A study published in PLOS Genetics in October 2023 revealed unusual flexibility in the genetic code, suggesting more variations may exist among related microorganisms.

Researchers pinpointed specific tRNA genes linked to the reassigned codons and observed a high frequency of TGA near gene regions, possibly serving as a backup stop signal to prevent overreading.

Follow-up work through December 2024 identified three additional uncultivated Phyllopharyngea ciliates where UAG encodes leucine and two where UAG encodes glutamine, with independent origins across lineages and UAA remaining a stop codon.

The findings arose from the Earlham Institute using advanced, tiny-sample DNA sequencing methods, potentially analyzing a single cell.

Collectively, these studies show substantial genetic-code variation among ciliates, with wide-ranging implications for evolutionary biology, genetics, and synthetic biology.

Historically, TAA and TAG were thought to change together to the same amino acid, but PL0344 demonstrated they can be reassigned to different amino acids, indicating less constrained codon evolution.

Dr. Jamie McGowan noted the role of serendipity in the discovery and cautioned that nature can produce surprising genetic variations beyond engineered expectations.

In March 2026, single-cell sequencing revealed three new evolutionary lineages of Bodo protists with distinct bacterial partners, underscoring hidden protist diversity and the value of single-cell approaches.

Key reflections emphasize that translation machinery is more adaptable than assumed and that natural examples can inform engineered genetic codes while revealing ongoing undiscovered microbial diversity.

Broader implications were reinforced by later work showing similar codon variations in other ciliates, indicating greater genetic-code diversity among microorganisms than previously thought.

Routine sequencing of the freshwater protist Oligohymenophorea sp. PL0344 disclosed a novel code: TAA and TAG now encode two different amino acids, lysine and glutamic acid respectively, while TGA remains a stop codon.

Overall, the discoveries challenge the universal genetic-code framework and suggest translation can be more flexible than previously imagined.