{"id":1016,"date":"2026-06-08T02:29:14","date_gmt":"2026-06-08T06:29:14","guid":{"rendered":""},"modified":"2026-06-08T02:29:14","modified_gmt":"2026-06-08T06:29:14","slug":"dna-4-vs-dna-8","status":"publish","type":"post","link":"https:\/\/c2creset.ondigit.us\/?p=1016","title":{"rendered":"DNA-4 vs DNA-8"},"content":{"rendered":"

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

A new genetic system with 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 information. Nowadays, 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 information density. They called this 8-letter synthetic genetic system “hachimoji” DNA (“hachi” means 8 in Japanese and “moji” letter).<\/span><\/span><\/p>\n

The crystaline structure of a hachimoji double 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). Notice the geometric regularity of the pairs, a requirement for evolution: <\/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’s 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

\"\"     \"\"<\/span><\/span><\/p>\n

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

The DNA-8 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 nitro groups to the translated RNA molecules. In order to avoid any bio-hazards, they designed the DNA-8 to be NOT self-sufficient.<\/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 “Schrödinger requirement” for a Darwinian system of molecular evolution, an important hallmark for supporting life. Erwin Schrödinger 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 ‘letters’ are designed to do that.<\/span><\/span><\/p>\n

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

\"\"<\/p>\n

T7 Polymerase<\/span><\/span><\/strong><\/span><\/p>\n

To transcribe DNA-8 into RNA, scientists adapted a natural enzyme (T7 polymerase), so that it could 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 is an RNA polymerase from the T7 bacteriophage that catalyzes the formation of RNA from DNA in the 5’→ 3′ direction.<\/span><\/span><\/p>\n