Genetic Code Received Four New Letters – Meet The “Hachimoji DNA”

If we think of genetic code as an alphabet that only has four letters we might find it hard to get past the limits. Some scientists succeeded in adding four letters to the genetic alphabet which bring new possibilities in data storage, synthetic biology, and even when astronauts are searching for other types of life on other planets.

At the heart of all living things, there is a genetic code which is elegantly simple. The famous double helix structure of the DNA includes two halves which are built from bases, four small molecules, namely, thymine, adenine, guanine (ATCG), and cytosine. What the DNA codes depend on is the order in which these molecules appear, similar to what you would see in a computer, but not with numbers.

Thanks to a team of scientists from the Foundation for Applied Molecular Evolution in Florida, four new bases were added, and they are called “hachimoji DNA” (translated from Japanese it means eight-letter DNA). So, the genetic code’s potential information density is doubled.

Scientists created the “Hachimoji DNA” – Genetic code received four new letter

It is not the first time scientist try to expand the genetic code. Another team of scientists at the Scripps Research Institute in California managed in 2014 to add two extra bases to the DNA while three years later in 2017 they showed that proteins that do not exist in nature could be built by bacteria using this code.

The DNA’s double helix is held together thanks to some hydrogen bonds that are located between complementary bases – C pairs with G and A pairs with T.

Water-repelling molecules were used by the scientist at the Scripps because they repel the other bases even though they stick together. It is impossible to have extended stretches of unnatural bases because these bases need to be sandwiched between natural bases, so the uses of the code get limited this way.