Scientists Crack 8-Letter DNA Code

Researchers at the University of California San Diego have made a significant breakthrough in synthetic biology, demonstrating that a natural enzyme can accurately read and transcribe an expanded eight-letter genetic alphabet. This achievement has implications for creating new diagnostics, therapeutics, and engineered biological systems.

The genetic alphabet used by all known life on Earth consists of four letters. However, the University of California San Diego researchers have shown that RNA polymerase, an enzyme responsible for reading DNA and producing RNA, can accurately transcribe an eight-letter genetic alphabet. The study, published in Nature Communications, focused on RNA polymerase from Escherichia coli (E. coli) bacteria.

The researchers used biochemical experiments and high-resolution cryo-electron microscopy to capture detailed structural snapshots of RNA polymerase recognizing synthetic DNA letters. They found that the enzyme recognizes synthetic DNA letters through the same biochemical and structural signals as natural base pairs. This discovery helps explain how expanded genetic information can be faithfully transcribed.

The study has significant implications for the field of synthetic biology. By expanding the language of DNA, scientists may be able to custom-engineer biological systems that perform functions or produce compounds not found in nature. This could lead to the development of new diagnostics, therapeutics, and engineered biological systems.

## Why it matters The ability to accurately transcribe an expanded genetic alphabet has the potential to revolutionize the field of synthetic biology. By allowing cells to process synthetic genetic information using their natural molecular machinery, scientists may be able to create new biological systems that can perform a wide range of functions. This could have significant implications for fields such as medicine, agriculture, and biotechnology.

The study's findings are also supported by a related study published in Proceedings of the National Academy of Sciences, which reported that RNA polymerase can recognize another pair of synthetic base pairs without hydrogen bonds to hold them together. The paper 'Structural Basis of Transcription of the Hachimoji Eight-Letter Alphabet by E. coli RNA Polymerase' was published in Nature Communications with the DOI www.nature.com/articles/s41467-026-76668-0.