Scientists have doubled the genetic alphabet to eight letters

Science · Published 13 October 2026 Swipe more like this →

In short: All life on Earth relies on a four-letter DNA code. But new research shows we can expand this biological vocabulary, using synthetic bases to create entirely new functions in medicine, data storage, and even the search for extraterrestrial life.

For all known organisms, DNA uses a four-letter alphabet: adenine, thymine, cytosine, and guanine (A, T, C, and G). However, researchers at UC San Diego have demonstrated that the essential enzyme RNA polymerase can accurately read and transcribe an expanded eight-letter genetic system. By using high-resolution cryo-electron microscopy, the team observed E. coli bacteria processing synthetic base pairs, finding that the enzyme uses many of the same structural signals to recognize these artificial letters as it does for natural ones.

This expansion is not just a theoretical exercise. One study published in PNAS on August 12, 2026, revealed that RNA polymerase can even recognize synthetic pairs that lack the hydrogen bonds typically required to hold DNA together. Such breakthroughs suggest that the molecular machinery of existing cells can be repurposed to handle synthetic genetic information, potentially allowing us to engineer biological systems that produce compounds not found in nature.

The challenge has historically been reading this expanded code. Because standard sequencers were built for the four natural bases, decoding non-canonical bases was considered too complex. An AI-based technique utilising nanopore sequencing was created by a group headed by the A*STAR Genome Institute of Singapore. By training models on a library of artificial DNA, they successfully taught machines to identify the unique electrical signals of new 'letters,' paving the way for advanced diagnostics and new therapeutics.

General information, not professional advice. Spotted an error? Flag the card or see corrections and complaints.

Intellect Plus is a visual educational discovery platform for exploring fascinating facts and ideas. Brain Food, Not Brain Rot. What is Intellect Plus?

Related

• Beyond the four-letter code: scientists have created life with six-letter DNA
• Beyond the four-letter alphabet: The dawn of synthetic biology
• The four-letter alphabet that writes the entire story of life
• Beyond the 20 amino acids: the quest to rewrite the language of life
• The molecular machinery that powers life and modern medicine
• Exploring the diverse voices behind SciShow's educational content
• Mastering the complex logic of calculus through basic math
• A molecular prosthetic to repair the roots of cystic fibrosis
• The hidden math powering your favorite streaming recommendations
• Astronomers detect a massive black hole collision three billion light-years from Earth
• Neutron stars are giant atomic nuclei as massive as stars but only kilometers wide.
• Why watching math videos is not enough to master the subject

More in Science · Latest · A–Z · All topics