers commented: “DNA is among the most dense and stable information media known”.