UC San Diego Scientists Demonstrate RNA Polymerase Can Read Expanded DNA Alphabet

Researchers at the University of California, San Diego, have shown that the core enzyme RNA polymerase can accurately transcribe a synthetic DNA alphabet containing eight distinct letters, doubling the standard four‑letter system used by all known life. Using high‑resolution imaging, the team observed that the enzyme processes the synthetic bases in ways that closely resemble its handling of natural nucleotides. This demonstration confirms that the cellular machinery can accommodate expanded genetic codes without losing fidelity. The result brings scientists closer to constructing organisms with expanded genetic systems capable of performing entirely new biological functions, potentially leading to innovative biotechnological tools.