Scientists have created synthetic DNA with four extra letters
DNA stores information in four key compounds – guanine, cytosine, adenine and thymine, commonly referred to as G, C, A and T, respectively. In the new study, scientists doubled this number of bricks of life, creating for the first time a synthetic, 8-letter genetic language that appears to store and transcribe information just like natural DNA.
In DNA are encoded all the information thatore make living organisms what they are. The information is „written” with an alphabet of just four letters. Scientists have just created artificial DNA, to which theorego they added four extra letters and it seems that synthetic DNA behaves just like natural ones.
All life on Earth is built on the same foundations. Those letters mentioned earlier are nucleotides – four nitrogenous bases thatore are the building blocks of DNA. Two purine – An adenine and a guanine and two pyrimidines – cytosine and thymine. Each of these substances, for ease of use, is designated by a single letter. And so, respectively, A – is adenine, T – thymine, C – cytosine and G, whichorally marked guanine. Wayob their ordering provides organisms with instructions to build proteins.
In a study published on „Science”, teamo³ scientistow under the direction of Steven Benner, founder of the Foundation for Applied Molecular Evolution, suggests that an expanded genetic alphabet moTheoretically roalso support life.
– This is a real landmark,” said Floyd Romesberg of the Scripps Research Institute. – There is nothing special about these four chemicalsow, whichore evolved on Earth. This is a conceptual breakthrough,” he added.
Normally, when a pair of DNA strands twists around aoł himself in the subojnej helix, the chemicals on each strand form a pair: A binds to T and C binds to G. Researchers for years have prob They add more pairs of these compoundsoInto the genetic code. In 2017, the Romesberg lab expanded the genetic alphabet to include two new artificial nitrogen bases – d5SICS and dNaM – labeled with the letters X and Y. Artificial bases have been inserted into the DNA of the living bacterium Escherichia coli, paving the way for the creation of entirely new synthetic proteins. For more on this topic, see Scientists have created polsynthetic life capable of producing proteins.
However, the latest research is the first toore have shown that artificial bases recognize and bind to each other and that subojna helix, whichorą form, maintains its structure.
Syndromeo³ Benner created synthetic letters by improving the molecular structure of regular bases. DNA letters combine to form hydrogen bonds. Each contains hydrogen atoms, whichore are attracted to the atomicoIn nitrogen or oxygen in their partner. Based on these relationships, scientists created four artificial nucleotides: P, B, Z and S. They have the same shape as natural DNA letters, but their binding patterns have been changed.
Scientists in the publication described how theyob combine these four synthetic bases with natural ones. The eight-letter code of DNA has been made more interesting by scientistscoin the named „hachimoji”, What the words mean in Japanese „eight” and „letter”.
The researchers conducted a series of experimentsoin, ktore have shown that their artificial sequences have a commonolne properties with natural DNA, whichore are essential for sustaining life. To function as an information storage system, DNA must follow predictable rules, so the compositeoł first showed that in a similar wayob to regular bases, the synthetic bases formed robust pairs of. Scientists have created hundreds of synthetic DNA molecules and confirmed that the letters bind to their partners in a predictable wayob.
They then showed that the structure subohelix remains stable no matter what order the synthetic bases were in. This is important because for life to evolve, DNA sequences must be able to change without breaking down the entire structure. Finally, the compositeoł has shown that synthetic DNA can be faithfully transcribed into RNA, and the conversion of DNA into RNA is a key step in transcribing genetic information into proteins.
– The ability to store information is of little interest to evolution. One must be able to transfer this information to a molecule, whichora does something – noted Benner.
The research was funded by NASA. This is not the case. One of the purposes of theoin NASA is the search for life on other planets, such as, for example, Mars, where liquid water once existed and there was a dense atmosphere, or the moons of the outer solar system – Europa and Enceladus, where there are huge oceans under thick layers of ice. This work expands our knowledge of typeoin molecules, whichore can serve as a basis for life on other, unknown worlds. This research could translate into a more effective search for life beyond Earth.
Adding letters to DNA may also have more mundane applications. With this work, other scientists can potentially create RNA or DNA sequences thatore can function better than the natural ones. For example, Benner’s group has shown that DNA strands containing Z and P bind better to the comork than sequences with standard four bases.
The eight-letter version can also store more information. With it, new proteins can be created. SyndromeoBenner has also developed further pairs of new rules, opening up the possibility of creating DNA structures containing 10 or even 12 letters.