{"id":1016,"date":"2026-06-08T02:29:14","date_gmt":"2026-06-08T06:29:14","guid":{"rendered":""},"modified":"2026-08-08T12:30:33","modified_gmt":"2026-08-08T12:30:33","slug":"dna-4-vs-dna-8","status":"publish","type":"post","link":"https:\/\/aboutyou.name\/?p=1016","title":{"rendered":"DNA-4 vs DNA-8"},"content":{"rendered":"

DNA-8<\/span><\/strong><\/span><\/p>\n

A new genetic system
\nwith 8 building blocks<\/span><\/span><\/strong><\/span><\/p>\n

One of the main characteristics of life is that it can store and pass on genetic info. This is done by DNA using just 4 building blocks: guanine, cytosine, adenine and thymine (G, A, C and T). Pairs of DNA strands form a double helix with T bonding to A and C bonding to G.<\/span><\/span><\/p>\n

Now, researchers have doubled the genetic code to 8 bases, thus doubling its info-density. They called this 8-letter synthetic genetic system \u201chachimoji\u201d DNA (\u201chachi\u201d means 8 in Japanese and \u201cmoji\u201d letter).<\/span><\/span><\/p>\n

The crystaline structure of a hachimoji dble helix is built from 4 naturally-occurring bases<\/span><\/a>, G (green), A (red), C (blue), T (yellow), and 4 synthetic bases, B (cyan), S (pink), P (purple), and Z (orange). Its geometric regularity is a requirement for evolution<\/span>: <\/span><\/span><\/p>\n

\"\"<\/p>\n

The system is made up of 4 natural nucleotides<\/span><\/a> and 4 synthetic nucleotides. They all fit seamlessly into the DNA\u2019s helical structure, maintaining its natural shape, and evolving just like natural DNA.<\/span><\/p>\n

The new building blocks fit the size and shape of the G:C and A:T pairs and bind with them. They are P and B, analogues of purine<\/span><\/a>, and Z and S, analogues of pyrimidine<\/span><\/a>. These duplexes form P:Z and B:S pairs.<\/span><\/span><\/p>\n

\"\"\u00a0 \u00a0 \u00a0\"\"<\/span><\/span><\/p>\n

The 4 natural (left) DNA bases
\n+ 4 unnatural (right) bases
\nforming the 8 letter DNA.<\/span><\/strong><\/span><\/span><\/span><\/p>\n

The researchers decided to mimic nature and use hydrogen bonded base pairs, only altering the pattern of bond donors and acceptors. <\/span><\/span>They added functionality by adding N2<\/sub> groups to the translated RNA molecules. In order to avoid bio-hazards, the DNA-8 is designed to be NOT self-sufficient.<\/span><\/span><\/p>\n

Like natural DNA, hachimoji DNA supports life in that it pairs in a predictable way, and copies itself to make a hachimoji RNA. RNA is important for life since it is via this molecule that DNA transfers information<\/span><\/a> before it is sent to proteins.<\/span><\/span><\/p>\n

This 8-letter DNA has additional functionality and translates into RNA that behaves more like a protein, making life without them a possibility.<\/span><\/p>\n

This new DNA also meets the \u201cSchr\u00f6dinger requirement\u201d for a Darwinian system of molecular evolution, an important hallmark for supporting life. Erwin Schr\u00f6dinger created quantum chemistry, and noted that to store information, a genetic material must have different building blocks, just like an alphabet must have different letters.<\/span><\/span><\/p>\n

From a physics perspective, these building blocks must be able to replace each other without geometrically disrupting the size or shape of the double helix to support evolution. The extra nucleotide \u2018letters\u2019 are designed to do that.<\/span><\/span><\/p>\n

Engineering enzymes to transcribe DNA into RNA\u00a0<\/span><\/span>will be important for future synthetic biology applications. It expands the scope of molecular structures that might be capable of supporting life.<\/span><\/p>\n

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\nT7 Polymerase<\/span><\/span><\/strong><\/span><\/p>\n

To transcribe DNA-8 into RNA, scientists adapted a natural enzyme (T7 polymerase), so as to accept unnatural genetic molecules, by changing amino acids in the protein, and finding ones that accept DNA-8 to make RNA-8.<\/span><\/span><\/p>\n

T7 RNA Polymerase comes from the T7 bacteriophage that catalyzes the formation of RNA from DNA in the 5’\u2192 3′ direction.<\/span><\/span><\/p>\n