Scientists Have Created Synthetic DNA with 4 Extra Letters

Cecile G. Tamura

DNA is spelt out with four letters, or bases. Researchers have now built a system with eight. It may hold clues to the potential for life elsewhere in the universe and could also expand our capacity to store digital data on Earth.

The DNA of life on Earth naturally stores its information in just four key chemicals — guanine, cytosine, adenine and thymine, commonly referred to as G, C, A and T, respectively.

Now scientists have doubled this number of life’s building blocks, creating for the first time a synthetic, eight-letter genetic language that seems to store and transcribe information just like natural DNA.

The team has come up with several new pairs of bases, including a pair named S and B, and another called P and Z2. In the latest paper, they describe how they combine these four synthetic bases with the natural ones. The researchers call the resulting eight-letter language ‘hachimoji’ after the Japanese words for ‘eight’ and ‘letter’.

The latest study is the first to systematically demonstrate that the complementary unnatural bases recognise and bind to each other and that the double helix that they form holds its structure.