Researchers at the Earlham Institute have identified a previously unknown protist species that reassigns two genetic stop codons to code for amino acids instead, marking a rare departure from the standard rules of life.
The organism, named Oligohymenophorea sp. PL0344, was collected from a freshwater pond at Oxford University Parks during a routine test of a single-cell DNA sequencing method. Dr. Jamie McGowan, a postdoctoral scientist leading the work, described the find as pure chance that revealed how little is known about protist genetics. In this ciliate, the codons TAA and TAG no longer signal the end of a gene but instead specify lysine and glutamic acid, respectively, while only TGA functions as a stop signal.
