Scientists have successfully reduced the genetic code of E. coli, a bacterium commonly used in biotechnology and industry, from 64 codons to just 57. This achievement was made possible by a massive effort that involved over 101,000 codon changes and meticulous experimentation.
The researchers started with an existing genome reduction project called Syn61, which had already shrunk the E. coli genome to 61 codons in 2019. The new team took this project further, dividing the genome into sections and swapping out redundant codons with synonymous ones that perform the same function.
Their goal was not only to reduce the genetic code but also to create a new strain of bacteria that could grow faster while maintaining its viability. After making six sense codon swaps and replacing a stop codon with a synonymous one, they successfully shortened the genetic code to 57 codons.
The resulting bacteria grew around four times slower than the parent strain, but researchers found that it showed a distinct gene expression profile, indicating broad physiological adaptation. This new strain has potential applications in biotechnology, including virus-resistant organisms and the synthesis of novel proteins and polymers with new properties.
The study raises questions about the limits of reducing genetic code and creating organisms with entirely novel biochemistries. Researchers say that this work exemplifies how genome synthesis can move the genome sequences of organisms into new regions of sequence space that may not have been accessed by natural life.
Source: https://phys.org/news/2025-08-scientists-genetic-code-coli-usual.html